The influence of a single session of aerobic exercise on blood pressure during daily activities
This investigation assessed the effects of acute exercise on blood pressure (BP) during a person's day-to-day life. It was hypothesized that there would be a reduction of systolic BP (SBP) and diastolic BP (DBP) at 1, 3, 5, and 7 hours following exercise as compared to a control condition. Additionally, it was speculated that those subjects with a greater reactivity to the cold pressor task would show a larger reduction than all subjects in mean BP. A secondary hypothesis was that there would be an attenuation of cardiovascular reactivity (CVR) following exercise.
Fifteen college aged students enrolled in health education courses at Virginia Tech wore an ambulatory blood pressure (ABP) monitor for 2 days. These days were scheduled to be as equivalent in demands and activities as possible. On the morning prior to monitoring they took part in either an exercise or a control condition. During the exercise session they cycled for 30 minutes at 10% of their V02max. On the control day, they read for 30 minutes. The order of these two conditions was counterbalanced across subjects.
Subjects then wore the ABP monitor for 12 hours while engaging in their usual activities. It was programmed to take readings every 20 minutes. A self-monitoring diary was filled out immediately following each cuff inflation.
No significant differences were found between exercise and control days in either mean SBP or mean DBP. A subset of subjects most reactive to the cold pressor test also failed to show a significant effect. An analysis of standard deviations of mean BP did not reveal significant differences in CVR between the treatment and the control day. The selfmonitoring data indicated no significant differences across days in mood, stress, perception of the environment, and position/activity.
This study does not support the hypothesis that SBP and DBP are attenuated during a person's daily activities following acute exercise. A number of limitations, however, might have reduced the power of the analysis. Differing schedules and demands between testing days may have introduced random error. In addition, the subjects tested have a number of characteristics which possibly render them relatively unresponsive to the exercise intervention. Future research, in which these limitations are corrected, will be necessary to determine if exercise exerts an acute effect on mean BP in the natural environment in populations at greater cardiovascular risk.