Acute whole-body cooling for exercise-induced hyperthermia: a systematic review

Abstract

Objective: To assess existing original research addressing the efficiency of whole-body cooling modalities in the treatment of exertional hyperthermia.

Data sources: During April 2007, we searched MEDLINE, EMBASE, Scopus, SportDiscus, CINAHL, and Cochrane Reviews databases as well as ProQuest for theses and dissertations to identify research studies evaluating whole-body cooling treatments without limits. Key words were cooling, cryotherapy, water immersion, cold-water immersion, ice-water immersion, icing, fanning, bath, baths, cooling modality, heat illness, heat illnesses, exertional heatstroke, exertional heat stroke, heat exhaustion, hyperthermia, hyperthermic, hyperpyrexia, exercise, exertion, running, football, military, runners, marathoner, physical activity, marathoning, soccer, and tennis.

Data synthesis: Two independent reviewers graded each study on the Physiotherapy Evidence Database (PEDro) scale. Seven of 89 research articles met all inclusion criteria and a minimum score of 4 out of 10 on the PEDro scale.

Conclusions: After an extensive and critical review of the available research on whole-body cooling for the treatment of exertional hyperthermia, we concluded that ice-water immersion provides the most efficient cooling. Further research comparing whole-body cooling modalities is needed to identify other acceptable means. When ice-water immersion is not possible, continual dousing with water combined with fanning the patient is an alternative method until more advanced cooling means can be used. Until future investigators identify other acceptable whole-body cooling modalities for exercise-induced hyperthermia, ice-water immersion and cold-water immersion are the methods proven to have the fastest cooling rates.

Keywords: cryotherapy; evidence-based practice; exertional heat illness; modalities.

Figure 1. Selection process for articles included in the systematic review. PEDro indicates Physiotherapy Evidence Database.

Figure 2. Mean cooling rates from case reports and critically reviewed articles. Mean cooling rates defined as unacceptable are <0.078°C · min⁻¹, acceptable are 0.078°C to 0.154°C · min⁻¹, and ideal are ≥0.155°C · min⁻¹. IV indicates intravenous.

^a Ice-water immersion, 2°C (n  =  7): 0.35°C · min⁻¹. ^b Ice-water immersion, 1–3°C (n  =  14): 0.2°C · min⁻¹. ^c Cold-water immersion, 20°C (n  =  7): 0.19°C · min⁻¹. ^d Cold-water immersion, 8°C (n  =  7): 0.19°C · min⁻¹. ^e Fine spray (temperature not reported) (n  =  2): 0.175°C · min⁻¹. ^f Cold-water immersion, 14.03°C (n  =  17): 0.16°C · min⁻¹. ^g Ice-water immersion, 5.15°C (n  =  17): 0.16°C · min⁻¹. ^h Dousing with water while fanning (n  =  52): 0.15°C · min⁻¹. ⁱ Cold-water immersion (temperature not reported) (n  =  39): 0.15°C · min⁻¹. ^j Cold-water immersion, 14°C (n  =  7): 0.15°C · min⁻¹. ^k Continual dousing with ice-bag massage (n  =  5): 0.14°C · min⁻¹. ^l Cold-water immersion, 7°C (n  =  7): 0.129°C · min⁻¹. ^m Ice-wet towels (n  =  7): 0.11°C · min⁻¹. ⁿ IV fluids and ice packs at major arteries (n  =  1): 0.107°C · min⁻¹. ^o Helicopter downdraft with spraying (n  =  2): 0.102°C · min⁻¹. ^p IV fluids and ice-wet towels (n  =  1): 0.097°C · min⁻¹. ^q IV fluids (n  =  1): 0.076°C · min⁻¹. ^r Fine spray, compressed air, and fanning (n  =  6): 0.076°C · min⁻¹. ^s Fine spray with fanning (n  =  6): 0.073°C · min⁻¹. ^t Sitting on stool, 21.1°C (n  =  6): 0.066°C · min⁻¹. ^u Fine spray for 3 minutes with fanning (n  =  6): 0.05°C · min⁻¹. ^v Cold IV and dousing with water (n  =  1): 0.05°C · min⁻¹. ^w Dousing with water (n  =  1): 0.044°C · min⁻¹. ^x Cold-water immersion, 14.4°C (n  =  6): 0.044°C · min⁻¹. ^y IV fluid with haloperidol (n  =  1): 0.041°C · min⁻¹. ^z Fanning and compressed air (n  =  6): 0.04°C · min⁻¹. ^aa Ice packs at major arteries and dousing with fanning (n  =  5): 0.036°C · min⁻¹. ^bb Dousing with water while fanning (n  =  5): 0.035°C · min⁻¹. ^cc Ice packs covering body (n  =  5): 0.034°C · min⁻¹. ^dd Ice packs at major arteries (n  =  5): 0.028°C · min⁻¹. ^ee Lying on stretcher (n  =  5): 0.027°C · min⁻¹. ^ff Fanning only (n  =  6): 0.02°C · min⁻¹. ^gg Repeated gastric lavage (n  =  1): 0.018°C · min⁻¹. ^hh IV fluid with paracetamol (n  =  1): 0.015°C · min⁻¹. ⁱⁱ Ice cubes on chest (n  =  1): 0.008°C · min⁻¹. ^jj Cooling blankets (n  =  1): 0.0076°C · min⁻¹. ^kk Cooling blankets (n  =  1): 0.0°C · min⁻¹.