Acute effects of exercise on plasma catecholamines in sedentary and athletic women with normal and abnormal menses.

Norepinephrine plays a role in the regulation of luteinizing hormone secretion and may therefore be involved in the etiology of exercise-induced menstrual dysfunction. This study evaluated both intraexercise and postexercise responses of epinephrine, norepinephrine, and dopamine in sedentary women and women runners with normal and abnormal menstruation. Five eumenorrheic nonrunners and five eumenorrheic, four oligomenorrheic, and five amenorrheic runners were evaluated on 2 consecutive days. On day 1, the women cycled on a bicycle ergometer against an increasing work load until exhaustion, and on day 2, the women underwent a submaximal exercise regimen. Serial blood draws were taken at specified time intervals during intraexercise and postexercise periods on both days. The data collected during exercise for all groups showed that epinephrine and norepinephrine had a sixfold to sevenfold rise on day 1 and had a threefold rise on day 2. Dopamine increased twofold during both exercise protocols. On day 1 norepinephrine displayed a significantly higher percentage change from baseline to peak levels for oligomenorrheic and amenorrheic runners than for eumenorrheic runners and sedentary women. This latter finding is consistent with the hypothesis that periodic marked elevations in norepinephrine levels during maximal exercise may interfere with pulsatile luteinizing hormone release and hence may play a role in the occurrence of menstrual dysfunction in women runners.