Pró-Reitoria Acadêmica Escola de Saúde e Medicina Programa de Pós-Graduação Stricto Sensu em Educação Física

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1 Pró-Reitoria Acadêmica Escola de Saúde e Medicina Programa de Pós-Graduação Stricto Sensu em Educação Física EFEITOS AGUDOS E CRÔNICOS DO TREINAMENTO DE FORÇA SOBRE FATORES DE RISCO CARDIOVASCULAR EM MULHERES DE MEIA IDADE PORTADORAS DE SOBREPESO/OBESIDADE E/OU SÍNDROME METABÓLICA. Autor: Ramires Alsamir Tibana Orientador: Prof. Dr. Jonato Prestes Brasília - DF 2013

2 UNIVERSIDADE CATÓLICA DE BRASÍLIA PROGRAMA DE PÓS-GRADUAÇÃO STRICTO SENSU EM EDUCAÇÃO FÍSICA EFEITOS AGUDOS E CRÔNICOS DO TREINAMENTO DE FORÇA SOBRE FATORES DE RISCO CARDIOVASCULAR EM MULHERES DE MEIA IDADE PORTADORAS DE SOBREPESO/OBESIDADE E/OU SÍNDROME METABÓLICA Ramires Alsamir Tibana BRASÍLIA 2013

3 T552e 7,5cm Tibana, Ramires Alsamir. Efeitos agudos e crônicos do treinamento de força sobre fatores de risco cardiovascular em mulheres de meia idade portadoras de sobrepeso/obesidade e/ou síndrome matabólica. / Ramires Alsamir Tibana f.: il.; 30 cm Dissertação (mestrado) Universidade Católica de Brasília, Orientação: Prof. Dr. Jonato Prestes 1. Exercícios físicos. 2. Mulheres de meia idade. 3. Obesidade. 4. Pressão arterial. 5. Frequência cardíaca. I. Prestes, Jonato, orient,. II. Título. CDU Ficha elaborada pela Biblioteca Pós-Graduação da UCB

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5 DEDICATÓRIA Mãe, Nada que eu te dedique É suficiente Para o tanto que me destes Nada que eu te dê É bastante Para o tanto que me servistes Nada que eu te sirva É justo Para o tanto que me ensinastes Nada que eu te aprenda É sábio Do que o teu amor por mim Foi assim que me dedicastes a vida É assim que te dedico meu amor e minhas conquistas a ti.

6 AGRADECIMENTOS Agradeço: Aos meus pais Airton Gomes Tibana (in memorian), Adriana Flávia Alves de Lima, minha tia Alessandra Alves de Lima e a minha avó Maria Miriam de Freitas Lima (in memorian) pelo amor, carinho e apoio durante toda minha vida. Aos meus irmãos Diego Ramon Tibana e Airton Gomes Tibana Júnior por me ajudarem durante toda caminhada da minha vida. Ao meu amor Anne Caroline Azevedo Zansavio pelo amor, carinho, respeito e compreensão durante todo esse processo da graduação e do mestrado. Ao professor, orientador e amigo Dr. Jonato Prestes por acreditar na minha capacidade, pela orientação competente tanto no meio acadêmico como nos ensinamentos da vida e pelo exemplo como pesquisador e ser humano. Agradeço também o incentivo que me deu para fazer parte do Mestrado na Western Kentucky University, em parceria com nossos amigos Dr. James Navalta e Dr. Guilherme Borges Pereira, o que com certeza acrescentou ainda mais para nós o significado da palavra "The Spirit Makes the Master." Aos colegas, amigos e professores do Centro Universitário Euro Americano que aguçaram meu gosto pela Educação Física e pela iniciação científica na área. Aos meus amigos da Universidade Católica de Brasília, Alessandro de Oliveira Silva, Dahan da Cunha Nascimento, Darlan Lopes de Farias, Denis Vieira, Renato André Sousa da Silva, Tatiane Gomes Teixeira, Vânia Orsano, Vinicius Carolino de Souza e Vitor Tajra pela ajuda nos momentos mais difíceis desse processo. Aos meus amigos de infância, Luiz Felipe e Pedro Ferreira, Ellen e Edson Galvão, Gustavo e Lucas Souto, Raphael Sousa e Rafael Bandeira. A Universidade Católica de Brasília por fornecer os equipamentos e instalações necessárias para o desenvolvimento do meu projeto de pesquisa.e ao Centro de Aperfeiçoamento em Pessoal de Ensino Superior (CAPES), pela concessão da bolsa (tipo I e II). Muito obrigado a todos!

7 É melhor tentar e falhar, que preocupar-se e ver a vida passar. É melhor tentar, ainda que em vão que sentar-se, fazendo nada até o final. Eu prefiro na chuva caminhar, que em dias frios em casa me esconder. Prefiro ser feliz embora louco, que em conformidade viver Martin Luther King

8 SUMÁRIO 1. RESUMO ABSTRACT INTRODUÇÃO OBJETIVOS ARTIGOS Treinamento de força e Síndrome Metabólica: Uma revisão sistemática Acute effects of resistance exercise on clinical and 24-hour ambulatory blood pressure in middle-aged overweight and obese women Women with metabolic syndrome present different autonomic modulation and blood pressure response to an acute resistance exercise session compared with women without metabolic syndrome Effects of eight weeks of resistance training on the risk factors of metabolic syndrome in overweight /obese women - "A Pilot Study" REFERÊNCIAS ANEXOS

9 7 RESUMO EFEITOS AGUDOS E CRÔNICOS DO TREINAMENTO DE FORÇA SOBRE FATORES DE RISCO CARDIOVASCULAR EM MULHERES DE MEIA IDADE PORTADORAS DE SOBREPESO/OBESIDADE E/OU SÍNDROME METABÓLICA Objetivos: O objetivo do presente estudo foi avaliar os efeitos agudos e crônicos do treinamento de força (TF) sobre os fatores de risco cardiovascular em mulheres com sobrepeso/obesidade e/ou síndrome metabólica. Este estudo foi dividido em quatro etapas: (1) revisão sistemática para elucidar a efetividade do TF para a prevenção e tratamento dos fatores de risco cardiovascular em pacientes com síndrome metabólica (SM); (2) avaliar o comportamento clínico e ambulatorial da pressão arterial (PA) após uma sessão de TF aguda realizado entre 20:00-21:00 e de uma sessão controle em mulheres portadoras de sobrepeso/obesidade; (3) avaliar o comportamento clínico da PA e da variabilidade da frequência cardíaca (VFC) e ambulatorial da PA após uma sessão de TF aguda realizado entre 20:00-21:00 e de uma sessão controle em mulheres portadoras de SM e (4) avaliar os efeitos do TF realizado durante oito semanas sem controle dietético sobre os fatores de risco da SM em mulheres com sobrepeso/obesidade. Métodos: Participaram do presente estudo mulheres sedentárias (18-49 anos) com e sem fatores de risco para SM. As voluntárias submetidas ao TF agudo realizaram seis exercícios (leg press na máquina, cadeira extensora, cadeira flexora, supino vertical na máquina, puxada frontal e desenvolvimento na máquina) com 3 séries de 10 repetições e intensidade de 60% de uma repetição máxima (1RM). Após as sessões aguda do TF e controle (35 minutos na posição sentada) foram monitoradas clinicamente a pressão arterial sistólica (PAS), diastólica (PAD) e média (PAM), durante 60 minutos e após foi inserido no braço não dominante o monitor ambulatorial da pressão arterial (MAPA) para análise da PAS, PAD e PAM durante 24h. A VFC foi monitorada após a sessão de TF durante 60 minutos pós-exercício. O estudo crônico foi realizado durante oito semanas (3x) de TF para o corpo todo com intensidade de 8-12 repetições máximas e 1 minuto de intervalo de recuperação entre os exercícios e séries. Antes e após as oito semanas foram realizadas avaliações antropométricas, bioquímicas, pressóricas e de força muscular. Resultados: Coletivamente, estes dados demonstram que uma sessão aguda do TF é capaz de diminuir a PA clínica e ambulatorial tanto em mulheres com sobrepeso/obesidade como em mulheres com SM, com similar resposta autonômica pós exercício em mulheres com e sem SM. Além disso, o TF realizado durante oito semanas sem o controle dietético e sem a realização de exercícios aeróbios foi pouco efetivo em alterar a glicose sanguínea, PA, circunferência da cintura, os triglicerídeos e o HDL. No entanto, o TF realizado em curto prazo foi efetivo em aumentar a força muscular absoluta e relativa e o volume muscular do quadríceps. Conclusões: Uma sessão aguda do TF é capaz de diminuir a PA clínica e ambulatorial em mulheres com sobrepeso/obesidade e SM. No entanto, o TF crônico sem controle dietético não reduz os fatores de risco cardiovascular em mulheres com SM. PALAVRAS-CHAVE: Treinamento de força; Síndrome metabólica; Obesidade; Pressão arterial; Variabilidade da frequência cardíaca.

10 8 ABSTRACT ACUTE AND CHRONIC EFFECTS OF RESISTANCE TRAINING ON CARDIOVASCULAR RISK FACTORS IN MIDDLE AGED WOMEN WITH OVERWEIGHT/OBESITY AND/OR METABOLIC SYNDROME Objectives: The aim of the present study was to evaluate the acute and chronic effects of resistance training (RT) on cardiovascular risk factors in women with overweight/obesity and/or metabolic syndrome. This study was divided in four steps: (1) systematic review to elucidate the effectiveness of RT to prevent and treatment of cardiovascular risk factors in patients with metabolic syndrome (MetS); (2) to evaluate the clinical and ambulatory behavior of blood pressure (BP) after a acute RT session completed between 08:00-09:00 p.m. and of a control session in women with overweight/obesity; (3) to evaluate the clinical and ambulatory behavior of BP, and heart rate variability (HRV) after an acute RT session completed between 08:00-09:00 p.m. and a control session in women with Met and (4) to evaluate the effects of a eightweek RT without dietetic control on the risk factors of MetS in women with overweight/obesity. Methods: Sedentary women (18-49 years) with and without risk factors for MetS participated in this study. Volunteers were submitted to a acute RT session with six exercises (machine leg press, leg extension, leg curl, machine chest, frontal lat pull-down and machine shoulder press) with 3 sets of 10 repetitions and an intensity of 60% of one repetition maximum (1RM). After the acute RT and control session (35 minutes in the seated position) systolic (SBP) (PAS), diastolic (DBP) and mean blood pressure (MBP) were clinically monitored during 60 minutes and after this, the ambulatory monitor of BP (MAPA) was inserted to the non dominant arm to the analysis of SBP, DBP and MBP during 24h. The HRV was monitored after the RT session during 60 minutes post-exercise. The chronic study was performed during eight weeks (3x) of RT for the whole body with a intensity of 8-12 repetitions maximum and 1 minute rest interval between exercises and sets. Before and after the eight weeks anthropometric, biochemical, BP and muscle strength evaluations were completed. Results: Collectively, these data demonstrated that an acute RT session is capable of decreasing clinical and ambulatory BP both in women with overweight/obesity and MetS, with similar autonomic response post exercise in with and without MetS. Moreover, the eight-week RT without dietetic control and aerobic exercise presented a low effectiveness in modifying blood glucose, BP, waist circumference, triglycerides and HDL. However, short-term RT was effective in increasing absolute and relative muscle strength and muscle volume of the quadriceps. Conclusions: An acute RT session is capable if decreasing clinical and ambulatory BP in women with overweight /obesity and MetS. However, chronic RT without dietetic control did not decrease cardiovascular risk factor in women with MetS. KEY WORDS; Strength training; Metabolic Syndrome; Obesity; Blood pressure; Heart rate variability.

