Chronic And Acute Effect Of Training And Competition On Hormone Levels In Amateur Masters Cyclists

The popularity of amateur masters cyclists (AMC) regularly engaging in high intensity training and competition is increasing. Limited data exist on hormonal changes in AMC during intense training and long races. While some studies demonstrate the beneficial effects of lifelong exercise, others suggest that intense exercise can lead to hypogonadism in men. PURPOSE: To examine hormone levels at baseline (BL) and post competition (PC) during a multistage cycling race in highly trained male AMC. METHODS: 18 male AMC competing in a multistage mountain bike race volunteered to participate in the study. Six weeks before the race a BL evaluation was conducted including anthropometric data and cardiopulmonary maximal exercise test (CPET), participants also reported their physical activity and training habits in the prior three months. Blood samples for total testosterone (TT), cortisol and IGF1 levels were obtained at BL and one hour PC of 1st and 2nd race stages. Race times and exercise intensity expressed as heart rate zone were recorded for each stage. RESULTS: Mean age was 50 ± 5.6 years, weight 76.9 ± 7.9, % fat mass 18.9 ± 2.5. On CPET participants achieved mean V̇O2max of 50.7 ± 6.5 ml/kg/min, maximal power was 327.5 ± 45 W, respiratory anaerobic threshold was 86% of V̇O2max. The average reported cycling distance was 210 ± 63 km/week. The first and second stages of the race were completed with average times of 5:57 hours (94.2 K with 1158 m elevation) and 5:27 hours (90.2 K with 1204 elevation), respectively. Time spent in high intensity (4-5 zones) was 31% and 21% of racing stages 1 and 2, respectively. BL hormonal profile was within normal range for TT 16.8 ± 5.2 nmol/L (normal range 6.7-25.7); cortisol 281 ± 57 nmol/L (normal ranges 101 - 536) and IGF1 186.8 ± 47.9 ng/ml (normal range:78-210). TT levels PC deceased by 32% after stage 1 and 39%, after stage 2 (p < 0.0001), cortisol levels increased by 62% after stage 1 and 50% after stage 2 (P = 0.002) and IGF1 increased by 15% after stage 1 and 12% after stage 2 (P = 0.004) in comparison to BL levels. CONCLUSIONS: Adoption of long-term physical training in AMC, did not reduce TT levels to below normal levels. The race resulted in an acute increase in serum cortisol and IGF levels and a decline in testosterone levels.