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dc.contributor.authorKenny, Glen P
dc.contributor.authorPoirier, Martin P
dc.contributor.authorMetsios, George S.
dc.contributor.authorBoulay, Pierre
dc.contributor.authorDervis, Sheila
dc.contributor.authorFriesen, Brian J
dc.contributor.authorMalcolm, Janine
dc.contributor.authorSigal, Ronald J
dc.contributor.authorSeely, Andrew J E
dc.contributor.authorFlouris, Andreas D
dc.date.accessioned2017-05-10T15:44:57Z
dc.date.available2017-05-10T15:44:57Z
dc.date.issued2016-09-30
dc.identifier.citationKenny GP., Poirier MP., Metsios GS., Boulay P., Dervis S., Friesen B.J, Malcolm J., Sigal RJ., Seely AJ., Flouris AD. (2017) 'Hyperthermia and cardiovascular strain during an extreme heat exposure in young versus older adults', Temperature, 4(1) pp. 79-88. doi: 10.1080/23328940.2016.1230171
dc.identifier.issn2332-8940
dc.identifier.pmid28349096
dc.identifier.doi10.1080/23328940.2016.1230171
dc.identifier.urihttp://hdl.handle.net/2436/620473
dc.description.abstractWe examined whether older individuals experience greater levels of hyperthermia and cardiovascular strain during an extreme heat exposure compared to young adults. During a 3-hour extreme heat exposure (44°C, 30% relative humidity), we compared body heat storage, core temperature (rectal, visceral) and cardiovascular (heart rate, cardiac output, mean arterial pressure, limb blood flow) responses of young adults (n = 30, 19-28 years) against those of older adults (n = 30, 55-73 years). Direct calorimetry measured whole-body evaporative and dry heat exchange. Body heat storage was calculated as the temporal summation of heat production (indirect calorimetry) and whole-body heat loss (direct calorimetry) over the exposure period. While both groups gained a similar amount of heat in the first hour, the older adults showed an attenuated increase in evaporative heat loss (p < 0.033) in the first 30-min. Thereafter, the older adults were unable to compensate for a greater rate of heat gain (11 ± 1 ; p < 0.05) with a corresponding increase in evaporative heat loss. Older adults stored more heat (358 ± 173 kJ) relative to their younger (202 ± 92 kJ; p < 0.001) counterparts at the end of the exposure leading to greater elevations in rectal (p = 0.043) and visceral (p = 0.05) temperatures, albeit not clinically significant (rise < 0.5°C). Older adults experienced a reduction in calf blood flow (p < 0.01) with heat stress, yet no differences in cardiac output, blood pressure or heart rate. We conclude, in healthy habitually active individuals, despite no clinically observable cardiovascular or temperature changes, older adults experience greater heat gain and decreased limb perfusion in response to 3-hour heat exposure.
dc.language.isoen
dc.publisherTaylor & Francis
dc.relation.urlhttps://www.tandfonline.com/doi/full/10.1080/23328940.2016.1230171
dc.subjectaging
dc.subjectcalorimetry
dc.subjectclimate change
dc.subjectextreme heat events
dc.subjectheat stress
dc.titleHyperthermia and cardiovascular strain during an extreme heat exposure in young versus older adults
dc.typeJournal article
dc.identifier.journalTemperature
dc.date.accepted2016-08-25
rioxxterms.funderUniversity of Wolverhampton
rioxxterms.identifier.projectUOW100517GM
rioxxterms.versionVoR
rioxxterms.licenseref.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/
rioxxterms.licenseref.startdate2017-05-10
dc.source.volume4
dc.source.issue1
dc.source.beginpage79
dc.source.endpage88
refterms.dateFCD2018-10-19T09:05:57Z
refterms.versionFCDVoR
refterms.dateFOA2017-05-10T00:00:00Z
html.description.abstractWe examined whether older individuals experience greater levels of hyperthermia and cardiovascular strain during an extreme heat exposure compared to young adults. During a 3-hour extreme heat exposure (44°C, 30% relative humidity), we compared body heat storage, core temperature (rectal, visceral) and cardiovascular (heart rate, cardiac output, mean arterial pressure, limb blood flow) responses of young adults (n = 30, 19-28 years) against those of older adults (n = 30, 55-73 years). Direct calorimetry measured whole-body evaporative and dry heat exchange. Body heat storage was calculated as the temporal summation of heat production (indirect calorimetry) and whole-body heat loss (direct calorimetry) over the exposure period. While both groups gained a similar amount of heat in the first hour, the older adults showed an attenuated increase in evaporative heat loss (p < 0.033) in the first 30-min. Thereafter, the older adults were unable to compensate for a greater rate of heat gain (11 ± 1 ; p < 0.05) with a corresponding increase in evaporative heat loss. Older adults stored more heat (358 ± 173 kJ) relative to their younger (202 ± 92 kJ; p < 0.001) counterparts at the end of the exposure leading to greater elevations in rectal (p = 0.043) and visceral (p = 0.05) temperatures, albeit not clinically significant (rise < 0.5°C). Older adults experienced a reduction in calf blood flow (p < 0.01) with heat stress, yet no differences in cardiac output, blood pressure or heart rate. We conclude, in healthy habitually active individuals, despite no clinically observable cardiovascular or temperature changes, older adults experience greater heat gain and decreased limb perfusion in response to 3-hour heat exposure.


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