The magnitude and duration of ambulatory blood pressure reduction following acute exercise

The purpose of this study was to observe the magnitude and duration of the ambulatory blood pressure (BP) reduction following exercise and to identify the peak intervals of BP reduction throughout the 24-h diurnal period. Subjects were 25 normo- (N = 116.7/ 78.2+/-10.0/7.2 mm Hg) and 21 hypertensive (H = 140.8/96.9+/-13.9/9.6 mm Hg) adults. Twenty-four hour ambulatory blood pressures (SBP = systolic and DBP = diastolic) were recorded following exercise (E = 50 min @ 50% VO2 max) and during a non-exercise control day (C). The 24-h pressures were compared between the E and C days for (1) duration and magnitude of the BP reduction following exercise, and for (2) the time of day for the diurnal patterns to exhibit reductions in BP. No BP differences were found for N between E and C days. Significant reductions in BP were found for 24-h average SBP (decrease 6.8 mm Hg) and DBP (decrease 4.1 mm Hg), daytime (06.00-22.00 hrs) SBP (decrease 6.9 mm Hg) and DBP (decrease 3.3 mm Hg), and sleep (22.00-06.00) SBP (decrease 5.1 mm Hg) and DBP (decrease 4.4 mm Hg) for H subjects only. H also demonstrated an 11 h reduction in SBP (chi = decrease 8.3+/-2.2 mm Hg) and 4h reduction in DBP (chi = decrease 6.0+/-1.7 mm Hg) following exercise. For the diurnal variation, the peak interval of reduction in SBP (chi = 17.0+/-2.6 mm Hg) was for 11 h; from 11.00-21.00 hrs. For DBP, a significant reduction (chi = decrease 5.7+/-0.7 mm Hg) was found for 5 h; from 11.00-15.00 h. Thus, exercise reduces both systolic and diastolic BP for a significant length of time postexercise as well as reduces pressures during the time of day that typically exhibits higher diurnal pressures.