Mallika S Sarma1, Cara J Ocobock2,3, Sarah Martin4, Shannon Rochelle4, Brendan P Croom5, Lee T Gettler2,3. 1. Human Spaceflight Lab, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. 2. Department of Anthropology, University of Notre Dame, Notre Dame, Indiana, USA. 3. The Eck Institute for Global health, University of Notre Dame, Notre Dame, Indiana, USA. 4. NOLS Rocky Mountain, The National Outdoor Leadership School, Lander, Wyoming, USA. 5. Independent Scholar, Baltimore, Maryland, USA.
Abstract
OBJECTIVES: An energetically demanding environment like a wilderness expedition can lead to potent stressors on human physiology and homeostatic balance causing shifts in energy expenditure and body composition. These shifts likely have consequences on overall health and performance and may potentially differ by sex. It is therefore critical to understand the potential differential body composition and energy expenditure changes in response to a novel and challenging environment in both males and female bodies. METHODS: Data were collected from 75 healthy individuals (female = 41; ages 18-53) throughout a 3-month long expedition in the American Rockies. Body mass, body fat, and lean muscle mass were measured before, during, and after the course. Physical activity intensity and energy expenditure were also measured in a subset of participants using the wGT3X-BT Actigraph wrist monitor and an accompanying Bluetooth heart rate monitor. RESULTS: Over the 3-month period, individuals initially experienced declines in body mass, body fat percentage, and lean muscle mass. Participants partially rebounded from these deficits to maintain overall body mass with a slight recomposition of body fat and lean muscle mass. Our data also demonstrated that sex moderated total energy expenditure, where females experienced a modest decline whereas males experienced an increase in energy expenditure from the beginning to the end of the course. CONCLUSIONS: Understanding changes in energy storage in the body and variation in energy expenditure between sexes during a 3-month expedition has critical implications for maintaining health and performance in an energetically demanding environment where resources may be scarce.
OBJECTIVES: An energetically demanding environment like a wilderness expedition can lead to potent stressors on human physiology and homeostatic balance causing shifts in energy expenditure and body composition. These shifts likely have consequences on overall health and performance and may potentially differ by sex. It is therefore critical to understand the potential differential body composition and energy expenditure changes in response to a novel and challenging environment in both males and female bodies. METHODS: Data were collected from 75 healthy individuals (female = 41; ages 18-53) throughout a 3-month long expedition in the American Rockies. Body mass, body fat, and lean muscle mass were measured before, during, and after the course. Physical activity intensity and energy expenditure were also measured in a subset of participants using the wGT3X-BT Actigraph wrist monitor and an accompanying Bluetooth heart rate monitor. RESULTS: Over the 3-month period, individuals initially experienced declines in body mass, body fat percentage, and lean muscle mass. Participants partially rebounded from these deficits to maintain overall body mass with a slight recomposition of body fat and lean muscle mass. Our data also demonstrated that sex moderated total energy expenditure, where females experienced a modest decline whereas males experienced an increase in energy expenditure from the beginning to the end of the course. CONCLUSIONS: Understanding changes in energy storage in the body and variation in energy expenditure between sexes during a 3-month expedition has critical implications for maintaining health and performance in an energetically demanding environment where resources may be scarce.
Authors: Lori G Borrud; Katherine M Flegal; Anne C Looker; James E Everhart; Tamara B Harris; John A Shepherd Journal: Vital Health Stat 11 Date: 2010-04
Authors: B Braun; J T Mawson; S R Muza; S B Dominick; G A Brooks; M A Horning; P B Rock; L G Moore; R S Mazzeo; S C Ezeji-Okoye; G E Butterfield Journal: J Appl Physiol (1985) Date: 2000-01
Authors: Caitlin Thurber; Lara R Dugas; Cara Ocobock; Bryce Carlson; John R Speakman; Herman Pontzer Journal: Sci Adv Date: 2019-06-05 Impact factor: 14.136