Efeito da privação parcial do sono e do exercício intervalado de alta intensidade sobre a pressão arterial e modulação autonômica cardíaca em jovens com diferentes níveis de atividade física

Abstract

Introduction: Sleep deprivation is a recurrent practice in modern society and associated with low levels of physical activity, predisposes the population to cardiovascular morbidity and mortality. On the other hand, the level of physical activity can be a protective factor Against the deleterious effects of sleep deprivation, since the practice of regular physical activity promotes an improvement in cardiorespiratory and metabolic health, improving physical conditioning. Objectives: To evaluate in normotensive young people with different levels of physical activity the responses of blood pressure and cardiac autonomic activity to a night of partial sleep deprivation and the impact of a session of High Intensity Interval Exercise (HIIE). Methods: 13 young people (24.6 ± 3.7 years old) classified as Low Physical Activity Level (LPAL) and 12 young people (age 24.1 ± 2.6 years old) with Moderate / High Physical Activity Level (MHPAL) were evaluated who randomly underwent four experimental sessions: two nights with habitual sleep (HS+ control session and HS + HIIE) and two nights with partial sleep deprivation (PSD + control session and PSD + HIIE ). The HIIE consisted of 10 stimuli / passive recovery (without exercise) from 1: 1min to 92% of HRmax. All participants underwent exercise testing, accelerometry and anthropometric assessment, ambulatory blood pressure assessment and ECG before and after the session. Holter was used to assess cardiac autonomic modulation during sleep. Partial sleep deprivation was performed using 50% of each participant's usual sleep time. The data were tabulated in Excel and SPSS (Statistical Package for the Social Sciences, IBM®). BP values and cardiac autonomic modulation were assessed using the t test, Mann Whitney U test or Wilcoxon test in order to assess the magnitude of the differences between sessions (post vs. pre) and between sessions (post vs. post). The logarithmic transformation was used in the absolute components of the high (HF) and low frequency (LF) band of the heart rate. The level of statistical significance was set at p≤0.05 and the size of the effect (Cohen d). Results: There was a significant difference for the 24-hour DBP only between the groups in the exercise session (MHPAL -2mmHg vs. LPAL 1mmHg, p = 0.05; d = 0.56). The HS + HIIE session promoted better post-exercise hypotension responses (PEH) in the MHPAL group for 60 minutes, wakefulness, sleep and 24 hours in SBP and DBP (p> 0.05), similar response in SBP in sleep was observed in session PSD + HIIE (p = 0.012; d = 1.12) and 24 hours (p = 0.04; d = 0.85). For intergroup comparison, the MHPAL group showed greater reductions for SBP and DBP in sleep (-8mmHg vs. -1mmHg, p = 0.039; d = 0.94; -5mmHg vs. 4mmHg, p = 0.050; d = 0.97, respectively) and DBP 24 hours (-4mmHg vs. 1mmHg, p = 0.05; d = 0.56). In the cardiac autonomic evaluation, we identified an increase in SDNN in restorative sleep both in the session with PSD and in the session with HS (p≤0.05). The MHPAL group showed a reduction in cardiac autonomic balance in sessions with SH (LF / HF, ∆ = -0.7, p = 0.028; d = 0.51) and PSD (LF / HF, ∆ = -0.8, p = 0.026; d = 0.71) during restorative sleep, differently not observed in the LPAL group (p> 0.05). Conclusion: Young people with MHPAL when performing an HIIE session with private sleep partially show decreases in SBP and DBP during restorative sleep and in 24-hour SBP. These pressure responses may contribute to a reduction in sympathetic activity and an increase in heart rate variability.