11 9 OBJETIVOS O objetivo principal desta dissertação é estudar os diversos aspectos envolvidos nos efeitos agudos e crônicos do treinamento de força sobre os fatores de risco cardiovascular em mulheres com sobrepeso/obesidade e síndrome metabólica. Buscamos estudar as respostas agudas da pressão arterial (clínica e ambulatorial) e da variabilidade da frequência cardíaca após uma sessão de treinamento de força, além disso, investigamos as adaptações crônicas ocorridas ao longo de 8 semanas de treinamento de força sem restrição e aconselhamento dietético em mulheres com sobrepeso e obesidade. A presente dissertação resultou em quatro (4) artigos científicos, cujos objetivos específicos foram: 1. Realizar uma revisão sistemática do treinamento de força nos fatores de risco cardiovascular em pacientes com síndrome metabólica. Tibana RA, Prestes J. Treinamento de força e síndrome metabólica: uma revisão sistemática. Revista Brasileira de Cardiologia, Analisar os efeitos agudos do exercício resistido sobre a pressão arterial clínica e ambulatorial em mulheres de meia idade com sobrepeso/obesidade Tibana RA, Pereira GB, Navalta JW, Bottaro M, Prestes J. Acute effects of resistance exercise on 24-h blood pressure in middle aged overweight and obese women. International Journal of Sports Medicine, Analisar os efeitos agudos do exercício resistido sobre a pressão arterial clínica e ambulatorial e a variabilidade da frequência cardíaca em mulheres de meia idade com e sem síndrome metabólica Tibana RA, Boullosa DA, Leicht AS, Prestes J. Women with metabolic syndrome present different autonomic modulation and blood pressure response to an acute resistance exercise session compared with women without metabolic syndrome. Clinical Physiology and Functional Imaging Analisar os efeitos crônicos do treinamento de forca sobre os fatores de risco cardiovascular e a força muscular em mulheres com sobrepeso/obesidade. Tibana RA, Navalta J, Bottaro M, Vieira D, Tajra V, Silva AO,, de Farias DL, Pereira GB, de Souza JC, Balsamo S, Cavaglieri CR, Prestes J. Effects of eight weeks of

12 resistance training on the risk factors of metabolic syndrome in overweight /obese women - "A Pilot Study". Diabetology & Metabolic Syndrome,

13 Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Artigo de Revisão Treinamento de Força e Síndrome Metabólica: uma revisão sistemática Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão 1 Resistance Training and Metabolic Syndrome: a systematic review Ramires Alsamir Tibana, Jonato Prestes Resumo resistance training e metabolic diseases dos artigos evidenciou aumento da força muscular e da massa livre de gordura. A revisão fornece dados Palavras-chave: Abstract treinamento resistidodoenças metabólicas, and resistance Although muscle strength is inversely related to the Keywords: Programa de Pós-graduação (Mestrado e Doutorado) em Educação Física - Universidade Católica de Brasília - Brasília, DF - Brasil Correspondência: Ramires Alsamir Tibana ramiires@hotmail.com Q.S. 7, lote 1 - Bloco G - Águas Claras, Taguatinga Brasília, DF - Brasil Recebido em: 30/12/2012 Aceito em: 17/01/

14 Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Introdução 1 conjunto de fatores de risco cardiovascular como forte associação entre os riscos de desenvolvimento doenças cardiovasculares em National Health and Nutrition Examination Survey. Em relação 11 indicam 11. mortalidade e no diminuição dos fatores de risco cardiovascular elevada. Quadro 1 OMS, 1998 NCEP: ATPIII, 2001 IDF, 2006 alterada e Componentes insulina Pressão arterial Glicose sérica National Cholesterol Education Program Adult Treatment PanelInternational Diabetes Federation 67

15 Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão Seleção dos artigos Public Medline resistance training e metabolic diseases exclusão foram: artigos sem abstract ou com o mesmo força muscular e massa livre de gordura. De forma Bases de dados pesquisadas 218 PubMed LILACS SciELO Artigos completos analisados 18 Excluídos Estudos incluídos na revisão 5 1. Stensvold et al Bateman et al Potteiger et al Geisler et al Layne et al Excluídos 200 Revisões / Estudos com animais / Outros exercícios / Outras doenças Artigos excluídos após leitura completa do texto Figura 1 68

16 Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Discussão crítica dos dados encontrados Fatores ambientais e síndrome metabólica Wagner et al. Figura 2 69

17 Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão Quadro 2 Fatores ambientais relacionados com a síndrome metabólica Fatores ambientais Estresse no açúcar de Assistir televisão cigarro excessivo de álcool Estudo et al. et al. Dunstan et al. Wagner et al. et al. 31 et al. 32 População Ingleses Americanos Australianos Faixa etária (anos) Acompanhamento (anos) Estudo transversal Estudo transversal Estudo transversal Mulheres Risco (95% CI) Homens Conclusões principais televisão semanalmente está atividades sedentárias associado com álcool está associado a diversos fatores de risco National Cholesterol Education Programazard ratio International Diabetes Federation como o de fumar da saúde e da doença» 70. Por. A. Síndrome metabólica, morbidades e mortalidade

18 Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro. do risco de doenças cardiovasculares em cardiovasculares e coronarianas e aumento de duas vezes no acidente vascular encefálico como de duas vezes em todas as causas de tem sido associada com o risco de desenvolvimento e. muscular estão associadas a todas as causas de Treinamento de força e síndrome metabólica diferentes modelos e métodos de treinamento. Delorme apud Todd et al. f o r m a s m a i s c o n h e c i d a s e e f i c a z e s d e idosos e crianças. adultos adolescentes Quadro 3 Risco de morbidades e mortalidade associados com a síndrome metabólica Doenças Estudo População Idade Acompanhamento Risco (95% CI) Tipo (média ± DP) (anos) Mulheres Homens de estudo (anos) Todas as causas de mortalidade et al. doenças et al. coronarianas doenças et al. cardiovasculares Mortalidade Americanos et al. sistema digestivo Pajunen et al. AVE et al. et al. Penninx Americanos et al. National Cholesterol Education Programazard ratio 71

19 Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão a associação da força muscular com a diminuição dos fatores de risco cardiovascular elevada. diminuir citocinas inflamatórias e aumentar a força analisaram durante risco cardiovascular e morfologia do músculo alteração com a ativação de vias intramusculares força muscular. 72 et al. al. não realização concomitante do treinamento

20 Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Quadro 4 Efeitos crônicos do treinamento de força sobre os fatores de risco cardiovascular em indivíduos com síndrome metabólica Estudo Potteiger et al. Geisler et al. Amostra Idade (anos) Protocolo / Duração CC/ IMC HDL TRG GLC PAS PAD Força / MLG - Score Fontes de Financiamento Vinculação Acadêmica 73

21 Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão Referências 74 fatores de risco cardiovascular em mulheres

22 Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro 75

23 Rev Bras Cardiol. 2013;26(1):66-76 janeiro/fevereiro Tibana e Prestes Treinamento de Força e Síndrome Metabólica Artigo de Revisão 76

24 460 Clinical Sciences Acute Eects of Resistance Exercise on 24-h Blood Pressure in Middle Aged Overweight and Obese Women Authors R. A. Tibana 1, 2, G. B. Pereira 3, J. W. Navalta 4, M. Bottaro 5, J. Prestes 1 Aliations 1 Graduate Program on Physical Education, Catholic University of Brasilia, Brasilia, Brazil 2 Department of Physical Education, Euro-American University Center (UNIEURO), Brasilia, Brazil 3 Physiological Sciences, Federal University of São Carlos, São Carlos, Brazil 4 Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, United States 5 College of Physical Education, University of Brasilia, Brasilia, Brazil Key words resistance exercise hypotension overweight cardiovascular events Abstract This investigation was designed to evaluate responses of blood pressure (BP) following an acute resistance exercise (RE) session. Middle-aged women (N = 13) who were classiþ ed as overweight (N = 8) or obese (N = 5) according to body mass index (BMI) participated in the investigation. Participants were randomly submitted to a control session (30-min seated rest) and a exercise session (3 sets, 10 repetitions at 60 % 1RM of exercises for the upper and lower body) with systolic (SBP), diastolic (DBP) and mean blood pressure (MBP) obtained at rest and 10, 20, 30, 40, 50, and 60-min following exercise, and through 24 h. Acute RE decreased SBP at 10, 30, and 40-min compared with pre-exercise and control (P < 0.05). DBP decreased at 10 and 40-min post-exercise compared with the control trial (P < 0.05). Both SBP and DBP decreased in the nighttime period ( 4.2 mmhg and 4.1 mmhg, respectively) and in the overall 24 h period ( 3.6 mmhg and 4.5 mmhg, respectively) following the acute RE session when compared with the control trial. These Þ ndings indicate important beneþ ts of acute RE on BP circadian rhythm, particularly at night as well as in the morning, which are critical periods associated with increased risk for cardiovascular events. accepted after revision August 23, 2012 Bibliography DOI /s Published online: October 12, 2012 Int J Sports Med 2013; 34: Georg Thieme Verlag KG Stuttgart New York ISSN Correspondence Dr. Jonato Prestes Graduate Program on Physical Education Catholic University of Brasilia Q.S. 07 Lote 01 Bloco G Brasilia Brazil Tel.: + 21/55/ Fax: + 21/55/ jonatop@gmail.com Introduction Obesity is one of the primary contributing factors to hypertension, as risk estimates from the Framingham Heart Study suggest that approximately 78 % of the cases in men and 65 % in women can be directly attributed to obesity [ 9 ]. While the United States is the world-wide leader in overweight index, several Latin American countries have a concerning number. For example, in Brazil, a national survey conducted in on 95.5 million adults over the age of 20 years indicated that the incidence of overweight individuals was 8 times greater than those considered in weight deþ cit. In that survey, 38.8 million (40.6 %) were considered overweight [body mass index (BMI) kg m 2 ], and 10.5 million were classiþ ed as obese (BMI > 30 kg m 2 ) [ 16 ]. Thus, obesity and hypertension are serious public health problems aecting the worldwide population [ 8 ]. Regular physical exercise has been recommended as a worthwhile tool in the prevention and treatment of both obesity and hypertension [ 6, 22 ]. Previous studies reported that an acute exercise session (a single exercise bout) could reduce blood pressure during the recovery period [ 17, 22 ]. Furthermore, meta-analyses indicated that aerobic training is eective in reducing clinical blood pressure in the general population, as well as in hypertensive subjects [ 7, 22 ]. Regarding resistance exercise (RE), most studies investigating blood pressure revealed a signiþ cant post-exercise hypotensive eect (PEH). However, data regarding 24 h blood pressure (BP) and the post-exercise hypotensive eect are both scarce and controversial [ 4, 7, 22 ]. PEH is characterized by a signiþ cant reduction in BP during the recovery period, and this phenomenon has been accepted to have clinical relevance (cardiovascular protection). Considering the extensive evidence for the increased prevalence of cardiovascular events, such as strokes and myocardial ischemia in the early morning hours [ 7, 25 ], it is important to investigate whether PEH presents a sucient duration up to the morning period. The monitoring of 24 h BP enables the recording of the circadian rhythm of blood pressure under everyday circumstances, with most individuals displaying diurnal and nocturnal variations in both systolic and diastolic blood pressure. To the best of our knowledge, only 6 studies have investigated the acute response of 24 h BP to RE, with none utilizing obese subjects. In 4 of these studies, 24 h BP levels were signiþ cantly decreased Tibana RA et al. Acute Eects of Resistance Int J Sports Med 2013; 34:

