This investigation assessed the effects of acute aerobic exercise (AE) on cardiovascular reactivity (CVR) to a non-exercise stressor. Nineteen untrained, healthy male volunteers were stratified on diastolic blood pressure (DBP) response to the cold pressor test (CPT), then randomly assigned to either a minimal exercise condition (5 min of freewheel cycling) or 30 min of exercise on a bicycle ergometer at 55-60% V02max. Heart rate (HR) and BP were monitored during the resting, arousal, and recovery phases of the CPT at 1 hr, 3 hr, and 24 hr post-exercise. Results revealed statistically non-significant response and recovery effects; however, two important trends emerged. The 30 minute exercise group exhibited a tendency toward a reduced DBP response to the CPT during the 1 hour post-exercise session (p=0.08) and SBP response to the CPT was lower in the 30 minute exercise group at 3 hours post-exercise (p=0.08). These findings provide only minimal support for the effectiveness of 30 minutes of AE at 55-60% V02max in attenuating physiological response to the CPT in untrained males. / Master of Science