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Front. Physiol. | doi: 10.3389/fphys.2018.01761

Negative Energy Balance does not alter Fat Free Mass during the Yukon Arctic Ultra – the Longest and the Coldest Ultramarathon

  • 1Charité Universitätsmedizin Berlin, Germany
  • 2University of Alaska Fairbanks, United States

Purpose: The objective of this study was to determine alterations in caloric balance, body composition, metabolites, and cytokines in athletes participating in the Yukon Arctic Ultra. Methods: Ten participants traveling on foot in the 2017 692-km event were recruited for the study. Measurements and samples were obtained at pre-event, 278-km (C1), 384-km (C2), and post-event. Body composition measurements were obtained using bioelectrical impedance analysis. Accelerometer devices were utilized to provide an estimation of caloric expenditure and dietary recalls provided assessments of caloric intake. Blood serum samples were collected, processed, and analyzed using enzyme-linked immunosorbent assays or nuclear magnetic resonance. Results were analyzed using linear mixed model, presented as means±SD and considered significant at P<0.05. Results: Participants (37±10 yr; body mass index: 24.4±2.5 kg/m2; 8 males, 2 females) were recruited. Four males and one female completed the entire event in 260±19 hours. Caloric intake/expenditure was 4,126±1,115 kcal/day and 6,387±781 kcal/day, respectively, indicating a caloric deficit of 2,261±1,543 kcal/day. Total mass, body mass index, and fat mass were reduced at each time point of the event. Fat free mass was unchanged throughout the event. Follistatin was increased at C1 (1,715±876 pg/mL) in comparison to baseline. Acetoacetate increased significantly at post-event (6.1±1.5 mg/ml). Conclusions: Despite a pronounced caloric deficit and sustained activity under extreme cold conditions, fat free mass was preserved with an increase in serum follistatin and acetoacetate. Future studies should be directed at the role of nutrient strategies and/or training methods on the retention of fat free mass under these conditions.

Keywords: Body Composition, cold exposure, Cytokines, extreme environment, Ultramarathon

Received: 03 Aug 2018; Accepted: 22 Nov 2018.

Edited by:

Martin Burtscher, University of Innsbruck, Austria

Reviewed by:

Tadej Debevec, Faculty of Sport, University of Ljubljana, Slovenia
Audrey Bergouignan, UMR7178 Institut pluridisciplinaire Hubert Curien (IPHC), France  

Copyright: © 2018 Schalt, Johannsen, Kim, Chen, Murphy, Coker, Gunga, Coker and Steinach. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Mathias Steinach, Charité Universitätsmedizin Berlin, Berlin, 10117, Berlin, Germany, mathias.steinach@charite.de