Efeitos agudos do exercício físico contínuo e intervalado sobre a pressão arterial, controle autonômico cardíaco e reatividade pressórica em jovens com obesidade

Abstract

Changes in metabolic, hemodynamic and cardiac autonomic profiles due to increased obesity and reduced levels of physical activity have been observed in young adults in early adulthood, contributing to the early development of cardiovascular diseases. Different combinations of duration and intensity of physical exercise have been investigated regarding the acute benefits provided on blood pressure, blood pressure reactivity and cardiac autonomic modulation. Purpose: To compare the acute effects of moderate-intensity continuous exercise (MICE) and high intensity interval exercise (HIIE) on the hemodynamic and autonomic cardiac parameters of adult obese adults. Methods: Ten men obeses (23.0 ± 0.7 years, 32.8 ± 0.9 kg / M²) were submitted to two sessions of physical exercise and one control (CT) without exercise, characterized by 20 minutes of rest, a MICE lasting 30min at 50-60% of the reserve heart rate (HRR) and an HIIE session lasting 20min with 4 sets of 3min at 80-90% of the HRR 2min of active 2 min of active recovery at 15W, at 60 rpm, followed by 120min recovery, for assessment of systolic blood pressure (SBP), diastolic (DBP) and mean (MBP) at rest and every 10 min after exercise, as well, for analysis of heart rate variability (HRV) by the indices LnLFu.n. (Sympathetic activity), LnHFu.n. (Parasympathetic activity) and the LF / HF ratio (sympatho-vagal activity) (POLAR®RS800CX) analyzed at rest and every 5 minutes after exercise after rest and 30 min after the experimental session the CPT was performed with one hand immersion for 1 minute In a vessel with water maintained at 4 ° C, with BP analyzed in the pre-immersion (T0), and during immersion at 30 (T30) and 60 seconds (T60) and two minutes after hand withdrawal from the recipient (T180 seconds). Results: At rest, systolic blood pressure - SBP (126.55 ± 1.82 mmHg) and diastolic - DBP (78.08 ± 2.47 mmHg) was considered normal. In addition, the young had higher SBP and mean arterial pressure (MAP) in the T30 and T60, and in the T60 for the DBP at rest, while in the T60 they were higher in the DBP and in the T30 and T60 in the recovery MAP . In EI, SBP was higher in T30, and DBP and MAP were higher in T30 and T60 at rest, as SBP and MAP were higher in T30 and T60. Although during the recovery period there were fewer times when PA was significantly greater, no significant differences were observed in the BP values of the corresponding moments of CPT between rest and recovery. After the HIIE, higher cardiac sympathetic nerve activity (ANS) was observed compared to the CT session, after elevation of the LnLFu.n index after HIIE (HIIE, 4.46 ± 0.04 vs. MICE: 4.09 ± 0 , 16, p = 0.042). In addition, there was only post-exercise hypotension (PEH) in the SBP at R70 (Δ-11 ± 2.0, p = 0.03) and R80 (Δ-8 ± 1.4, p = 0.02), And in MAP, R100 (Δ-7 ± 1.2, p = 0.03). The parasympathetic LnRMSSD index was restored to rest at R15 and R55 in session MICE and HIIE, respectively. In addition, higher HR and parasympathetic withdrawal (RMSSD index) was observed after HIIE. Conclusion: A single 30-min continuous exercise session at moderate intensity or a 20-min session of high-intensity interval exercise were not able to promote BP pressure reactivity attenuation. HIIE was able to promote PEH of greater magnitude and duration compared to MICE. The PEH occurred only after reestablishment of the parasympathetic indices and almost complete recovery of the HR, late in the HIIE session.