Myocardial Infarction and Exercise Training: Evidence from Basic Science.

In 2016, cardiovascular disease remains the first cause of mortality worldwide [1]. Coronary artery disease, which is the most important precursor of myocardial infarction (MI), is the main component of total cardiovascular mortality, being responsible for approximately seven million of deaths [1]. In approximately 20% of infarcted patients, MI is recurrent in the first year after the event [2]. Moreover, among cardiovascular disease, coronary artery disease accounts for the most increased index of life years lost due to morbidity and/or mortality [1]. Sedentarism highly contributes to cardiovascular disease burden, especially for coronary artery disease, and is also one of the MI risk factors [3]. For many years, it was recommended to avoid physical activity after a cardiovascular event; nowadays, it is a consensus that exercise training (ET) should be part of cardiac rehabilitation programs. There is increasing evidence confirming that, when adequately prescribed and supervised, ET after MI can prevent future complications and increase the quality of life and longevity of infarcted patients [4, 5]. ET after MI follows international specialized guidelines; however, there are different protocols adopted by several societies worldwide in cardiac rehabilitation [6], and there is still lack of information on which type and regimen of exercise may be the ideal after MI, as well as how these exercises act to promote beneficial effects to cardiovascular and other organic systems. Thus, experimental studies are important contributors to elicit mechanisms behind clinical results, and to test and compare different ET protocols. Therefore, exercise prescription can be optimized, individualized, and safely practiced by patients. In this chapter, we present a brief review of MI pathophysiology followed by an updated discussion of the most relevant discoveries regarding ET and MI in basic science.

Cardioprotection afforded by exercise training prior to myocardial infarction is associated with autonomic function improvement.

BACKGROUND: It has been suggested that exercise training (ET) protects against the pathological remodeling and ventricular dysfunction induced by myocardial infarction (MI). However, it remains unclear whether the positive adjustments on baroreflex and cardiac autonomic modulations promoted by ET may afford a cardioprotective mechanism. The aim of this study was to evaluate the effects of aerobic ET, prior to MI, on cardiac remodeling and function, as well as on baroreflex sensitivity and autonomic modulation in rats. METHODS: Male Wistar rats were divided into 4 groups: sedentary rats submitted to Sham surgery (C); trained rats submitted to Sham surgery (TC); sedentary rats submitted to MI (I), trained rats submitted to MI (TI). Sham and MI were performed after ET period. After surgeries, echocardiographic, hemodynamic and autonomic (baroreflex sensitivity, cardiovascular autonomic modulation) evaluations were conducted. RESULTS: Prior ET prevented an additional decline in exercise capacity in TI group in comparison with I. MI area was not modified by previous ET. ET was able to increase the survival and prevent additional left ventricle dysfunction in TI rats. Although changes in hemodynamic evaluations were not observed, ET prevented the decrease of baroreflex sensitivity, and autonomic dysfunction in TI animals when compared with I animals. Importantly, cardiac improvement was associated with the prevention of cardiac autonomic impairment in studied groups. CONCLUSIONS: Prior ET was effective in changing aerobic capacity, left ventricular morphology and function in rats undergoing MI. Furthermore, these cardioprotective effects were associated with attenuated cardiac autonomic dysfunction observed in trained rats. Although these cause-effect relationships can only be inferred, rather than confirmed, our study suggests that positive adaptations of autonomic function by ET can play a vital role in preventing changes associated with cardiovascular disease, particularly in relation to MI.

Multicomponent Exercise Improves Hemodynamic Parameters and Mobility, but Not Maximal Walking Speed, Transfer Capacity, and Executive Function of Older Type II Diabetic Patients.

