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Age-related reductions in heart rate variability do not worsen during exposure to humid compared to dry heat: A secondary analysis


Carrillo, AE and Flouris, AD and Herry, CL and Notley, SR and Macartney, M and Seely, AJE and Wright Beatty, HE and Kenny, GP, Age-related reductions in heart rate variability do not worsen during exposure to humid compared to dry heat: A secondary analysis, Temperature, 6, (4) pp. 341-345. ISSN 2332-8940 (2019) [Refereed Article]

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Copyright 2019 Informa UK Limited, trading as Taylor & Francis Group

DOI: doi:10.1080/23328940.2019.1684791


We conducted a secondary analysis to investigate whether age-related attenuations in heart rate variability (HRV) worsen during exposure to moderate, dry (36.5C, 20% RH) or humid (36.5C, 60% RH) heat conditions that resulted in greater body heat storage among older compared to young participants, and during humid compared to dry heat, regardless of age. Six HRV indices [heart rate (HR), coefficient of variation (CoV), detrended fluctuation analysis: α1, low frequency power, high frequency power, and low/high frequency ratio] were assessed in 10 young (21 3 y) and 9 older (65 5 y) adults for 15-min prior to (baseline), and at the end of a 120-min exposure to dry and humid heat while seated at rest. Our results demonstrated a condition (dry and humid) x time (baseline and end) interaction effect on HR (p = 0.047) such that HR gradually increased during humid heat exposure yet remained similar during dry heat exposure across groups. We also found an age-related attenuation in CoV at baseline for both the dry (young: 0.097 0.023%; older: 0.054 0.016%) and humid (young: 0.093 0.034%; older: 0.056 0.014%) heat conditions (p < 0.02). Those age-related attenuations in CoV, however, were not magnified throughout the exposure nor different between conditions (p > 0.05). While older adults stored more heat during a brief 120-min exposure to dry heat compared to their young counterparts, this was not paralleled by further age-related impairments in HRV even when body heat storage and cardiovascular strain were exacerbated by exposure to humid heat.

Item Details

Item Type:Refereed Article
Keywords:aging, autonomic nervous system, heat stress, parasympathetic nervous system, relative humidity, sympathetic nervous system
Research Division:Biomedical and Clinical Sciences
Research Group:Neurosciences
Research Field:Autonomic nervous system
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Macartney, M (Mr Michael Macartney)
ID Code:136923
Year Published:2019
Deposited By:Health Sciences
Deposited On:2020-01-22
Last Modified:2020-05-22

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