Abstract des Autors

Objective: To examine different hormonal responses to heavy endurance training and overtraining in female athletes. Design: Submaximal and maximal treadmill tests, self-report mood measures, and stress hormone analyses were repeated at baseline, after 4 weeks and at the end of 6 to 9 weeks of experimental intensive training and after 4 to 6 weeks of recovery. Subjects: Fifteen healthy female endurance athletes increased their intensive training volume by 130% and base training volume by 100% (ETG, n=9) or served as controls (CG, n=6). Main Outcome Measures: Maximal oxygen uptake (VO2max), mood dynamics, blood catecholamines, cortisol and testosterone at rest and after submaximal and maximal exercise, and nocturnal urine catecholamines. Results: Five females from the ETG demonstrated an overtraining state (OA subgroup) at the end of the training period. Their VO2max decreased (mean+/-SEM) from 53.0+/-2.2 ml/kg/min (range, 46.8-59.2) to 50.2+/-2.3 ml/kg/min (range, 43.8-56.6) (p<0.01). Maximal treadmill performance expressed as oxygen demand decreased (mean +/- SEM) from 56.0+/-1.6 ml/kg/min (range, 51.5-60.5) to 52.2+/-1.1 ml/kg/min (range, 49.1-55.3) (p<0.01). Maximal heart rate also decreased (mean+/-SEM) from 190+/-1 bpm (range, 185-197) to 186+/-2 bpm (range, 184-193) (p<0.05), and the athletes experienced mood disturbances. Plasma adrenaline levels at maximal and noradrenaline at submaximal work rate decreased during the last 2 to 5 training weeks (p<0.05), and serum cortisol levels at maximal work rate decreased during the first 4 training weeks (p<0.05) in the ETG. Plasma adrenaline at maximal work rate decreased during the first 4 training weeks (p<0.05) in the OA subgroup. There were no changes in the CG. Individual hormonal response types to heavy training and overtraining were found. Conclusions: Hormone responses to exercise load are superior in indicating heavy training-induced stress when compared with resting hormone levels. These responses indicated decreased sympathoadrenal and/or adrenocortical activity (or exhaustion of the adrenal gland or the central nervous system). Individual hormonal profiles are needed to follow up training effects. Marked individual differences were found in training- and overtraining-induced hormonal changes. Verf.-Referat