Sex differences in vascular and endothelial responses to acute mental stress

Objective: 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. Methods: 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 × heart rate) was calculated. Results: 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). Interpretation: 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.