TY - JOUR

T1 - Burn size and environmental conditions modify thermoregulatory responses to exercise in burn survivors

AU - Belval, Luke N.

AU - Cramer, Matthew N.

AU - Moralez, Gilbert

AU - Huang Dpt, Mu

AU - Watso, Joseph C.

AU - Fischer, Mads

AU - Crandall, Craig G.

N1 - Publisher Copyright: © The Author(s) 2023. Published by Oxford University Press on behalf of the American Burn Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

PY - 2024

Y1 - 2024

N2 - This project tested the hypothesis that burn survivors can perform mild/moderate-intensity exercise in temperate and hot environments without excessive elevations in core body temperature. Burn survivors with low (23±5%TBSA; N=11), moderate (40±5%TBSA; N=9), and high (60±8%TBSA; N=9) burn injuries performed 60 minutes of cycle ergometry exercise (72±15 watts) in a 25°C and 23% relative humidity environment (i.e., temperate) and in a 40°C and 21% relative humidity environment (i.e., hot). Absolute gastrointestinal temperatures (TGI) and changes in TGI (ΔTGI) were obtained. Participants with an absolute TGI of >38.5°C and/or a ΔTGI of >1.5°C were categorized as being at risk for hyperthermia. For the temperate environment, exercise increased ΔTGI in all groups (Low: 0.72±0.21°C; Moderate: 0.42±0.22°C; High: 0.77±0.25°C, all P<0.01 from pre-exercise baselines), resulting in similar absolute end-exercise TGI values (P=0.19). Importantly, no participant was categorized as being at risk for hyperthermia, based upon the aforementioned criteria. For the hot environment, ΔTGI at the end of the exercise bout was greater for the High group when compared to the Low group (P=0.049). Notably, 33% of the Moderate cohort and 56% of the High cohort reached or exceeded a core temperature of 38.5°C, while none in the Low cohort exceeded this threshold. These data suggest that individuals with a substantial %TBSA burned can perform mild/moderate intensity exercise for 60 minutes in temperate environmental conditions without risk of excessive elevations in TGI. Conversely, the risk of excessive elevations in TGI during mild/moderate intensity exercise in a hot environment increases with the %TBSA burned.

AB - This project tested the hypothesis that burn survivors can perform mild/moderate-intensity exercise in temperate and hot environments without excessive elevations in core body temperature. Burn survivors with low (23±5%TBSA; N=11), moderate (40±5%TBSA; N=9), and high (60±8%TBSA; N=9) burn injuries performed 60 minutes of cycle ergometry exercise (72±15 watts) in a 25°C and 23% relative humidity environment (i.e., temperate) and in a 40°C and 21% relative humidity environment (i.e., hot). Absolute gastrointestinal temperatures (TGI) and changes in TGI (ΔTGI) were obtained. Participants with an absolute TGI of >38.5°C and/or a ΔTGI of >1.5°C were categorized as being at risk for hyperthermia. For the temperate environment, exercise increased ΔTGI in all groups (Low: 0.72±0.21°C; Moderate: 0.42±0.22°C; High: 0.77±0.25°C, all P<0.01 from pre-exercise baselines), resulting in similar absolute end-exercise TGI values (P=0.19). Importantly, no participant was categorized as being at risk for hyperthermia, based upon the aforementioned criteria. For the hot environment, ΔTGI at the end of the exercise bout was greater for the High group when compared to the Low group (P=0.049). Notably, 33% of the Moderate cohort and 56% of the High cohort reached or exceeded a core temperature of 38.5°C, while none in the Low cohort exceeded this threshold. These data suggest that individuals with a substantial %TBSA burned can perform mild/moderate intensity exercise for 60 minutes in temperate environmental conditions without risk of excessive elevations in TGI. Conversely, the risk of excessive elevations in TGI during mild/moderate intensity exercise in a hot environment increases with the %TBSA burned.

KW - air temperature

KW - exercise

KW - rehabilitation

KW - thermoregulation

U2 - 10.1093/jbcr/irad128

DO - 10.1093/jbcr/irad128

M3 - Journal article

C2 - 37615621

VL - 45

SP - 227

EP - 233

JO - Journal of Burn Care and Research

JF - Journal of Burn Care and Research

SN - 1559-047X

IS - 1

ER -