Do older females store more heat than younger females during exercise in the heat?
|DOI||Resolve DOI: http://doi.org/10.1249/MSS.0b013e31829d24cc|
|Author||Search for: Larose, Joanie; Search for: Wright, Heather E.; Search for: Sigal, Ronald J.; Search for: Boulay, Pierre; Search for: Hardcastle, Stephen; Search for: Kenny, Glen P.|
|Journal title||Medicine & Science in Sports & Exercise|
|Subject||aging, heat stress; thermoregulation; skin blood flow; sweating; calorimetry|
|Abstract||Introduction: Aging is associated with a reduction in the body’s capacity to dissipate heat. To date, few studies have examined age-related changes in thermoregulatory function during short exercise periods in the heat in older females. Purpose: This study aimed to investigate the effects of age on whole-body heat loss during intermittent exercise in the heat in young and older females. Methods: Direct and indirect calorimetry was used to measure whole-body evaporative heat loss (EHL), change in body heat content, and metabolic heat production. Eleven young (Y) (mean T SD age = 24 T 4 yr) and 13 older (O) (51 T 8 yr) females matched for body surface area (Y, 1.72 T 0.15; O, 1.75 T 0.12 m2) and fitness (V˙ O2max) (Y, 36.7 T 6.8 mL O2Ikgj1Iminj1; O, 33.8 T 8.0 mL O2Ikgj1Iminj1) performed four bouts of 15-min cycling (Ex1, Ex2, Ex3, and Ex4) at a constant rate of heat production (300 W) at 35-C and 20% relative humidity. Each exercise bout was separated by 15 min of rest. Results: EHL was reduced in O compared with Y during Ex1 (O, 199 T6 W; Y, 240 T9 W; P = 0.001), Ex2 (O, 238 T4 W; Y, 261 T 9 W, P = 0.023), and Ex3 (O, 249 T 4 W; Y, 274 T 11 W; P = 0.040). EHL was not different between groups during Ex4 or during the recovery periods. Older females had a greater change in body heat content compared with young females (O, 270 T 20 kJ; Y, 166 T 20 kJ; P = 0.001). Conclusion: These findings suggest that older females have a lower capacity for whole-body EHL compared with younger females during short intermittent exercise in the heat performed at a fixed rate of metabolic heat production|
|Publisher||American College of Sports Medicine|
This is a non-NRC publication
"Non-NRC publications" are publications authored by NRC employees prior to their employment by NRC.
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