25 Clinical Sciences 461 [ 1, 13, 20, 28 ]. In addition, 3 of the studies evaluating 24 h BP were conducted with normotensive subjects [ 1, 26, 27 ], while the remaining investigations used hypertensive subjects as volunteers [ 13, 20, 28 ]. Additionally, in 4 of these studies exercise sessions were completed in the morning (08:00 12:00 a.m.), while the remaining 2 did not report the exact period in which exercise was performed. Thus, the aim of the present study was to evaluate the clinical behavior of BP following an acute RE session performed between 8:00 9:00 p.m. in obese subjects. Our initial hypothesis was that an acute RE session performed at night would decrease BP during the post-exercise period, primarily in the sleeping period and early morning hours. Methods Subjects Following an estimation of sample size required for primary comparisons (see in statistical analysis), 13 sedentary (deþ ned as accruing less than 2 h per week of physical activity during the last year) middle-aged adult women were recruited. As inclusion criteria, the only participants included were those classiþ ed as overweight (N = 8) or obese (N = 5) by BMI measurement according to the World Health Organization (WHO): overweight BMI = kg m 2 and obese > 30.0 kg m 2. Each subject completed a thorough physical examination, including a medical history, resting and exercise electrocardiogram [ 30 ], blood pressure assessment, anthropometric, and orthopaedic evaluation prior to participation in the experimental protocols. The general characteristics of the sample are presented in Table 1. Subjects with physical disabilities, diagnosis of diabetes, cardiovascular diseases, hypertension (systolic blood pressure > 140 mmhg and diastolic blood pressure > 90 mmhg) [ 32 ], musculoskeletal disease, recent use of any medication and smoking or drug/alcohol abuse were excluded from the trial. All participants signed an informed consent document and the study was approved by the Universidade Católica de Brasília Research Ethics Committee for Human Use (protocol #376/2010). Additionally, the study met the ethical standards proposed by of the International Journal of Sports Medicine [ 14 ]. Study design Subjects completed 2 weeks of familiarization prior to testing. During the familiarization weeks, individuals were advised regarding the execution of proper technique, and completed 3 sessionsweek 1, with 1 exercise for each main muscle group (same exercises of the experimental RE session) performing 3 sets of submaximal repetitions at ~60 % of estimated 10RM. After the familiarization period, subjects completed a 1-repetition maximum test (1RM) to determine maximal strength for each exercise. 3 days later participants were randomly assigned to 2 sessions (i. e., control and exercise) within a 4-week period with at least 72 h of rest between sessions. In the exercise session, participants remained seated quietly for 15 min before completing 3 sets of 10 repetitions of the following exercises: machine leg press, leg extension, leg curl, chest press, lat front pull-down and machine shoulder press at 60 % 1RM followed by 15 repetitions of abdominal crunches. A rest interval of 1-min was used between sets and exercises (the total duration of the session was 30 min). Subjects were instructed to perform each repetition at a moderate velocity (i. e., 2 s concentric and 2 s eccentric) and were supervised Table 1 Subjects characteristics. Anthropometric variables Mean ± standard deviation Minimum- Maximum age (years) 33.5 ± 8.9 (21 49) body Mass (kg) 79.5 ± 12.1 ( ) height (m) 1.61 ± 0.07 ( ) neck Circumference (cm) 35.1 ± 1.8 ( ) waist circumference (cm) 91.6 ± 8.7 ( ) hip circumference (cm) ± 9.3 ( ) waist-hip ratio 0.83 ± 0.07 ( ) waist-height ratio 0.57 ± 0.07 ( ) Body Composition Variables body mass index (kg m 2 ) 30.7 ± 4.2 ( ) fat percentage ( %) 36.2 ± 3.4 ( ) fat mass (kg) 28.6 ± 6.5 ( ) fat-free mass (kg) 46.6 ± 6.1 ( ) body Adiposity Index ( %) 19.9 ± 3.6 ( ) Skinfold thickness, mm sub-scapular 32.8 ± 9.1 ( ) triceps 39.4 ± 10.4 ( ) axillar medium 30.3 ± 7.2 ( ) chest 18.7 ± 5.3 ( ) abdomen 38.3 ± 4.7 (28 45) thigh 41.6 ± 11.7 (14 58) supra-iliac 35.8 ± 4.79 ( ) mm ± 37.0 ( ) Hemodynamic variables systolic blood pressure (mmhg) ± 13.0 ( ) diastolic blood pressure (mmhg) 82.4 ± 10.1 (63 90) mean blood pressure (mmhg) 96.5 ± 10.8 ( ) heart rate (bpm) 79.1 ± 9.5 (64 93) by a experienced researcher. The control session consisted of 30 min of seated rest. All subjects were encouraged to avoid smoking, alcohol and caeine consumption, as well as unusual physical activity before each trial. Also, subjects were instructed to go to bed at 11:00 p.m. and awake at 06:00 a.m. on experimental days. Maximal strength testing After 2 weeks of adaptation to the exercises, 1RM tests were performed on 4 dierent days separated by a minimum of 48 h. All tests were performed with 10 min rest intervals between each exercise. The order of the exercises was as follows: chest press, front lat pull-down and machine shoulder press (days 1 and 2); machine leg press, leg extension and leg curl (days 3 and 4) (JOHNSON, USA). The protocol consisted of a light warm-up of 10 min of treadmill running followed by 8 repetitions at 50 % of estimated 1RM (according to the participants capacity veriþ ed in the 2 weeks of adaptation). After a 1-min rest, subjects performed 3 repetitions at 70 % of the estimated 1RM. Following 3 minutes of rest, participants completed 3 5 1RM attempts interspersed with 3-to-5 min rest intervals, with progressively heavier weights (~5 %) until the 1RM was determined. The range of motion and exercise technique were standardized according to the descriptions of Brown and Weir [ 2 ]. After 48 h, all tests were repeated for the determination of the intraclass correlation (chest press, r = 0.99; front lat pull-down, r = 0.97; machine shoulder press, r = 0.98; machine leg press, r = 0.97; leg extension, r = 0.98; and leg curl, r = 0.98). Anthropometric and body composition evaluation Height and weight were measured for the calculation of the BMI. All circumferences were obtained in triplicate using a nonelastic Tibana RA et al. Acute Eects of Resistance Int J Sports Med 2013; 34:

26 462 Clinical Sciences tape measure, and averaged to determine the Þ nal reported circumference. In addition, body fat percentage was determined by the Jackson and Pollock 7 site skinfold protocol [ 24 ] using a Lange skinfold caliper (Beta Technology Inc, Santa Cruz, CA, USA). 3 measurements were made at each skinfold site and the average value was used to calculate body composition. Blood pressure measurement Systolic (SBP), diastolic (DBP) and mean BP (MBP) were measured with an oscillometric device (Microlife 3AC1-1, Widnau, Switzerland) according to the recommendations of the Sociedade Brasileira de Cardiologia [ 32 ]. The cu size was adapted to the circumference of the arm of each participant according to the manufacture s recommendations. SBP and DBP values were used to determine MBP according to the following equation: MBP = DBP + [(SBP DBP)/3]. Heart rate (HR) was measured by a HR monitor (Polar S810i, Polar Electo Oy, Kempele, Finland). All BP measures were assessed in triplicate (measurements separated by 1 min) with the mean value used for analysis. BP and HR measurements were performed after 15 min of seated rest (0); and 10 min (10); 20 min (20); 30 min (30); 40 min (40); 50 min (50); and 60 min (60) after the control or exercise sessions. During BP measurements participants remained seated quietly under a controlled room temperature. 24 h blood pressure 24 h BP was measured in the non-dominant arm with an oscillometric monitor (Dyna-MAPA, Cardios, Brazil). The monitor was programmed to perform measures every 15 min during the day-time (7:00 a.m. 10:00 p.m.) and every 30 min during the night-time (11:00 p.m. 6:00 a.m.). All 24 h measures of BP were performed during week days (i. e., Monday Friday), and were initiated between 9:00 10:00 p,m. All participants were advised to maintain their habitual activities and diet (this was guaranteed by a dietary recall follow-up), refrain from programmed exercise, avoid smoking, alcohol and caeine consumption, and to stop and relax the arm during each measurement. Data from 24 h monitoring were calculated and analyzed as follows: mean Systolic Blood Pressure (mmhg) Mean Blood Pressure (mmhg) Diastolic Blood Pressure (mmhg) # 78 # # 76 * 74 * * 72 * * Control Exercise Control Exercise 98 * 93 # * * 88 * * * 83 # 78 * * * Time (min) Time (min) Control Exercise Heart Rate (bpm) Fig. 1 Systolic, diastolic, mean blood pressure and heart rate obtained by oscillometric methods before (time 0) and after (times 10 60) the experimental sessions: control and exercise. *Dierent from control period (p 0.05); # Dierent from rest (p 0.05). Values are presented as mean ± SD Control Exercise of all measurements during the 24 h period; mean of all measures performed during the daytime; and mean of all measures performed during the night-time. Statistical analysis SigniÞ cance levels were set at p The Shapiro-Wilk normality test and a homoscedasticity test (Mauchly) were used to test the normal distribution of the data. A 2-way ANOVA with repeated measures [2 7 protocol (exercise and control) blood pressure measures (REP-post )] was utilized to determine dierences in clinical BP. The Bonferroni post hoc test was used when indicated by ANOVA. A dependent Student s t-test was used to determine dierences in 24 h BP. Considering a power of 75 %, an alpha error of 0.05, and assuming a standard deviation of 5 mmhg; the sample size necessary to detect a mean decrease of 4 mmhg in SBP, DBP and MBP was calculated to be 13 individuals. Data were analyzed using the Statistical Package for Social Sciences (SPSS, v.19, Chicago, IL). Results Subjects characteristics Subject characteristics are presented in Table 1. Subjects were classiþ ed as overweight or obese according to the anthropometric values of body mass index, body adiposity index, neck, waist and hip circumferences, waist-to-hip and waist-to-height ratios and skinfold thickness. Hemodynamic parameters such as SBP, DBP, MBP and HR were considered to be within normal range. Blood pressure Pre-session SBP, DBP, MBP and HR were not dierent between the control and resistance exercise trials ( Fig. 1 ). Results indicated that an acute RE session had a signiþ cant eect (p < 0.05) on blood pressure ( Fig. 1 ). There was a decrease in SBP at 10 ( 5.6 mmhg [ 5.0,10.1 CI]; 5.1 mmhg [ 5.3,13.5 CI]), 30 (-7.2 mmhg [ 3.3,19.5 CI]; -8.9 mmhg [-2.3,7.5 CI]) and 40 ( 6.8 mmhg [ 4.3,13.5 CI]; 7.6 mmhg [ 4.0,12.2 CI]) minutes following the RE session as compared with pre-exercise and control periods, respectively ( Fig. 1 ). DBP values were decreased at 10 ( 5.7 mmhg; -3.7,14.2 CI) and 40 ( 6.1 mmhg; 4.6,11.7 CI) minutes after exercise compared with the control period ( Fig. 1 ). There was a decrease in MBP at 10 ( 5.6 mmhg; 5.1,10.9 CI), 30 ( 6.2 mmhg; 2.8,7.5 CI) and 40 ( 6.6 mmhg; 3.3,7.5 CI) minutes after the RE session as compared with the control period and only at 10 ( 4.3 mmhg; 2.2,9.3 CI) minutes compared with pre-exercise ( Fig. 1 ). Heart rate was signiþ cantly (p < 0.05) higher at 10, 20, 30, 40, 50 and 60 min after the RE session as compared with the control period and only at 10 min compared with pre-exercise ( Fig. 1 ). Fig. 2 presents mean values of 24 h, daytime and night-time periods of BP in the non-exercise control and after the acute RE session. Mean SBP values decreased in the 24 h ( 3.6 mmhg; 5.3,12.5 CI) and night-time ( 4.2 mmhg; 4.0,12.3 CI) periods after the RE session (P < 0.05), while DBP decreased at 24 h ( 4.5 mmhg; 4.4,11.0 CI) and night-time ( 4.1 mmhg; 3.2,11.4 CI) as compared with the control period (P < 0.05, Fig. 2 panel A). MBP also decreased at 24 h ( 3.4 mmhg; 4.6,11.4 CI) and night-time ( 4.9 mmhg; 2.3,12.1 CI) after the RE session as compared with the control period (P < 0.05, Fig. 2 panel C). There were no signiþ cant BP alterations in daytime measures after the RE session as compared with the control period, SBP Tibana RA et al. Acute Eects of Resistance Int J Sports Med 2013; 34:

