How to prevent and treat hypothermia

February 21, 2019 How to
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Preventing hypothermia is a real consideration for us in the mountains. Even in the warmest days in summer, one can become hypothermic if not adequately dressed and allowed to chill. The nights are always cold in the mountains, the water in rivers and lakes is cold. An unplanned dip in a mountain lake in the summer could escalate to something dangerous if you don’t take care to warm up. 

What is hypothermia?

Our body functions the best at a temperature of 37 degrees Celsius. We can tolerate a temperature range of two degrees warmer or cooler, meaning we can be at 35-39 degrees Celsius safely, though obviously not comfortably. Between 37 and 35 degrees it’s known as cold stress, and our body kicks into action causing us to shiver to generate heat. Below 35 degrees, it’s officially hypothermia.

Once our body temperature drops below 35 degrees, we need to be concerned and treat for hypothermia.

How can you get hypothermic?

Hypothermia, defined as the generalized cooling of core body temperature can happen easily and quickly due to exposure, especially in the mountains. In colder Northern climates, such as the one in Canada, it can happen any time of year. 

You can get hypothermic if you’re not moving, for example if you’re out hiking, you get injured and don’t have enough layers to stay warm when stationary. Once we stop moving our body often isn’t able to produce enough heat to keep us warm, so we have to wear lots of layers. This is an especially important point when it comes to glacier travel or skiing in avalanche terrain. Should the unthinkable happen, for example we fall into a crevasse or are partially buried by an avalanche, once we’re immobile, we can cool fast. 

An unplanned swim in a river while canoeing or rafting can turn serious if we don’t have a change of clothes, especially on a cooler day. 

It’s important to remember that hypothermia is not an event that just happens suddenly, it’s very gradual. 

Your body shunts blood away from extremities and into your core to warm essential organs, and your head. This survival strategy is in place because you can survive without a few fingers, so the more important core organs are kept warm as a matter of priority.

protect yourself in the cold lifeoutdoors

Stages of hypothermia

First there is cold stress, which isn’t hypothermia, but can develop into it if not treated.

Cold Stress

Body temperature: 35-37 degrees C

The body temperature is between 35-37 degrees C. In this case, the patient is able to take care of themselves. The shivering begins in this stage, and the patient will begin mumbling in their speech, and stumbling around. They may be tired or dehydrated, and energy levels may be low in this stage.

How to treat

  • Stop all heat loss, for example layer up, or get out of the wind or water
  • Eat and drink lots of water
  • Move around, increase activity and physical output

The presence of cold stress is a sure sign that hypothermia can develop. Make sure some movement is initiated as passive rewarming, for example just laying down and covering yourself with layers won’t be enough to speed rewarming. You need to move around.

Mild Hypothermia

Body temperature: 32-35 degrees C

If allowed to continue, mild hypothermia will develop. Body temperature will be between 32-35 degrees C.  The patients level of consciousness will be stable, and will likely be shivering uncontrollably. Shivering at this stage will be quite intense, as the body is trying desperately to stop the cooling.

The patient will also be pale, will have a faster pulse and a rapid breathing rate. They may have trouble with finger dexterity, for example clumsy fingers unable to close zippers.

Mild hypothermia is classified as shivering hypothermia without a loss of consciousness (or altered level of consciousness, abbreviated LOC).

How to treat

  • Keep the patient shivering
  • Stop all physical activity
  • Stop all heat loss, it’s a good idea to cover them with something very warm like a sleeping bag
  • Give food and lots of water
  • Encourage shivering – it will warm the person up
  • Keep the person stationary for 30 minutes until they improve

Moderate Hypothermia

Body temperature: 28-32 degrees C

If you’re unable to halt mild hypothermia, body temperature will continue to drop. In moderate hypothermia, body temperature will be between 28-32 degrees C.  

In moderate hypothermia, you’ll see a changing level of consciousness, though the person will still be conscious, just not fully alert, and they’ll likely stop shivering. This stage requires gentle handling. The person will either be shivering violently, very slightly, or not at all.  Their pulse and breathing will be rapid.

How to treat

  • The main goal in this stage is to keep the person shivering
  • Stop all physical activity, and bundle them up
  • Stop all heat loss
  • Passive heat will help here, such as a hot water bottle or heat packs. Put these on the core areas such as the chest and back. Warming the extremities (arms, fingers, legs) will have not effect because the capillaries are constricted and can’t absorb heat.
  • Keep them in a horizontal position
  • If they are alert enough, try to give them food and water, keeping in mind they may have difficulty swallowing

Severe Hypothermia

Body temperature: below 28 degrees C

Body temperature will be below 28 degrees C.  At this body temperature, the body can no longer remain conscious and the patient will pass out. This stage is particularly dangerous because the body would have stopped shivering, and therefore cutting off heat production even more.  Respirations will be shallow and pulse rate weak and hard to find. 

This is the critical stage where you really need to treat the person gently

How to treat

  • Don’t move them at all if possible
  • Monitor breathing and pulse, if breathing stops, begin artificial respiration
  • CPR may be necessary, monitor the pulse
  • Keep packaged and halt all heat loss as much as possible
  • Attempt to add heat to the core of the body as before
  • Immediate evacuation should be done, and if not possible, stabilize them as much as possible, patients have survived long periods of CPR if kept warm 

How to deal with hypothermia

The most important thing is to recognize hypothermia quickly in order to stop it from progressing.  Once, while out backcountry skiing in -25 temperatures, I wasn’t dressed quite warm enough and was very uncomfortable. When we arrived at our vehicle and began to remove gear and pack the car, I got even colder.  Shivering very violently, I had problems using zippers and putting on clothing to try to get myself warm. My fingers didn’t seem to be working that well.  I also started having problems speaking, forming sentences seemed difficult and extraneous. 

It was a very uncomfortable state. Aside from being very cold, I also felt slightly mentally impaired. If allowed to persist, this would definitely develop into hypothermia. This is the closest I’ve ever become to becoming dangerously hypothermic. Living in a cold climate one becomes very good at managing the cold!

To prevent hypothermia, or the danger of developing hypothermia, it’s important to always bring lots of layers on your outings. Take care when you stop to put on extra layers, and make sure to wear quick-drying base layers because wet layers become very clammy once your body cools down, speeding cooling. When you stop, layer with a down jacket or insulating layer.