title: Novel application of chemical cold packs for treatment of exercise-induced hyperthermia: a randomized controlled trial.
abstract: OBJECTIVE
  Heat-related illness is a common disease with significant morbidity and mortality. Despite no proven efficacy, application of chemical cold packs (CCP) to the skin overlying the large vessels of the neck, groin, and axillae is a traditional recommended cooling modality. The study objective was to compare the cooling rates of CCP applied to these traditional areas vs the glabrous skin surfaces of the cheeks, palms, and soles in exercise-induced hyperthermia.
  
  
  METHODS
  Ten healthy adult male volunteers walked on a treadmill in a heated room (40°±0.5°C) while wearing insulated military overgarments until their esophageal temperatures (Tes) reached 39.2°C. Each participant had three heat stress trials on separate days: no treatment followed by randomly ordered traditional (neck, groin, and axillae) cooling and glabrous skin cooling.
  
  
  RESULTS
  With no treatment, Tes remained stable after the first 5 minutes of the heat trial (ΔTes=0.12°±0.07°C/10 min). Traditional cooling followed a linear decline (ΔTes=0.17°±0.04°C/10 min; P<.001). Glabrous cooling enhanced the treatment effect by a steeper decline (ΔTes=0.30°±0.06°C/10 min; P<.001), significantly different from traditional cooling by 2-way analysis of variance (P<.001).
  
  
  CONCLUSIONS
  Application of CCP to glabrous skin surfaces was more effective for treating exercise-induced heat stress than the traditional CCP cooling intervention. This novel cooling technique may be beneficial as an adjunctive treatment for heat-related illness in the prehospital environment.
authors.affiliation: Division of Emergency Medicine, Stanford University School of Medicine, Stanford, CA (Drs Lissoway, Lipman, and Weiss).
authors.forename: John B
authors.initials: JB
authors.lastname: Lissoway
authors.affiliation: Division of Emergency Medicine, Stanford University School of Medicine, Stanford, CA (Drs Lissoway, Lipman, and Weiss). Electronic address: grantlip@hotmail.com.
authors.forename: Grant S
authors.initials: GS
authors.lastname: Lipman
authors.affiliation: Department of Biology, Stanford University, Stanford, CA (Drs Grahn and Heller; Mr Cao).
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Grahn
authors.affiliation: Department of Biology, Stanford University, Stanford, CA (Drs Grahn and Heller; Mr Cao).
authors.forename: Vinh H
authors.initials: VH
authors.lastname: Cao
authors.affiliation: Stanford-Kaiser Emergency Medicine Residency, Stanford, CA (Dr Shaheen).
authors.forename: Michael
authors.initials: M
authors.lastname: Shaheen
authors.affiliation: Department of Engineering, Stanford University, Stanford, CA (Dr Phan).
authors.forename: Samson
authors.initials: S
authors.lastname: Phan
authors.affiliation: Division of Emergency Medicine, Stanford University School of Medicine, Stanford, CA (Drs Lissoway, Lipman, and Weiss).
authors.forename: Eric A
authors.initials: EA
authors.lastname: Weiss
authors.affiliation: Department of Biology, Stanford University, Stanford, CA (Drs Grahn and Heller; Mr Cao).
authors.forename: H Craig
authors.initials: HC
authors.lastname: Heller
mesh_terms: D001833:Body Temperature Regulation; D017679:Cryotherapy / Q000295:instrumentation* / Q000379:methods; D015444:Exercise / Q000502:physiology*; D005334:Fever / Q000628:therapy*; D006358:Hot Temperature; D006801:Humans; D008297:Male
keywords: chemical cold packs; cooling; exercise; glabrous; heat-related illness; hyperthermia