Interactive effects of age and hydration state on human thermoregulatory function during exercise in hot-dry conditions
Meade RD, Notley SR, D'Souza AW, Dervis S, Boulay P, Sigal RJ, Kenny GP
Acta physiologica (Oxford, England) · 12 citations
How it was studied
- Design
- Controlled clinical trial (classified by our AI screen)
- Studied in
- People
- Main outcome
- Health markers and function
Who paid for it
- Funding
- Independent funding
- Government
- Government of Ontario
- Government
- Alberta Innovates - Health Solutions
- Government
- Natural Sciences and Engineering Research Council of Canada
- Government
- Queen Elizabeth II Graduate Scholarship in Science and Technology
- Government
- Alberta Innovates-Health Solutions
- University or hospital
- University of Ottawa Research Chair
- University or hospital
- Human and Environmental Physiology Research Unit
Based on 7 listed funder(s).
Publication
- Published
- 2018-11-27 · Acta Physiol (Oxf) · vol. 226 · issue 1 · p. e13226
- Publisher
- Wiley
- Cited
- 22 citations · more than 76% of similar papers · 1.0× the field average
- References
- 47 works
- Access
- Paywalled
- Research areas
- Thermoregulation and physiological responses · Exercise and Physiological Responses · Body Composition Measurement Techniques
- Keywords
- Thermoregulation, Relative humidity, Medicine, Chemistry, Ageing, Animal science, Internal medicine, Thermodynamics
- MeSH
- humans, exercise, humidity, body temperature regulation, aging, heart rate, adult, middle aged, male, hot temperature, young adult, organism hydration status
7 authors
From CA
- Robert D. MeadeUniversity of Ottawa
- Sean R. NotleyUniversity of Ottawa
- Andrew W. D’SouzaUniversity of Ottawa
- Sheila DervisUniversity of Ottawa
- Pierre BoulayUniversité de Sherbrooke
- Ronald J. SigalUniversity of Ottawa; University of Calgary; Ottawa Hospital; Ottawa Hospital Research Institute
Abstract
Aim
Ageing and hypohydration independently attenuate heat dissipation during exercise; however, the interactive effects of these factors remain unclear. We assessed the hypothesis that ageing suppresses hypohydration-induced reductions in whole-body heat loss during exercise in the heat.
Methods
On two occasions, eight young (mean [SD]: 24 [4] years) and eight middle-aged (59 [5] years) men performed 30-minute bouts of light (heat production of 175 W m-2 ) and moderate (275 W m-2 ) cycling (separated by 15-minute rest) in the heat (40°C, 15% relative humidity) when euhydrated and hypohydrated (~4% reduction in body mass). Heat production and whole-body net heat exchange (evaporative heat loss + dry heat gain) were measured via indirect and direct calorimetry (respectively) and heat storage was calculated via their temporal summation.
Results
Net heat exchange was reduced, while heat storage was elevated, in the middle-aged men during moderate exercise when euhydrated (both P ≤ 0.01). In the young, evaporative heat loss was attenuated in the hypohydrated vs euhydrated condition during light (199 ± 6 vs 211 ± 10 W m-2 ; P ≤ 0.01) and moderate (287 ± 15 vs 307 ± 13 W m-2 ; P ≤ 0.01) exercise, but was similar in the middle-aged men, averaging 223 ± 6 and 299 ± 15 W m-2 , respectively, across conditions (both P ≥ 0.32). Heat storage was thereby exacerbated by hypohydration in the young (both P < 0.01) but not the middle-aged (both P ≥ 0.32) during both exercise bouts and, as a result, was similar between groups when hypohydrated (both P ≥ 0.50).
Conclusion
Hypohydration attenuates heat loss via sweating in young but not middle-aged men, indicating that ageing impairs one's ability to mitigate further sweat-induced fluid loss during hypohydration.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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