Recognising hypothermia and rewarming gently
Hypothermia often develops gradually – in the cold, but also in wet and windy conditions on cool days. Early signs are shivering, clumsiness and declining concentration; confusion, drowsiness or shivering that stops while the person is still cold are warning signs. Protect from further cooling, insulate, handle gently and call the emergency number (112 in the EU). This text does not replace a first-aid course.
- Start immediately; rewarming takes a long time
Explained simply
Your body is like a small stove that makes heat all the time. At the same time it gives heat away – to cold air, to wind, to wet clothing and to cold ground. If more heat is lost than the stove can make, the body cools down inside. This is called hypothermia. By the way, it can also happen on days above freezing when you are wet, the wind is blowing and you are exhausted.
At first you shiver, become clumsy and find it harder to concentrate. It becomes dangerous when someone seems confused, speaks unclearly, becomes very drowsy or stops shivering although they are still cold. The shivering does not stop because things are getting better, but because the body can no longer manage it. Then call the local emergency number at once (112 in the EU).
Helping is like a house in winter: first close the windows and doors, then turn on the heating. So first get out of the wind and wet, insulate underneath against the cold ground, put on dry things and a wrap around them – and only then gently add warmth at the belly and chest. This text does not replace a first-aid course.
How it works
The body loses heat in several ways at once. Wind keeps carrying away the layer of warm air right next to the skin. Wet clothing conducts heat away much faster than dry clothing, and water on the skin evaporates and cools as it does so. Anyone sitting or lying on cold ground constantly gives heat to it through contact. That is why you can become dangerously cold even at temperatures above freezing.
The body first defends itself against the cold by shivering: the muscles work rapidly and produce heat as they do. It also narrows the blood vessels in the skin, hands and feet to keep the heat in the trunk, where the heart, lungs and brain are. That is why hands and feet get cold and pale first. Over time the body runs out of strength, and the brain and muscles work less well – the person becomes clumsy, slow and finally confused.
First aid follows a clear logic: first stop further heat loss, then add heat. Heat added from outside is wasted as long as wind and wet carry it straight away again. In severe hypothermia the circulation is also fragile. That is why the person should then be moved very gently and preferably lying down, and should not exert themselves.
Recognising the signs
Early signs are shivering, cold and pale skin, clumsiness, stumbling, apathy and declining concentration. Often someone also becomes irritable or quiet. The tricky part: the person affected often does not notice it themselves, because the cold also slows down thinking. So in a group, keep an eye on each other.
Warning signs are confusion, slurred speech, marked drowsiness, unconsciousness and shivering that stops although the person is still cold. They point to severe hypothermia. Then you call the emergency number at once (112 in the EU), do not let the person walk any more and handle them very gently.
If the person does not respond, check breathing especially carefully – in severe hypothermia it can be very slow and shallow. If they are not breathing normally, act as for an unresponsive person and follow the dispatcher. This entry deliberately gives no temperature thresholds: lay people judge the situation by the signs, not by a thermometer.
What really matters
The first step is shelter: into a building, a vehicle or a spot out of the wind. With warning signs, carry the person gently rather than letting them walk. Then comes insulation underneath – sleeping mat, backpack, clothing or branches. The ground is often forgotten, yet it draws away a particularly large amount of heat.
In shelter you carefully replace wet clothing with dry clothing without moving the person much. If that is not possible, the wet clothing stays on and you wrap the person especially well on the outside. Blankets or a sleeping bag go around the whole body, and the head and neck are covered too. On the very outside an emergency blanket or plastic sheet keeps out wind and moisture – like a shell around an egg.
Only now do you add heat, and to the trunk: hot-water bottles or heat packs wrapped in cloth on the chest, armpits and back. That is where the vital organs are that need the warmth most urgently. If the person is fully alert and can swallow safely, they may drink warm, sweet drinks. Afterwards you stay with them, monitor consciousness and breathing and report changes to the dispatcher.
Safety: what to watch out for
No alcohol ‘to warm up’: it only creates a warm feeling because the blood vessels in the skin widen – but that tends to make even more heat escape, and judgement suffers. Rubbing or massaging arms and legs is also off-limits, as are hot baths or showers for confused or drowsy people.
Heat sources never go directly on the skin. Cold skin senses heat poorly, so burns can happen without the person noticing. Always wrap hot-water bottles and heat packs in a cloth. You do not treat frostbite on hands, feet or face yourself – that needs medical help.
