Blood pressure reduction following prolonged exercise in young and middle-aged endurance athletes

Abstract

Previous studies examining the relationship between exercise dose and post-exercise hypotension (PEH) have employed a limited range of exercise duration and subject age. We extended the dose-response curve by studying two intensities of prolonged exercise that may produce a greater magnitude of PEH and reveal age differences in the exercise dose-response relationship for PEH. Two groups of healthy recreational endurance athletes were studied: Young (n = 17; age 28 ± 1.1 years) and middle-aged participants (n = 18; 52 ± 0.90 years). They performed on separate occasions, 120 min of prolonged exercise (running) at moderate (60% VO2max) and high intensities (80% VO2max). PEH after 1 hour of recovery was similar within each age group for either exercise intensity, but was significantly greater in the middle-aged group (moderate intensity, -12.3 ± 1.6 mmHg; high intensity, -15.1 ± 1.7 mmHg) compared with the young group (moderate intensity, -1.2 ± 1.7 mmHg; high intensity, -5.7 ± 2.5 mmHg; p < 0.05). Stepwise regression showed that baseline blood pressure but not age was significantly related to the degree of PEH. Thus, the greater PEH seen in the middle-aged group is attributed to their higher baseline blood pressure (124 ± 3.0/79 ± 2.0 mmHg) than the young group (111 ± 2.0/69 ± 1.8 mmHg). A reduced total peripheral resistance following exercise was the primary contributor to PEH across both age groups and exercise intensities. We conclude that prolonged exercise induces a significant PEH regardless of exercise intensity.