Physical exercise at high altitude is associated with testicular dysfunction leading to a reduced sperm concentration due to an altered spermiation

OBJECTIVE: To explore the effect of physical exercise at high altitudes (HA) on male reproductive system. DESIGN: Prospective study. SETTING: Andrology Clinic, University of L'Aquila, Italy. PATIENT(S): Seven male mountaineers involved in an expedition at 5,900 m. INTERVENTION(S): Semen analysis, sperm DNA fragmentation with flow cytometry, and reproductive hormone levels. MAIN OUTCOME MEASURE(S): Hormone levels were evaluated at sea level (SL) at baseline (SL-pre), after 22 days of exercise at HA (intermediate), and after 10 days upon reaching SL (SL-post). Sperm parameters, percentage of sperm with fragmented DNA, and body composition measures were evaluated at SL-pre and at SL-post. RESULT(S): A reduction of sperm concentration, of body mass index (BMI), of waist circumference, and of percentage of body fat was observed at SL-post compared with SL-pre values. Increased levels of FSH and PRL were observed at the intermediate point, and normalized at SL-post, whereas T was higher at SL-post compared with SL-pre levels. CONCLUSION(S): Physical exercise at HA is associated with a testicular dysfunction leading to a reduced sperm concentration probably through an altered spermiation. The improved body composition after physical exercise might explain the higher T levels observed after the expedition.