Treinamento misto em circuito: estresse fisiológico e seus efeitos sobre a rigidez arterial em indivíduos com histórico de acidente vascular cerebral.

Abstract

This thesis is composed of two studies addressing the mixed circuit training (MCT) physiological strain and its effects on arterial stiffness in people after stroke. The physiological strain study aims: (i) to investigate the intensity (%HRR and %VO2R) and energy expenditure (kcal) induced by a single MCT bouts; (ii) to investigate the between-day reproducibility of the variations of the measurements after the MCT bouts. Effects on arterial stiffness study aims: (i) to investigate the effects of a MCT bout on the laboratory variables of arterial stiffness and on the ambulatory arterial stiffness index (AASI); (ii) to investigate the between-day reproducibility of the variations of arterial stiffness measurements after MCT bouts. Seven participants (58 ± 12 yr) performed a CPET, a non-exercise control session (CTL), and two bouts of MCT on separate days in a randomized counterbalanced order. The MCT included 3 circuits of 10 resistance exercises at 15-repetition maximum intensity, with each set of resistance exercise interspersed with 45-s of walking. Expired gases were collected during the MCT and CTL and for 40 min afterwards. Brachial-radial pulse wave velocity (br-PWV), radial artery compliance (AC) and reflection index (RI1,2) were assessed 10 min before and 60 min after CTL and MCT. AASI was calculated from 24-h recovery ambulatory blood pressure monitoring. Results from the physiological strain study: Mean %VO2R (1st MCT: 51.1%, P=0.037; 2nd MCT: 54.0%, P=0.009) and %HRR (1st MCT: 66.4%, P=0.007; 2nd MCT: 67.9%, P=0.010) exceeded the recommended minimum intensity of 40%. Both %VO2R (P=0.586 and 0.987, respectively) and %HRR (P=0.681 and 0.237, respectively) during the 1st and 2nd bouts of MCT were not significantly different to their corresponding GET values. Mean net total energy expenditure significantly exceeded the minimum recommend energy expenditure in the 1st (192 kcal, P=0.048) and 2nd (201 kcal, P=0.023) bouts of MCT. Between-day reproducibility for %HRR, %VO2R, and energy expenditure were excellent (ICC2,1: 0.92-0.97). Results from the effects on arterial stiffness study: Compared to CTL, at 60 min of recovery from the 1st and 2nd bouts of MCT, lower values were observed for br-PWV (mean diff = -3.9 and -3.7 m/s, respectively, P < 0.01; ICC2,1 = 0.75) and RI1,2 (mean diff = -16.1 and -16.0 %, respectively, P < 0.05; ICC2,1 = 0.83) concomitant with higher AC (mean diff = 1.2 and 1.0 × 10-6 cm5/dyna, respectively, P < 0.01; ICC2,1 = 0.40). The 24-h AASI was reduced after bouts of MCT vs. CTL (1st and 2nd bouts of MCT vs. CTL: mean diff = -0.32 and -0.29 units, respectively, P < 0.001; ICC2,1 = 0.64). Conclusions: MCT elicit exercise intensities and energy expenditures recommended for improving health-related fitness in people after stroke and these responses demonstrated excellent between-day reproducibility. A single bout of MCT reduces arterial stiffness during laboratory (60 min) and ambulatory (24 h) recovery phases in this population with moderate-to-high between-day reproducibility.