Accumulation of physical activity: blood pressure reduction between 10-min walking sessions.

The accumulation of intermittent bouts of physical activity (PA) has been found to reduce blood pressure (BP) in prehypertension and hypertension. Yet, the BP response among several short sessions within the accumulation of PA in a single day has not been examined. The purpose of the study was (1) to investigate the BP reduction during the rest periods following three successive 10-min walking sessions accumulated over a 3-h period in prehypertensive adults and (2) to observe the role of autonomic modulation during the rest periods following each short PA session. Adults with prehypertension (131.9+/-4.7/82.5+/-6.4 mm Hg) participated in the study. BP using ambulatory monitoring and autonomic modulation through heart rate variability (HRV) using Holter monitoring were measured at baseline and during the rest periods following three short sessions (three 10-min treadmill walks at 50% of peak oxygen uptake (VO2peak); at least 50 min apart) over a 3-h period. Variables of BP and autonomic modulation were averaged for the baseline and for the rest periods following each 10-min walk. One-way analysis of variance with repeated measures was used to test the differences over time in BP and HRV (P<0.05). A significant main effect was found in systolic BP (P=0.039), whereas none was found in diastolic BP (P=0.630). Systolic BP was decreased following the third short session (-4.0+/-7.4 mm Hg) compared to baseline. No significance was found in any of the autonomic modulation variables. In conclusion, accumulating intermittent bouts of PA, as short as 10 min, total 30-min walk sessions may reduce systolic BP in prehypertension.