Danielle Lueck, Licensed Athletic Trainer
Aurora Sports Medicine Institute
As Wisconsin days get shorter and the temperature drops, it's important for the outdoor runner to properly prepare for changes in the environment. Frostbite, hypothermia, and chilblain all pose a threat to winter runners. To avoid these potential hazards, proper recognition, treatment, and prevention strategies are a must.
A decrease in core body temperature to below 95 degrees Fahrenheit is characteristic of hypothermia. Labeled as mild, moderate, or severe based on the body's core temperature and other varying characteristics, hypothermia is caused by prolonged exposure to cold, wet, and/or windy conditions.
Mild hypothermia signs and symptoms:
- Core body temperature between 98.6 and 95 degrees Fahrenheit
- Mild amnesia
- Cold to the touch and/or shivering
- Frequent urination
- Runny nose
Moderate hypothermia signs and symptoms:
- Core body temperature between 94 and 90 degrees Fahrenheit
- Decreased breathing rate and pulse
- Blue lips
- Slurred speech
- Dilated pupils
- Decreased blood pressure
- Decreased ability to think and/or loss of consciousness
An individual with severe hypothermia will typically be comatose; have very low blood pressure, irregular breathing rate and pulse; and may go into cardiac arrest.
With any form of hypothermia, it's important to move the individual from the cold and into a warm environment. Remove damp or wet clothing, replacing it with warm, dry clothing and blankets. It is recommended when applying heat, focus on the trunk, armpit, chest, and groin areas. By re-warming the core first instead of extremities, the risk of cardiac arrhythmias and death can be reduced.
A runner with mild hypothermia should be encouraged to drink warm, nonalcoholic drinks and consume foods with six to eight percent carbohydrates. Individuals suffering from moderate to severe hypothermia should always be transported to the hospital. In addition, vital signs should be monitored until a physician begins treatment.
Frostbite is the body's protective response to cold weather. To maintain core body temperature, blood flow increases to your core as it decreases to the extremities. Frostbite occurs when the body's tissue temperature drops below 28 degrees Fahrenheit. It typically starts at the nose, ears, fingertips and toes and then works its way deeper under the skin. Identified by severity, the three stages of frostbite are: frostnip, mild frostbite, and severe frostbite.
- Mild frostbite can be recognized by red, dry, waxy skin; swelling; tingling/burning sensation; white or blue-gray skin color; limited movement; and cold, firm skin.
- Severe or deep frostbite is distinguished by hard, cold, waxy immobile skin that is white, gray, black, or purple; burning, throbbing, aching, or shooting pain; decreased circulation; numbness or tingling; and blistering within 36 to 72 hours.
With any type of cold-induced injury, always rule out hypothermia first. If frostbite does occur, proper treatment and referral to a medical professional is the primary course of action. To treat mild or superficial frostbite, slowly re-warm the area at room temperature. When re-warming severely frostbitten tissue, immerse the area in warm water (98 to 104 degrees Fahrenheit). Regardless of severity, the re-warmed tissue should always be protected from further risk of refreezing, as this will cause the tissue to die. When treating frostbite, DO NOT rub the tissue as it will cause more damage.
Chilblain is an exaggerated inflammatory response to cold (below 50 degrees Fahrenheit) that most commonly occurs during prolonged exposure to cold (i.e., lasting between one and five hours). It typically appears in extremities that are kept wet for long periods of time due to sweat or water – hand and feet present the greatest risk. A runner with chilblain will experience redness, swelling, itching, tenderness, and pain.
Treatment for this condition is relatively simple. Remove wet and constrictive clothing. The area should be washed, then dried, covered, and elevated. Avoid lotions, creams, heat, and friction massages. If blistering occurs, do not disturb the blisters.
To prevent possible exposure to frostbite, runners can consult the National Weather Service Wind Chill Chart. By combining temperature with wind speed, this chart can determine exposure time relative to developing frostbite during outdoor activities.
