Hypothermia and frostbite: signs, first aid and prevention

Cold kills hundreds of people every winter across Europe and North America, most of them older people living alone, people without shelter or people who fell asleep outdoors after drinking. Hypothermia comes on slowly, and the person doesn’t realize they’re in danger because the cold also affects judgment. Recognizing the signs in others is essential.

For winter preparation, see also our guides to winter storms and extreme cold and heating without power.

Hypothermia

Hypothermia means body temperature has dropped below 95 °F (35 °C).

Stage	Body temperature	Signs
Mild	95–90 °F (35–32 °C)	Strong shivering, cold pale skin, clumsy hands, slurred speech, tiredness
Moderate	90–82 °F (32–28 °C)	Shivering slows or stops, confusion, drowsiness, slow movements, odd behavior (some remove clothing)
Severe	Below 82 °F (28 °C)	Unconsciousness, very weak breathing and pulse, may appear dead

What to do

1. Call the emergency number for any sign of moderate or severe hypothermia.
2. Move them to shelter and warmth, gently. Rough handling can trigger dangerous heart rhythms.
3. Remove wet clothing and replace it with dry clothes.
4. Wrap them in blankets with the head and neck covered. Insulate them from the ground too.
5. Warm the trunk, not the arms and legs: chest, neck, armpits, groin. Warm (not hot) packs wrapped in a towel, or skin-to-skin contact under a blanket.
6. If they’re conscious and swallowing normally, give warm, sweet drinks. No alcohol, no coffee.
7. If they’re not breathing, start CPR. Don’t give up easily: people with severe hypothermia can survive prolonged resuscitation.

What not to do

• Don’t put them in hot water or use direct heat.
• Don’t rub their arms and legs.
• Don’t give alcohol.
• Don’t let them walk if hypothermia is moderate.

Frostbite

Frostbite usually affects fingers, toes, nose, ears and cheeks.

Degree	Signs
Superficial (frostnip)	Red then white skin, numbness, tingling. Returns to normal after warming.
Partial thickness	White or grayish skin, hard on the surface, clear blisters after rewarming.
Deep	Hard, wood-like skin, white or gray-blue; blood-filled blisters, then blackened areas. Medical emergency.

What to do

1. Get indoors and remove rings, watches and tight clothing.
2. If there’s no risk of refreezing, soak the area in warm water (98–102 °F / 37–39 °C, comfortable to your elbow) for 15–30 minutes.
3. Pat dry and put dry sterile dressings between fingers and toes.
4. Take a pain reliever if needed: rewarming hurts.
5. See a doctor for partial-thickness and deep frostbite.

What not to do

• Don’t rub with snow or your hands: it damages tissue further.
• Don’t use direct heat: fire, radiator, hair dryer, hot water bottle. Numb skin can’t feel burns.
• Don’t pop blisters.
• Don’t rewarm if it could refreeze before you reach shelter: refreezing does more damage.

Prevention

• Dress in layers: a moisture-wicking base layer, an insulating layer, and a wind- and waterproof outer layer.
• Hat, gloves, scarf, thick socks. Mittens are warmer than gloves.
• Stay dry: change out of wet clothes immediately.
• Eat and drink warm fluids.
• No alcohol in extreme cold.
• Check on older and isolated people around you.
• Winter car kit: see what to do if you’re stuck in a car in snow.