During an altitude training camp (23 days, 1850 m above sea level) we collected night urine from 36 German elite rowers in order to measure the excretion of urea, creatinine, 17-ketosteroids (17-KS), and 17-hydroxycorticosteroids (17-OHCS). 17-KS and 17-OHCS represent the major metabolites from endogenous anabolic and catabolic steroid hormone systems. There was no significant change in the excretion of 17-OHCS during the training camp (mean value: females 0.0025 +/- 0.0011, males 0.0033 +/- 0.0012 mg/kgbw.h). Significant increases in the excretion of 17-KS (mean value: females 0.007 +/- 0.003, males 0.0092 +/- 0.0039 mg/kgbw.h) and in the ratio 17-KS/17-OHCS (mean value: females 3.13 +/- 1.65, males 3.11 +/- 1.71) were found during the first week and towards the end of the training camp. To investigate training effects on the excretion of these hormone metabolites, we used a recently described classification for rowing training (categories I to IV of rowing-specific training according to lactate levels and non-rowing specific categories) and a corresponding rowing data base. More than 80% of training was performed at a lactate level lower than 2 mmol/l. Using multiple regression analysis, the general finding was that in males the ratio of 17-KS/17-OHCS increased with rowing specific and non specific training regimes where a lactate level below 2 mmol/l was observed. Training at higher lactate levels caused a decrease in the ratio that may be interpreted as a shift in the production from endogenous androgenic steroid hormones to cortisol. No significant effects of single training variables were found in female rowers, which indicates major training influences on testosterone metabolism. The influence of further factors such as a relationship between urine urea and 17-KS in males are described and need further explanation.