How Much Do You Know About Frostbite During Sports?

The recent Beijing Winter Olympics has inspired everyone's love for ice and snow sports, and many friends have developed a strong interest in skiing, skating and other sports. Ice and snow sports are fun, but they also have certain risks. In addition to possible muscle and ligament injuries, there may also be frostbite that may be overlooked. Below, the editor will discuss with you the topic of low temperature and sports.

In addition to affecting a person's ability to exercise, hypothermia can be life-threatening in severe cases. Frostbite refers to direct frostbite that occurs when the skin surface is exposed to salt water at −0.55°C or air below −3°C. Exposed tissues with poor blood perfusion are most often affected (hands, feet, head). The exposure time leading to injury ranges from a few seconds to several hours, depending on personal factors such as environmental conditions, degree of physical activity, and protective clothing. When tissue temperature is below freezing, extracellular ice crystals form in some temperature-sensitive tissues, leading to mechanical damage to cells and increased osmotic pressure, causing inflammation, microvascular thrombosis, ischemia, and hypoxia. Intracellular ice crystals may then form. Thawing increases tissue edema, causing inflammatory responses and reperfusion injury.

Numbness of the skin is a sign that you are at risk for frostbite. Pale spots on the skin indicate superficial frostbite, which is characterized by partial freezing of the skin and mild edema. The injured area should be rewarmed by contact with warm skin (one's own or someone else's) and further injury should be avoided. When frostbite is severe, the injured area feels cold to the touch and patients often describe the injury as "like a piece of wood." Frostbitten areas should not be rewarmed immediately unless there is no guarantee that secondary frostbite can be avoided. Frostbite occurs in 7% to 11% of the general population and is more common in rural, northern climates and in occupations that involve high physical exertion and prolonged exposure to cold air.

Normal people can hardly escape frostbite, and patients with underlying diseases should be prepared for cold weather when exposed to cold air for a long time. For example:

1) Some diseases that affect neural, vascular, and metabolic functions, as well as related tissue perfusion and microvascular function, may increase the risk of frostbite.

2) Autonomic and peripheral nerve diseases (such as diabetes) can impair nerve control and thermal sensation.

3) Central nervous system diseases (eg, amyotrophic lateral sclerosis, spinal cord injury) can impair mobility, temperature regulation, and heart and vascular control.

4) Vascular disease can impair tissue perfusion and responsiveness.

5) Endocrine diseases (such as hypothyroidism, hypopituitarism, adrenal insufficiency) can reduce metabolic heat production in cold weather.

6) Mental illness predisposes to frostbite by increasing risky behaviors.

7) Various drugs that affect circulation, metabolism, and fluid balance may predispose to frostbite.

When determining whether there is a risk of frostbite, not only the temperature but also the wind speed should be considered, because wind can significantly increase convective heat loss, reduce the thermal insulation capacity of clothing, and increase evaporative heat loss. When exercising outdoors, it should be noted that moist skin is more susceptible to frostbite; contact with volatile liquids (such as light liquid fuels) increases the risk of frostbite, and insufficient exercise intensity can lead to low tissue perfusion, rapid drop in skin temperature, and subsequent frostbite. Avoid direct exposure of the skin to cold air, and wear a windproof and well-insulated coat. Wearing multiple layers of gloves can help (for example, a thinner mitten can be worn under a thick glove to maintain finger flexibility).

Once frostbite occurs, how should we deal with it? Everyone should remember the following points:

If frostbite is suspected, further exposure to cold air should be avoided and the person should be placed in a warm, dry environment.

Wet clothing should be removed, and the injured area should be protected from direct mechanical trauma (eg, if frostbite occurs in the lower extremities, weight bearing should be avoided).

Spontaneous thawing or reheating by friction or heat sources (e.g. flame, vehicle engine) should be avoided.

Thawing can be initiated using the patient's own or a rescuer's body heat (e.g., by placing the affected area in the armpit).

If conditions permit, a 37°C to 39°C water bath should be used until the skin softens and reddens.

The integrity of the blister should be maintained and efforts should be made to prevent secondary infection. Expert medical evaluation is required.

If the condition is serious, please go to the hospital immediately.

We hope that the above content can help everyone enjoy ice and snow sports more safely. You are also welcome to come to the Rehabilitation Medicine Department of Xinhua Hospital for consultation on issues such as sports injuries and exercise.
References:

1. Castellani, J., Eglin, C., Ikäheimo, T., Montgomery, H., Paal, P., & Tipton, M. (2021). ACSM Expert Consensus Statement: Injury Prevention and Exercise Performance during Cold-Weather Exercise. Current Sports Medicine Reports, 20(11), 594-607. doi: 10.1249/jsr.0000000000000907