Hypothermia Basics

 In General

Hypothermia is not a condition to be taken lightly. As much as it’s easy to assume it can only happen in winter or if you fall into cold water, it can happen in a number of environments and in any season. No matter what the scenario, time is of the essence in getting a hypothermic individual on the path to recovery, so CSAR member Joel (a paramedic with additional team training specific to hypothermia) has put together some ‘Cold Notes’ on recognizing, treating and preventing hypothermia.


In wilderness environments, hypothermia results from:

  • Inadequate protection from the cold
  • Inadequate food for metabolic fuel to be burned during exercise
  • Inadequate fluid intake resulting in dehydration


Hypothermia can be divided into mild, moderate, and severe stages:


  • The person is cold but alert, vigorously shivering and has normal vital signs. Core temperature is 35-32°C.
  • Their ability to re-warm without an external heat source is good
  • They have some motor skill impairment. Mental impairment could also occur.
  • The mnemonic used for mildly hypothermic patients is UMBLES: Fumbles, Stumbles, Tumbles, Mumbles and Grumbles. So, if it walks like an Umbles and talks like an Umbles… they have mild hypothermia.


  • Thermoregulatory responses are slow and disappear. Shivering decreases and eventually stops.
  • Core temperature is 32-28 °C. At 32°C shivering will stop. Consciousness is lost at 30°C.


  • When the core temperature drops below 28°C, individuals will be unable to re-warm themselves without an external heat source.
  • Rigidity and spontaneous ventricular fibrillation occurs followed with cardiac arrest. In simple terms, they become so cold their heartbeat rhythm is disturbed and may stop.

People who are cold stressed with light shivering are encouraged to walk/run/do light exercise to re-warm themselves. If they are shivering vigorously with the ‘Umbles’ they should be positioned laying flat. Move and touch them as gently as possible, keeping them flat to avoid triggering heart irregularities. Prevent further heat loss by removing them from the environment, removing wet clothing and packaging them to get to the hospital. The packaging, or ‘hypothermia wrap’, should have lots of insulation (clothes/blankets) wrapped around the patient and a vapour barrier wrapped around the outside of the insulation.

Some tips to stay warm and dry:

  • Wear layered clothing – do not wear cotton!
  • Protect exposed skin – cover your hands and head
  • Avoid becoming dehydrated
  • Eat high energy food
  • Always making sure that you travel with the “Ten Essentials” for backcountry travel. Take a look here.


Keep cool folks, but don’t freeze.


Thanks Joel!

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