The present study aimed to investigate the effects of a 6-month multicomponent exercise program (MCEP) on functional, cognitive, and hemodynamic parameters of older Type 2 diabetes mellitus (T2DM) patients. Moreover, additional analyses were performed to evaluate if T2DM patients present impaired adaptability in response to physical exercise when compared to nondiabetic volunteers. A total of 72 T2DM patients and 72 age-matched healthy volunteers (CG) were recruited and submitted to functional, cognitive, and hemodynamic evaluations before and after six months of a MCEP. The program of exercise was performed twice a week at moderate intensity. Results indicate T2DM and nondiabetic patients present an increase in mobility (i.e., usual walking speed) after the MCEP. However, improvements in maximal walking speed, transfer capacity, and executive function were only observed in the CG. On the other hand, only T2DM group reveals a marked decline in blood pressure. In conclusion, data of the current study indicate that a 6-month MCEP improves mobility and reduce blood pressure in T2DM patients. However, maximal walking speed, transfer capacity, and executive function were only improved in CG, indicating that T2DM may present impaired adaptability in response to physical stimulus.

Multicomponent exercise decreases blood pressure, heart rate and double product in normotensive and hypertensive older patients with high blood pressure.

OBJECTIVE: The present study aimed to investigate the effects of a 6-month multicomponent exercise program on blood pressure, heart rate, and double product of uncontrolled and controlled normotensive and hypertensive older patients. METHODS: The study included 183 subjects, 97 normotensives, of which 53 were controlled normotensives (CNS), and 44 uncontrolled normotensives (UNS), as well as 86 hypertensives, of which 43 were controlled hypertensives (CHS), and 43 uncontrolled hypertensives (UHS). Volunteers were recruited and blood pressure and heart rate measurements were made before and after a 6-month multicomponent exercise program. The program of physical exercise was performed twice a week for 26 weeks. The physical exercises program was based on functional and walking exercises. Exercise sessions were performed at moderate intensity. RESULTS: The results indicated that UHS showed a marked decrease in systolic (-8.0mmHg), diastolic (-11.1mmHg), mean (-10.1mmHg), and pulse pressures, heart rate (-6.8bpm), and double product (-1640bpmmmHg), when compared to baseline. Similarly, diastolic (-5.5mmHg) and mean arterial (-4.8mmHg) pressures were significantly decreased in UNS. Concomitantly, significant changes could be observed in the body mass index (-0.9kg/m2; -1.5kg/m2) and waist circumference (-3.3cm; only UHS) of UNS and UHS, which may be associated with the changes observed in blood pressure. CONCLUSIONS: In conclusion, the data of the present study indicate that a 6-month multicomponent exercise program may lead to significant reductions in blood pressure, heart rate, and double product of normotensive and hypertensive patients with high blood pressure values.

Low blood pressure is sustained during subsequent activities of daily living performed after power training in older women.

The present study aimed to examine the effects of a prior session of power training on blood pressure values during tasks that mimic the activities of daily living in hypertensive and normotensive older women. A randomized crossover experimental design was used for this study. Eleven older women (age, 66.1±1.2 years; body mass index, 26.7±4.8 kg/m2; systolic blood pressure, 133.9±23.4 mmHg) were recruited to participate. Volunteers were randomly underwent to a single session of physical exercise equalized by training volume, characterized by 3 sets of 8-10 repetitions in 8 different exercises. However, Power training session was performed at a higher intensity (moderate) than Sham session (rest/very, very easy ). Immediately after the end of the exercise session, subjects were assigned to perform five tasks that mimic the activities of daily living. Hemodynamic parameters were recorded before and immediately after the session of physical exercise, as well as in the end of each of the tasks. Results demonstrated significant elevations in systolic blood pressure and pulse pressure values during the performance of the tasks after the Sham session. However, values were not altered in the power training session. Data of the present study indicate that an acute session of power training can maintain blood pressure values lower during the subsequent performance of tasks that mimic activities of daily living in older women.

Effects of Multicomponent Exercise on Functional and Cognitive Parameters of Hypertensive Patients: A Quasi-Experimental Study.

