Hypothermia, How to prevent it, spot it, and treat it.

Winter on the trails will result in added exposure to the elements, and weather conditions can change rapidly. Hypothermia is a scary word bandied about regularly by mountain runners and race directors, but would you know how to spot it, or treat it, if you or a member of your crew showed the signs?

Essentially, hypothermia is caused by a combination of cold and fatigue. Long periods of time in low temperatures with insufficient protection against wind, cold or rain can be deadly. Your core body temperature drops rapidly when you slow or stop, even for a brief while.

Hypothermia is when your core body temperature drops below the required norm; 35 degrees Celsius. When you begin to run, you're cold. As you run, your core body temperature rises, you are producing heat. But your OUTSIDE is still cold. You can only lose the heat you've built up in your core when the heat reaches the skin and begins to dissipate. At that point, you get hot and begin to sweat. All is well, you are losing the heat you need to lose.

But when you stop, slow, fall or become injured, the situation changes.

Very mild hypothermia is seen often, in the form of shivering and vasoconstriction (when your fingernail beds turn blue).If you are running in a group, and one of the crew starts falling behind, stumbles and speaks with a slur, they are showing signs of the onset of hypothermia. They may also start shivering, or begin to talk incoherently. Symptoms can include increased urination, nausea, slow pulse, lethargy and a decrease in alertness. In severe cases, muscles become rigid and the victim can lose consciousness.

The risk of falling down, getting lost, or injury is much higher even in the pre-hypothermic state due to loss of coordination and compromised decision-making.

Treating Hypothermia

Stop your crew, and move the person out of the wind. The victim should never be left alone as they are at high risk of wandering off, becoming lost or injuring themselves further. Warm cold water by putting the bottles next to your body before giving it to the victim. Use body heat. Try to erect a shelter and if possible help them put on dry clothes. Cover their hands and head. Use an emergency (space) blanket. If the victim is conscious, place bottles of warm liquids on the skin next to brachial and femoral arteries. If you have managed to get to a shelter or tent, do not put the patient into a cold sleeping bag; they aren’t generating enough body heat to warm it. Pre-warm it by someone else getting into it first and moving around a lot.

Call emergency or rescue services. Go to a hospital as soon as possible. The latter stages of hypothermia can be fatal.

If light is failing or the temperature dropping, look for shelter as low on the slopes as possible. Temperatures drop increasingly at greater heights.

Preventing Hypothermia

In cold and/or wet conditions, monitor yourself. Dehydration makes you more prone to hypothermia, so does hypoglycaemia. Fuel and hydrate correctly. Run with a partner, and dress appropriately. Consider your clothing a system rather than individual clothing items. Next to your skin, wear a snug-fitting, moisture-wicking top that will move perspiration away from your body. Over this, add a windbreaker or lightweight waterproof-breathable jacket to block wind and rain and hold in body heat. Prevent overheating by unzipping and venting the various layers to allow extra body heat to escape. If the conditions are very cold, wear an insulating top made from hydrophobic materials such as fleece or wool.


Runner with a twisted ankle airlifted from HMC 2013 after becoming hypothermic. He became immobile in a cool, shaded area and his core temperature dropped suddenly.

Words by Kim Stephens