Hypothermia and Cold Injury: Recognition and Prevention

Hypothermia does not require extreme cold. Wet, wind, and 40°F is a more common combination than deep winter, because people dress for the temperature rather than for the conditions. This guide covers prevention and recognition. Anything beyond that — assessment and treatment — belongs to trained responders and medical professionals, and a wilderness first aid course is genuinely worth taking if you spend time in cold conditions.

1. 1

   Understand how you actually lose heat

   Wet clothing conducts heat away from the body far faster than dry clothing, and wind strips the warm air layer at the skin. That is why the dangerous combination is wet plus wind plus moderate cold rather than dry extreme cold. Add fatigue and inadequate food, and your body has less capacity to generate heat in the first place.

2. 2

   Know the early signs, in yourself and others

   Persistent shivering, clumsiness with hands, stumbling, slurred or slowed speech, and unusual apathy or poor decision-making. The judgement changes are the dangerous part, because someone becoming hypothermic often stops recognising that anything is wrong. Watch your partners rather than relying on self-assessment.

3. 3

   Prevent it by staying dry and fed

   Keep your insulating layers dry, use a shell before you get wet rather than after, and eat regularly — your body needs fuel to produce heat. Change out of wet clothing at camp rather than waiting to warm up in it, and carry sleep clothes that have never been hiked in.

   What to wear hikingFabric choices that prevent heat loss

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4. 4

   Manage the sweat cycle deliberately

   Sweating on a climb and then chilling at the top is the classic path into trouble. Remove layers before you start climbing rather than once you are soaked, and put them back on immediately when you stop. Being slightly cold while moving is correct.

5. 5

   Act early rather than pushing on

   If someone in your group is shivering persistently, fumbling with zips, or making poor decisions, stop. Get them out of wind, into dry insulation, and give warm sweet drinks and food if they are fully alert and able to swallow safely. Then reassess whether to continue or turn back — continuing is what turns a manageable situation into a serious one.

6. 6

   Know when this stops being a field problem

   Confusion, stopping shivering while still cold, loss of consciousness, or any deterioration despite warming are medical emergencies that need professional help and evacuation. Call for help early rather than late; a satellite communicator makes that possible where there is no phone signal.

   Satellite communicatorsCalling for help without phone coverage

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Risk Factors