The effect of ski training at altitude and racing on pituitary, adrenal and testicular function in men.

The effect of similar prolonged exercise on hormonal changes was studied at sea level and at moderate altitude. Four cross-country skiers participated in a 30-km race and five biathlonists in a 20-km race at sea level in Finland and during altitude training and racing at 1650 m in Les Saisies, France. Venous blood samples were taken at both altitudes before the race between 0800 and 0900 hours and 25-35 min after the race. Resting blood samples were also taken before and after the altitude training and the period of racing. Serum testosterone concentration was higher before the race at altitude than at sea level (19%, P < 0.02), and 30 min after the race growth hormone (GH) concentration was higher at sea level than at moderate altitude (P < 0.002). There were not significant differences in serum luteinising hormone between the altitudes. Serum cortisol concentration was higher after the altitude training and the period of racing than before (P < 0.02) but no difference was observed in testosterone. We concluded, that since the profiles of the anabolic-catabolic hormone concentrations measured are indicators of the performance level of athletes, our data indicated that to follow them during altitude training could be beneficial in optimizing training programme for individual athletes. We also concluded, that the lower GH concentration after racing at moderate altitude may have been a consequence of decreased racing speed and/or increased physical performance.