Impact of Season and Oral Contraceptive use on Cortisol Levelsin Physically Active Women

Abstract

Open Access Research Articletraining sessions and periods, [19,30,31]and the time needed for recovery is considered to be much longer compared to OR [22]. Because of both gradual onset of OR and gradual transition from OR to OTS, it is important to detect symptoms at an early stage [30].No single, specific, and reliable biological parameter to diagnose OR and OTS at an early stage has been found, and there has been only little improvement in recent years in developing tools suitable for diagnostics [1,22,30,45]. Hence, physicians and trainers are looking for new ways to diagnose and monitor athletes that may be at risk [1,28].The resting cortisol level has been suggested to play an interesting role in detecting OR and OTS since it is thought to indicate stress [19,31]. However, levels of resting cortisol has been both increased, decreased and unchanged in over trained athletes, and the research has mainly been performed on male athletes [3,18,25,32,33,44,46].Female athletes have become a common part of the sports environment [21]and since most research has been performed on male athletes, studies on female athletes are warranted. Oral Contraceptive (OC) use is prevalent in female athletes [21,41] and the impact of OC use and non-use on cortisol levels in female athletes are not well studied. Hence the influence of both the exogenous and the endogenous hormonal profiles on athletic performance should be investigated [41]. An administration of estrogen, as in women with OC use, can cause increase in total plasma cortisol [8,10], and in free cortisol [39]. Coolens et al. [12] showed elevated cortisol levels in estrogen treated women, but unbound cortisol levels were similar to the control group. Since estrogen could influence cortisol levels, studies on female athletes should include both OC users and nonusers. Moreover, since seasonal periodicity in various endocrine functions can occur [24,37] it seems crucial to determine if this may effect cortisol levels differently in OC users and non-users. As the role of cortisol in indicating stress is multifaceted and complex there is a need to investigate both seasonal variation and impact of oral contraceptive use on cortisol levels to evaluate if cortisol could be used to diagnose and monitor female athletes that may be at risk to develop OR and OTS. AbstractWhen athletes optimize their physical performance, an imbalance could occur between the strain of training, time for recovery and the athlete's individual tolerance of stress that could lead to overreaching and overtraining syndrome. Cortisol has been suggested to be a biological, diagnostic marker to detect overreaching and overtraining syndrome, since it is thought to indicate stress. This study aimed to provide normative data on cortisol levels, hence investigate seasonality and impact of oral contraceptive use to elucidate if cortisol could be used as a diagnostic marker to detect overreaching and overtraining syndrome in female athletes. The women, divided in two groups, oral contraceptive users (n = 15) and ...