Severe hypothermia belongs in hospital; it cannot be safely ‘thawed out’ outdoors or at home. So call the emergency number early with warning signs, injuries or if the person cannot get to warmth on their own. And think of yourself: anyone helping others in cold and wind is cooling down too.
Typical situations
Many cases do not occur in deep winter but in rain, wind and temperatures above freezing – for example on a hike that takes longer than planned, when exhaustion and too little food come into play. Anyone who has fallen into water also cools down quickly, because water draws heat from the body much faster than air.
Hypothermia also happens indoors. Older people in unheated rooms, for example during a heating or power failure, are particularly at risk. Then it helps to keep one room warm, wear several layers, offer warm drinks and check regularly on vulnerable neighbours. Grills or gas stoves have no place for heating indoors – they can release poisonous carbon monoxide.
Prevention is easiest: weatherproof clothing in layers, spare clothes in your backpack, a sleeping mat and an emergency blanket, turning back in good time and eating and drinking enough. An emergency blanket weighs next to nothing and can help a great deal in an emergency. You learn the hands-on skills for emergencies on a first-aid course.
Step by step
- 1
Recognise the signs
Look for shivering, cold and pale skin, clumsiness, stumbling, apathy and declining concentration. Confusion, slurred speech, drowsiness or shivering that stops while the person is still cold are warning signs.
- 2
Call for help
With warning signs, injury or if the person cannot get to warmth on their own, call the emergency number immediately (112 in the EU). When in doubt, call early.
- 3
Shelter from wind and wet
Move them into a building, vehicle or a sheltered spot – in severe hypothermia carry them gently rather than letting them walk.
- 4
Insulate from the ground
Put a sleeping mat, backpack, clothing or branches underneath the person. Cold ground draws away a lot of heat.
- 5
Replace wet clothing
In shelter carefully remove wet clothing and replace it with dry clothing without moving the person much. If that is not possible, leave the wet clothing on and wrap them well on the outside.
- 6
Wrap up, cover the head
Wrap in blankets or a sleeping bag, cover head and neck and add an emergency blanket or plastic sheet on the outside as a wind and vapour barrier.
- 7
Add heat gently
Place heat sources such as hot-water bottles or heat packs wrapped in cloth on the chest, armpits and back, never directly on the skin. If the person is fully alert and can swallow safely, give warm, sweet drinks.
- 8
Monitor and stay
Stay with the person, monitor consciousness and breathing and report changes to the dispatcher.
Common mistakes
- Overlooking early signs such as clumsiness and irritability
- Letting the person keep walking despite warning signs
- Rubbing or massaging arms and legs
- Giving alcohol "to warm up"
- Putting hot objects directly on the skin
- Forgetting insulation from the ground
Quick view
Materials
Emergency blanket
As a wind and vapour barrier over the insulation
Tears easily once punctured; short-term shelter only.
Conductive – keep away from power lines.
Sleeping pad
Insulation from the ground
Wool blanket / duvet
Keep away from candles, stoves and heaters.
Dry spare clothing
Carry it in waterproof packaging – wet clothing barely insulates.
Double-wall insulated bottle
Warm, sweet drink – only for alert people
Never heat directly.
Suitable for
- People who are cold and shivering after cold, wet or wind
- The wait until help arrives, outdoors or in a cold home
Not suitable for
- Treating frostbite on hands, feet or face – get medical help for that
- "Thawing out" severe hypothermia yourself at home – it belongs in hospital
Prerequisites
- Shelter from wind and wet within reach
- Insulating material and dry clothing if possible
Safety
- This text does not replace a first-aid course. First aid is learned through hands-on practice under instruction. In an emergency always call professional help – via the local emergency number (112 in the EU) – and follow the dispatcher's instructions.
- No alcohol, no rubbing or massaging arms and legs, no hot baths or showers for confused or drowsy people. Never put heat sources directly on the skin – risk of burns, cold skin senses heat poorly.
How it works
The body loses heat through wind, wet, cold ground and cold air faster than it can produce it. First aid first stops further heat loss: shelter from wind and wet, insulation underneath, dry layers and an outer wrap. Only then is heat added – gently and to the trunk. In severe hypothermia the circulation is fragile; rough handling and exertion should be avoided.
