Last week’s entry discussed general keys to preventing environmental cold injuries by having an emergency action plan in place, having appropriately trained personnel available, learning to layer correctly to minimize heat loss and knowing who may be most susceptible. Specific injuries or conditions may require specific prevention steps, but proper recognition and initial first aid are also important. I will focus primarily on hypothermia and frostbite since they happen most often, but there are other conditions to be aware of. Recognizing the signs and symptoms an athlete shows when presenting with an injury such as frostbite or hypothermia is critical. Taking the appropriate steps to minimize the severity of the injury and getting appropriate treatment are also important.

Hypothermia, defined as a core temperature of 95o F or lower, affects a variety of body systems, getting more severe as the core temperature continues to drop. Sometimes hypothermia is referred to as accidental hypothermia in the literature to differentiate it from the therapeutically induced hypothermia utilized by medical professionals. The severity of injury is described as mild, moderate, and severe and each stage presents with specific signs and symptoms. The ability to recognize these signs and symptoms can help you understand the severity of hypothermia without assessing core temperature. Assessing core temperature requires the use a specifically designed thermometer and most typical clinical thermometers are inaccurate at temperatures below 95oF. Seeking immediately medical treatment for someone suffering from hypothermia is critical, especially as the condition becomes progressively worse.

Signs and symptoms of mild hypothermia include a core temperature between 98.6oF and 95oF, vigorous shivering, lethargy, loss of fine motor control among others. As the patient progresses to mild hypothermia the core temperature is between 90oF and 94oF, respirations and pulse slow, cyanosis (blue hue to skin) is present and shivering ceases. As the patient reaches severe hypothermia the core temperature is below 90oF and may even be comatose. The complete list of signs and symptoms are available by clicking the “Cheat Sheet” link at the bottom of this post. I have simply tried to highlight some of the signs and symptoms here.

Athletes most likely to suffer from hypothermia are those who experience prolonged exposure to cold, wet, or windy conditions, or some combinations of these. This means those soccer and football games in the late fall could put your athlete at risk if not properly prepared. The easiest way to prevent hypothermia is to properly layer under (and over) the uniform to maintain warmth and to stay properly hydrated. Most athletes do not remember to drink when it is cold since the thirst mechanism is not as obvious.

If you believe someone may be suffering from mild hypothermia it is important to remove them from the weather conditions and remove any wet clothing. Using blankets to warm them is also appropriate. Providing warm food and fluids are also acceptable. Do not rub hands and fingers to warm them as this could cause further tissue damage if frostbite is also present. Immediate referral and transport to a hospital is important for anyone suffering from hypothermia, no matter the stage.

Frostbite is the actual freezing of body tissues and often happens to the face and extremities. Frostbite can happen in cold, dry conditions while wet conditions can exacerbate the condition and is a result of the body shunting blood to the core to keep vital organs warm. Coming into contact with cold objects (such as a lacrosse stick) can also result in frostbite. The stages are frostnip (precursor to frostbite), mild frostbite and severe frostbite.

Frostnip is freezing of the most superficial layers of the skin as a result of cold, windy conditions or coming in contact with a cold object (typically metal). Mild frostbite results in freezing of the skin and subcutaneous tissues, while severe frostbite is freezing of the skin, subcutaneous tissues and other tissues below that including muscle and bone. Signs and symptoms include “waxy,” pale skin initially and can progress to a mottled skin, edema and/or transient numbness and tingling. See “Cheat Sheet” for a complete list.

If you believe someone may be suffering from frostbite it is important to know that you should not rub the injury to warm it, it causes further tissue damage. If blisters are present, do not break them open as it increases the risk of infection. Finally, if you decide to re-warm (slowly) the extremity make sure there will not be an opportunity for the tissues to refreeze making the tissue damage more severe. While frostnip may not require further referral, mild and severe frostbite are likely to need immediate referral for further medical treatment.

Chilblains (pernio) results from extended exposure (1 – 5 hours) to cold, wet conditions and most often affects the hands and feet. Can occur in similar conditions as trench foot, but is typically a more superficial and less severe injury. Signs and symptoms often include red or cyanotic skin, numbness and tingling, swelling and tenderness among others (see “Cheat Sheet”).

If you believe someone is suffering from chilblains remove the wet and constrictive clothing. As with frostbite do not rub skin or break open any blisters that may be present. The patient should also be non-weight bearing if it is the lower extremity that is affected. Immediate referral may be necessary depending on the severity of the condition.

Immersion (trench) foot is similar to chilblains, in that it occurs with prolonged exposure to cold and wet. Exposure typically ranges from 12 hours to 4 days and often results from wearing continually wet boots and socks. Signs and symptoms include cyanotic skin, numbness and tingling, or skin fissures and macerations.

Raynaud’s syndrome (or phenomenon) is the result of constriction of blood vessels in the fingers (most often) that leads to a white, pale appearance. Raynaud’s is aggravated by cold conditions. Often times, avoidance of cold conditions is recommended for managing this poorly understood condition.

Cold urticaria is an allergy to cold temperatures. Exposure to cold will cause redness, itching, and hives on the exposed skin. Avoidance of cold conditions is recommended for people with this condition.

Signs and symptoms "cheat sheet" 

Baumhakel, M. & Bohm, M. (2010). Recent achievements in the management of Raynaud’s phenomenon. Vascular Health and Risk Management, 6: 207 – 214. Available at:

Biem, J., Koehncke, N., Classen, D., & Dosman, J. (2003). A the bedside: Management of hypothermia and frostbite. Canadian Medical Association Journal, 168(3): 305 – 311. Available at:

Cappaert, T.A., Stone, J.A.,Castellani, J.W., Krause, B.A., Smith, D. & Stephens, B.A. (2008). National Athletic Trainers’ Association position statement: Environmental cold injuries. Journal of Athletic Training, 43(6): 640 – 658. Available at:

Castellani, J.W., Young, A.J., Ducharme, M.B., Giesbrecht, G.G., Glickman, E., and Sallis, R.E. (2006). Prevention of cold injuries during exercise. Medicine and Science in Sports and Exercise, 38 (11): 2012 – 2029. Available at:

Submitted by Heather L. Clemons, MS, MBA, ATC