Acute effects of morning versus evening aerobic exercise on nocturnal blood pressure in healthy young men.

[Purpose] To determine the optimal timing of aerobic exercise for nocturnal blood pressure (BP), this study compared the acute effects of morning and evening moderate-intensity aerobic exercise (65% heart rate reserve, 30 min) on nocturnal BP, and sleep quality. [Participants and Methods] This randomized crossover study included 15 healthy young male participants who randomly completed three experimental trials: (1) morning trial (09:30-10:00), (2) evening trial (17:30-18:00), and (3) a sedentary control trial. The exercise consisted of cycling for 30 min at 65% heart rate reserve. Nocturnal systolic BP (SBP), and sleep efficiency were assessed using the oscillometric method, and actigraphy, respectively. [Results] The morning trial produced a lower nocturnal SBP than both the evening (Cohen's d=0.82) and control trials (Cohen's d=1.23), whereas the evening trial also produced a lower nocturnal SBP than the control trial (Cohen's d=0.32). Sleep efficiency was higher in the morning trial than in both the evening (Cohen's d=5.42) and control trials (Cohen's d=5.12). [Conclusion] Morning aerobic exercise more effectively promoted nocturnal BP dipping among healthy young men than did evening exercise.