27 Clinical Sciences 463 a 160 b * * Systolic Blood Pressure (mmhg) 24-h nighttime daytime 24-h nighttime daytime Control Exercise Control Exercise c 120 Mean Blood Pressure (mmhg) * Diastolic Blood Pressure (mmhg) Fig h (24-h), daytime and nighttime ambulatory blood pressure monitoring, after a single resistance exercise session (postexercise) or a nonexercise control period (control). Systolic blood pressure (panel a ); diastolic blood pressure (panel b ); mean blood pressure (panel c ); *dierent from control period (p 0.05). Values are presented as mean ± SD. (p = 0.45; 8.3,11.5 CI), DBP (p = 0.25; 7.6,11.0 CI) and MBP (p = 0.25; 6.2,11.4 CI) ( Fig. 2 panels A, B and C, respectively). Data obtained each hour during sleep and awake states revealed a decrease in SBP values at 02:00 a.m. ( 6.5 mmhg; 1.8,14.9 CI), 05:00 am ( 6.5 mmhg;. 2.9,15.9 CI), 09:00 a.m. ( 11.1 mmhg; 1.9,24.0 CI) and 7:00 pm ( 6.7 mmhg; -8.8,22.3 CI) after the acute RE session as compared with the control period ( Fig. 3 ). DBP decreased after the acute RE session at 02:00 a.m. ( 6.9 mmhg; 0.8,13.3 CI), 05:00 a.m. ( 4.7 mmhg; 5.1,14.7 CI), 08:00 a.m. ( 6.8 mmhg; 3.3,16.1 CI) and 7:00 p.m. ( 7.4 mmhg; 5.2,15.3 CI) as compared with the control session. There was a signiþ cant reduction in MBP after the acute exercise session during the Þ rst monitoring hours: 01:00 am ( 6.2 mmhg; 4.3,16.6 CI), 02:00 a.m. ( 6.3 mmhg; 0.6,13.4 CI), 05:00 a.m. ( 5.5 mmhg; 3.9,15.1 CI), 08:00 a.m. ( 5.9 mmhg; 3.5,15.4 CI), 09:00 a.m. ( 6.4 mmhg; 2.0,14.8 CI) and at 7:00 p.m. ( 5.8 mmhg; 5.3,14.9 CI) compared with the control period ( Fig. 3 ). Discussion The purpose of the study was to investigate the eects of an acute RE session on BP in overweight/obese subjects. Our initial hypothesis was conþ rmed, as an acute RE session decreased BP. Furthermore, the results indicate that the RE session induced a drop of BP during bedtime, and upon-awakening in the morning hours. This is an important observation, considering the higher incidence of cardiovascular events during the morning. Additionally, the RE protocol used in the present study was of moderate submaximal intensity, which facilitates a daily prescription that sedentary/overweight/obese subjects can safely perform. In the present study, overweight/obese subjects presented elevated body mass index, body adiposity index, neck, waist and hip circumferences, waist-to-hip and waist-to-height ratios and * * 24-h nighttime daytime Control Exercise * Systolic Blood Pressure (mmhg) Diastolic Blood Pressure (mmhg) Mean Blood Pressure (mmhg) * bedtime * * upon-awakening * * 75 * 70 * * * Control Exercise Fig. 3 Systolic, diastolic and mean blood pressure determined by ambulatory blood pressure monitoring after resistance exercise session and control session; *dierent from control period (p 0.05). Values are presented as mean ± SD. skinfold thickness. These anthropometric indexes are associated with several cardiovascular diseases such as coronary heart disease, heart failure, strokes, renal and metabolic outcomes, and increased risk of death from all causes for both men and women in all age groups [ 1, 4 ]. Individuals from the present study completed the RE session between 8:00 9:00 p.m., and we observed an immediate postexercise hypotension response characterized by a decrease in SBP, DBP and MBP. PEH has already been reported after a RE in normotensive [ 1, 5, 19, 29, 31 ] and other populations [ 13, 19, 20, 28 ]. Our results are in accordance with previous investigations in which decreases in BP (~5 7 mmhg) were observed by auscultatory, oscillometric and intra-arterial measurements up to min after RE [ 19, 28 ]. Also, this is the Þ rst study to report PEH in overweight/ obese subjects. The mechanisms underlying the reduction of BP following exercise have been studied. Some proposals indicate a decreased cardiac output and peripheral vascular resistance due to lowered sympathetic activity, inducing transduction for vascular tone [ 3, 5, 11 ], higher activity of the plasma kallikrein system mediating nitric oxide release [ 12 ], and alterations in cerebral blood ß ow induced by exercise [ 5 ]. The practical use of 24 h blood pressure monitoring has been recently expanded, with increasing use in daily clinical practice. Strong evidence suggest a better correlation of 24 h BP measurements with overall target organ damage score, left ventricular mass, impaired left ventricular function, albuminuria, brain damage and microvascular disease, and especially retinopathy [ 10 ]. Our results highlighted the beneþ cial eects of an acute submaximal RE session in eectively decreasing SBP, DBP and MBP during 24 h and night-time monitoring. However, Roltsch et al. [ 27 ] found no alterations in SBP and DBP following an acute * * * * * * Tibana RA et al. Acute Eects of Resistance Int J Sports Med 2013; 34:

28 464 Clinical Sciences RE session compared with a non-exercise control day in young, normotensive men and women. Alternatively, Morais et al. [ 21 ] compared the lowering eects of early morning exercise (aerobic versus resistance exercise) on subsequent BP responses of individuals with type-2 diabetes. There was a decrease in BP, which had a prolonged eect up to night-time and sleeping hours, with a more pronounced eect of resistance exercise, mainly on nocturnal BP. Taken together, these results indicate that BP responses to RE are inß uenced by the population, age, medications, type of BP monitoring and initial values of BP, independent of training status. SBP and DBP exhibit distinct 24 h patterns among individuals. In the so-called normal dippers, BP is reduced by % more during time spent asleep compared with during the daytime [ 25 ]. In addition, the occurrence of many acute cardiovascular events such as myocardial infarction, sudden cardiac death, pulmonary embolism, critical limb ischemia, and aortic aneurysm rupture, are more susceptible to happen upon peak awakening in the morning and during the secondary early evening peak [ 7, 15 ]. Generally, BP starts to increase in the early morning between 4 6 h [ 31 ]. During the daytime, there are typically 2 peaks, the Þ rst upon awaking and the second late in the afternoon [ 25 ]. In our study, subjects reported their awakening to be between 06:00 07:00 a.m. SBP, DBP and MBP demonstrated lower values at 02:00 a.m., 05:00 a.m., 09:00 a.m. and 7:00 p.m. Considering this, an acute RE session promotes signiþ cant PEH, which is relevant for overweight/obese subjects that are under a higher risk than normal weight subjects, especially at those periods when BP peaks. To note, the RE session in the present investigation, was performed between 8:00 9:00 p.m., which could be favorable to induce the reduction of blood pressure during sleep and the Þ rst morning hours. In addition, the MAPEC study reported that taking 1 hypertensive medication before sleeping promotes greater cardiovascular protection in comparison to the use of these medications upon awakening [ 15 ]. The present study has certain limitations. The circadian patterns of SBP and DBP in normal conditions have a strong genetic dependency in terms of daytime, the amplitude of variation, and peak time during a 24 h period. In addition, PEH mechanisms were not investigated and body composition was determined by the skinfold thickness method, apart from the relatively small sample size that was utilized. Finally, based on the promising results of the present investigation chronic training and a potential exercise dose-response should be investigated. In summary, an acute submaximal RE session signiþ cantly reduced BP in overweight/obese women. These Þ ndings indicate an important acute eect of RE on BP circadian rhythm, especially at night-time, upon awakening and in the morning. References 1 Bermudes A M, Vassallo D V, Vasquez E C, Lima E G. Ambulatory blood pressure monitoring in normotensive individuals undergoing two single exercise sessions: resistive exercise training and aerobic exercise training. Arq Bras Cardiol 2004 ; 82 : Brown L E, Weir J P. Procedures recommendation I: Accurate assessment of muscular strength and power. JEP online 2001 ; 4 : Brum P C, Da Silva G J, Moreira E D, Ida F, Negrão C E, Krieger E M. Exercise training increases baroreceptor gain sensitivity in normal and hypertensive rats. Hypertension 2000 ; 36 : Cardoso C G Jr, Gomides R S, Queiroz A C, Pinto L G, da Silveira Lobo F, Tinucci T, Mion D Jr, de Moraes Forjaz C L. 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Relevance of blood pressure variation in the circadian onset of cardiovascular events. J Hypertens 2005 ; 23 : S35 S39 11 Halliwill J R. Mechanisms and clinical implications of post-exercise hypotension in humans. Exerc Sport Sci Rev 2001 ; 29 : Halliwill J R, Minson C T, Joyner M J. Eect of systemic nitric oxide synthase inhibition on postexercise hypotension in humans. J Appl Physiol 2000 ; 89 : Hardy D O, Tucker L A. The eects of a single bout of strength training on ambulatory blood pressure levels in 24 mildly hypertensive men. Am J Health Promot 1998 ; 13 : Harriss D J, Atkinson G. Update ethical standards in sport and exercise science research. Int J Sports Med 2011 ; 32 : Hermida R C, Ayala D E, Mojón A, Fernández J R. Inß uence of circadian time of hypertension treatment on cardiovascular risk: results of the MAPEC study. Chronobiol Int 2010 ; 27 : Instituto Brasileiro de GeograÞ a e Estatística (IBGE). 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Diabetes Metab 2011 ; 37 : Pescatello L S, Franklin B A, Fagard R, Farquhar W B, Kelley G A, Ray C A. American College of Sports Medicine. American College of Sports Medicine position stand. Exercise and hypertension. Med Sci Sports Exerc 2004 ; 36 : Perlo D, Sokolow M, Cowan R. The prognostic value of ambulatory blood pressures. JAMA 1983 ; 249 : Pollock M L, Jackson A S. Research progress in validation of clinical methods of assessing body composition. Med Sci Sports Exerc 1984 ; 16 : Portaluppi F, Tiseo R, Smolensky M H, Hermida R C, Ayala D E, Fabbian F. Circadian rhythms and cardiovascular health. Sleep Med Rev 2012 ; 16 : Queiroz AC C, Gagliardi JF L, Forjaz CL M, Rezk C C. Clinic and ambulatory blood pressure responses after resistance exercise. J Strength Cond Res 2009 ; 23 : Roltsch M H, Mendez T, Wilund K R, Hagberg J M. Acute resistive exercise does not aect ambulatory blood pressure in young men and women. Med Sci Sports Exerc 2001 ; 33 : Scher L M, Ferriolli E, Moriguti J C, Scher R, Lima N K. The eect of dierent volumes of acute resistance exercise on elderly individuals with treated hypertension. J Strength Cond Res 2011 ; 25 : Snyder F, Hobson A, Morrison D F, Goldfrank F. Changes in respiration, heart rate and systolic blood pressure in human sleep. J Appl Physiol 1964 ; 19 : Tavel M E. Stress testing in cardiac evaluation: Current concepts with emphasis on the ECG. Chest 2001 ; 119 : Weber M A. The 24-h blood pressure pattern: does it have implications for morbidity and mortality? Am J Cardiol 2002 ; 89 : 27 A 33 A 32 VI diretrizes brasileiras de hipertensão. Sociedade Brasileira de Hipertensão. Sociedade Brasileira de Nefrologia. Arq Bras Cardiol 2010 ; 95 : 1 51 Tibana RA et al. Acute Eects of Resistance Int J Sports Med 2013; 34:

