Influence Of Sex Differences On Post-exercise Hypotension

PURPOSE: A single bout of exercise can lead to postexercise reductions in arterial blood pressure below resting levels, so-called post-exercise hypotension (PEH), which is considered a cause of postexercise syncope. Thus, elucidating the factors inducing PEH is important. Many studies investigating PEH have employed male participants, and as a result, the influence of sex differences on PEH remains poorly understood. This study aimed to investigate the influence of sex differences on post-exercise hypotension. METHODS: Twelve males [age: 22 ± 2 years, height: 1.74 ± 0.05 m, body weight: 70.9 ± 7.9 kg, peak oxygen uptake (VO2peak): 45.8 ± 6.3 mL/kg/min] and 13 females in the early follicular phase (age: 23 ± 4 years, height: 1.58 ± 0.05 m, body weight: 55.9 ± 6.7 kg, VO2peak: 40.7 ± 6.0 mL/kg/min) were enrolled. After the 30 minutes of pre-exercise rest (baseline), they performed constant-work load cycling exercise for 60 minutes at 70% peak oxygen uptake (VO2peak), followed by 30 minutes of recovery. The participant’s blood pressures were measured every 10 minutes during baseline and every 5 minutes during post-exercise recovery. As the appearance of post-exercise minimum value of blood pressures differed among the participants, the maximum changes in blood pressures from baseline were calculated (i.e., baseline value – minimum value during recovery period) to determine the magnitude of PEH. RESULTS: The maximum changes in mean arterial pressure (MAP) (–8.3 ± 4.7 vs. –4.1 ± 6.0 mmHg) and diastolic arterial pressure (-7.5 ± 4.2 vs. -3.4 ± 4.2 mmHg) from baseline were both higher in males than in females (both P < 0.05). In addition, the maximum change in systolic arterial pressure tended to be greater in males than in the females (–11.9 ± 7.7 vs. –6.4 ± 5.6 mmHg, P = 0.053). The maximum change in MAP was negatively correlated with VO2peak (r = –0.453, P = 0.023) and tended to be associated with the exercise work rate (r = –0.371, P = 0.068). CONCLUSION: Our results suggest that male participants exhibit a greater magnitude of PEH than female participants. In particular, sex differences could be associated with fitness level (i.e., VO2peak) and absolute exercise workload.