Cardiovascular Responses to Stress: II. Relationships to Aerobic Exercise Patterns

A sample of 174 men aged 18–22 years were divided into thirds based on self‐reported levels of weekly aerobic exercise. Heart rate, systolic and diastolic blood pressure, and pre‐ejection period responses of these low, moderate, and high exercise groups were compared during a pretask rest and a later acclimated rest, a bicycle exercise task, a purported shock‐avoidance reaction time task, and the cold pressor test. The low exercise subjects showed higher heart rates and marginally higher diastolic blood pressures than the high exercise subjects at rest. The low exercise subjects also showed greater myocardial responses to the mild exercise task and the reaction time task than the high exercise subjects, as reflected by group differences in heart rate, systolic blood pressure, and pre ejection period measures after covariance adjustment for baseline differences. Group differences observed in response to the cold pressor test were smaller and generally nonsignificant. These results were interpreted as evidence that aerobic exercise training may decrease beta‐adrenergic myocardial responses to physical and behavioral challenges.