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Night physical exercises bring more cardiac benefits to hypertensive patients

Publicado em 06 outubro 2021

Physical activity provides many benefits to hypertensive individuals. But it can be significantly enhanced if the exercises are practiced at night, between 18:00 and 21:00. This is shown by a study published in the journal Blood Pressure Monitoring, which focused on the cardiac recovery rate (CRT), that is, the measure of heart rate reduction after activity interruption.

Comparing the responses of 49 middle-aged hypertensive men medicated for at least four months with the same type of drug to structured aerobic workouts performed in the morning and evening for ten weeks, the analysis concluded that night training improved the rapid phase so much. (measured 60 seconds after the peak of physical effort) as the slow phase (measured 300 seconds later) of CRT.

According to Leandro Campos de Brito, a postdoctoral fellow who conducted the research under the guidance of Professor Cláudia Lúcia de Moraes Forjaz, from the School of Physical Education and Sport at the University of São Paulo (EEFE-USP), the results showed that approximately 25% of the people do not adapt to exercise to control pressure and therefore need different strategies like this one to exercise at times that can increase the benefits. “There are two branches in the cardiac autonomic system: the sympathetic, which makes the heart slow down and the parasympathetic, which makes it beat harder. It is expected that, after a period of training with physical exercises, the power of the parasympathetic will increase [coração mais relaxado] and that of the sympathetic one decreases”, said Brito.

For the experiment, the volunteers were randomly allocated into three groups: the morning training, between 7:00 and 9:00, the night training, between 18:00 and 21:00 and the control group (no aerobic training). The practice was performed three times a week for ten weeks, in which the first two groups pedaled the ergometric bicycle for 30 minutes in the first two weeks and 45 minutes in the others, with moderate intensity and the control group stretched for 30 minutes. In the initial and final evaluations of the study, the heart recovery rate of the volunteers was measured 60 and 300 seconds after the end of the exercise. “The TRC allows us to infer how this behavior occurs, through the measurement performed in the first 60 seconds [resposta tipicamente parassimpática] and 300 seconds after the end of a maximal cardiopulmonary effort test, with the latter response suggesting both the action of the parasympathetic nerve, recovering the heart beat, and the sympathetic deceleration, whose activity was accumulated during exercise”, completes the researcher, who wanted to precisely assess the chronic effect of the activity for cardiovascular benefits in general.

This also included CRT responses as a measure of heart rate reduction after exercise cessation. It is a variable capable of providing a marker of the autonomic mechanisms that regulate the functioning of the heart. According to the researchers, the fact that the two phases – fast and slow – of CRT have increased with night training indicates that practicing activities at this time improves both branches of the cardiac autonomic system (parasympathetic and sympathetic). The results also show that the beneficial effect is not limited to the moment the participants practiced the exercises. “We evaluated people in the morning and at night and those who trained at night showed better results in both evaluations”, concludes Brito. But he warns. “It’s important to say that when it comes to exercising, anytime is better than notime. In other words: it is necessary to exercise. What we tried in this work was to maximize the responses.”

With FAPESP Agency