Associação entre concentrações séricas de cortisol, parâmetros autonômicos cardíacos e índices de rigidez arterial em indivíduos de meia idade e idosos praticantes do treinamento de força

Abstract

Adrenal function and aging have been the object of intense interest in recent years. Natural aging results in subtle changes in cortisol secretion. The increase in serum levels of this glucocorticoid with advancing age is able of develop several injury to the organism and exacerbating immunosenescence, which can extend to the endocrine and cardiovascular system, shown changes related to cardiac autonomic control and arterial stiffness. These changes, linked to the cardiovascular and endocrine systems, can be prevented, or when installed, optimized, for old man practitioners of exercise training, which is a non-pharmacological treatment method that benefits the functioning and integration of all physiological systems. The aim of this study was to assess the association between serum cortisol levels, cardiac autonomic modulation and arterial stiffness in old man practitioners of resistant training (RT). One hundred and twenty volunteers of both sexes were allocated in 4 groups (30 each group): sedentary (MAS) and trained middle age (MAT) aged of 40-59 yrs; sedentary (OAS) and trained old age (OAT) aged 60 or older yrs. Hemodynamic parameters, linear and non-linear analyses of heart rate variability (HRV), pulse wave velocity (PWV), augmention index (AIx), total vascular resistance (TVR) and concentrations of cortisol were measured at rest. Higher resting bradycardia was observed in both trained groups when compared to their respective sedentary groups (p <0.05). The OAS group had a higher HR at rest than MAT (p <0.01). The OAS obtained high values of systolic blood pressure, mean, pulse pressure (PP), PWV, AIx and TVR when compared to the other groups (p <0.05). When analyzing HRV, we observed that both trained groups showed greater vagal modulation and reduced cardiac sympathetic modulation when compared to their respective sedentary groups (p <0.05). It was also observed that the OAS show greater sympathetic activity and less vagal activity than both groups of middle-aged individuals (p <0.05). Serum cortisol concentrations were significantly lower in trained MA and OA groups compared to sedentary MA and OA groups (p <0.05). In this sense, the OAS obtained higher concentrations of cortisol compared to the other groups (p <0.05). There was a significant and negative correlation between serum cortisol levels and parasympathetic modulation (r = -0.411; p <0.001) and a significant and positive correlation between serum cortisol levels and cardiac sympathetic modulation (r = 0.393; p <0.001). In relation to arterial stiffness, a significant and positive correlation between cortisol concentrations and PWV (r = 0.359; p <0.001) and RVT (r = 0.389; p <0.001) was also observed. Our data allow us to conclude that resistance training performed by old man and middle-aged individuals reduces the concentration of cortisol, and this reduction is correlated with better HRV indices and arterial stiffness.