Purpose. The present study aimed to investigate the impact of a 6-month multicomponent exercise program (MCEP) on physical function and cognitive parameters of normotensive (NTS) and hypertensive (HTS) older patients and verify if age can influence the adaptations in response to the exercise. Methods. A total of 218 subjects, 101 NTS and 117 HTS, were recruited and underwent functional and cognitive evaluations before and after six months of a MCEP. The program of exercise was performed twice a week, for 26 weeks. The physical exercises were thought to mimic the activities of daily living and, therefore, aggregated functional and walking exercises. Exercise sessions were performed at moderate intensity. Results. Data indicated that HTS and NST patients showed a similar increase in the performance of walking speed test and one-leg stand test after the MCEP. Regarding age, results did not show differences in the magnitude of adaptations between old and young HTS and NTS patients. Conclusions. Data of the present study indicated that a 6-month MCEP was able to increase equally balance and mobility in NTS and HTS patients. Moreover, data demonstrated that aging did not seem to impair the capacity to adapt in response to exercise in both groups.

Effects of inspiratory muscle exercise in the pulmonary function, autonomic modulation, and hemodynamic variables in older women with metabolic syndrome.

The aim of the present study was to investigate the effects of inspiratory muscle exercise (IME) on metabolic and hemodynamic parameters, cardiac autonomic modulation and respiratory function of older women with metabolic syndrome (MS). For this, sixteen older women with MS and 12 aged-matched controls participated of the present study. Two days before and 2 days after the main experiment, fasting blood samples (i.e., total cholesterol, triglycerides and blood glucose), cardiac autonomic modulation (i.e., heart rate variability), and respiratory muscle function were obtained and evaluated. The sessions of physical exercise was based on a IME, which was performed during 7 days. Each session of IME was performed during 20 min, at 30% of maximal static inspiratory pressure. In the results, MS group presented higher levels of triglycerides, blood glucose, and systolic blood pressure when compared to control group. IME was not able to change these variables. However, although MS group showed impaired respiratory muscle strength and function, as well as cardiac autonomic modulation, IME was able to improve these parameters. Thus, the data showed that seven days of IME are capable to improve respiratory function and cardiac autonomic modulation of older women with MS. These results indicate that IME can be a profitable therapy to counteracting the clinical markers of MS, once repeated sessions of acute IME can cause chronical alterations on respiratory function and cardiac autonomic modulation.

Resistance training after myocardial infarction in rats: its role on cardiac and autonomic function.

BACKGROUND: Although resistance exercise training is part of cardiovascular rehabilitation programs, little is known about its role on the cardiac and autonomic function after myocardial infarction. OBJECTIVE: To evaluate the effects of resistance exercise training, started early after myocardial infarction, on cardiac function, hemodynamic profile, and autonomic modulation in rats. METHODS: Male Wistar rats were divided into four groups: sedentary control, trained control, sedentary infarcted and trained infarcted rats. Each group with n = 9 rats. The animals underwent maximum load test and echocardiography at the beginning and at the end of the resistance exercise training (in an adapted ladder, 40% to 60% of the maximum load test, 3 months, 5 days/week). At the end, hemodynamic, baroreflex sensitivity and autonomic modulation assessments were made. RESULTS: The maximum load test increased in groups trained control (+32%) and trained infarcted (+46%) in relation to groups sedentary control and sedentary infarcted. Although no change occurred regarding the myocardial infarction size and systolic function, the E/A ratio (-23%), myocardial performance index (-39%) and systolic blood pressure (+6%) improved with resistance exercise training in group trained infarcted. Concomitantly, the training provided additional benefits in the high frequency bands of the pulse interval (+45%), as well as in the low frequency band of systolic blood pressure (-46%) in rats from group trained infarcted in relation to group sedentary infarcted. CONCLUSION: Resistance exercise training alone may be an important and safe tool in the management of patients after myocardial infarction, considering that it does not lead to significant changes in the ventricular function, reduces the global cardiac stress, and significantly improves the vascular and cardiac autonomic modulation in infarcted rats.

