Haemodynamic changes during acute emotional stress in man with special reference to the capacitance vessels

Abstract

It has been established that in acute emotional stress (for example mental arithmetics) the raised cardiac output is shifted from the viscera and skin to the skeletal muscle and myocardium. The present study was undertaken to fill the gap in information about the behaviour of the capacitance vascular bed during emotional stress. The investigation was carried out in 6 healthy normotensives, 9 normotensive patients with chronic renal disease, 19 hypertensive renal patients and 12 essential hypertensives. As there was no statistically significant difference in their response to emotional stress they were eventually analyzed as one group (46 subjects). The emotional stress caused a rise of mean blood pressure by 19 mm Hg, the heart rate by 16/min and the cardiac index by 1.42 ml/min/m2. Total peripheral vascular resistance did not change significantly. Central and peripheral venous pressure rose by 2 and 2.5 mm Hg. The forearm muscle blood flow increased from 4.0 to 7.8 ml/min/100 g and the forearm vascular resistance decreased by 10.8 dyn·cm−5·s·105. It was found that this rise in forearm muscle blood flow was not accompanied by any significant rise in the forearm blood volume. The venous distensibility had a tendency to decrease with the exception of some hypertensive subjects who had the lowest venous distensibility at rest. These changes are suggestive of a stiffening of the peripheral veins, preventing pooling of the additional blood supplying the muscles during emotional stress in the extremities. This supports the conclusion that the veins play an active part in the cardiovascular response to emotional stress.