29 Clin Physiol Funct Imaging (2013) doi: /cpf Women with metabolic syndrome present different autonomic modulation and blood pressure response to an acute resistance exercise session compared with women without metabolic syndrome Ramires A. Tibana 1,2, Daniel A. Boullosa 1, Anthony S. Leicht 3 and Jonato Prestes 1 1 Graduation Program on Physical Education, Catholic University of Brasilia, 2 Department of Physical Education, Euro-American University Center (UNIEURO), Brasilia, Brazil and 3 Institute of Sport and Exercise Science, James Cook University, Townsville, Qld, Australia Summary Correspondence Jonato Prestes, Graduate Program on Physical Education, Catholic University of Brasilia, Q.S. 07 Lote 01 Bloco G , Brasilia, Brazil jonatop@gmail.com Accepted for publication Received 11 September 2012; accepted 26 February 2013 Key words cardiovascular response; heart rate variability; metabolic syndrome; resistance training Metabolic syndrome (MetS) is a cluster of risk factors in individuals with high risk of diabetes and heart disease. Resistance training (RT) has been proposed to be a safe, effective and worthwhile method for the prevention and treatment of metabolic and cardiovascular diseases. However, no study has analysed the acute response of blood pressure (BP) and autonomic control of heart rate (HR) after a RT session in female patients with MetS. The aim of the present study was to analyse the response of laboratory assessed and ambulatory BP and cardiac autonomic modulation after a RT session in women with MetS. Nine women without MetS ( years) and 10 women with MetS ( years) completed one experimental exercise session and a control session. Laboratory BP, heart rate variability (HRV) and ambulatory BP of each subject were measured at rest, over 60 min, and for 24 h after the end of the sessions, respectively. There was a significant reduction in systolic blood pressure (SBP), night time diastolic blood pressure (DBP) and mean blood pressure (MBP) only for women with MetS, for all periods after the RT session when compared with the control session (P<005). Significantly lower laboratory values of SBP and DBP (10, 30 and 40 min postexercise) and MBP (10, 40 and 50 min postexercise) were observed in women with MetS (P<005). Patients with MetS exhibited significant lower basal HRV and a lower autonomic responsiveness during the 60 min of acute recovery. These results confirmed that an acute session of resistance exercise induced a lower BP during day time and sleeping hours in women with MetS that may offer a cardio-protective effect. Women with MetS exhibited an impaired autonomic modulation at rest and a lower acute autonomic responsiveness to a RT session. The dissociation between BP and HRV responses suggests that other factors than autonomic control could be involved in the hypotensive effect of a RT session in MetS patients. Introduction Diagnosis of Metabolic Syndrome (MetS) is characterized by the identification of several cardiovascular risk factors such as: abdominal obesity, hypertension, insulin resistance, glucose intolerance and dyslipidaemia (Cornier et al., 2008). Various epidemiologic studies have shown strong associations between these risk factors and the development of other pathologies such as gastrointestinal cancer (Matthews et al., 2010), diabetes mellitus (Wilson et al., 2005), cardiovascular disease (CVD) (Isomaa et al., 2001) or even premature mortality (Lakka et al., 2002). While systemic hypertension has been reported in patients with MetS (Cornier et al., 2008), paradoxically, this risk factor has been one of the less studied. Additionally, hypertension alone is a risk factor for several cardiovascular diseases, such as stroke, coronary heart disease, heart failure, peripheral arterial disease and renal insufficiency (Pescatello et al., 2004). Mozaffarian et al. (2008) reported that the mortality rate of MetS patients with hypertension was 26% higher compared 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by Blackwell Publishing Ltd 1

30 2 Metabolic syndrome and resistance exercise, R. A. Tibana et al. with those without MetS. One possible mechanism underlying the link between MetS and cardiovascular events may be an abnormal modulation of autonomic activity (Assoumou et al., 2010). Autonomic nervous activity impairment, as reflected by lower short-term and long-term heart rate variability (HRV), has been recently reported in female elderly patients with MetS (Assoumou et al., 2010). Interestingly, exercise has been recommended as a valuable tool to promote acute decreases in blood pressure (BP) (Ciccolo et al., 2010). Moreover, independent of the chronic effects of regular training, an acute decrease in BP below resting values may occur after exercise, a physiological phenomenon called postexercise hypotension (PEH) with important clinical relevance (Pescatello et al., 2004; Liu et al., 2012). Although the hypotensive effects of aerobic exercise have been widely confirmed, the drop in BP after resistance training (RT) has produced controversial results (Cardoso et al., 2010). Nevertheless, various systematic reviews and meta-analysis have highlighted RT as a worthwhile and efficient method to decrease BP (Anunciacß~ao & Polito, 2011; Cornelissen & Fagard, 2005). In this sense, a study from Tibana et al. (2012) revealed that an acute submaximal RT session was effective in decreasing systolic (SBP), diastolic (DBP) and mean BP (MBP) during 24 h and night time. Similarly, Hardy & Tucker (1998) found a significant decrease in day time BP (i.e. 1 h after RT) in a group of mild hypertensive sedentary men. However, another study revealed no changes in SBP and DBP following an acute RT session compared with a non-exercise control day in young, normotensive men and women (Roltsch et al., 2001). Therefore, the potential effectiveness of acute RT sessions on BP control requires elucidation as these acute effects may contribute to long-term BP control for patients with MetS. Furthermore, the evaluation of the autonomic control of heart rate (HR) via HRV analysis could be an important tool for the monitoring of patients with MetS. Several studies have examined resting HRV in patients with MetS; however, none to our knowledge have examined exercise or postexercise responses for MetS sufferers. Many studies have analysed the acute effect of both aerobic and RT exercises on HRV in healthy people (Heffernan, et al. 2006; Lima et al., 2011) noting significant normal HRV changes. A similar examination in patients with MetS may clarify the role of the autonomic nervous system in the manifestation of MetS. However, to the best of our knowledge, no further study has examined the acute response of 24 h BP and autonomic nervous system after exercise and in particular RT in patients with MetS. Thus, the aim of the present study was to analyse the response of laboratory assessed and ambulatory BP and HRV after a RT session in women with MetS. Female patients with MetS were examined as they represent the majority of patients when considering waist circumference as the greatest contributor to MetS diagnosis and have received less research consideration (Dutra et al., 2012). The hypothesis was that women with MetS would present a higher decrease in BP and a lower responsiveness of the autonomic nervous system after exercise compared with women without MetS. Methods Subjects Nineteen sedentary women aged years were invited to participate in this study that was approved by the Research Ethics Committee of the Catholic University of Brasilia (protocol 376/2010). All participants were informed of all the risks and benefits before the investigation and signed an informed written consent. Inclusion criteria were the following: age years, sedentary, non-smokers and without a history of coronary artery disease. Exclusion criteria included the following: (i) use of drugs that could affect cardiovascular response and (ii) cardiovascular and/or orthopaedic problems that could limit the execution of the proposed exercises. Participants were advised to refrain from coffee or alcohol ingestion in the 24 h before tests and to avoid any type of vigorous physical activity 48 h before and 24 h after the experimental protocols. Metabolic Syndrome Definition Participants diagnosed with MetS were classified according to the criteria of the National Cholesterol Education Program s Adult Treatment Panel III (NCEP:ATPIII): waist circumference > 88 cm; Triglycerides 150 mg dl 1 ; high-density lipoprotein-cholesterol (HDL-C) < 50 mg dl 1 ; fasting glucose 110 mg dl 1 ; systolic BP (SBP) 130 mmhg or diastolic BP (DBP) 85 mmhg. As previously described in earlier STRRIDE studies, the MetS z score used for this study was a continuous score of the 5 MetS variables. A modified z score was calculated for each variable using individual subject data using the Adult Treatment Panel (ATP) III criteria. The equations used to calculate the MetS z score were as follows: {z score = [(50 HDL)/118] + [(TG 150)/662] + [(fasting blood glucose 110)/104] + [(waist circumference 88)/ 92] + [(mean arterial pressure 100)/87]/100}. Experimental protocol Subjects completed 2 weeks of familiarization prior to testing. In the familiarization weeks, individuals were advised regarding proper RT technique and completed three sessions/week, with one exercise of each main muscle group consisting of three sets of submaximal repetitions. After the familiarization period, subjects completed a maximal strength test of each RT exercise and two experimental sessions (i.e. control and exercise separated by at least 72 h) that were randomly performed within a 4-week period. During the exercise session, participants remained seated quietly for 15 min before completing three sets of 10 repetitions of the following exercises: machine leg press, leg extension, leg curl, chest press, 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by Blackwell Publishing Ltd

