Gender differences in cardiovascular and hypothalamic-pituitary-adrenal axis responses to psychological stress in healthy older adult men and women.

Gender differences in the neuroendocrine and cardiovascular response to psychological stress may contribute to the gender differences in the prevalence of diseases associated with hypothalamic-pituitary-adrenal (HPA) axis reactivity such as cardiovascular disease (CVD), diabetes and hypertension. We measured plasma ACTH, cortisol, heart rate (HR), and blood pressure (BP) responses in 8 men and 8 women (55-75 years) exposed to the Matt Stress Reactivity Protocol (MSRP), a psychological challenge. The MSRP elicited significant increases in HR, systolic-, and diastolic BP, ACTH and cortisol (all p<0.01). Men had significantly greater cortisol and diastolic BP responses compared to women (p<0.05). Additionally, a positive correlation between the ACTH and cortisol responses was only found in the males (r=0.71, p<0.05). There were no group differences in HR, systolic BP, or ACTH responses. We conclude, that among older adults, men respond to psychological stress with greater increases in cortisol, compared to women. This greater activation of the HPA axis could translate into an elevated risk for CVD, diabetes and hypertension and may be related to the higher prevalence of these diseases in males. Gender differences in brain structures and/or cognitive processes may be responsible for these sexually dimorphic stress responses.