Advantages
- Effective with simple means
- Prevents further deterioration until help arrives
Disadvantages
- Rewarming outdoors takes a long time
- Severe hypothermia cannot be treated safely outside hospital
Deep knowledge
Background
The Wilderness Medical Society hypothermia guidelines describe out-of-hospital first care chiefly as preventing further heat loss through shelter, insulation and a wrap with a heat and vapour barrier, and applying heat sources to the trunk. People with severe hypothermia should be moved gently and kept horizontal.
Hypothermia does not only occur in frost. Many cases occur at temperatures above freezing when rain, wind, exhaustion and too little food come together – for example while hiking or after falling into water.
Variants
- Cold home
- Older people in unheated homes, for example during a heating or power failure, can also become hypothermic. Keep one room warm, wear several layers, offer warm drinks and check regularly on vulnerable neighbours. No grills or gas stoves for heating indoors.
Common mistakes
- Overlooking early signs such as clumsiness and irritability
- Letting the person keep walking despite warning signs
- Rubbing or massaging arms and legs
- Giving alcohol "to warm up"
- Putting hot objects directly on the skin
- Forgetting insulation from the ground
Limits and risks
- Does not replace a first-aid course
- No treatment of frostbite
- Severe hypothermia belongs in hospital
- No temperature thresholds – assessment is based on signs
Material alternatives
Derived from material properties: a substitute must have all relevant properties. Observe the notes on the substitute.
- Sleeping pad
- Dry leaves, grass or conifer boughs (Collect only where allowed; no protected plants. Check for ticks and insects.), Backpack, Dry spare clothing (Carry it in waterproof packaging – wet clothing barely insulates.), Wool blanket / duvet (Keep away from candles, stoves and heaters.), Insulated cool box (Keeps cold only for a limited time; without ice packs or ice it is not a fridge.), Sleeping bag (Do not store compressed long-term; do not pack away damp.), Newspaper and cardboard (Flammable – keep away from candles, stoves, heaters and embers.), Insulated cooking box (hay box, thermal cooker) (Never put open flame or embers inside – only the hot, closed pot.)
- Wool blanket / duvet
- Sleeping pad, Dry leaves, grass or conifer boughs (Collect only where allowed; no protected plants. Check for ticks and insects.), Backpack, Dry spare clothing (Carry it in waterproof packaging – wet clothing barely insulates.), Insulated cool box (Keeps cold only for a limited time; without ice packs or ice it is not a fridge.), Sleeping bag (Do not store compressed long-term; do not pack away damp.), Newspaper and cardboard (Flammable – keep away from candles, stoves, heaters and embers.), Insulated cooking box (hay box, thermal cooker) (Never put open flame or embers inside – only the hot, closed pot.)
- Dry spare clothing
- Sleeping pad, Dry leaves, grass or conifer boughs (Collect only where allowed; no protected plants. Check for ticks and insects.), Backpack, Wool blanket / duvet (Keep away from candles, stoves and heaters.), Insulated cool box (Keeps cold only for a limited time; without ice packs or ice it is not a fridge.), Sleeping bag (Do not store compressed long-term; do not pack away damp.), Newspaper and cardboard (Flammable – keep away from candles, stoves, heaters and embers.), Insulated cooking box (hay box, thermal cooker) (Never put open flame or embers inside – only the hot, closed pot.)
- Double-wall insulated bottle
- Single-wall stainless steel bottle (Heat only single-wall bottles without paint/plastic; remove the lid before heating.), PET bottle (clear, max. 2 litres) (Do not heat or place in a fire.), Food-grade water container (Only use containers that never held chemicals or fuel.), Airtight food-grade storage container (Fill only when clean and completely dry; never use containers that previously held chemicals.), Collapsible water container or bag (Protect from sharp objects.), Food-grade water bag (Use only for drinking water, never for chemicals or fuel.), Fermentation jar or crock (Use only food-grade containers of glass, food-safe glazed stoneware or food-grade plastic – no metal containers for acidic food.), Resealable food bags (Use only bags intended for food; do not use with boiling water unless the manufacturer explicitly allows it.)
Results come exclusively from structured entries. No improvised instructions are generated.
Sources
Wilderness & Environmental Medicine (Wilderness Medical Society) (2019): Wilderness Medical Society Clinical Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2019 Update
Recognition, preventing further heat loss, wrapping, heat to the trunk, gentle handling
International Federation of Red Cross and Red Crescent Societies (IFRC) – Global First Aid Reference Centre (2020): International First Aid, Resuscitation, and Education Guidelines 2020
Lay first aid for hypothermia