Sex differences in vascular and endothelial responses to acute mental stress

Our objective was to assess the differences in systemic vascular and endothelial function in response to acute mental stress between men and women. The endothelium plays a pivotal role in vascular homeostasis and the development of atherosclerotic heart disease. The mechanism and presentation of cardiovascular events show a sex-based difference, although the sex difference in the vascular and endothelial response to mental stress is not known. Male (n = 34) and female (n = 53) subjects participated in a series of three different mental stress tasks during which vascular response was measured non-invasively using peripheral arterial tonometry. Endothelial function was assessed using reactive hyperemia peripheral arterial tonometry. Double product (systolic blood pressure x heart rate) was calculated. Males had a greater double product response (27.2 + 3.6% increase in double product vs. 19.2 + 1.7%; P = 0.01), and a greater vascular reactivity to mental stress. Females demonstrated a reduced response to reactive hyperemia (-0.47 vs. 13.74%; P = 0.01). Furthermore, a subgroup of females who showed the least vaso-reactivity to mental stress showed the greatest decline in endothelial function (-10.5 + 4% vs. 17.4 + 6.3%; P < 0.001). This study demonstrates sex-based differences in the vascular and endothelial responses to mental stress. The mental stress-induced reduction in endothelial function and increased double product seen in the females might manifest clinically as contributing to the pathophysiology of mental stress-mediated cardiovascular events in female patients and provide further information regarding the potential mechanism for sex differences in cardiac events.