- 20 to 30 degrees Fahrenheit: two top layers and one bottom layer
- 10 to 20 degrees Fahrenheit: two top and two bottom layers
- 0 to 10 degrees Fahrenheit: three top and two bottom layers
Determining clothing type for each layer
Regardless of how many layers are being worn, winter running clothing should fit well while allowing proper movement. Start with a long-sleeved wicking layer. Being close to the skin, this layer helps to pull moisture away from the body allowing it to evaporate. Effective moisture wicking materials are polyester and polypropylene.
When a middle layer is worn, it acts as an insulator against heat loss. Typically worn during very low wind chills, this layer should fit somewhat looser to trap heat while still permitting sweat to evaporate away from the skin. Suggested materials for this layer include Akwateck, Dryline, Polartec, polyester fleece, Microfleece, Thermafleece, and Thermax. The outermost layer should have venting abilities as well as zippers to transfer moisture away from the body and into the environment. Ideal locations for vents are around the armpits and back. In addition, this layer should be water repellent and wind resistant. Materials such as Climafit, Goretex, Microsuplex, nylon, supplex, and windstopper are best for this layer.
For men who are avid winter runners, investing in supportive moisture-wicking, wind-proof, breathable briefs, boxers or running tights is highly recommended for prevention of cold-related trauma to sensitive areas. A full selection of related products can be purchased at local running retailers or on-line at www.RoadRunnerSports.com.
Each runner has varying clothing preferences, but on very cold days make it a point to keep your skin properly covered. Shirts and jackets with thumb loops will help your clothing to stay in place while providing extra protection to the hands. Not only can you experience up to 30% heat loss through your extremities, your head can account for up to 40% of your body's heat loss. On especially cold days, the face and neck should be protected. Bundle up with a balaclava, hat, neck gaiter, or scarf. As a general rule of thumb, mittens are better to wear than gloves since they allow the fingers to share body heat.
It's important to keep your feet as dry as possible. Choose socks that have moisture evaporation properties that also allow for proper blood flow. Stay away from socks made of cotton. When deciding on running shoes, avoid those made of materials such as mesh that could potentially permit water inside the shoe. If you plan on running on snow and ice, your shoes should provide proper traction for these surfaces. Trail running shoes and YakTracks can make your run safer. Specifically, YakTracks are coils that fit on the bottom of your running shoes to provide more traction.
Other Tips: Health and Nutrition
Despite the drop in temperature, proper skin protection, nutrition, and hydration should always be followed. This includes wearing sunglasses, as well as sunscreen on any exposed area of your skin. The outdoor runner should also include a warm-up and cool-down to prevent injury. A proper five-minute warm-up will gradually increase body temperature, heart rate, respiration rate, and blood flow. By performing a cool-down after running, the body will have enough time to gradually transition from intense movement to normal daily activity while decreasing any post-run muscle soreness.
Heavy clothing coupled with an increase in effort to run in a winter climate often causes more energy to be used. Because of this, caloric requirements are higher for cold weather runners. Marathon runners training outside in the winter should eat carbohydrate-rich foods to maintain performance and decrease the chances of fatigue, as well as lean or plant proteins to support muscle tissue repair. And just because it's not hot outside, don't forget to maintain proper fluid intake over the winter months to prevent dehydration.
The American College of Sports Medicine has set guidelines regarding hydration and sports. Pre-exercise fluid intake should be 16 ounces (i.e., two cups) during the two hours prior to exercising. Fluid intake during exercise should be five to ten ounces (i.e., approximately one cup) of fluid every 15 to 20 minutes. Post-exercise fluid intake should be no less than one cup every 15 to 20 minutes for a duration of two hours after exercising, or four cups of fluid per each pound of body weight loss.
Winter running is the safest when using the buddy system. If this is not possible, a cell phone and proper identification should always be carried. Be wary of black ice on trails and avoid icy patches as they increase your risk of injury. Avoid running in dark areas at night; instead stick to well-lit sidewalks or trails. However, if you do plan to run after dusk, don't forget to invest in reflective gear or battery operated cap lights and LED arm bands.
Have additional questions on winter running, other sports medicine topics, or want to schedule a Free Injury Evaluation? Call the Aurora Sports Medicine Hotline™ at (414) 219-7776 or (800) 219-7776.
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