31 Metabolic syndrome and resistance exercise, R. A. Tibana et al. 3 front lat pull-down and machine shoulder press at an intensity of 60% of one repetition maximum (1RM) followed by 15 repetitions of abdominal crunches. A rest interval of one minute was used between sets and exercises. The total duration of this session was 30 min. The control session consisted of 30 min of seated rest. Maximal strength testing After 2 weeks of adaptation to the exercises (3 days a week), 1RM tests were performed on four different days separated by a minimum of 48 h. All tests were performed between 9:00 and 11:00 am with 10 min of rest between exercises. The order of the exercises was as follows: chest press, front lat pull-down and machine shoulder press (days 1 and 2); machine leg press, leg extension and leg curl (days 3 and 4) (Johnson, Landmark Drive, Cottage Grove, OR, USA). Tests were completed and then repeated after 48 h for the determination of test reliability (via intraclass correlation coefficient, ICC). The 1RM protocol consisted of a light warm-up of 10 min of treadmill running followed by eight repetitions with 50% of estimated 1RM (according to the participants capacity verified in the 2 weeks of adaptation). After a 1-min rest, participants performed three repetitions with a load of 70% estimated 1RM. After another three minutes of rest, participants performed various 1RM attempts interspersed with 3 5 min rest intervals with progressively heavier weights (~5%) until the 1RM was determined. The range of motion and exercise technique was standardized according to the descriptions of Brown and Weir (2001). This procedure was repeated on two separate days with 48 h between them with a high ICC (>097) determined for all exercise tests. Laboratory assessed blood pressure and heart rate Systolic (SBP), diastolic (DBP) and mean (MBP) BP and HR were measured with an oscillometric device (Microlife 3AC1-1, Widnau, Switzerland) according to the recommendations of the Brazilian Society of Cardiology (2010). The values of SBP and DBP were used to determine MBP by the following equation: MBP = DBP + [(SBP DBP)/3]. All BP and HR measures were assessed in triplicate (measurements separated by 1 min) with the mean value used for further analysis. The BP and HR measurements were performed: after 15 min of seated rest (Res); and 10 min (T10); 20 min (T20); 30 min (T30); 40 min (T40); 50 min (T50); and 60 min (T60) after the control or exercise session. Ambulatory blood pressure Ambulatory BP was measured in the non-dominant arm with an oscillometric monitor (Dyna-MAPA â ; Cardios, Sao Paulo, Brazil) for 24 h following the exercise and control sessions. The monitor was programmed to perform recordings every 15 min during the day time (08:00 18:00) and every 30 min during the night time (18:00 08:00). All ambulatory measures of BP were performed during a week day (i.e. Monday to Friday) and initiated between 9:00 and 10:00 pm. All participants were advised to maintain their habitual activities, refrain from programmed exercise and to stop and relax the arm during each measurement. Data from ambulatory monitoring were calculated and analysed as follows: mean of all measurements during the 24 h period (24 h); mean of all measures performed during the day time (Day time); and mean of all measures performed during the night time (Night time). Heart rate variability The autonomic modulation of HR was obtained from the spectral analysis of R-R intervals obtained from a heart rate monitor (S810i; Polar, Kempele, Finland) before, at 5 min, 30 min and 1 h after the end of the exercise session. There was no control session for HRV parameters. R-R intervals were recorded at a sampling rate of 1kHz with all intervals manually inspected to exclude artefacts with the corresponding software prior to analysis. Stationary periods with a range of beats were analysed with default values in a custom designed software (KUBIOS v2.; University of Kuopio, Kuopio, Finland) in accordance with the recommendations of the Task Force (1997) to identify the subbands of low (LF) ( Hz) and high frequency (HF) (015 04Hz). The normalized and the absolute power of each spectral component was analysed as previously described (Task Force, 1996). The analysis in the time domain was performed using R-R interval, the standard deviation of the normal-to-normal intervals (SDNN) and root mean square of the squared successive differences between the adjacent R-R intervals (RMSSD). Biochemical and cytokines analysis Before the adaptation sessions, fasting (12 h) venous blood samples were collected from the non-dominant arm into EDTA 1-mg ml 1 tubes. Samples were centrifuged at 8000 g with plasma separated and then stored at 80 for later analysis. Triglyceride, HDL-C, glucose, glycated haemoglobin and insulin were measured in the plasma samples by the following methods: enzymatic CHOP-POD; homogeneous HDL-cholesterol; Hexokinase; High-performance liquid chromatography (HPLC) and Electrochemoluminence, respectively. Results from insulin and glucose were used to calculate HOMA-IR, by the formula: HOMA-IR = Fasting glycemia (mmol L 1 ) 9 fasting insulin (lu ml 1 )/225. Serum TNF-a and IL-6 were assessed using commercially available enzyme-linked immunobsorbent assay (ELISA) kits (Invitrogen Corp., Carlsbad, CA, USA; EMD Chemicals Inc., San Diego, CA, USA). Standard curves were generated using commercially available microplate reader-compatible statistical software (MICROWIN 2000; Microtek Laborsysteme GmbH, Overath, Germany). All samples were determined in duplicate with the intra-assay coefficient of variation being 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by Blackwell Publishing Ltd

32 4 Metabolic syndrome and resistance exercise, R. A. Tibana et al %, the inter-assay coefficient of variation being 59 70% and the sensitivity being pg ml 1. These variables were analysed to identify the extent of MetS. Statistical analysis Statistical significance for all variables was fixed at P 005. The Shapiro Wilk and Levene tests were performed to check the normality and homogeneity of the data, respectively. To analyse the differences in laboratory SBP, DBP, MBP, HR and HRV parameters, the appropriate 2-way ANOVA with post hoc Bonferroni correction or Friedman s test was used. Independent Student s t-test or where appropriate, Mann Whitney test, was used to compare the resting characteristics of both groups. Dependent Student s t-test was used to compare mean values of 24 h, night time and day time ambulatory SBP, DBP and MBP (control vs. exercise). Mann Whitney test was used to compare the variation (post- and prevalues in mmhg) between groups (with and without metabolic syndrome). Considering a power (1 b) of 080 and an alpha error of 005, the sample size used in this research allowed identifying a large effect size (f 2 = 060) for BP and HRV parameters in both groups. The Statistical Package for the Social Sciences (SPSS, v.19; IBM Corporation, Armonk, NY, USA) was used. Results Anthropometric, hemodynamic and biochemical variables for both groups are presented in Table 1. As expected, women with MetS presented with significantly higher values for all the following variables: body mass, body mass index, waist, hip and neck circumferences, percentage body fat, lean body mass, fat mass, IL-6, insulin, SBP, DBP, MBP, HOMA-IR and triglycerides, when compared with the group of females without MetS (Table 1). Ambulatory values of SBP, DBP and MBP from day time and night time are presented in Table 2. There was a significant lower SBP, DBP (24 h and night time) and MBP in women with MetS after the RT session when compared with the control session. Post- and predelta values revealed greater differences in SBP, DBP and MBP during 24 h and night time periods for patients with MetS compared with women without MetS (Table 2). Laboratory responses for SBP, DBP, MBP and HR are presented in Figs 1 and 2. There was a significant group 9 time interaction with significantly lower values of SBP and DBP at P10, P30 and P40; and MBP at P10, P30 and P40, only in women with MetS (Fig. 1). There was also a significant time effect for HR, with both groups exhibiting a greater HR at all times (P10, P20, P30, P40, P50 and P60) after exercise compared with the control session (Figs 1 and 2). HRV before and after the RT session is presented in Table 3. Pre-exercise values of all selected HRV parameters were significantly different between groups, indicating an autonomic imbalance for the MetS group. There was a significant group 9 time interaction for LF/HF ratio after RT, specifically Table 1 at min of recovery, highlighting a greater autonomic responsiveness of women without MetS as compared with the MetS group. Absolute HF decreased immediately after RT for both groups. All HRV parameters returned to pre-exercise values 1 h after the RT session in both groups (Table 3). Discussion Participants characteristics. Without MetS (n = 9) MetS (n = 10) P Age (y) Body mass (kg) a Height (m) Body mass index a (kg/m 2 ) Neck circumference a (cm) Waist circumference a (cm) Hip circumference (cm) Body fat (%) a Fat body mass a (kg) Lean body mass a (kg) IL a TNF-a b 119 ( ) 176 (47 276) 038 Blood Glucose (mg dl) Insulin (lui/ml) b 46 (27 94) a 73 (37 237) 005 Haemoglobin A1c (%) HOMA-IR b 10 (06 18) 21 (08 57) 010 Triglycerides 58 (44 94) a 101 (90 200) 002 (mg/dl) b HDL-C (mg dl) SBP (mmhg) <0001 DBP (mmhg) <0001 MBP (mmhg) <0001 MetS z-score <0001 HDL, High-Density Lipoprotein; SBP, systolic blood pressure; DBP, diastolic blood pressure; MBP, mean blood pressure; MetS, metabolic syndrome; IL-6, interleukin-6; TNF-a, tumour necrosis factor-alpha. Values are mean SD unless otherwise stated. Difference between groups was checked by independent Student s t-test for parametric data or Mann Whitney test for nonparametric data. a Significantly different between groups. b Values expressed as median (Inter-quartile range). The main findings of the present study were that as follows: 1 Patients with MetS exhibited lower SBP, DBP and MBP in the 24 h following RT with greater reductions in BP (24 h and night time periods) compared with non-mets females. 2 Only women with MetS exhibited a significant decrease in laboratory assessed SBP, DBP and MBP at 10, 30 and 40 min 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by Blackwell Publishing Ltd

33 Metabolic syndrome and resistance exercise, R. A. Tibana et al. 5 Table 2 Systolic, diastolic and mean blood pressure (BP) responses measured during 24 h, night time and day time periods in the control condition and after the acute resistance exercise session in women with (n = 10) and without metabolic syndrome (n = 9). Exercise Control P (exercise versus control) Metabolic syndrome 24 h SBP (mmhg) * ** 24 h DBP (mmhg) * ** 24 h MBP (mmhg) * ** Night Time SBP (mmhg) * ** Night Time DBP (mmhg) * ** Night Time MBP (mmhg) * ** Day Time SBP (mmhg) * Day Time DBP (mmhg) Day Time MBP (mmhg) * Without metabolic syndrome 24 h SBP (mmhg) h DBP (mmhg) h MBP (mmhg) Night Time SBP (mmhg) Night Time DBP (mmhg) * Night Time MBP (mmhg) Day Time SBP (mmhg) Day Time DBP (mmhg) Day Time MBP (mmhg) SBP, systolic blood pressure; DBP, diastolic blood pressure; MBP, mean blood pressure. Values are mean SD. Difference between groups was checked by independent Student s t-test for parametric data or Mann Whitney test for nonparametric data. *Significantly different from control (P<005). variation (post pre values in mmhg). **Statistically significant difference between groups (with and without metabolic syndrome) (P<005). following an acute RT session compared with the control session. 3 Women with MetS exhibited a lower pre-exercise cardiac autonomic modulation (higher HR, LFnu and LF/HF with lower SDNN, RMSSD and HFnu) and a lower autonomic responsiveness compared with women without MetS. The greater reduction of 24 h BP after a RT session for patients with MetS was in agreement with previous reports in other populations (Melo et al., 2006; Queiroz et al., 2009), showing that individuals with higher resting BP presented a superior hypotensive effect. This result is particularly important for patients with MetS, considering that previous studies have found a higher probability of death from cardiovascular disease in women with MetS (Lakka et al., 2002). In this sense, our results revealed that women with MetS can benefit from a decrease in clinic and ambulatory BP after an acute RT session with ten submaximal repetitions at 60% of 1RM (moderate intensity) of six exercises. In this regard, it should be noted that contrary to previous studies, the design of the present RT session is very similar to those performed in a real setting, thus signifying a greater ecological validity of the present investigation. To note, Hardy & Tucker (1998) observed that this hypotensive response lasted up only to one hour. More recently, Melo et al. (2006) showed that the decrease in BP after exercise lasted up to 10 h. Nevertheless, the results of the present study are in accordance with other investigations using long-term BP analysis, where hypotension lasted up to 24 h after exercise (Wallace et al., 1999; Taylor- Tolbert et al., 2000). To note, the analysis of 24 h BP has strong correlation with overall target organ damage score, left ventricular mass, impaired left ventricular function, albuminuria, brain damage and microvascular disease and especially retinopathy (Giles, 2005), reinforcing the relevance our results in women with MetS. Tibana et al. (2012) found that an acute submaximal resistance exercise session was effective in decreasing SBP, DBP and MBP during 24 h and night time in overweight and obese women. Moreover, Hermida et al. (2011) established a relationship between decreasing BP during night time and reduced cardiovascular risk in subjects with normal or elevated BP, suggesting risk-reduction benefits even below the current diagnostic threshold of 120 mmhg. Morais et al. (2011) compared the lowering effects of aerobic versus resistance exercise on subsequent BP responses in individuals with type 2 diabetes. Results revealed that postexercise BP decrease lasted up to sleeping hours, with a more pronounced effect of resistance exercise, mainly on nocturnal BP drop. Thus, one of the main findings of our study was that a RT session induced a prolonged hypotensive effect in a group of women with MetS, which was not evident in the healthy non- MetS group. Probably the selection of the exercises and the training load could be an important aspect for inducing a greater BP drop during a longer period. While one novelty of the current study refers to the employment of a more realistic 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by Blackwell Publishing Ltd

