Carbohydrate, but Not Fat, Oxidation is Reduced During Moderate-Intensity Exercise Performed in 33 vs. 18 °C at Matched Heart Rates

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aut.relation.endpage2085
aut.relation.issue9
aut.relation.journalEuropean Journal of Applied Physiology
aut.relation.startpage2073
aut.relation.volume123
dc.contributor.authorCharoensap, Thanchanok
dc.contributor.authorKilding, Andrew E
dc.contributor.authorMaunder, Ed
dc.date.accessioned2023-11-24T03:13:51Z
dc.date.available2023-11-24T03:13:51Z
dc.date.issued2023-05-18
dc.description.abstractPURPOSE: Exposure to environmental heat stress increases carbohydrate oxidation and extracellular heat shock protein 70 (HSP70) concentrations during endurance exercise at matched absolute, external work rates. However, a reduction in absolute work rate typically occurs when unacclimated endurance athletes train and/or compete in hot environments. We sought to determine the effect of environmental heat stress on carbohydrate oxidation rates and plasma HSP70 expression during exercise at matched heart rates (HR). METHODS: Ten endurance-trained, male cyclists performed two experimental trials in an acute, randomised, counterbalanced cross-over design. Each trial involved a 90-min bout of cycling exercise at 95% of the HR associated with the first ventilatory threshold in either 18 (TEMP) or 33 °C (HEAT), with ~ 60% relative humidity. RESULTS: Mean power output (17 ± 11%, P < 0.001) and whole-body energy expenditure (14 ± 8%, P < 0.001) were significantly lower in HEAT. Whole-body carbohydrate oxidation rates were significantly lower in HEAT (19 ± 11%, P = 0.002), while fat oxidation rates were not different between-trials. The heat stress-induced reduction in carbohydrate oxidation was associated with the observed reduction in power output (r = 0.64, 95% CI, 0.01, 0.91, P = 0.05) and augmented sweat rates (r = 0.85, 95% CI, 0.49, 0.96, P = 0.002). Plasma HSP70 and adrenaline concentrations were not increased with exercise in either environment. CONCLUSION: These data contribute to our understanding of how moderate environmental heat stress is likely to influence substrate oxidation and plasma HSP70 expression in an ecologically-valid model of endurance exercise.
dc.identifier.citationEuropean Journal of Applied Physiology, ISSN: 1439-6319 (Print); 1439-6327 (Online), Springer, 123(9), 2073-2085. doi: 10.1007/s00421-023-05225-0
dc.identifier.doi10.1007/s00421-023-05225-0
dc.identifier.issn1439-6319
dc.identifier.issn1439-6327
dc.identifier.urihttp://hdl.handle.net/10292/17002
dc.languageeng
dc.publisherSpringer
dc.relation.urihttps://link.springer.com/article/10.1007/s00421-023-05225-0
dc.rightsOpen Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
dc.rights.accessrightsOpenAccess
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.subjectCycling
dc.subjectHeat
dc.subjectIntensity
dc.subjectSubstrate metabolism
dc.subjectCycling
dc.subjectHeat
dc.subjectIntensity
dc.subjectSubstrate metabolism
dc.subject42 Health Sciences
dc.subject4207 Sports Science and Exercise
dc.subjectCardiovascular
dc.subjectPrevention
dc.subjectHeart Disease
dc.subjectCardiovascular
dc.subject1106 Human Movement and Sports Sciences
dc.subjectSport Sciences
dc.subject3202 Clinical sciences
dc.subject3208 Medical physiology
dc.subject4207 Sports science and exercise
dc.subject.meshHumans
dc.subject.meshMale
dc.subject.meshHeart Rate
dc.subject.meshExercise
dc.subject.meshOxidation-Reduction
dc.subject.meshEnergy Metabolism
dc.subject.meshCarbohydrates
dc.subject.meshHumans
dc.subject.meshCarbohydrates
dc.subject.meshExercise
dc.subject.meshEnergy Metabolism
dc.subject.meshOxidation-Reduction
dc.subject.meshHeart Rate
dc.subject.meshMale
dc.subject.meshHumans
dc.subject.meshMale
dc.subject.meshHeart Rate
dc.subject.meshExercise
dc.subject.meshOxidation-Reduction
dc.subject.meshEnergy Metabolism
dc.subject.meshCarbohydrates
dc.titleCarbohydrate, but Not Fat, Oxidation is Reduced During Moderate-Intensity Exercise Performed in 33 vs. 18 °C at Matched Heart Rates
dc.typeJournal Article
pubs.elements-id506968
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