Cold weather can turn dangerous quietly, long before anyone thinks the word emergency. Hypothermia happens when the body loses heat faster than it can make it, and it can affect walkers, workers, older people at home and children just as easily. This guide explains how to recognise it, how to prevent it, and how to give safe first aid. It is general information, not a substitute for medical training or professional care.
What hypothermia actually is
Hypothermia is a dangerous drop in body temperature, defined as a core temperature below 35C, compared with the normal 37C. As the body cools, the heart, nervous system and other organs cannot work properly. Left untreated it can lead to failure of the heart and breathing, and can be fatal. It does not only happen in extreme conditions or deep snow. Cool, damp, windy British weather is a common cause, and a mildly chilly night can be enough for someone who is frail, wet, exhausted or unable to move around to generate heat.
Recognising the signs
Early hypothermia often shows as constant shivering, cold and pale skin, tiredness and a lack of energy. As it worsens the shivering may stop, and you may see slurred or mumbled speech, slow or shallow breathing, confusion, poor coordination or clumsiness, and drowsiness. The person may deny anything is wrong or behave out of character. This confusion is dangerous because it stops people helping themselves.
Signs differ by age. A baby with hypothermia may be cold to touch, unusually quiet or floppy, drowsy, and may refuse to feed, rather than crying loudly. Older adults can slip into hypothermia indoors during a cold spell without obvious shivering. If you suspect hypothermia, act on your instinct rather than waiting for every symptom to appear.
How cold, wet and wind combine
Temperature on a thermometer only tells part of the story. Wind strips warmth away from the skin far faster than still air, an effect known as wind chill, so a breezy day can feel and behave much colder than the reading suggests. Wet clothing makes things worse again, because water carries heat away from the body many times faster than air. Rain, sweat, a river crossing or a fall into water can all soak someone through. The most dangerous combination is being cold, wet and exposed to wind at the same time, especially when tired or short of food. Understanding this helps you take the risk seriously before anyone is in trouble.
Preventing hypothermia
Prevention is mostly about staying warm, dry and fuelled. Dress in several thin layers rather than one thick one, so you can add or remove them as you warm up or cool down, and choose materials that keep some warmth when damp. Add a windproof and waterproof outer layer, and cover the head, neck and hands, as a lot of heat is lost from these. Keep clothing dry, change out of wet layers as soon as you can, and shelter from the wind whenever you stop.
Keep the body fuelled with regular food and warm, sweet drinks, as the body needs energy to make heat. Avoid alcohol, which makes you feel warm while actually increasing heat loss and clouding judgement. Plan for the weather turning colder or wetter than forecast, carry an extra layer and an emergency blanket, and check on older relatives and neighbours during cold spells to make sure their home is warm enough.
First aid: warming someone safely
If someone shows signs of hypothermia, move them somewhere warm and sheltered as gently as you can, out of wind and rain. Remove any wet clothing and replace it with dry clothes or blankets, then wrap them in blankets or a sleeping bag, remembering to cover the head while leaving the face clear. Insulate them from cold ground, which draws heat away quickly, by putting a mat, rucksack or spare clothing underneath them.
Aim to warm the core of the body gradually rather than all at once. Warmth against the chest, tummy and armpits is helpful. If the person is fully conscious and able to swallow, you can give warm, not hot, sweet drinks, but never give anything to someone who is drowsy or confused. Stay with them, keep monitoring their breathing and responsiveness, and reassure them calmly while you arrange further help.
When to call 999
Call 999 for an ambulance if someone is severely affected: if they are unconscious, very confused or difficult to rouse, if they have stopped shivering despite being very cold, if their breathing becomes slow or shallow, or if a baby is cold, floppy and unusually quiet. Also seek emergency help if they do not improve, if they fell into cold water, or if you are simply not sure. While you wait, keep warming them gently as described and stay with them. If they become unresponsive and are not breathing normally, be ready to start CPR and follow the 999 call handler's instructions. This guide does not replace professional medical assessment.
What not to do
Some well-meant actions make hypothermia worse. Do not rub or massage the skin or the arms and legs, as this can be harmful and does not safely rewarm someone. Do not use direct, intense heat such as hot water bottles placed against bare skin, heat lamps, radiators or a hot bath, because rapid surface warming can be dangerous and can strain the heart. Never give alcohol, and do not give food or drink to anyone who is not fully alert. Handle a severely hypothermic person very gently, keeping movement to a minimum, because rough handling or sudden exertion can disturb the heart. If in any doubt, keep them warm and still and get emergency help rather than trying to rewarm them quickly yourself.
Frostbite and other cold injuries
Cold can also injure the skin directly. Frostbite usually affects exposed or poorly protected areas such as fingers, toes, ears, the nose and cheeks. Early warning signs include cold, tingling or numb skin that may look pale, red or blotchy, and skin that later becomes hard, waxy and white. Do not rub the affected part, and do not thaw it if there is any chance it could refreeze before you reach safety, as a repeated freeze and thaw causes far worse damage. Protect the area, keep the person warm, and get medical help. Remember that frostbite and hypothermia often occur together, so treat the whole person, not just the skin.
What to do next
Take a few practical steps now, before you need them. Put together a small cold-weather kit with an emergency foil blanket, a spare warm layer, hat and gloves, and something high in energy to eat, and keep one in your bag and car through the colder months. Check the forecast, including wind and rain, before heading outdoors, and tell someone your plans. Learn basic first aid through a recognised UK provider such as the British Red Cross or St John Ambulance so the steps feel familiar under pressure. Look in on older or unwell relatives and neighbours during cold snaps. And if you are ever faced with a severe case, do not hesitate to call 999.
