Heat tolerance of Fire Service Instructors

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Objectives: Fire Service Instructors (FSI) experience repeated fire exposures a median of 13 ± 8 times a month; consequently they may develop an acclimatised state. However, the chronic immunological implications of heat acclimation are yet to be understood. This study aimed to establish whether FSI exhibit an increased heat tolerance and altered immunological response to heat exposures, compared to non-exposed individuals. The study also aimed to identify if heat tolerance is related to symptoms of ill health. Methods: Twenty-two participants were recruited: 11 FSI (age: 41 ± 7 yrs, body mass: 77.4 ± 12.2 kg, height: 174.1 ± 8.2 cm) and 11 non-exposed controls (CON) (age: 41 ± 7 yrs, body mass: 75.9 ± 12.2 kg, height: 177.0 ± 8.1 cm). Participants completed a 40 min heat occupational tolerance test (HOTT) exercising at 6 W kg −1 (50.0 ± 1.0 °C, 12.3 ± 3.3% relative humidity) on two occasions, separated by 2 months. Physiological and perceptual measures were collected throughout and venous blood samples were collected prior to and post exposure. Results: FSI displayed significantly reduced peak rectal temperature (T re ) (−0.42 °C), change in T re (−0.33 °C), and thermal sensation (−1.0) and increased sweat rate (+0.25 L h −1 ) at the end of the HOTT compared to CON (p < 0.05). FSI exhibited similar responses to the HOTT as CON for all haematological variables. However, resting interleukin-6, interleukin-1β and immunoglobulin G were significantly greater in FSI than CON. There was no difference in responses following the 2 month working period. FSI peak T re was negatively correlated with symptoms of ill health (r pb = −0.473, p = 0.026) and the number of fire exposures in the previous 2 weeks (r s = −0.589, p = 0.004). Conclusion: Despite increased heat tolerance compared to non-exposed individuals, FSI may develop a maladaptation to repeated fire exposures, with elevated resting cytokine levels and an increased prevalence of ill health symptoms.

Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalJournal of Thermal Biology
Volume82
DOIs
Publication statusPublished - 16 Mar 2019

Fingerprint

teachers
heat tolerance
Fires
heat
signs and symptoms (animals and humans)
Hot Temperature
Health
Temperature
Thermotolerance
sweat
temperature
Sweat
Acclimatization
immunoglobulin G
testing
interleukin-1
Humidity
Interleukin-1
interleukin-6
Interleukin-6

Keywords

  • Fire service
  • Heat tolerance
  • Inflammation

Cite this

@article{2e3a0b06f0ac4e0ea79ff5437a539e8d,
title = "Heat tolerance of Fire Service Instructors",
abstract = "Objectives: Fire Service Instructors (FSI) experience repeated fire exposures a median of 13 ± 8 times a month; consequently they may develop an acclimatised state. However, the chronic immunological implications of heat acclimation are yet to be understood. This study aimed to establish whether FSI exhibit an increased heat tolerance and altered immunological response to heat exposures, compared to non-exposed individuals. The study also aimed to identify if heat tolerance is related to symptoms of ill health. Methods: Twenty-two participants were recruited: 11 FSI (age: 41 ± 7 yrs, body mass: 77.4 ± 12.2 kg, height: 174.1 ± 8.2 cm) and 11 non-exposed controls (CON) (age: 41 ± 7 yrs, body mass: 75.9 ± 12.2 kg, height: 177.0 ± 8.1 cm). Participants completed a 40 min heat occupational tolerance test (HOTT) exercising at 6 W kg −1 (50.0 ± 1.0 °C, 12.3 ± 3.3{\%} relative humidity) on two occasions, separated by 2 months. Physiological and perceptual measures were collected throughout and venous blood samples were collected prior to and post exposure. Results: FSI displayed significantly reduced peak rectal temperature (T re ) (−0.42 °C), change in T re (−0.33 °C), and thermal sensation (−1.0) and increased sweat rate (+0.25 L h −1 ) at the end of the HOTT compared to CON (p < 0.05). FSI exhibited similar responses to the HOTT as CON for all haematological variables. However, resting interleukin-6, interleukin-1β and immunoglobulin G were significantly greater in FSI than CON. There was no difference in responses following the 2 month working period. FSI peak T re was negatively correlated with symptoms of ill health (r pb = −0.473, p = 0.026) and the number of fire exposures in the previous 2 weeks (r s = −0.589, p = 0.004). Conclusion: Despite increased heat tolerance compared to non-exposed individuals, FSI may develop a maladaptation to repeated fire exposures, with elevated resting cytokine levels and an increased prevalence of ill health symptoms.",
keywords = "Fire service, Heat tolerance, Inflammation",
author = "Watkins, {Emily R.} and Mark Hayes and Peter Watt and Richardson, {Alan J.}",
year = "2019",
month = "3",
day = "16",
doi = "10.1016/j.jtherbio.2019.03.005",
language = "English",
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}

Heat tolerance of Fire Service Instructors. / Watkins, Emily R.; Hayes, Mark; Watt, Peter; Richardson, Alan J.

