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 language | English |
|---|---|
| Pages (from-to) | 1-9 |
| Number of pages | 9 |
| Journal | Journal of Thermal Biology |
| Volume | 82 |
| DOIs | |
| Publication status | Published - 16 Mar 2019 |
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Keywords
- Fire service
- Heat tolerance
- Inflammation
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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 journal › Article › Research › peer-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
UR - http://www.scopus.com/inward/record.url?scp=85063078700&partnerID=8YFLogxK
U2 - 10.1016/j.jtherbio.2019.03.005
DO - 10.1016/j.jtherbio.2019.03.005
M3 - Article
VL - 82
SP - 1
EP - 9
JO - Journal of Thermal Biology
T2 - Journal of Thermal Biology
JF - Journal of Thermal Biology
SN - 0306-4565
ER -