Impact of 14 Days of Bed Rest in Older Adults and an Exercise Countermeasure on Body Composition, Muscle Strength, and Cardiovascular Function: Canadian Space Agency Standard Measures.

Autor:	Hajj-Boutros G; Research Institute of the McGill University Health Centre, Montréal, Québec, Canada, guy.elhajjboutros@mail.mcgill.ca., Sonjak V; Research Institute of the McGill University Health Centre, Montréal, Québec, Canada., Faust A; Research Institute of the McGill University Health Centre, Montréal, Québec, Canada., Hedge E; Department of Kinesiology, Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada., Mastrandrea C; Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada., Lagacé JC; Faculté des Sciences de l'activité Physique, Centre de Recherche sur le Vieillissement, Université de Sherbrooke, Sherbrooke, Québec, Canada., St-Martin P; Faculté des Sciences de l'activité Physique, Centre de Recherche sur le Vieillissement, Université de Sherbrooke, Sherbrooke, Québec, Canada., Naz Divsalar D; Department of Biomedical Physiology and Kinesiology, Aerospace Physiology Laboratory, Simon Fraser University, Burnaby, British Columbia, Canada., Sadeghian F; Department of Biomedical Physiology and Kinesiology, Aerospace Physiology Laboratory, Simon Fraser University, Burnaby, British Columbia, Canada., Chevalier S; Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.; School of Human Nutrition, McGill University, Montreal, Québec, Canada., Liu-Ambrose T; Aging, Mobility and Cognitive Neuroscience Laboratory, Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada., Blaber AP; Department of Biomedical Physiology and Kinesiology, Aerospace Physiology Laboratory, Simon Fraser University, Burnaby, British Columbia, Canada., Dionne IJ; Faculté des Sciences de l'activité Physique, Centre de Recherche sur le Vieillissement, Université de Sherbrooke, Sherbrooke, Québec, Canada., Duchesne S; Department of Radiology and Nuclear Medicine, Université Laval, Quebec City, Québec, Canada.; CERVO Brain Research Center, Quebec City, Québec, Canada., Hughson R; Department of Kinesiology, Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada., Kontulainen S; College of Kinesiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada., Theou O; Division of Geriatric Medicine, Queen Elizabeth II Health Sciences Centre, Nova Scotia Health, Halifax, Nova Scotia, Canada., Morais JA; Research Institute of the McGill University Health Centre, Montréal, Québec, Canada.; Division of Geriatric Medicine, Faculty of Medicine, McGill University, Montreal, Québec, Canada.
Jazyk:	angličtina
Zdroj:	Gerontology [Gerontology] 2023; Vol. 69 (11), pp. 1284-1294. Date of Electronic Publication: 2023 Sep 15.
DOI:	10.1159/000534063
Abstrakt:	Introduction: Head-down bed rest (HDBR) has long been used as an analog to microgravity, and it also enables studying the changes occurring with aging. Exercise is the most effective countermeasure for the deleterious effects of inactivity. The aim of this study was to investigate the efficacy of an exercise countermeasure in healthy older participants on attenuating musculoskeletal deconditioning, cardiovascular fitness level, and muscle strength during 14 days of HDBR as part of the standard measures of the Canadian Space Agency. Methods: Twenty-three participants (12 males and 11 females), aged 55-65 years, were admitted for a 26-day inpatient stay at the McGill University Health Centre. After 5 days of baseline assessment tests, they underwent 14 days of continuous HDBR followed by 7 days of recovery with repeated tests. Participants were randomized to passive physiotherapy or an exercise countermeasure during the HDBR period consisting of 3 sessions per day of either high-intensity interval training (HIIT) or low-intensity cycling or strength exercises for the lower and upper body. Peak aerobic power (V̇O2peak) was determined using indirect calorimetry. Body composition was assessed by dual-energy X-ray absorptiometry, and several muscle group strengths were evaluated using an adjustable chair dynamometer. A vertical jump was used to assess whole-body power output, and a tilt test was used to measure cardiovascular and orthostatic challenges. Additionally, changes in various blood parameters were measured as well as the effects of exercise countermeasure on these measurements. Results: There were no differences at baseline in main characteristics between the control and exercise groups. The exercise group maintained V̇O2peak levels similar to baseline, whereas it decreased in the control group following 14 days of HDBR. Body weight significantly decreased in both groups. Total and leg lean masses decreased in both groups. However, total body fat mass decreased only in the exercise group. Isometric and isokinetic knee extension muscle strength were significantly reduced in both groups. Peak velocity, flight height, and flight time were significantly reduced in both groups with HDBR. Conclusion: In this first Canadian HDBR study in older adults, an exercise countermeasure helped maintain aerobic fitness and lean body mass without affecting the reduction of knee extension strength. However, it was ineffective in protecting against orthostatic intolerance. These results support HIIT as a promising approach to preserve astronaut health and functioning during space missions, and to prevent deconditioning as a result of hospitalization in older adults. (© 2023 The Author(s). Published by S. Karger AG, Basel.)
Databáze:	MEDLINE
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