Differential effects of exercise training intensity on blood pressure and cardiovascular responses to stress in borderline hypertensive humans

Abstract

Background: Psychologic stress has been associated with the development of hypertension. Aerobic exercise training appears to decrease cardiovascular responses to psychologic stress.

Objective: To determine the efficacy of low-intensity and moderate-intensity exercise training in reducing blood pressure and cardiovascular responses to stress.

Design: We sought to compare the cardiovascular responses to a psychologic stressor, the Stroop Color Word Task (Stroop), before and after 12 weeks of low-intensity (about 45% maximal oxygen uptake) and moderate-intensity (about 75% maximal oxygen uptake) aerobic exercise training.

Methods: Eighteen borderline hypertensive subjects (resting blood pressure 139 +/- 9/92 +/- 9 mmHg) were divided randomly into three groups: control (no exercise), low-intensity exercise (40-50% maximal oxygen uptake), and moderate-intensity exercise (70-80% maximal oxygen uptake). Training groups exercised three times per week at the prescribed exercise intensity. Heart rate and blood pressure were recorded during the Stroop before, and after 4 and 8 weeks of exercise training.

Results: In the low-intensity exercise group, exercise training attenuated mean blood pressure, systolic blood pressure, and diastolic blood pressure responses to the Stroop and decreased resting blood pressure. The moderate-intensity exercise group demonstrated a reduced diastolic blood pressure response to the Stroop.

Conclusions: These results suggest that, in borderline hypertensive humans, 12 weeks of aerobic exercise training attenuates the cardiovascular responses to the Stroop. Furthermore, low-intensity exercise training appears to be a more effective stimulus than moderate-intensity exercise training in reducing resting blood pressure and blood pressure responses to stress.