Protective effects of accumulated aerobic exercise in infarcted old rats / Efeitos protetores do exercício aeróbio acumulado em ratos idosos infartados

Background: Aerobic exercise exerts cardioprotective effects on myocardial infarction. However, there is lack of information about the possible protective effects of continuous or accumulated aerobic exercise performed prior to myocardial infarction in aging. Objective: To evaluate the preventive effects of continuous or accumulated aerobic exercise on physical capacity, pulmonary congestion and ventricular weight in rats submitted to myocardial infarction. Methods: Old male Wistar rats were divided into four groups: sham control, sedentary infarcted, continuous aerobic exercise submitted to myocardial infarction, and accumulated aerobic exercise submitted to myocardial infarction. Body weight and maximum speed were evaluated at the beginning and at the end of the protocol. Trained groups performed continuous (1 h a day) or accumulated (30 minutes in the morning and 30 minutes in the afternoon) exercise. All groups, except the sham control, were submitted to myocardial infarction surgery at the end of the protocol. Heart, skeletal muscles, as well as wet and dry lung were weighed. The significance level in statistical analysis was established at p < 0.05. Results: Both continuous and accumulated exercise caused an increase in physical capacity in rats, as well as prevented its further impairment after myocardial infarction, and in the accumulated exercise group this prevention was greater. The continuous exercise group demonstrated an increase in lung water content, while the accumulated exercise group presented a reduction in body weight and an increase in left ventricle relative weight. Conclusion: In conclusion, the data of the present study indicate that accumulated aerobic exercise present a better protective effect than continuous aerobic training in the context of myocardial infarction and aging

Multicomponent exercise decreases blood pressure, heart rate and double product in normotensive and hypertensive older patients with high blood pressure / El ejercicio multicomponente disminuye los parámetros hemodinámicos en pacientes ancianos normotensos e hipertensos no controlados

Abstract Objective: The present study aimed to investigate the effects of a 6-month multicomponent exercise program on blood pressure, heart rate, and double product of uncontrolled and controlled normotensive and hypertensive older patients. Methods: The study included 183 subjects, 97 normotensives, of which 53 were controlled normotensives (CNS), and 44 uncontrolled normotensives (UNS), as well as 86 hypertensives, of which 43 were controlled hypertensives (CHS), and 43 uncontrolled hypertensives (UHS). Volunteers were recruited and blood pressure and heart rate measurements were made before and after a 6-month multicomponent exercise program. The program of physical exercise was performed twice a week for 26 weeks. The physical exercises program was based on functional and walking exercises. Exercise sessions were performed at moderate intensity. Results: The results indicated that UHS showed a marked decrease in systolic (−8.0 mmHg), diastolic (−11.1 mmHg), mean (−10.1 mmHg), and pulse pressures, heart rate (−6.8 bpm), and double product (−1640 bpm mmHg), when compared to baseline. Similarly, diastolic (−5.5 mmHg) and mean arterial (−4.8 mmHg) pressures were significantly decreased in UNS. Concomitantly, significant changes could be observed in the body mass index (−0.9 kg/m2;−1.5 kg/m2) and waist circumference (−3.3 cm; only UHS) of UNS and UHS, which may be associated with the changes observed in blood pressure. Conclusions: In conclusion, the data of the present study indicate that a 6-month multicomponent exercise program may lead to significant reductions in blood pressure, heart rate, and double product of normotensive and hypertensive patients with high blood pressure values.

