INTRODUCTION: Cortisol is the main glucocorticoid in the body and has a catabolic function inducing the breakdown of muscle proteins and adipose tissue. The cortisol secretion is activated in response to physical and psychological stress. In accordance, also exercise has been shown to increase its secretion (Brownlee et al. 2007). Testosterone is a multifunctional anabolic hormone having an important role in the growth and maintenance of skeletal muscle, bone and red blood cells (Zitzmann & Nieschlag 2001). In athletes, the testosterone/cortisol (T/C) ratio can be used to obtain information on the anabolic-catabolic balance of the body (Adlercreutz et al. 1986) and hence, to evaluate the effect of training load changes on stress and recovery. METHOD: 4 young male (18.5±1.05 yr) and female (17.9±0.86 yr) cross-country skiers from Vuokatti-Ruka Sports Academy were recruited in the study. The volunteers donated blood and saliva samples 8 times during their training and competition season (Aug. 2014 - Mar. 2015). Samples were taken at rest in the morning after overnight fasting. Various analytes, including serum cortisol and free testosterone, were analyzed as routine clinical laboratory analytics from blood samples. Salivary cortisol and testosterone were analyzed from collected saliva samples. RESULTS: The changes in cortisol levels appeared to be connected to the training load exhibiting an average increase of 24 ± 11 % during the most intensive training period while decreasing during less strenuous training period. The salivary cortisol values showed correlation to blood values. Free testosterone levels also initially increased together with the increasing training load or were at least stable, the highest increase being 2.55-fold, suggesting that the training load was not too high and resulted in improvement of physical performance. However, around the time of the most strenuous training, the free testosterone started to decrease in four study persons the highest decrease being 41 %. The decrease was stabilized or reversed close to competitive season except in one study person. Variation in the T/C ratio was mainly modest indicating a balance between anabolic and catabolic activity in the body. DISCUSSION: Cortisol and testosterone levels can be used to follow stress and recovery of the body, although they may reveal only relatively high changes in the training load or severe metabolic imbalances. The collection of saliva samples is non-invasive and suitable for field conditions. The biomarker levels in saliva reflect hormonal changes in the blood at least satisfactorily. In the literature, there are very few long term studies following testosterone or cortisol levels in athletes, and thus this study produced important and interesting information. --- The hosting University of Jyväskylä is planning to publish conference proceedings "Science and Nordic Skiing III". In case you are interested in this publication please contact the editors (Anni Hakkarainen anni.s.j.hakkarainen@jyu.fi) to become registered for the book.
© Copyright 2015 3rd International Congress on Science and Nordic Skiing - ICSNS 2015. 5-8 June 2015, Vuokatti, Finland. Veröffentlicht von University of Jyväskylä; University of Salzburg. Alle Rechte vorbehalten.