Plasma catecholamines and cardiovascular responses to cold and mental activity

Abstract

Plasma epinephrine (E) and norepinephrine (NE) and blood pressure and heart rate variations were measured in 12 males before, during and after a cold hand test (5.degree. C for 2 min), a mental arithmetic test and a combination of these tests. Although the cold and mental tests had comparable effects on blood pressure, the heart rate response was greater with the mental test. The mental test produced a greater increase of E than the cold test, but the effect of the cold test was greater on NE than on E. Change in heart rate were significantly correlated with E variations but not with NE; changes in blood pressure were correlated with NE. Resting NE was correlated with resting blood pressure and resting E with resting heart rate. The levels of basal E were positively correlated with the increase in E during the test. Cardiovascular changes were differently modified by a mental and a cold test. Apparently these change are related to differences in E and NE responses in the presence of these tests.