Endothelial function and hemodynamic responses during mental stress

The hemodynamic basis of blood pressure responses during psychological stress shows striking individual differences that share an interesting similarity with risk for cardiovascular disease. Factors accounting for these individual differences are poorly understood. The present study examined the relationship of vascular endothelial function to stress-induced hemodynamic responses.

Subjects were 40 healthy men and women, aged 25 to 44 years. Hemodynamic responses were assessed during exposure to a battery of four diverse laboratory stressors. Endothelium-dependent arterial dilation (EDAD) was measured by ultrasound imaging of the brachial artery in response to reactive hyperemia.

High EDAD response was associated with lower resting systolic (p < .01) and diastolic blood pressure (p < .05). EDAD response was unrelated to blood pressure responses during stress. However, systemic vascular resistance responses during laboratory stress were significantly greater (p < .02) for individuals with low EDAD responses.

Exaggerated systemic vascular resistance responses during stress may reflect endothelial dysfunction. This association may help explain the growing evidence of a relationship between stress hemodynamics and cardiovascular disease risk. The nature of this association is discussed in terms of a possible interplay between the sympathetic nervous system and the endothelium in regulation of vascular tone.