In: Journal of Thermal Biology, Vol. 82, 16.03.2019, p. 1-9.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Heat tolerance of Fire Service Instructors

AU - Watkins, Emily R.

AU - Hayes, Mark

AU - Watt, Peter

AU - Richardson, Alan J.

PY - 2019/3/16

Y1 - 2019/3/16

N2 - Objectives: Fire Service Instructors (FSI) experience repeated fire exposures a median of 13 ± 8 times a month; consequently they may develop an acclimatised state. However, the chronic immunological implications of heat acclimation are yet to be understood. This study aimed to establish whether FSI exhibit an increased heat tolerance and altered immunological response to heat exposures, compared to non-exposed individuals. The study also aimed to identify if heat tolerance is related to symptoms of ill health. Methods: Twenty-two participants were recruited: 11 FSI (age: 41 ± 7 yrs, body mass: 77.4 ± 12.2 kg, height: 174.1 ± 8.2 cm) and 11 non-exposed controls (CON) (age: 41 ± 7 yrs, body mass: 75.9 ± 12.2 kg, height: 177.0 ± 8.1 cm). Participants completed a 40 min heat occupational tolerance test (HOTT) exercising at 6 W kg −1 (50.0 ± 1.0 °C, 12.3 ± 3.3% relative humidity) on two occasions, separated by 2 months. Physiological and perceptual measures were collected throughout and venous blood samples were collected prior to and post exposure. Results: FSI displayed significantly reduced peak rectal temperature (T re ) (−0.42 °C), change in T re (−0.33 °C), and thermal sensation (−1.0) and increased sweat rate (+0.25 L h −1 ) at the end of the HOTT compared to CON (p < 0.05). FSI exhibited similar responses to the HOTT as CON for all haematological variables. However, resting interleukin-6, interleukin-1β and immunoglobulin G were significantly greater in FSI than CON. There was no difference in responses following the 2 month working period. FSI peak T re was negatively correlated with symptoms of ill health (r pb = −0.473, p = 0.026) and the number of fire exposures in the previous 2 weeks (r s = −0.589, p = 0.004). Conclusion: Despite increased heat tolerance compared to non-exposed individuals, FSI may develop a maladaptation to repeated fire exposures, with elevated resting cytokine levels and an increased prevalence of ill health symptoms.

AB - Objectives: Fire Service Instructors (FSI) experience repeated fire exposures a median of 13 ± 8 times a month; consequently they may develop an acclimatised state. However, the chronic immunological implications of heat acclimation are yet to be understood. This study aimed to establish whether FSI exhibit an increased heat tolerance and altered immunological response to heat exposures, compared to non-exposed individuals. The study also aimed to identify if heat tolerance is related to symptoms of ill health. Methods: Twenty-two participants were recruited: 11 FSI (age: 41 ± 7 yrs, body mass: 77.4 ± 12.2 kg, height: 174.1 ± 8.2 cm) and 11 non-exposed controls (CON) (age: 41 ± 7 yrs, body mass: 75.9 ± 12.2 kg, height: 177.0 ± 8.1 cm). Participants completed a 40 min heat occupational tolerance test (HOTT) exercising at 6 W kg −1 (50.0 ± 1.0 °C, 12.3 ± 3.3% relative humidity) on two occasions, separated by 2 months. Physiological and perceptual measures were collected throughout and venous blood samples were collected prior to and post exposure. Results: FSI displayed significantly reduced peak rectal temperature (T re ) (−0.42 °C), change in T re (−0.33 °C), and thermal sensation (−1.0) and increased sweat rate (+0.25 L h −1 ) at the end of the HOTT compared to CON (p < 0.05). FSI exhibited similar responses to the HOTT as CON for all haematological variables. However, resting interleukin-6, interleukin-1β and immunoglobulin G were significantly greater in FSI than CON. There was no difference in responses following the 2 month working period. FSI peak T re was negatively correlated with symptoms of ill health (r pb = −0.473, p = 0.026) and the number of fire exposures in the previous 2 weeks (r s = −0.589, p = 0.004). Conclusion: Despite increased heat tolerance compared to non-exposed individuals, FSI may develop a maladaptation to repeated fire exposures, with elevated resting cytokine levels and an increased prevalence of ill health symptoms.

KW - Fire service

KW - Heat tolerance

KW - Inflammation

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JF - Journal of Thermal Biology

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