Hypothermia

Hypothermia is when the core body temperature drops to a level where normal brain and muscle function is impaired - usually at or below 35°C. When the body cannot cope, it goes into survival mode, shutting down non-essential functions. Hypothermia occurs when the body cannot make up for the amount of heat lost.

Did you know?

7% of outdoor recreation fatalities were caused by hypothermia
There and Back, 2016

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Preventing Hypothermia

Hypothermia can be avoided by wearing appropriate clothing and ensuring you have sufficient food and shelter.

Effective Planning
  • Wear the right fabrics - Clothing only retains what heat your body produces. Certain fabrics, such as wool and synthetics, draw moisture away from the body and retain warmth. Avoid cotton clothing – when cotton gets wet it ceases to insulate you. Watch the video here
  • Always take wind and rain protection - A good outer layer that will protect you from rain and wind is essential. This will significantly reduce the chance of hypothermia. Be smart about when you put this on as well – don’t leave it until you’re already wet or cold.
  • Eat nutritious food and stay hydrated - Food gives us the energy required to keep the body warm. On cooler days, you’ll need more food. Drink regularly, this includes a hot beverage to start and end the day.
  • Have a solid plan - Before you go, check the weather and choose a trip that suits the skills, equipment and preparedness to encounter the forecasted conditions of everyone in the group.
Recognising the symptoms
  • If walking in cold, wet or windy conditions, watch for early signs of exhaustion or hypothermia. These include:
    • Lack of co-ordination
    • Confusion and disorientation
    • Slurred speech
    • Irrational behaviour
  • When a person is becoming hypothermic, they will often insist that they are okay.

Video: Lachlan Forsyth tries to get hypothermia so you don’t have to.


Treatment

If the patient is conscious and still talking (can swallow safely), the first thing to do is prevent further heat loss.
  • Insulate them from the ground 
  • If they can be helped out of their wet clothes and into dry clothes whilst in shelter, do so. If this is not possible, allow them to keep wet clothes on but cover them completely in a tarpaulin or bivvy bag (water proof ‘vapour barrier’) until they are in a sheltered position like a hut or a tent where they can get changed.
  • Ensure they eat and drink. Carbohydrates, including sugars, will help their body to produce heat.
  • If they are conscious and talking and have eaten, then gentle movement helps to generate warmth (moving legs and arms, can be sitting down when doing so until they feel well enough to walk again). 
If they are semi-conscious or unconscious: Prompt evacuation must be organised (activate your PLB)
  • It is not safe to give them food or drink because they may choke
  • They need to be moved carefully (carried horizontally to shelter) and not be allowed to try to stand or walk since it can cause collapse
  • Insulation from the ground with a cell foam mat and from the wind by being wrapped in a tarpaulin or bivvy bag and sleeping bag and dry clothes will reduce further heat loss, which can cause cardiac arrest
  • Warm water bottles in the armpits, by the neck and on the chest may help reduce further heat loss, but does not deliver adequate heat energy to effectively rewarm
  • This patient must be evacuated as a matter of life and death 
  • Sharing body heat in a sleeping bag or sharing exhaled air does not rewarm the patient, this is an old wives’ tale.

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