Elevated brain temperature under severe heat exposure impairs cortical motor activity and executive function  

作　　者：Xiang Ren Tan Mary C.Stephenson Sharifah Badriyah Alhadad Kelvin W.Z.Loh Tuck Wah Soong Jason K.W.Lee Ivan C.C.Low 

机构地区：[1]Health and Social Sciences,Singapore Institute of Technology,Singapore 138683,Singapore [2]Human Potential Translational Research Programme,Yong Loo Lin School of Medicine,National University of Singapore,Singapore 117597,Singapore [3]Centre for Translational Magnetic Resonance Research,Yong Loo Lin School of Medicine,National University of Singapore,Singapore 117549,Singapore [4]Department of Physiology,Yong Loo Lin School of Medicine,National University of Singapore,Singapore 117593,Singapore [5]Heat Resilience and Performance Centre,Yong Loo Lin School of Medicine,National University of Singapore,Singapore 117510,Singapore [6]N.1 Institute for Health,National University of Singapore,Singapore 117456,Singapore [7]Campus for Research Excellence and Technological Enterprise(CREATE),Singapore 138602,Singapore

出　　处：《Journal of Sport and Health Science》2024年第2期233-244,共12页运动与健康科学（英文）

基　　金：supported by Defence Innovative Research Program(DIRP)Grant(PA No.9015102335)from Defence Research&Technology Office,Ministry of Defence,Singapore。

摘　　要：Background:Excessive heat exposure can lead to hyperthermia in humans,which impairs physical performance and disrupts cognitive function.While heat is a known physiological stressor,it is unclear how severe heat stress affects brain physiology and function.Methods:Eleven healthy participants were subjected to heat stress from prolonged exercise or warm water immersion until their rectal temperatures(T_(re))attained 39.5℃,inducing exertional or passive hyperthermia,respectively.In a separate trial,blended ice was ingested before and during exercise as a cooling strategy.Data were compared to a control condition with seated rest(normothermic).Brain temperature(T_(br)),cerebral perfusion,and task-based brain activity were assessed using magnetic resonance imaging techniques.Results:T_(br)in motor cortex was found to be tightly regulated at rest(37.3℃±0.4℃(mean±SD))despite fluctuations in T_(re).With the development of hyperthermia,T_(br)increases and dovetails with the rising T_(re).Bilateral motor cortical activity was suppressed during high-intensity plantarflexion tasks,implying a reduced central motor drive in hyperthermic participants(T_(re)=38.5℃±0.1℃).Global gray matter perfusion and regional perfusion in sensorimotor cortex were reduced with passive hyperthermia.Executive function was poorer under a passive hyperthermic state,and this could relate to compromised visual processing as indicated by the reduced activation of left lateral-occipital cortex.Conversely,ingestion of blended ice before and during exercise alleviated the rise in both T_(re)and T_(bc)and mitigated heat-related neural perturbations.Conclusion:Severe heat exposure elevates T_(br),disrupts motor cortical activity and executive function,and this can lead to impairment of physical and cognitive performance.

关 键 词：Brain functional activity COGNITION Heat stress HYPERTHERMIA Motor function 

分 类 号：G804.2[文化科学—运动人体科学]