34 6 Metabolic syndrome and resistance exercise, R. A. Tibana et al. (a) (b) (c) (d) Figure 1 Oscillometric systolic blood pressure (SBP, panel a), diastolic blood pressure (DBP, panel B), mean blood pressure (MBP, panel c) and heart rate (HR, panel d) in the control condition and after the acute resistance training session in women with metabolic syndrome. Values are mean SD. *Significantly different from control session, *P<005. Differences were checked by 2-way ANOVA (condition x time). (a) (b) (c) (d) Figure 2 Oscillometric systolic blood pressure (SBP, panel a), diastolic blood pressure (DBP, panel b), and mean blood pressure (MBP, panel c) and heart rate (HR, panel D) in the control condition and after the acute resistance training session in women without metabolic syndrome. Values are mean SD. *Significantly different from control session, *P<005. Differences were checked by 2-way ANOVA (condition x time). RT session, further studies should be conducted to evaluate the dose response of other RT sessions with different exercises and training loads. The comparison between studies is sometimes difficult, as the use of clinic BP may limit the time-course analysis of postexercise hypotension. Recently, it has been proposed that 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by Blackwell Publishing Ltd

35 Metabolic syndrome and resistance exercise, R. A. Tibana et al. 7 Table 3 Heart rate variability indexes measured before and after the acute resistance exercise session. Without MetS (n = 9) MetS (n = 10) R-R (ms) Rest *, ** ** min post ** ** min post min post SDNN (ms) Rest * min post * min post * min post * RMSSD (ms) Rest * min post min post * min post * LF (n.u.) Rest * min post min post * min post HF (n.u.) Rest ** ** min post *, ** min post * min post LF (ms 2 ) Rest a min post a min post a * min post a * HF (ms 2 ) Rest a * min post a *** *** min post a * min post a * LF/HF Rest a 17 (11 7)* 33 (16 212)** min post a 26 (08 72)* 40 (24 212) min post a 32 (19 57)* 80 (12 179) min post a 24 (02 49) 37 (08 77) 031 P (inter-group comparison) LF, low-frequency component; HF, high-frequency component. MetS, metabolic syndrome; SDNN, normal-to-normal intervals; RMSSD, root mean square of the squared successive differences between the adjacent R-R intervals. Differences between group and time were checked by 2-way ANOVA. Friedman test was used for nonparametric data. Values are mean SD, unless otherwise stated. a Data presented as median (inter-quartile range). *Significantly different from MetS (P<005). **Significantly different from 25 to 30 min post (P<005). ***Significantly different from rest (P<005). the decrease in BP observed up to 45 min after an acute resistance exercise session can be attenuated by chronic training in hypertensive stage 1 patient not using antihypertensive medication (Moraes et al., 2012). Our results are similar to a previous investigation in which decreases in BP (~5 mmhg) was observed by auscultatory and oscillometric and intra-arterial measurements up to min after RT (MacDonald et al., 1999; Scher, et al. 2011; Tibana et al., 2012). The potential mechanisms responsible for postexercise hypotension are a decreased cardiac output and peripheral vascular resistance (Halliwill, 2001). On the other hand, the extent by which these mechanisms modulated the results of the present study remains to be determined. Additionally, genetic factors, such as polymorphisms, may influence the cardiovascular response to RT in sedentary women (Souza et al., 2013). As expected, women with MetS exhibited a lower HRV in resting condition as compared to healthy females without MetS. This finding is in agreement with the recent work of Assoumou et al. (2010) who reported a lower short- and long-term HRV in female elderly patients with MetS. Moreover, this finding confirms the expected autonomic imbalance individually observed in the pathologies associated with MetS. The reduction in the activity of the autonomic nervous system observed in MetS subjects may be explained by the underlying pathophysiology of MetS. Recently, Weber et al. (2010) have reported that those subjects with a low vagal tone exhibited an impaired recovery of cardiovascular, endocrine and immune markers after a mental stress test. This suggests that patients with MetS may be at a greater risk to stressors as a consequence of their lower autonomic control of HR (Boullosa et al., 2012). Therefore, further studies should examine these responses for verifying the role of the hypothalamicpituitary-adrenal (HPA) axis in stress tolerance to different stressors in this and other metabolic diseases. In the current study, the autonomic modulation was also monitored after the RT session and in agreement with previous studies (Rezk et al., 2006; Lima et al., 2011), there was a significant decrement in HRV reflecting increased sympathetic and/or lower parasympathetic modulatory control of HR. Interestingly, HRV parameters were lower in the MetS group along the whole acute recovery. To the best of our knowledge, this is the first study to report such finding in patients with MetS. Furthermore, the interactions observed with the ANOVA for HRV parameters suggest a lower autonomic responsiveness in patients with MetS when compared with controls. From a cardiovascular point of view, these considerations are very important given the associated lower risk of those patients with a greater autonomic control of HR (Huikuri et al., 1994) and a better stress tolerance for those individuals with a greater autonomic responsiveness (Boullosa et al., 2012). Nevertheless, the restoration of basal HRV one hour after the RT session suggests that this training modality could be safe in patients with MetS. Interestingly, BP still remained low while HRV returned to normal levels 60 min after the RT session. Therefore, the lower BP for MetS after an acute RT session appears to be a result of additional factors and not only autonomic control of HR. This is an interesting finding that warrants further investigations Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by Blackwell Publishing Ltd

36 8 Metabolic syndrome and resistance exercise, R. A. Tibana et al. Conclusion In summary, an acute session of RT performed with three sets of 10 submaximal repetitions at 60% of 1RM elicited a lowering effect on BP during day time and sleeping hours in women with MetS, but not in women without MetS. To note, the acute RT session was submaximal which suggests an excellent practical application in daily prescription for this population. Additionally, women with MetS present an impaired autonomic modulation at rest that appears to be less responsive following RT exercise when compared with women without MetS. Additional studies investigating the effects of different exercise order, intensity and volume on BP in people with MetS are warranted, especially in a chronic perspective. Acknowledgment We would like to acknowledge the support of Centro Universitario Euro-Americano (UNIEURO, Brasılia, Brazil) and CAPES/PROSUP. Conflict of interest The authors have no conflicts of interest. 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38 Tibana et al. Diabetology & Metabolic Syndrome 2013, 5:11 DIABETOLOGY & METABOLIC SYNDROME RESEARCH Open Access Effects of eight weeks of resistance training on the risk factors of metabolic syndrome in overweight /obese women - A Pilot Study Ramires Alsamir Tibana 1,2*, James Navalta 3, Martim Bottaro 4, Denis Vieira 1, Vitor Tajra 1, Alessandro de Oliveira Silva 1, Darlan Lopes de Farias 1, Guilherme Borges Pereira 1, Jéssica Cardoso de Souza 1, Sandor Balsamo 2,6, Claudia Regina Cavaglieri 5 and Jonato Prestes 1* Abstract Background: The purpose of the present study was to examine the effects of eight weeks of resistance training (RT) on anthropometric, cardiovascular and biochemical risk factors of metabolic syndrome (MetS), and neuromuscular variables on overweight/obese women. Methods: Fourteen middle-aged (33.9 ± 8.6 years) overweight/obese women (body mass index - BMI 29.6 ± 4.1 kg/m 2 ) underwent 24 sessions (3 times/week) of a whole body RT program with 3 sets of 8 12 repetitions maximum (RM). The following variables were evaluated: maximum strength on chest press and frontal lat pull-down; isometric hand-grip strength; biceps brachii (BB) and rectus femoris (RF) muscle thickness, body mass; BMI; body adiposity index (BAI); waist, hip and neck circumferences; visceral fat volume; blood glucose; glycated hemoglobin (HbA1c); insulin; HDL-C and triglycerides. Results: There was an increase of chest press (from 52.9 ± 9.7 to 59.8 ± 7.7 kg; P = 0.02) and front lat pull-down (from 51.5 ± 7.5 to 57.6 ± 9.2 kg; P = 0.01) muscle strength, isometric handgrip (P = 0.02) and RF muscle thickness (from 42.2 ± 8.5 to 45.1 ± 7.3 mm; P = 0.02) after the 8 week RT program. There were no statistically significant alterations on plasma glucose, HbA1c, insulin, triglycerides, HDL-C, anthropometric indexes and BB muscle thickness (p > 0.05). Conclusions: A RT program without caloric restriction promotes an increase on muscle thickness and strength, with no effects on risk factors of MetS in overweight/obese women. Keywords: Resistance training, Obesity, Overweight, Metabolic syndrome Introduction The prevalence of Metabolic Syndrome (MetS) has been increasing worldwide, in parallel with the increasing prevalence of obesity. MetS is characterized by the grouping of several cardiovascular risk factors such as: abdominal obesity, hypertension, insulin resistance, glucose intolerance/type 2 diabetes, and dyslipidemia [1]. Furthermore, various epidemiologic studies have shown strong associations between these risk factors and * Correspondence: ramiires@hotmail.com; jonatop@gmail.com 1 Graduate Program on Physical Education, Catholic University of Brasilia, Q.S. 07 Lote 01 Bloco G, , Brasilia, Brazil 2 Department of Physical Education, Euro-American University Center (UNIEURO), Brasilia, Brazil Full list of author information is available at the end of the article the development of other chronic diseases problems such as gastrointestinal cancer [2], diabetes [3], cardiovascular disease (CVD) [4], or even premature mortality [5,6]. Thus, the development of strategies to prevent and treat MetS, overweight and obesity are of great importance. Sedentary behavior which includes activities such as lying down, sitting, watching television, using the computer, and other forms of screen based entertainment are positively associated with an increased risk of type 2 diabetes [7,8], cancer [9], MetS [10], and all-cause and CVD mortality [7,8]. Therefore, lifestyle modifications [11] and exercise have been consistently recommended for the treatment and prevention of hypertension and metabolic diseases. Aerobic exercises such as walking 2013 Tibana et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

