in emotive subjects ( ratio na/a less than 1 at rest ) the apprehension of muscular work promoted a difference in catecholamine responses : norepinephrine release was not affected by subject 's anxiety , while epinephrine secretion , already elevated before the test , reached a high degree of magnitude in the first minutes of muscular work , remaining nearly constant until exhaustion .
C0007412
catecholamine
C0028351
norepinephrine