THERMOREGULATORY RESPONSES IN ELITE CROSS-COUNTRY SKIERS DURING INTERNATIONAL COMPETITIONS AND TRAINING

Wolfgang Schobersberger^1,2Maarit Valtonen³Anika Köck^2,4Sebastien Racinais⁵Yannis Pitsiladis^6,7Panagiotis Verdoukas⁷Borja Muñiz⁸Rikhard maki-heikkila⁹Johanna Kaarina Ihalainen^10,3Dominique Gagnon^10,11,12,13Tobias Dünnwald^1*

• ¹Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT TIROL-Private University for Health Sciences and Health Technology, Hall in Tyrol, Austria
• ²Tirol Kliniken GmbH Innsbruck, Innsbruck, Austria
• ³Finnish Institute of High Performance Sport KIHU, Jyväskylä, Finland
• ⁴Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT TIROL - Private University for Health Sciences and Health Technology, Hall in Tyrol, Austria
• ⁵CREPS Montpellier - Font-Romeu, Environmental Stress Unit, Montpellier, France
• ⁶Department of Sports and Health Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
• ⁷Human Telemetrics LTD, London, United Kingdom
• ⁸EXER-GENUD (Growth, Exercise, Nutrition and Development) Research Group, Faculty of Health and Sport Sciences, University of Zaragoza, Zaragoza, Spain
• ⁹Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
• ¹⁰Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
• ¹¹Helsinki Clinic for Sport and Exercise Medicine, Helsinki, Finland
• ¹²Department of Sport and Exercise Medicine, Faculty of Medicine, University of Helsinki, Helsinki, Finland
• ¹³Center for Research in Occupational Safety and Health, Laurentian University, Sudbury, Canada

Background: The aim of this study was to describe the thermoregulatory responses of elite athletes during competitions and training of the international cross-country skiing FIS Scandinavian Cup in Finland, held under cold (sub-zero) ambient conditions. Methods: Core and skin temperature were continuously recorded during two competition formats, a 10 km (n=18; 10m, 8f) and a 20 km race (n=14; 9m, 5f) and during training (n=11; 7m, 4f) using electronic temperature pills and temperature sensors fixed on the chest, arm, hand and thigh, respectively. Heart rate and skiing speed were continuously recorded using heart rate monitors with integrated GPS technology. Ambient temperatures during the measuring period ranged from -13.0 to -1.3°C. Results: Mean core temperature (Tcore) increased significantly during the 10 km classic (39.0±0.4°C), the 20 km freestyle (39.2±0.7°C)) races (all p<0.001) and during trainings (38.3±0.5°C). In contrast, skin temperature decreased on all 4 locations (all p<0.001), with the greatest decreases measured on the thigh (18.7±4.1°C (10 km race), 20.7±4.6°C (20 km race), (18.5±3.2°C (training)). During both races, heart rate significantly increased over time while racing speed decreased (p<0.001, respectively). Mean skin temperature of the thigh correlated with skiing speed in the 10 km (r=0.573, p=0.041) and the 20 km race (r=0.682, p=0.021). Conclusion: To summarize, despite low ambient temperatures under real competition and training conditions, the athletes exhibited high heat generation, which enabled them to maintain a high core temperature. In contrast, the skin temperature dropped sharply during competitions and trainings. The association between the low mean skin temperature and the lower racing speed should be investigated further.