Cold Water Immersion: The Gold Standard for Exertional Heatstroke Treatment

Douglas J. Casa; Brendon P. McDermott; Elaine C. Lee; Susan W. Yeargin; Lawrence E. Armstrong; Carl M. Maresh


Exerc Sport Sci Rev. 2007;35(3):141-149. 

In This Article

Abstract and Introduction/Historical Perspective


The key to maximize the chances of surviving exertional heatstroke is rapidly decreasing the elevated core body temperature. Many methods exist to cool the body, but current evidence strongly supports the use of cold water. Preferably, the athlete should be immersed in cold water. If lack of equipment or staff prevents immersion, a continual dousing with cold water provides an effective cooling modality. We refute the many criticisms of this treatment and provide scientific evidence supporting cold water immersion for exertional heatstroke.

Introduction/Historical Perspective


..."But sunstroke gives no such warning. It strikes down its victim with his full armor on. Youth, health, and strength oppose no obstacle to its power; nay, it would seem, in some instances, to seek out such as these, as if boldly to flaunt its power, and in the very glare of day to deal its final blow."

From Levick J.J., Remarks on sunstroke. Am. J. Med. 37:43, 1859.

Exertional heatstroke (EHS) is a potentially lethal outcome for any athlete, laborer, soldier, or other individual who participates in physical activity in warm or hot conditions. Although the condition is relatively rare, its incidence rate is as high as 1 in 1000 at some athletic events.[8] Because these events often include 10,000 or more participants, the event medical staff may treat 10 or more cases of EHS. This medical emergency requires extensive logistical planning to assure optimal onsite treatment.

Heatstroke is not new to the medical community.[5] In 24 B.C., Roman soldiers with heatstroke were instructed to drink olive oil and wine while rubbing both liquids on the body.[18] In the 1500s, physicians recommended stimulating friction and bloodletting to "release the heat".[27] In the 18th century, the cause of heatstroke was once thought to be drinking cold water. Patients would receive the diagnosis of "hurt by drinking cold water." Amazingly, public pumps were posted with signs warning about the risk of sudden death from drinking cold water.[27]

Recently (in a historical sense, i.e., 50 to 100 yrs or so ago), a widely circulated opinion has encouraged some in the medical community to avoid using cold water immersion (CWI) for the acute treatment of heatstroke.[19,30] This line of thinking has reached the medical community, including athletic trainers, team physicians, emergency department physicians, emergency medical technicians, registered nurses, first aid-trained coaches, and others. The number one criticism of CWI is that patients will actually heat up (or at least not cool down) in CWI because of peripheral vasoconstriction (PVC) and shivering. However, scientific evidence strongly refutes this criticism. Evidence from basic physiological studies looking at the effect of CWI on cooling rates in hyperthermic individuals and treatment of actual EHS victims clearly shows that CWI has cooling rates superior to any other known modality.[2,10,11,21,22]

We have recently stated, "it is quite difficult, if not impossible, to kill an otherwise healthy athlete experiencing EHS if rapid cooling via cold/ice water immersion is implemented within a few minutes after collapse".[9] Any delay in the process of rapidly cooling an individual experiencing EHS, whether it is caused by a delay in the initiation of treatment or the use of an inferior coding modality, can dramatically increase the likelihood of morbidity and mortality associated with the condition.

The hypothesis to be presented in this article is that CWI should be the preferred method of treatment of EHS because of superior cooling rates and unsurpassed survival rates. Hence, additionally, this review aims to conclusively refute the myth that CWI hinders cooling of hyperthermic athletes because of PVC and shivering. Protocols regarding the treatment of EHS should be in accordance with best practices.


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