Plasma catecholamines at rest and exercise in subjects with high- and low-trait anxiety

The purpose of this study was to compare the plasma catecholamine concentration at rest and in response to exercise in subjects with low and high trait anxiety (TA). Six subjects with low TA and six subjects with high TA were selected among 149 males college students on the basis of their results on three TA tests (STAI, IPAT, 16 PF). Plasma norepinephrine (NE) and epinephrine (E) concentrations (pg/ml) were measured at rest in supine position and during mild and moderate exercises of 5 min duration (about 40% and 60% of the individual VO2max) on bicycle ergometer. Plasma E concentrations at rest and exercise were not significantly different in subjects with low (33 +/- 6, 82 +/- 11, and 197 +/- 49) or high TA (41 +/- 7, 62 +/- 13, and 229 +/- 52). Plasma NE concentration was not significantly different at rest and in response to mild exercise in low (235 +/- 52; 666 +/- 64) and high-TA subjects (223 +/- 36; 610 +/- 88) but was significantly higher in high-TA than in low-TA subjects in response to moderate exercise (2510 +/- 618 vs. 1243 +/- 234). These results show 1) that plasma NE and E concentrations at rest and in response to light exercise are similar in low- and high-TA subjects, and 2) that subjects with high TA have a greater plasma NE response to the psychologic stress and/or to the homeostatic challenge of moderate exercise.