Exercise and vascular adaptation in asymptomatic humans

Item does not contain fulltextBeneficial effects of exercise training on the vasculature have been consistently reported in subjects with cardiovascular risk factors or disease, whereas studies in apparently healthy subjects have been less uniform. In this review, we examine evidence pertaining to the impact of exercise training on conduit and resistance vessel function and structure in asymptomatic subjects. Studies of arterial function in vivo have mainly focused on the endothelial nitric oxide dilator system, which has generally been shown to improve following training. Some evidence suggests that the magnitude of benefit depends upon the intensity or volume of training and the relative impact of exercise on upregulation of dilator pathways versus effects of inflammation and/or oxidation. Favourable effects of training on autonomic balance, baroreflex function and brainstem modulation of sympathetic control have been reported, but there is also evidence that basal vasoconstrictor tone increases as a result of training such that improvements in intrinsic vasodilator function and arterial remodelling are counterbalanced at rest. Studies of compliance suggest increases in both the arterial and the venous sides of the circulation, particularly in older subjects. In terms of mechanisms, shear stress appears to be a key signal to improvement in vascular function, whilst increases in pulse pressure and associated haemodynamics during bouts of exercise may transduce vascular adaptation, even in vascular beds which are distant from the active muscle. Different exercise modalities are associated with idiosyncratic patterns of blood flow and shear stress, and this may have some impact on the magnitude of exercise training effects on arterial function and remodelling. Other studies support the theory that that there may be different time course effects of training on specific vasodilator and constrictor pathways. A new era of understanding of the direct impacts of exercise and training on the vasculature is evolving, and future studies will benefit greatly from technological advances which allow direct characterization of arterial function and structure

Efeito do exercício aeróbico e resistido no controle autonômico e nas variáveis hemodinâmicas de jovens saudáveis Effect of resistance and aerobic exercise on the autonomic control and hemodynamic variables in health young individuals

A prática de exercícios aeróbicos e resistidos provoca ajustes agudos e crônicos distintos. Já foram documentadas diferenças hemodinâmicas e musculares entre os exercícios; todavia, quanto aos ajustes autonômicos, os estudos são escassos e controversos. O objetivo deste estudo foi analisar as adaptações hemodinâmicas e autonômicas após uma sessão de exercício aeróbico (30 minutos, bicicleta ergométrica) e resistido (três séries de 12 repetições para os principais grupamentos musculares), em indivíduos jovens e saudáveis. Para tanto, utilizamos medidas da pressão arterial (PA), frequência cardíaca (FC), cálculo do duplo produto e análise da variabilidade da FC (VFC) nos domínios do tempo e da frequência e a Plotagem de Poincaré. Neste protocolo, a FC durante o exercício aeróbico foi maior do que no resistido (153,32 ± 2,76 vs. 143,10 ± 3,38 bpm, respectivamente). O exercício aeróbico gerou aumento da PA sistólica durante o exercício (7,25 ± 1,97 mmHg). Já o exercício resistido provocou aumento tanto da PA sistólica quanto da diastólica durante sua execução (14,83 ± 1,53; 11,92 ± 1,69 mmHg, respectivamente). Não foi observada hipotensão pós-exercício para nenhuma das sessões. Ao comparar o exercício aeróbico com o resistido na fase de recuperação, verificamos diminuição na VFC no resistido nas variáveis: RMSSD (37,74 ± 5,30 vs. 19,50 ± 2,32), NN50 (94,13 ± 23,65 vs. 27,63 ± 6,68), PNN50 (16,10 ± 4,72 vs. 3,53 ± 0,89), SD1 (26,65 ± 3,85 vs. 13,73 ± 1,66), SD2 (88,98 ± 10,71 vs. 61,88 ± 5,49) e HF (257,25 ± 45,08 vs. 102,75 ± 18,75 ms²). Concluiu-se que, para os protocolos investigados, o trabalho cardiovascular durante o exercício foi semelhante, resultando principalmente do aumento da FC no exercício aeróbico e do aumento da PAS no resistido. No período de recuperação, o exercício resistido promoveu maior alteração autonômica, compatível com manutenção do balanço simpatovagal aumentado.<br>The practice of aerobic and resistance exercises provokes distinct acute and chronic adjustments. Hemodynamic and muscular differences between both exercises have been already documented; nevertheless, regarding the autonomic adjustments, there are few and controversial studies. Therefore, the aim of this study was to analyze the hemodynamic and autonomic adaptations after one bout of aerobic exercise (30 minutes, ergometric bicycle) and resistance exercise (three series of 12 repetitions to the main muscle groups), in young and healthy individuals. For this purpose, blood pressure (BP) and heart rate (HR) were measured, as well as the calculation of the double product and analysis of heart rate variability in time and frequency domains and by Poincaré's Plot. In this protocol, HR during the aerobic exercise was higher than in the resistance exercise (153.32 ± 2.76 vs. 143.10 ± 3.38 bpm, respectively). Aerobic exercise caused an increase in systolic BP during the exercise (7.25 ± 1.52 mmHg) whereas resistance exercise provoked an increase in both, systolic and diastolic BP during its execution (14.83 ± 1.53; 11.92 ± 1.69 mmHg, respectively). Post-exercise hypotension was not observed after none of the exercise sessions. When comparing aerobic exercise with resistance exercise in the recovery phase, it was verified a decrease in HR variability in the resistance session for the following variables: RMMSD (37.74 ± 5.30 vs. 19.50 ± 2.32), NN50 (94.13 ± 23.65 vs. 27.63 ± 6.68), PNN50 (16.10 ± 4.72 vs. 3.53±0.89), SD1 (26.65 ± 3.85 vs. 13.73 ± 1.66), SD2 (88.98 ± 10.71 vs. 61.88 ± 5.49) e HF (257.25 ± 45.08 vs. 102.75 ± 18.75 ms²). In conclusion, in the investigated protocol, the cardiovascular work during the exercise sessions was similar, due to HR increase in the aerobic exercise and of systolic BP increase in the resistance exercise. In the recovery phase, resistance exercise promoted enhanced autonomic alteration, compatible with the maintenance if an increased sympatho-vagal balance