39 Tibana et al. Diabetology & Metabolic Syndrome 2013, 5:11 Page 2 of 8 and bicycling have been widely used to prevent the development of metabolic and cardiovascular risk factors, MetS, type 2 diabetes, CVD, and premature mortality [12]. Nevertheless, the inclusion of resistance training (RT) as an integral part of an exercise program which also includes aerobic or combined exercise has been endorsed by the American Heart Association [13], the American College of Sports Medicine [14] and the American Diabetes Association [15]. Recent studies have suggested that lower levels of muscular strength are associated with the prevalence of MetS [16,17], obesity [18], hypertension [19] and premature mortality [20]. Moreover, RT for persons with MetS induces no additional systemic elevation of pro-inflammatory cytokines [21] and is effective in reducing clinical and 24 h blood pressure in middle-aged overweight/obese women [22]. However, Stensvold et al., [23] found minimal effects of RT on risk factors of MetS. The conflicting data reinforce the necessity of more studies investigating the effects of RT on the risk factors of MetS. The purpose of the present study was to examine the effects of eight weeks of RT on anthropometric, cardiovascular and biochemical risk factors of MetS, and neuromuscular variables in overweight/obese women. The initial hypothesis was that chronic RT without dietary restriction would improve neuromuscular variables and decrease some risk factors of MetS, such as blood pressure and waist circumference. Methods Subjects Initially, 20 women from the local community volunteered to participate from posters and lectures about the study. However, only 14 completed the study, with three volunteers excluded due to caloric restriction and three excluded from the statistical analysis because they missed more than 25% of the training sessions (Figure 1). Individuals completed a thorough physical examination, including a medical history, resting and exercise electrocardiogram [24], blood pressure assessment, anthropometric, and orthopaedic evaluation prior to participation in the experimental protocols. As inclusion criteria, the only participants included were those aged between y, classified as overweight (N = 9) or obese (N = 5) by BMI measurement according to the World Health Organization (WHO): overweight BMI = kg m 2 and obese > 30.0 kg m 2, and those without consistent RT for the past six months before the study period. Women with physical disabilities, under caloric restriction, diagnosis of diabetes, cardiovascular diseases, hypertension (systolic blood pressure > 140 mmhg and diastolic blood pressure > 90 mmhg) [25], musculoskeletal disease, recent use of medication and smoking or drug/alcohol abuse were excluded from the trial. Sedentary state was defined Figure 1 Scheme of the study design. Diagram of the selection process of the volunteers. by the International physical activity questionnaire (IPAQ). All participants signed an informed consent document and the study was approved by the Catholic University of Brasilia Research Ethics Committee for Human Use (protocol #279/2010). Study design The present study was designed to investigate the effects of eight weeks of RT on muscle thickness and strength, anthropometric, biochemical and cardiovascular risk factors of MetS in overweight/obese women. All testing and training sessions were conducted between 08:00 09:00 pm. Subjects were advised to maintain their normal daily eating habits throughout the study (this was guaranteed by a dietary recall follow-up). Prior to physical evaluation, participants reported to the laboratory between 08:00 10:00 am following an overnight fast, for blood sampling from the antecubital vein for subsequent analysis of biochemical variables. Anthropometric variables, isometric handgrip strength, muscle thickness by ultrasound and thorough physical examination were determined. Volunteers completed two weeks of familiarization prior to testing (3 sessions/ week, with one exercise for each main muscle group which were the same exercises used during RT), where they were advised regarding the execution of proper technique. After the familiarization period, one-repetition maximum (1-RM) test and re-test were performed on the chest press and front lat pull-down on two nonconsecutive days with hours between tests. The RT protocol began three days after 1-RM testing and was performed on three non-consecutive days of the week,

40 Tibana et al. Diabetology & Metabolic Syndrome 2013, 5:11 Page 3 of 8 comprising three sets of 8 12 repetition maximum (RM) of twelve exercises, and 1-minute rest intervals between sets and exercises. Maximal strength testing After 2 weeks of adaptation to the exercises and 3 5 days after the last training session, 1-RM tests were performed on 2 different days separated by a minimum of 48 h. All tests were performed with 10 min rest intervals between each exercise. The order was as follows: chest press and front lat pull-down (JOHNSON, USA). The protocol consisted of a light warm-up of 10 min of treadmill running followed by 8 repetitions at 50% of estimated 1-RM (according to the participants capacity verified in the 2 weeks of adaptation). After a 1-min rest, subjects performed 3 repetitions at 70% of the estimated 1-RM. Following 3 minutes of rest, participants completed 3 5 attempts interspersed with 3-to-5 min rest intervals, with progressively heavier weights (~5%) until the 1-RM was determined. The range of motion and exercise technique were standardized according to the descriptions of Brown and Weir [26]. Isometric handgrip strength Isometric handgrip strength was determined by a manual mechanical dynamometer (Takei, T.K.K Grip strength dynamometer kg, Japan), according to the recommendations of Heyward [27]. Volunteers stood still with both arms extended and the forearm positioned in a neutral rotation. The handgrip width of the dynamometer was individually adjusted for each participant, according to hand size allowing the stem next to the body to be positioned on the second phalanges: index, medial and ring fingers. Three attempts were allowed interspersed with 1 min rest intervals. The best measure was used and relative isometric strength was determined as follows: Relative strength ¼ Absolute strength ðkgþ=body mass ðkgþ Muscle thickness Muscle thickness of the rectus femoris (RF) and biceps brachii (BB) were tested before and after the eight-week RT period. All tests were conducted at the same time of day, and participants were instructed to hydrate normally 24 h before the tests. Measures were taken 3 5 days after the last training session to prevent any residual effects (i.e. swelling) that could interfere with muscle thickness [28]. Participants were instructed to avoid any other type of exercise or intense activity. Muscle thickness was measured using B-Mode ultrasound (Philips-VMI, Ultra Vision Flip, model BF). A water-soluble transmission gel was applied to the measurement site and a 7.5-MHz ultrasound probe was placed perpendicular to the tissue interface while not depressing the skin. Muscle thickness of the use only RF and BB muscle from the dominant limb were measured according to the recommendations of Abe et al., [29]. Once the technician was satisfied with the quality of the image produced, the image on the monitor was frozen. With the image frozen, a cursor was enabled in order to measure muscle thickness, which was taken as the distance from the subcutaneous adipose tissue-muscle interface to muscle-bone interface [29]. A trained technician performed all the analysis. Total muscle mass Total muscle mass was estimated according to the equation proposed by Lee et al., [30]: Skeletal muscle mass ðkgþ¼ Ht m ð0:244 BMÞ þð7:8 Ht m Þ þ ð6:6 genderþ ð0:098 ageþ þ ðethnicity 3:3Þ Where: Ht m, height (m); BM, body mass (kg); gender: male = 1, female = 0; ethnicity: Asian = 1.4, African- American = 1.2, White = 0. Anthropometric variables Height and weight were measured for the calculation of the body mass index (BMI). All circumferences were obtained using non elastic tape, and measurements were obtained in triplicate and averaged to obtain the circumference score. Neck circumference was obtained with the subject sitting with the head in the Frankfort horizontal plane position. Briefly, a measuring tape was applied around the neck inferior to the laryngeal prominence and perpendicular to the long axis of the neck, while the minimal circumference was measured and recorded to the nearest 0.1 cm [31]. Waist circumference was measured at the midpoint between the lower rib margin and the (Yang et al., 2010). Body adiposity index (BAI) was determined by the following formula: (BAI = [(hip circumference)/((height)1.5) 18)] [32]. Volume of visceral fat The volume of visceral fat (VVF) was estimated using the predictive equation proposed by Petribu et al., [33] that uses as independent variables the waist-to-height ratio (WHtR) and fasting glucose (FG), as follows: VVF ¼ 130:941 þ ð198:673 WHtRÞ þ ð1:185 FGÞ; This equation was developed from a multiple regression analysis by adopting the ultrasonography as a reference standard.

41 Tibana et al. Diabetology & Metabolic Syndrome 2013, 5:11 Page 4 of 8 Blood pressure measurement Systolic (SBP), diastolic (DBP) and mean blood pressure (MBP) were measured before the initiation of the training program and four days after the RT was finished with an oscillometric device (Microlife 3 AC1-1, Widnau, Switzerland) according to the recommendations of the VI Brazilian Guidelines on Hypertension [25]. The cuff size was adapted to the circumference of the arm of each participant according to the manufacture s recommendations. SBP and DBP values were used to determine MBP according to the following equation: MBP ¼ DBP þ ½ðSBP DBPÞ=3Š Heart rate (HR) was measured by a HR monitor (Polar W S810i, Polar Electo Oy, Kempele, Finland). All blood pressure measures were assessed in triplicate (measurements separated by 1 min) with the mean value used for analysis. Biochemical parameters Participants reported to the laboratory between 08:00 10:00 am, after an overnight fast, for blood withdrawal from the antecubital vein. Plasmatic triglycerides, HDLcholesterol and glucose levels were measured by enzymatic CHOP-POD, homogeneous HDL-cholesterol and Hexokinase methods, respectively. Plasma insulin concentration was measured using a Roche Diagnostics Elecsys 2010 system (Roche Diagnostics, Indianapolis, IN, USA) by the sandwich principle. Glycated hemoglobin (HbA1c) was measured by turbidimetric immunoinhibition on an LX20 analyzer (Beckman Instruments, Brea, CA, USA). Resistance training program Subjects completed two weeks of familiarization prior to the RT program. In the familiarization weeks individuals:they were advised regarding proper RT technique and completed 3 sessions/week, with one exercise of each main muscle group consisting of 3 sets of submaximal repetitions. After the familiarization period subjects initiated The RT program consisting of 3 sessions/week during eight weeks. RT machines were from JOHNSON (Landmark Drive, Cottage Grove, USA). All training sessions were carefully supervised by three experienced professionals (ratio of supervision 1:2 1 professor for 2 participants). Participants were required to complete at least 85% of the exercise sessions. No major complications or cardiac events occurred during the study period. Figure 2 shows the exercise order that was strictly followed. The RT was divided into A (Monday) and B (Tuesday) and whole body (Friday) regiments. Abdominal crunches (three sets of 15 repetitions in all sessions) were included. For all listed exercises, three sets with 8 12 RM were performed, with a one-minute rest interval between Figure 2 Division of the RT sessions throughout the study. For all exercises, 3 sets of 8 12 repetitions maximum were performed with 1-minute rest interval between each set and exercise. each set and exercise. Training loads were monitored each session according to the increase in muscle capacity of the participants. The mean duration to complete one repetition was 3 4 s (both concentric and eccentric phases of the movement) and training sessions lasted min. The number of repetitions and the loads used for each exercise session were recorded. The loads were updated when necessary to keep the number of repetitions within the same range of RM and to provide a progressive overload. Additionally, correct breathing patterns were instructed to avoid Valsalva maneuver. Statistical analysis Data are reported as means ± standard deviation (SD). The normal distribution of the data was checked using The Shapiro-Wilk normality test and a homoscedasticity test (Mauchly). The pre and post-intervention variables were compared by using paired Student s t-test and Wilcoxon test for the nonparametric data. In addition, the correlation between delta (post-pre) of muscle strength and thickness with delta (post-pre) of anthropometric and biochemical variables were checked by means of Spearman correlation. The magnitude of differences was verified by the effect size (ES) of Cohen with threshold values of 0.2 (small), 0.6 (moderate), 1.2 (large), and 2.0 (very large) considered. Significance level was set at P < Considering the variable muscle strength, the estimated sample size required would be of seven individuals for a Power of 80%. All data were analyzed using the Statistical Package for Social Sciences (SPSS, v.19, Chicago, IL). Results Subjects general characteristics are presented in Table 1. There were no statistically significant alterations after