Resumen Objetivo: El presente estudio tuvo como objetivo investigar los efectos de un programa de ejercicios multicomponente de 6 meses sobre la presión arterial, la frecuencia cardíaca y el doble producto de pacientes mayores hipertensos y normotensos (incontrolados y controlados). Método: 183 sujetos, 97 normotensos - 53 normotensos controlados (SNC) y 44 normotensos no controlados (SNU) - y 86 hipertensos - 43 hipertensos controlados (CHS) y 43 hipertensos no controlados (UHS) -, fueron reclutados y sometidos a evaluaciones (presión arterial y frecuencia cardíaca) antes y después de un programa de ejercicios multicomponente de 6 meses. El programa de ejercicio se realizó dos veces por semana durante 26 semanas. El programa de ejercicios físicos se basó en ejercicios funcionales y de caminar. Las sesiones de ejercicio se realizaron a intensidad moderada. Resultados: Los resultados indicaron que UHS presentó una marcada disminución en presión sistólica (−8.0 mmHg), diastólica (−11.1 mmHg), media (−10.1 mmHg) y de pulso, frecuencia cardíaca (−6.8 lpm) y doble producto (−1640 lpm mmHg) cuando se compara con la línea base. De manera similar, las presiones diastólica (−5.5 mmHg) y arterial media (−4.8 mmHg) se redu- jeron significativamente en los SNU. Concomitantemente, fue posible observar alteraciones significativas en el índice de masa corporal (−0.9 kg/m2; −1.5 kg/m2) y circunferencia de cintura (−3.3 cm, solo UHS) de UNS y UHS, lo que puede estar asociado con los cambios observados en la presión arterial. Conclusiones: En conclusión, los datos del presente estudio indican que un programa de ejercicio multicomponente de 6 meses puede provocar reducciones significativas en la presión arterial, frecuencia cardíaca y doble producto de pacientes normotensos e hipertensos con valores de presión arterial alta.

Exercise training on cardiovascular diseases: Role of animal models in the elucidation of the mechanisms

Abstract Cardiovascular diseases, which include hypertension, coronary artery disease/myocardial infarction and heart failure, are one of the major causes of disability and death worldwide. On the other hand, physical exercise acts in the preventionand treatment of these conditions. In fact, several experiments performed in human beings have demonstrated the efficiency of physical exercise to alter clinical signals observed in these diseases, such as high blood pressure and exercise intolerance. However, even if human studies demonstrated the clinical efficiency of physical exercise, most extensive mechanisms responsible for this phenomenon still have to be elucidated. In this sense, studies using animal models seem to be a good option to demonstrate such mechanisms. Therefore, the aims of the present study are describing the main pathophysiological characteristics of the animal models used in the study of cardiovascular diseases, as well as the main mechanismsassociated with the benefits of physical exercise.(AU)

POWERLIFTING: Entendendo a modalidade / POWERLIFTING: Understanding the modality

O objetivo do presente estudo foi entender a modalidade powerlifting associada aos aspectos morfofuncionais que envolvem a modalidade. Para isso, foi realizada uma revisão bibliográfica com busca de artigos que tratavam da modalidade powerlifting associada às respostas morfológicas e neuromusculares. Foram selecionados artigos nacionais e internacionais, retirados das bases de dados: Medline, SciELO, PUBMED, Ebsco e Portal Periódicos Capes entre 2000 a 2013. As palavras-chave utilizadas em português e inglês foram: powerlifting, powerlifting and training, weight training, powerlifting and anthropometrics. Livros texto básicos também foram inseridos para complemento das informações. Os principais achados demonstraram que as variáveis antropométricas (massa corporal, estatura, adiposidade) e disposição corporal (arquitetura) podem influenciar no desempenho do atleta. Assim como as magnitudes de força podem auxiliar no desempenho dos atletas de powerlifting, existe um equilíbrio entre volume e intensidade com o objetivo de desenvolvimento de força com baixas alterações morfológicas. Dessa forma, o presente estudo realizou uma breve revisão da modalidade que pode auxiliar atletas e técnicos no entendimento das melhorias neuromusculares e nas respostas morfológicas relacionadas à modalidade.(AU)

The aim of this study was to understand powerlifting sport associated with morphofunctional aspects involving modality. For this, were a literature review search articles dealing with the powerlifting sport associated morphological and neuromuscular responses was performed. National and international articles drawn from the databases were selected: Medline, SciELO, PubMed, Ebsco and Portal Periodicos Capes between 2000-2013. The keywords used in Portuguese and English were: powerlifting, powerlifting and training, weight training, powerlifting and anthropometrics. Basic textbooks were also inserted to supplement the information. The main findings showed that the anthropometric variables (weight, height, body fat) and body disposal (architecture) can influence the performance of the athlete. As the magnitudes of force can assist the performance of athletes in powerlifting, there is a balance between volume and intensity with the aim of developing strength with low morphological changes. Thus, this study conducted a brief review of the modality that can help athletes and coaches in understanding the neuromuscular improvements and morphological responses related to the modality.(AU)

