Design:Psychological stress is associated with the development of hypertension. Exercise is purported to have a prophylactic effect on stress. Immediately after a single bout of aerobic exercise there is a transient decrease in blood pressureObjective:We sought to examine the cardiovascular responses to a psychological stressor, the Stroop color word task during the postexercise hypotensive period.Methods:Eight borderline hypertensive subjects (resting blood pressure 137±1.9/ 85 ±1.8 mmHg) participated in three randomly assigned experimental trials: Stroop color word task without prior exercise (Stroop); Stroop color word task administered 10min after 60min exercise at 60% maximal oxygen uptake (Ex + Stroop); and 60min exercise at 60% maximal oxygen uptake followed by 20 min seated recovery (Ex). Blood pressure and heart rate were monitored at the start and end of exercise and at every 2 min of recovery.Results:During the Stroop trial there were significant increases in mean arterial (MAP), systolic (SBP) and diastolic blood pressure (DBP). During the Ex + Stroop trial the increases in MAP, SBP and DBP during the Stroop color word task were significantly less than the increases without prior exercise. During recovery in the Ex trial there were significant decreases in MAP and SBP. However, there were no significant changes in DBP during the Ex trial.Conclusions:These results suggest that following an acute bout of exercise there is a reduction in blood pressure, and during this postexercise hypotensive period the blood pressure response to a psychological stressor is attenuated.