Aerobic exercise performed in the evening benefits elderly with hypertension: Study

In a study published in the Journal of Physiology, Researchers from the University of São Paulo's School of Physical Education and Sports in Brazil concluded that evening exercise is better for blood pressure regulation owing to improved cardiovascular control by the autonomic nervous system via a mechanism known as baroreflex sensitivity.

Baroreflex sensitivity modulates each heartbeat interval and regulates autonomic activity throughout the body. It involves sensitive fibres and artery wall deformations, particularly in the aortic arch and carotid body. When blood pressure decreases, these regions alert the brain's autonomic control centre, prompting the heart to beat faster and arteries to contract more. Conversely, if blood pressure rises, the heart slows down, and arteries relax. Essentially, baroreflex sensitivity adjusts arterial pressure beat by beat.

In the study, 23 elderly hypertension patients were divided into morning and evening training groups. Both groups cycled at moderate intensity for ten weeks, with three 45-minute sessions weekly. Researchers analysed key cardiovascular parameters, including systolic and diastolic blood pressure and heart rate, before and after the training period. They also monitored autonomic nervous system mechanisms, such as muscle sympathetic nerve activity and sympathetic baroreflex sensitivity, to assess blood pressure control.

The results showed that in the evening training group, all four analysed parameters demonstrated improvement: systolic and diastolic blood pressure, sympathetic baroreflex sensitivity, and muscle sympathetic nerve activity. However, in the morning training group, no improvements were observed in muscle sympathetic nerve activity, systolic blood pressure, or sympathetic baroreflex sensitivity.

“There are multiple mechanisms to regulate blood pressure, and although morning training was beneficial, only evening training improved short-term control of blood pressure by enhancing baroreflex sensitivity. This is important because baroreflex control has a positive effect on blood pressure regulation, and there aren’t any medications to modulate the mechanism,” said Leandro Campos de Brito, first author of the article.

Reference: John R. M. Renwick, Stuart P. S. Mladen, Workin’ on our night moves: leveraging the timing of aerobic exercise to enhance cardiovascular autonomic control in hypertensive older adults, The Journal of Physiology, 10.1113/JP286458.