Prevention of Cold Injuries during Exercise

John W. Castellani, Ph.D., FACSM; Andrew J. Young, Ph.D., FACSM; Michel B. Ducharme, Ph.D.; Gordon G. Giesbrecht, Ph.D.; Ellen Glickman, Ph.D., FACSM; Robert E. Sallis, M.D., FACSM


March 01, 2010

In This Article

Nonfreezing Cold Injuries

The most common nonfreezing cold injuries (NFCI) are trenchfoot and chilblains. Trenchfoot typically occurs when tissues are exposed to temperatures between 0 and 15°C (32-60°F) for prolonged periods of time,[75,174] whereas chilblains, a more superficial injury, can occur after just a few hours of exposure to bare skin.[75] These injuries may occur due to actual immersion or by the creation of a damp environment inside boots caused by sweat soaked socks. Diagnosing NFCI involves observation of clinical symptoms over time as different, distinct stages emerge days to months after the initial injury.[174]

Trenchfoot initially appears as a swollen, edematous foot with a feeling of numbness. The initial color is red but soon becomes pale and cyanotic if the injury is more severe. Peripheral pulses are hard to detect. Trenchfoot is accompanied by aches, increased pain sensitivity, and infections.[75] The exposure time needed to develop trenchfoot is quite variable, with estimates ranging from > 12 h to 3-4 d in cold-wet environments.[74,174] Most commonly, trenchfoot develops when wet socks and shoes are worn continuously over many days. The likelihood of trenchfoot in most sporting activities is low, except in winter hiking, camping, and expeditions.

Chilblain (also known as pernio or kibe) is a superficial cold injury typically occurring after 1-5 h in cold wet conditions,[75] at temperatures below 16°C (60°F). Small erythematous papules appear on the skin, most often on the dorsal surface of the fingers, but the ears, face and exposed shins are also common.[75] The lesions are swollen, tender, itchy and painful. Upon rewarming, the skin becomes inflamed, red and hot to the touch, swollen, with an itching or burning sensation that may continue for several hours after exposure. There are no lasting effects from chilblain.

Prevention of trenchfoot can be achieved by encouraging individuals to remain active and increase blood flow to the feet and keeping feet dry by continually changing socks. Changing socks 2-3 times throughout the day is mandatory in cold-wet environments during long-term exposure. Prophylactic treatment with antiperspirants containing aluminum hydroxide may also decrease sweating in the foot. Vapor barrier boots (some hiking boots, ski boots) and liners do not allow sweat from the foot to evaporate and sock changing is important. These boots and liners should be taken off each day, wiped out, and allowed to dry.[75,174] If regular boots are worn, these boots need time to dry to avoid getting moisture in the insulation.