Relation between aerobic fitness level and stress induced alterations in neuroendocrine and immune function.

Alterations in neuroendocrine and immune function were examined in sedentary (n=15) (VO2peak; 31.4+/-0.7 ml x kg(-1) x min(-1); 24.4+/-1.2yr), moderately active (n=15) (VO2peak; 45.4+/-1.1 ml x kg(-1) x min(-1); 24.2+/-1.1 yr) and aerobically trained (n=15) (VO2peak; 58.8+/-0.9 ml x kg(-1) x min(-1); 24.3+/-1.0 yr) men following exposure to an acute mild psychological stressor. Subjects had 2 min to prepare, and 3 min to deliver a speech in front of 3 observers. Blood samples were drawn from an indwelling catheter before, during and 30 min following the speech task (ST). Self-reported measures of anxiety were obtained prior to and immediately following the stressor. The ST resulted in significant alterations in the number and function of immune cells, and in self-reported anxiety scores. Plasma levels of norepinephrine increased during the speech task. The neuroendocrine and immune response to the chosen stressor were independent of subject aerobic fitness level.