Morning or Evening? Research Shows When Exercise Produces Greater Benefits for Older Hypertensives

The regulation of the mechanism that compensates for blood pressure changes varies depending on the duration of physical exercise.

Nighttime aerobic exercise has been shown to be more beneficial in regulating blood pressure in older adults hypertensive compared to training done in the morning. Study conducted at the School of Physical Education and Sports of University of Sao Paulo (EEFE-USP) have identified that the reason is related to the better regulation of a mechanism that compensates for sudden changes in blood pressure known as baroreflex sensitivity.

“There are multiple mechanisms for regulating blood pressure, and although morning training was beneficial, it was only evening training that provided short-term improvements in blood pressure control by improving baroreflex sensitivity. This is important because, in addition to controlling the positive triggers of the baroreflex effects on blood pressure control, there are no drugs available to modulate this mechanism,” Leandro Campos de Brito, author of the study article published in The Journal of Physiology.

The work is the result of Brito’s post-doctoral project, supported by Fapesp and supervised by EEFE-USP professor Cláudia Lúcia de Moraes Forjaz.

In the experiment, 23 patients diagnosed and treated for hypertension were divided into two groups: morning or evening training. Over the course of ten weeks, both performed workouts 45 minutes of moderate intensity cycling, three times a week.

Important cardiovascular parameters, such as systolic and diastolic blood pressure (blood pressure in the vessels) and heart rate (heart rate), were analyzed after ten minutes of rest. The data were collected before and at least three days after the volunteers completed the ten weeks of training.

In addition, the researchers monitored the mechanisms of the autonomic nervous system, which functions involuntarily, controlling heartbeat and blood pressure, for example, as well as sympathetic muscle nervous activity (which regulates peripheral blood flow through the contraction or relaxation of vessels in muscle tissue) and sympathetic baroreflex sensitivity (assessment of blood pressure control through changes in sympathetic muscle activity).

Those who trained at night showed improvements in the four aspects analyzed: systolic and diastolic blood pressure, sympathetic baroreflex sensitivity, and muscle sympathetic nervous activity. Those who trained in the morning had no reduction in muscle sympathetic nervous activity, nor an improvement in systolic blood pressure or sympathetic baroreflex sensitivity.

“Nighttime training was more effective in promoting cardiovascular autonomic improvement and reducing blood pressure. This can be partly explained by the improvement in baroreflex sensitivity and the reduction in muscle sympathetic nervous activity, which were greater at night. For now, we only know that baroreflex control is crucial – at least from a cardiovascular point of view – for evening training to be more beneficial than morning training, since it is what triggers the other benefits analyzed. However, we still have a lot of progress to make in this understanding,” explains Brito, who is currently a professor at the Oregon Institute of Occupational Health Sciences at Oregon Health & Science University, in the United States, and continues to investigate the issue through studies on the circadian rhythm.

The researcher points out that the control of the baroreflex regulates each heartbeat and controls the autonomic activity of the body. “It is a mechanism linked to sensitive fibers, to deformations of the arterial walls, which are located in specific points, such as the aortic arch and the carotid body. In this way, when the pressure decreases, this region sends information to the area of ​​the brain that controls the autonomic nervous system, which in turn sends information to the heart to beat faster and to the arteries to contract more strongly. If the pressure increases, it sends information to the heart to beat more strongly and the arteries to contract less, thus modulating the blood pressure beat by beat,” he explains.

In a previous study, the USP research team demonstrated that aerobic training performed at night induced a greater decrease in blood pressure than morning training in hypertensive men.

In another study, the more effective response of nighttime training in reducing blood pressure was also accompanied by a greater decrease in systemic vascular resistance and systolic blood pressure variability.

“Replication of results obtained in previous studies and in different groups of patients with hypertension, combined with the use of more precise techniques to assess key outcomes, strengthens our understanding of a greater autonomic benefit of aerobic exercise performed at night in patients with hypertension. This may be particularly important for people resistant to drug treatment,” he says.

Source: Terra

Ben

Ben Stock is a lifestyle journalist and author at Gossipify. He writes about topics such as health, wellness, travel, food and home decor. He provides practical advice and inspiration to improve well-being, keeps readers up to date with latest lifestyle news and trends, known for his engaging writing style, in-depth analysis and unique perspectives.