Effect of Mental Stress on Coronary Blood Flow in Humans

Abstract

Mental stress elicits diverse vascular responses in humans. The coronary circulation is responsible for providing the heart with adequate blood supply during stress. Psychological stress has been linked to the development of coronary artery disease. The effect of mental stress on coronary vascular conductance (CVC) was examined in both men (n=9) and women (n=8). Coronary blood flow velocity (Doppler ultrasound), MAP, and HR were monitored continuously before, during, and after 3 min of mental arithmetic. Mean arterial blood pressure (MAP; 85±2 and 84±4 mmHg) and heart rate (HR; 68±4 and 73±5 beats/min) at rest were not significantly different between men and women, respectively. Mental arithmetic increased HR and MAP (Δ17±3 beats/min and Δ17±2 mmHg, respectively) in all subjects. No sex differences in HR and MAP responses to mental arithmetic were observed (P>0.05). When all subjects were analyzed together, coronary blood velocity increased (17.9±1.4 to 22.5±1.5 cm/s; P=0.001) but CVC did not change with mental stress (0.27±0.02 to 0.29±0.02 cm/s/mmHg; P=0.38). However, when analyzed separately, men demonstrated a significant increase in CVC (Δ21±1%; P<0.002) and women elicited no change in CVC (Δ3±1%; P=0.63). These data indicate that women, unlike men, do not augment CVC during mental stress. Therefore, these results suggest that women may be more susceptible to adverse cardiac events during mental stress.