Cold Weather Health Risks: Frostbite, Hypothermia & Staying Safe This Winter

Chilly temperatures are a predictable part of winter, but periods of extreme cold pose real and significant health risks. Emergency departments see a rise in cold-related injuries during cold snaps, including frostbite, hypothermia, falls, and cardiac complications.

Understanding how cold affects the body, and how to respond to extreme weather conditions, can help reduce those risks. During extremely cold weather, staying warm and safe can be a challenge, particularly for vulnerable populations.

Understanding the Health Risks of Cold Exposure

When exposed to cold, the body prioritizes maintaining its core temperature. Blood vessels near the skin constrict to reduce heat loss, preserving warmth in the core but decreasing blood flow to the extremities – hands, feet, ears, and face. Prolonged exposure can lead to frostbite. If heat loss exceeds the body’s ability to generate warmth, core temperature drops, resulting in hypothermia, which can impair judgment, coordination, and heart rhythm.

Cold exposure also places additional strain on the cardiovascular system. Blood pressure increases in cold environments, and the heart works harder to maintain circulation, increasing the risk of cardiac events, especially in individuals with underlying heart disease.

Certain medications can increase vulnerability to the effects of cold exposure. Blood pressure medications can limit the body’s normal response to cold by reducing heart rate and circulation to the extremities. Diuretics increase fluid loss, raising the risk of dehydration, which can impair temperature regulation. Sedatives, opioids, and some psychiatric medications can dull awareness of cold stress and delay recognition of danger. Individuals taking these medications should be particularly mindful of limiting exposure time, taking frequent warming breaks, and protecting their hands, feet, and face.

Some groups are at higher risk for cold-related illness or injury. Infants and young children lose heat more quickly due to a higher surface-area-to-body-mass ratio and have limited ability to communicate discomfort. Older adults may have impaired temperature regulation or reduced mobility. People with diabetes, cardiovascular disease, peripheral vascular disease, or respiratory conditions also face higher risks, as do individuals experiencing housing insecurity. Checking in on vulnerable neighbors, family members, and others during extreme cold is crucial.

Temperature vs. Wind Chill

Air temperature alone doesn’t fully indicate how quickly the body can lose heat. Wind increases heat loss by removing the thin layer of warm air that normally surrounds the skin. This is why wind chill is used to estimate how cold conditions feel on exposed skin.

Health risks increase as wind-chill values drop. At wind-chill values around −27°C, exposed skin can freeze in 10 to 30 minutes. At −40°C, frostbite can occur in as little as five to 10 minutes. At −55°C or colder, frostbite can develop in under two minutes. These risks are even faster for children and exposed areas like the face and fingers.

Planning Ahead and Layering Up

Check the weather forecast and Environment Canada’s extreme cold and cold warnings, paying attention to wind-chill values and rapid temperature drops.

Dress in layers. A moisture-wicking base layer, like wool, keeps sweat off the skin. An insulating middle layer, such as fleece or down, helps trap heat. A wind-resistant and waterproof outer layer reduces heat loss from wind and moisture. Clothing should allow room for insulation, as overly tight layers reduce warmth.

Protect exposed skin. A hat, insulated mittens, scarf or face covering, and warm boots are essential when wind-chill values are very low. Mittens retain heat better than gloves, and covering the face can significantly reduce frostbite risk.

Limit time outdoors during extreme cold. Take warming breaks indoors when possible and be especially cautious with children, older adults, and people with chronic medical conditions.

Alcohol should be avoided before or during cold exposure, as it increases heat loss and impairs judgment.

Cold snaps also increase risk during travel. Vehicle breakdowns in extreme cold can quickly become medical emergencies. Drivers should ensure winter tires are in good condition, keep fuel tanks topped up, and carry an emergency kit that includes warm blankets, extra clothing, food, water, and a charged phone or battery pack.

Exercising Outdoors in the Cold

Physical activity in winter can be safe, but extreme cold requires adjustments. Cold, dry air can irritate the airways and trigger coughing, chest tightness, and shortness of breath, particularly in people with asthma or other respiratory conditions. Even in healthy individuals, high-intensity exercise in very cold air can cause airway inflammation.

Covering the mouth and nose with a scarf or mask helps warm and humidify inhaled air. Longer warm-ups, reduced intensity, and shorter outdoor sessions are advisable when temperatures or wind chills are very low. Chest discomfort, wheezing, or unusual shortness of breath are signs to stop and warm up indoors.

Cold conditions also increase the risk of muscle strains and falls due to stiffer muscles and slippery surfaces, making flexibility and caution especially important.

Recognizing Frostbite and Hypothermia

Frostbite occurs when skin and underlying tissues freeze. Early symptoms include numbness, tingling, and pale or waxy-appearing skin, most commonly affecting fingers, toes, ears, and the nose. As injury progresses, skin may become hard, blistered, or discolored.

If frostbite is suspected, get indoors immediately. Rewarm affected areas gradually using body heat or warm, not hot, water. Do not rub frozen skin or apply direct heat, which can worsen tissue damage. Medical assessment is important if numbness persists, blisters or discoloration develop, or pain increases after rewarming.

Hypothermia is a life-threatening medical emergency that can occur after prolonged cold exposure. Symptoms of mild hypothermia include shivering and complaining of numbness in fingers and toes. Moderate to severe hypothermia can lead to a lack of coordination and speech, confused behavior, and slow breathing. If severe hypothermia is suspected, call emergency services immediately.