TY - JOUR
T1 - Physiological demands and modulators of body core temperature in 162 tropical recreational runners during mass participation distance running in a warm-humid environment
AU - Sakamoto, Yu
AU - Alhadad, Sharifah Badriyah
AU - Zhang, Xiaohan
AU - Tan, Bing Yang
AU - Ang, Wee Hon
AU - Law, Lydia Yu Li
AU - Prakaash, Suriya
AU - Racinais, Sebastien
AU - Muniz-Pardos, Borja
AU - Bandiera, David
AU - de Barnola, Elena Comadran
AU - Iglesias, Dani Peña
AU - Pitsiladis, Yannis
AU - Lee, Jason Kai Wei
PY - 2025/7/16
Y1 - 2025/7/16
N2 - Objectives: To determine the physiological demands and modulators of body core temperature (Tc)of tropical recreational runners during mass participation distance running in awarm- humid environment (dry-bulb temperature: 27.2±0.4°C, Wet Bulb Globe Temperature: 26.0±0.3°C,relative humidity: 87±2%).Methods: 162 individuals participated in a 21km (n=84) or 10km (n=78) race. Participantsdemographics were recorded in a pre-race questionnaire, and in-race measurementsof environmental conditions, heart rate (HR, n=115), Tc (n=102), skintemperature from four sites (Tsk, n=34) and fluid balance (n=36) wereassessed. Real-time monitoring of HR, Tc and geolocation was conductedand accessed via a multi-user dashboard. Race split and finishing times were extractedfrom official race results. Correlation and multiple linear regression analyseswere performed between various parameters and peak Tc.Results: Participants achieved peak HR (21km: 183±9(154-209)bpm, 10km: 180±10(156- 204)bpm),Tc (21km: 39.4±0.6(38.3-40.8)°C, 10km: 39.3±0.6(38.2-41.1)°C) and Tsk(21km: 34.0±0.6(32.8-35.4) °C, 10km: 33.7±0.8(31.9-35.3) °C). Therewas no difference in mean HR (21km: 163±10(139-188)bpm, 10km: 163±11(133-180)bpm; p=0.516) and Tsk (21km: 32.9±0.9(31.6-34.9)°C,10km: 33.0±0.8(30.9-34.6)°C; p=0.735) between both races. Mean Tc washigher (p<0.05) in 21km (38.7±0.5(37.9-39.8)°C than in 10km (38.5±0.4(37.2-39.9)°C). Tskexhibited an ‘inverted-U’ profile in the 21km but plateaued in the 10km race. Bodymass loss was -2.5±1.1(-5.5 to -0.7)% and -1.3±0.7(-2.4 to +0.5)% for the 21km and10km participants, respectively. Starting Tc, mean HR, Body Surface Area,and average speed, but not age, estimated maximal aerobic capacity nor finishingtime, contributed to peak Tc.Conclusions: Recreational runners experienced high cardiovascular and thermal demands. Weobserved an ‘inverted-U’ Tsk profile in the 21km race in contrast toa plateau commonly described in laboratory-based findings. Starting Tc,mean HR, Body Surface Area, and average speedwere identified as modulators of peak Tc. Real-time monitoring and contributorsof peak Tc can inform targeted interventions to optimise safety ofrecreational populations competing in the heat.
AB - Objectives: To determine the physiological demands and modulators of body core temperature (Tc)of tropical recreational runners during mass participation distance running in awarm- humid environment (dry-bulb temperature: 27.2±0.4°C, Wet Bulb Globe Temperature: 26.0±0.3°C,relative humidity: 87±2%).Methods: 162 individuals participated in a 21km (n=84) or 10km (n=78) race. Participantsdemographics were recorded in a pre-race questionnaire, and in-race measurementsof environmental conditions, heart rate (HR, n=115), Tc (n=102), skintemperature from four sites (Tsk, n=34) and fluid balance (n=36) wereassessed. Real-time monitoring of HR, Tc and geolocation was conductedand accessed via a multi-user dashboard. Race split and finishing times were extractedfrom official race results. Correlation and multiple linear regression analyseswere performed between various parameters and peak Tc.Results: Participants achieved peak HR (21km: 183±9(154-209)bpm, 10km: 180±10(156- 204)bpm),Tc (21km: 39.4±0.6(38.3-40.8)°C, 10km: 39.3±0.6(38.2-41.1)°C) and Tsk(21km: 34.0±0.6(32.8-35.4) °C, 10km: 33.7±0.8(31.9-35.3) °C). Therewas no difference in mean HR (21km: 163±10(139-188)bpm, 10km: 163±11(133-180)bpm; p=0.516) and Tsk (21km: 32.9±0.9(31.6-34.9)°C,10km: 33.0±0.8(30.9-34.6)°C; p=0.735) between both races. Mean Tc washigher (p<0.05) in 21km (38.7±0.5(37.9-39.8)°C than in 10km (38.5±0.4(37.2-39.9)°C). Tskexhibited an ‘inverted-U’ profile in the 21km but plateaued in the 10km race. Bodymass loss was -2.5±1.1(-5.5 to -0.7)% and -1.3±0.7(-2.4 to +0.5)% for the 21km and10km participants, respectively. Starting Tc, mean HR, Body Surface Area,and average speed, but not age, estimated maximal aerobic capacity nor finishingtime, contributed to peak Tc.Conclusions: Recreational runners experienced high cardiovascular and thermal demands. Weobserved an ‘inverted-U’ Tsk profile in the 21km race in contrast toa plateau commonly described in laboratory-based findings. Starting Tc,mean HR, Body Surface Area, and average speedwere identified as modulators of peak Tc. Real-time monitoring and contributorsof peak Tc can inform targeted interventions to optimise safety ofrecreational populations competing in the heat.
KW - Hyperthermia
KW - Thermoregulation
KW - Recreational
KW - Fluid balance
KW - Real-time monitoring
M3 - Journal article
SN - 1746-1391
JO - European Journal of Sport Science
JF - European Journal of Sport Science
ER -