SOURCE: Cunha R, et al. Water aerobics is followed by short-time and immediate systolic blood pressure reduction in overweight and obese hypertensive women. J Am Soc Hypertens 2016;10:570-577.

Clinicians sometimes are concerned about the effect of exercise on blood pressure in hypertensive patients, primarily because of a well-recognized post-exercise hypotension phenomenon that can occur. Typically, hypertensive patients experience greater degrees of hypotension than normotensive patients. There is a paucity of evidence about whether hypotension occurs with similar frequency, intensity, and duration after water aerobics as it does during exercise on land. An additional attractive feature of water aerobics is that overweight and obese subjects sustain less joint stress. Injuries associated with water aerobics are much less common than during land exercise.

In a small crossover study of overweight and obese hypertensive women (n = 18), participants were randomized to either water aerobics (performed at 70-75% of predicted maximum heart rate for 45 minutes) or control (sedentary pool-side participation). Blood pressure was measured at 10-minute intervals three times after the 45-minute interval of exercise (or sedentary activity). Participants then crossed over so that the previously sedentary group performed aerobic exercise, and vice versa.

In study subjects, post-exercise changes did not occur in diastolic blood pressure. Systolic blood pressure changes were small (1-3 mmHg decline) and not of clinical relevance. Clinicians who provide exercise advice to overweight and obese hypertensive patients should find some reassurance about the safety of aerobic exercise in this population.