Effect of heat training and acclimation on the Athlete Biological Passport variables

Code: 23D09RF

The goal of our research is to investigate the impact of heat acclimation training as often perfomed by elite athletes on the variables of all modules of the Athlete Biological Passport (ABP) in highly trained endurance athletes. To better adapt to competition conditions or simply used an additional training stimulus, athletes have often sought to expose themselves to various environmental conditions. Classically performed in natural or simulated heat conditions, acclimation techniques are increasingly used by athletes, particularly relevant in preparation for major competitions in hot environments (e.g. Tokyo 2025 World Athletics Championships or 2025 UCI Road World Championships in Rwanda). Despite the ability of the ABP to indirectly outline doping scenarios, numerous endogenous and exogenous factors impacting hematological and steroidal profiles have been emphasized (Krumm & Faiss, 2021; Kuuranne et al., 2014). Therefore, the discrimination of confounding factors of the ABP is critical for an accurate interpretation of individual profiles by ABP experts. However, to the best of our knowledge, no study has yet investigated the impact of a heat acclimation protocol on the two ABP modules currently in use. Moreover, with the addition of an endocrine module and steroidal passport in blood (BSP) to the ABP, an in-depth assessment of the potential confounders would be paramount for the implementation of the latter tools. Therefore, by applying the latest recommendations for heat training in elite athletes (Racinais et al., 2015), this study would provide an accurate description of individual responses before, during and after a standardized heat acclimation protocol. Testing the hypothesis that heat training is related to significant hematological, steroidal, and endocrine variations, our study aims to assess the amplitude of a known source of variation on the current and upcoming ABP modules thereby providing additional information for the expert interpretation of individual profiles.