Quantitative correlation between cardiovascular and plasma epinephrine response to mental stress

To investigate the quantitative correlations between cardiovascular and endogenous catecholamine response to mental stress, we gave a mental arithmetic test to 20 young healthy men. A direct and non-invasive haemodynamic measurement was performed by serial M-mode echocardiography. Heart rate, blood pressure, cardiac output, stroke volume, ejection fraction, left ventricular end-systolic pressure-volume ratio and plasma epinephrine increased over the baseline period during the test. The peripheral resistance and left ventricular end-systolic volume decreased, whereas left ventricular end-diastolic volume and plasma norepinephrine were unaltered. Furthermore, the degree of change in each haemodynamic parameter showing significant reaction, was well correlated with that of the increase in plasma epinephrine. The data suggest that acute mental stress induces endogenous epinephrine secretion resulting in a beta-adrenergic activated state in the cardiovascular system, namely, positive chronotropism, positive inotropism and vasodilatation.