Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expedition

PurposeThe Alaska Mountain Wilderness Ski Classic (AMWSC) is a self-supported and self-oriented winter expedition that occurs in the remote North American Brooks Range, ∼200 km north of the Arctic Circle. Few investigations have evaluated sex-specific physiological responses under extreme cold and i...

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Main Authors: Melynda S. Coker, Michelle N. Ravelli, Timothy C. Shriver, Dale A. Schoeller, Dustin R. Slivka, Brent C. Ruby, Robert H. Coker
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Physiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fphys.2025.1543834/full
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author Melynda S. Coker
Michelle N. Ravelli
Timothy C. Shriver
Dale A. Schoeller
Dustin R. Slivka
Brent C. Ruby
Robert H. Coker
author_facet Melynda S. Coker
Michelle N. Ravelli
Timothy C. Shriver
Dale A. Schoeller
Dustin R. Slivka
Brent C. Ruby
Robert H. Coker
author_sort Melynda S. Coker
collection DOAJ
description PurposeThe Alaska Mountain Wilderness Ski Classic (AMWSC) is a self-supported and self-oriented winter expedition that occurs in the remote North American Brooks Range, ∼200 km north of the Arctic Circle. Few investigations have evaluated sex-specific physiological responses under extreme cold and isolated circumstances. Our study examined sex-specific differences in total energy expenditure (TEE), water turnover (WT), and changes in body composition during the expedition.MethodsTwenty adult participants (8 females, age: 41 ± 6 years, body mass index: 22.8 ± 1.9 kg/m2 and 12 males, age: 38 ± 4 years, body mass index: 22.7 ± 1.6 kg/m2) enrolled in and completed the study. TEE and WT were examined during the expedition using the doubly labeled water (DLW) method. Body composition was measured using multi-frequency bioelectrical impedance.ResultsThe duration of the expedition was similar in females (8.1 ± 1.6 days) and males (7.5 ± 0.9 days). Absolute rates of TEE were lower in females (20.8 ± 4.7 MJ/day) compared to males (31.1 ± 7.5 MJ/day). However, when expressed relative to fat free mass (FFM), rates of TEE were similar in females (0.42 ± 0.07 MJ/FFM/day) and males (0.45 ± 0.10 MJ/FFM/day). TEE/body mass plus pack weight (i.e., total load carriage) was lower in females compared to males. WT was reduced compared to previous reports of athletes exercising in thermoneutral and hot environments.ConclusionAbsolute rates of TEE were lower in females compared to males, but there was no difference when TEE was expressed relative to fat free mass. Estimates of TEE/total load carriage were lower in females than males, modestly suggesting greater functional efficiency in females during this expedition. Compared to other ultra-endurance events in warm environments, WT may have been reduced by lack of water availability, self-selected reductions in exercise intensity, and limited sweat loss.
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spelling doaj-art-efb4f26ef9ab4822a590a338e6f89f6f2025-08-20T03:53:27ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2025-04-011610.3389/fphys.2025.15438341543834Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expeditionMelynda S. Coker0Michelle N. Ravelli1Timothy C. Shriver2Dale A. Schoeller3Dustin R. Slivka4Brent C. Ruby5Robert H. Coker6Montana Center for Work Physiology and Exercise Metabolism, School of Integrative Physiology and Athletic Training, College of Health, University of Montana, Missoula, MT, United StatesIsotope Ratio Mass Spectrometry Core Laboratory, University of Wisconsin, Madison, WI, United StatesIsotope Ratio Mass Spectrometry Core Laboratory, University of Wisconsin, Madison, WI, United StatesIsotope Ratio Mass Spectrometry Core Laboratory, University of Wisconsin, Madison, WI, United StatesMontana Center for Work Physiology and Exercise Metabolism, School of Integrative Physiology and Athletic Training, College of Health, University of Montana, Missoula, MT, United StatesMontana Center for Work Physiology and Exercise Metabolism, School of Integrative Physiology and Athletic Training, College of Health, University of Montana, Missoula, MT, United StatesMontana Center for Work Physiology and Exercise Metabolism, School of Integrative Physiology and Athletic Training, College of Health, University of Montana, Missoula, MT, United StatesPurposeThe Alaska Mountain Wilderness Ski Classic (AMWSC) is a self-supported and self-oriented winter expedition that occurs in the remote North American Brooks Range, ∼200 km north of the Arctic Circle. Few investigations have evaluated sex-specific physiological responses under extreme cold and isolated circumstances. Our study examined sex-specific differences in total energy expenditure (TEE), water turnover (WT), and changes in body composition during the expedition.MethodsTwenty adult participants (8 females, age: 41 ± 6 years, body mass index: 22.8 ± 1.9 kg/m2 and 12 males, age: 38 ± 4 years, body mass index: 22.7 ± 1.6 kg/m2) enrolled in and completed the study. TEE and WT were examined during the expedition using the doubly labeled water (DLW) method. Body composition was measured using multi-frequency bioelectrical impedance.ResultsThe duration of the expedition was similar in females (8.1 ± 1.6 days) and males (7.5 ± 0.9 days). Absolute rates of TEE were lower in females (20.8 ± 4.7 MJ/day) compared to males (31.1 ± 7.5 MJ/day). However, when expressed relative to fat free mass (FFM), rates of TEE were similar in females (0.42 ± 0.07 MJ/FFM/day) and males (0.45 ± 0.10 MJ/FFM/day). TEE/body mass plus pack weight (i.e., total load carriage) was lower in females compared to males. WT was reduced compared to previous reports of athletes exercising in thermoneutral and hot environments.ConclusionAbsolute rates of TEE were lower in females compared to males, but there was no difference when TEE was expressed relative to fat free mass. Estimates of TEE/total load carriage were lower in females than males, modestly suggesting greater functional efficiency in females during this expedition. Compared to other ultra-endurance events in warm environments, WT may have been reduced by lack of water availability, self-selected reductions in exercise intensity, and limited sweat loss.https://www.frontiersin.org/articles/10.3389/fphys.2025.1543834/fullresiliencecoldphysical activitysurvivalhuman
spellingShingle Melynda S. Coker
Michelle N. Ravelli
Timothy C. Shriver
Dale A. Schoeller
Dustin R. Slivka
Brent C. Ruby
Robert H. Coker
Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expedition
Frontiers in Physiology
resilience
cold
physical activity
survival
human
title Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expedition
title_full Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expedition
title_fullStr Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expedition
title_full_unstemmed Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expedition
title_short Sex-specific energy expenditure during the Alaska mountain wilderness ski classic; insights from an Arctic winter expedition
title_sort sex specific energy expenditure during the alaska mountain wilderness ski classic insights from an arctic winter expedition
topic resilience
cold
physical activity
survival
human
url https://www.frontiersin.org/articles/10.3389/fphys.2025.1543834/full
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