title: Physical Effort Affects Heatstroke Thermoregulatory Response and Mortality in Rats.
abstract: Animals suffering from heatstroke (HS) after physical effort may have different heat-related core temperature (Tc) responses compared with passive HS. In the present study, conscious and unrestrained rats were exposed to ambient temperature (Ta) of 39.5°C ± 0.2°C with or without running (run-heated or rest-heated, respectively) until HS onset, which was defined as the systolic blood pressure starting to drop. In comparison with rest-heated rats, run-heated rats had a significantly shorter latency of HS onset. Physical effort did not have significant influence on hyperthermia severity (43.3°C ± 0.2°C at rest-heated, and 43.4°C ± 0.2°C at run-heated), but it could significantly decrease the thermal load to develop HS (315.1°C ± 37.3°C·min for rest-heated, and 133.5 ± 21.4 °C·min for run-heated). Working component during heat exposure may contribute to a decreased survival rate of HS (46.9% at rest-heated and 31.3% at run-heated). Impaired heat dissipation during recovery may be responsible for relative poor survival of run-heated rats. In both groups, survival was affected by Tc at HS onset and thermal area. Hypothermia (Tc <35°C) developed after HS onset, with no significant difference in Tc,min between the rest-heated and run-heated groups. These thermoregulatory responses to HS after physical effort may provide insight into HS pathophysiology.
authors.affiliation: *Department of Gastroenterology, 303 Hospital of People's Liberation Army of China, Nanning, PR China; †Department of Intensive Care Unit, General Hospital of GuangZhou Military Command, GuangZhou, PR China; ‡Department of Graduate School, Southern Medical University, Guangzhou, PR China; §Department of Neurology, The Fifth People's Hospital of Chongqing, Chongqing, PR China; and ∥State Key Laboratory of Organ Failure Research, Institute of Antibody Engineering, Southern Medical University, Guangzhou, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Geng
authors.forename: Na
authors.initials: N
authors.lastname: Peng
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Liu
authors.forename: Xing-Gui
authors.initials: XG
authors.lastname: Li
authors.forename: Bing-Lin
authors.initials: BL
authors.lastname: Li
authors.forename: Li-Qiong
authors.initials: LQ
authors.lastname: Peng
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ma
authors.forename: Lei
authors.initials: L
authors.lastname: Su
mesh_terms: D000064:Acclimatization; D000818:Animals; D062186:Arterial Pressure; D001794:Blood Pressure; D001831:Body Temperature; D001833:Body Temperature Regulation; D005334:Fever; D018883:Heat Stroke / Q000503:physiopathology*; D006358:Hot Temperature; D007035:Hypothermia; D008297:Male; D005082:Physical Exertion; D051381:Rats; D017207:Rats, Sprague-Dawley; D012307:Risk Factors; D012420:Running