Why Hypothermia Happens When You Least Expect It

The UK’s weather is notoriously changeable. A mild day in the Cairngorms or a summer walk on Dartmoor can turn cold and wet within minutes. Wind and rain strip heat from the body far faster than cold alone. Hypothermia occurs when your core temperature drops below 35°C. It is a medical emergency that can affect anyone, from a seasoned mountaineer to a day-tripper caught out by a sudden squall. In remote conditions, help may be hours away, so early recognition and decisive action are vital.

Recognising the Signs: Mild to Severe

Hypothermia creeps in gradually. Knowing the stages helps you act before it becomes critical.

• Mild hypothermia (35–32°C): Persistent shivering, cold pale skin, numbness in fingers and toes, clumsiness, slurred speech, and feelings of apathy or disorientation. The person may deny they are cold.
• Moderate hypothermia (32–28°C): Shivering may stop as the body runs out of energy. Confusion, drowsiness, slow shallow breathing, weak pulse, and loss of coordination. They may resist help.
• Severe hypothermia (below 28°C): Unconsciousness, no shivering, dilated pupils, very slow breathing and pulse, and risk of cardiac arrest. This is a life-threatening emergency.

Immediate Actions: Shelter, Dry, Insulate

If you suspect hypothermia, act immediately. Every minute counts.

• Move the person to shelter. Get them out of wind and rain. A tent, bothy, or even a makeshift shelter using a rucksack and tarpaulin can make a difference.
• Remove wet clothing. Cut clothing off if necessary to avoid moving them too much. Replace with dry layers. Pat the skin dry gently; do not rub.
• Insulate them from the ground. The ground conducts heat away rapidly. Use a sleeping mat, rucksack, branches, heather, or any dry material. Then wrap them in a sleeping bag, foil blanket, or extra clothing.
• Share body heat. If available, another person can get into a sleeping bag with them, skin-to-skin, to warm the core.
• Give warm sweet drinks only if fully conscious. No alcohol. Warm, sugary drinks can help mild cases. Do not attempt to give anything by mouth if they are drowsy or unconscious.
• Do not rub limbs or apply direct heat. Rubbing can push cold blood back to the core. Hot water bottles or direct heat can burn numb skin and cause erratic heart rhythms.

Rewarming the Core Safely

The priority is to rewarm the core, not the extremities. Warming cold arms and legs first can send cold, acidic blood back to the heart, potentially causing cardiac arrest.

Handle the person gently. Keep them horizontal and still. Avoid sudden movements or walking them out if moderate or severe. If you must move them, do so carefully on a stretcher or improvised drag.

Apply warmth to the core. Place warm packs or hands in the armpits, groin, and neck. Wrap the head and neck. Use your own body heat.

Monitor breathing. If they become unconscious and stop breathing, start CPR. In severe hypothermia, signs of life may be very faint. Continue CPR until help arrives.

When to Call for Help and How to Evacuate

Seek medical help immediately if symptoms worsen. In remote UK areas, call 999 and ask for the police, then mountain rescue. Give them:

• Your exact location, including a grid reference or a clear description of your surroundings.
• The number of people in your group and their condition.
• Any changes in symptoms.

Do not delay. If the person is confused, shivering has stopped, or they are drowsy, this is a medical emergency. Keep them warm and still. Do not leave them alone unless absolutely necessary to get a signal. If you must leave, note their location and return as quickly as possible.

Prevention: Plan, Pack, and Know Your Limits

The best treatment is prevention. Check a detailed mountain forecast before you set out. Pack spare dry layers, waterproofs, an emergency shelter or bivvy bag, a headtorch, high-energy food, and a hot flask. Wear synthetic or wool layers, not cotton. Cotton loses insulation when wet.

Know the signs of hypothermia and turn back early if the weather worsens or someone in your group is struggling. In remote UK conditions, humility is a strength. No summit is worth a life.