Resistance Training After Myocardial Infarction in Rats: Its Role on Cardiac and Autonomic Function / Treinamento Resistido Após Infarto do Miocárdio em Ratos: Papel na Função Cardíaca e Autonômica

Background: Although resistance exercise training is part of cardiovascular rehabilitation programs, little is known about its role on the cardiac and autonomic function after myocardial infarction. Objective: To evaluate the effects of resistance exercise training, started early after myocardial infarction, on cardiac function, hemodynamic profile, and autonomic modulation in rats. Methods: Male Wistar rats were divided into four groups: sedentary control, trained control, sedentary infarcted and trained infarcted rats. Each group with n = 9 rats. The animals underwent maximum load test and echocardiography at the beginning and at the end of the resistance exercise training (in an adapted ladder, 40% to 60% of the maximum load test, 3 months, 5 days/week). At the end, hemodynamic, baroreflex sensitivity and autonomic modulation assessments were made. Results: The maximum load test increased in groups trained control (+32%) and trained infarcted (+46%) in relation to groups sedentary control and sedentary infarcted. Although no change occurred regarding the myocardial infarction size and systolic function, the E/A ratio (-23%), myocardial performance index (-39%) and systolic blood pressure (+6%) improved with resistance exercise training in group trained infarcted. Concomitantly, the training provided additional benefits in the high frequency bands of the pulse interval (+45%), as well as in the low frequency band of systolic blood pressure (-46%) in rats from group trained infarcted in relation to group sedentary infarcted. Conclusion: Resistance exercise training alone may be an important and safe tool in the management of patients after myocardial infarction, considering that it does not lead to significant changes in the ventricular function, reduces the global cardiac stress, and significantly improves the vascular and cardiac autonomic modulation in infarcted rats. .

Fundamento: Embora o treinamento físico resistido esteja inserido nos programas de reabilitação cardiovascular, pouco se sabe sobre seu papel isolado na função cardíaca e autonômica após o infarto do miocárdio. Objetivo: Avaliar os efeitos do treinamento físico resistido iniciado precocemente após o infarto do miocárdio na função cardíaca, no perfil hemodinâmico e na modulação autonômica de ratos. Métodos: Ratos Wistar machos foram divididos em Grupos Controle Sedentário, Controle Treinado, Infartado Sedentário e Infartado Treinado. Cada grupo foi composto por 9 ratos. Os animais realizaram o teste de carga máxima e a ecocardiografia ao início e ao final do treinamento físico resistido (em escada adaptada, 40 a 60% do teste de carga máxima, 3 meses, 5 dias/semana). Ao final, foram realizadas avaliações hemodinâmicas, de sensibilidade barorreflexa e da modulação autonômica. Resultados: O teste de carga máxima aumentou nos Grupos Controle Treinado (+32%) e Infartado Treinado (+46%) em relação aos Grupos Controle Sedentário e Infartado Sedentário. Embora a área de infarto do miocárdio e a função sistólica não tenham sido alteradas, a relação E/A (-23%), o índice de desempenho miocárdico (-39%) e a pressão arterial sistólica (+6%) foram melhorados pelo treinamento físico resistido no Grupo Infartado Treinado. Paralelamente, o treinamento induziu os grupos a benefícios adicionais nas bandas de alta frequência do intervalo de pulso (+45%), bem como a banda de baixa frequência da pressão arterial sistólica (-46%) nos ratos do Grupo Infartado Treinado em relação aos do Infartado Sedentário. Conclusão: O treinamento físico resistido dinâmico ...