Extreme Weather: Hypothermia

Although most of my articles have been on navigation it is not a subject that is easily isolated. Generally, most of us associate navigation with finding our way in the mountains, deserts and jungles; however, as we have seen, navigation plays a big part in safety and providing the best life-sustaining facilities en-route.



 As the world opens-up to the traveller, more and more extreme places become accessible; this results in more incidents and bad experiences. As a traveller you should never underestimate the importance of self-reliance; it is your best weapon in the fight for survival in any environment. Although I am always more wary about hot weather rather than cold, they are both equally dangerous. This article takes a look at hypothermia and should not be confused with frostbite; the word hypothermia originates from the Greek ‘Hypo’ meaning under or below and ‘Therm’ meaning heat. The official definition of hypothermia in a human being is: A core or internal body temperature of less than 35 deg. C (95 deg. F).

Our normal internal body temperature of 37 deg. C (98.6 deg. F) is regulated by the hypothalamus in the brain; this controls all the things that help us retain or lose heat (muscles that control body hair, sweat glands etc.), these are known as ‘effectors’.

So, What’s the Problem?

If the hypothalamus controls our core temperature why do we need clothes? The reason is that the human body cannot compensate for the extremes in temperature, so we have to give it a hand; this is complicated further by movement, as all movement produces heat.

Why Is Hypothermia Such a Danger When in the Wilderness?

Cold itself is relatively easy to deal with and presents only a small problem. Wind presents us with a slightly larger problem and we refer to this as the ‘wind-chill factor’, but it’s water that puts the ‘cherry on the top’ so to speak.

Cold, wind and water together are potentially life threatening; water will remove body heat 25 times faster than still air. This is what concerns the wilderness traveller more than anything else. Your body will start to shut down the blood supply to your arms and legs in an effort to retain the correct core temperature; you have no control over this function. When this happens you will start to lose the function of your extremities along with your rational thought and the game, as they say, is over… It’s off to that big tent and sleeping bag in the sky!

What Can We Do?

Fortunately, there is a lot we can do. Injury and extenuating circumstances accepted, the remaining vast majority of deaths through hypothermia are caused through being idle or as we used to say ‘poor administration’. Let’s now take a look at how we can help ourselves.

Progress in extreme weather will be slow; the reason for this is not so much a physical one but more an administrative one. You need to be very aware of what your body requires and attend to them constantly. Below are a number of things to look out for.

1)  Keep yourself properly hydrated. The blood needs to be the correct ‘thickness’ if it is going to transport oxygen to your muscles efficiently; it also plays an enormous role in transferring heat and controlling your core temperature.

2)  Adjust your clothing as often as necessary to remain warm but as dry as possible; remember, sweat will have a chilling effect when you stop. You will always sweat where your rucksack is no matter what you do, make sure that this is the only area.

3)  If it starts to rain put your waterproofs on straight away (that’s why they are in the top of your rucksack just under the main top flap). You will need to slow down to prevent sweating and as soon as the rain stops take them off again.

4)  Be confident that you can start a fire with only your knife and sparking tool under any conditions.

5)  Remain properly nourished. Your walking ‘tucker’ should consist of nuts, raisins, flapjack and the suchlike; chocolate is O.K. for a quick boost but under certain circumstances can leave you with an energy ‘dip’. Try to choose foods that will produce a slower release in order to maintain a more consistent energy platform.

6)  Have your high-fat meal before you turn in and you will sleep warmer.

7)  Try and get your blood circulating a bit before you get into your sleeping bag; try a few press-ups or a short run, this normally does the trick.

8) If the conditions become dangerously extreme, seek shelter before you become too uncomfortable; you will know when you reach this point, don’t ignore it. If you are on your own this is your limit for ‘self help’; after this point your body will start to shut down bit by bit and apart from the physical limitations it is unlikely that you will be ‘switched-on’ enough mentally to deal with it.

How Do You Know That You Are Moving Toward Hypothermia?

It may sound incredibly basic but you will be getting cold! This is the first sign and you need to take notice; make and keep making the necessary adjustments and it is unlikely to advance further. If you are with a friend or group you will be looking out for each other; there are a few things to look out for that will alert you to the fact that they may be heading toward hypothermia. These early signs may include:

1)      Feeling cold, shivering.

2)      Slow, lethargic, poor coordination.

3)      Unusual difficulty in moving over rough ground.

4)      Change in character.

5)      Grumbling, unhappy, unreasonable.

6)      Slurring of speech.

It’s not uncommon for the victim in later stages to suddenly develop a burst of energy, often rushing off; in this situation you must physically restrain the person. Remember, in this state the burst of energy can make them extremely difficult to control and often the best way is to give them a good ‘whack’; This burst of energy is often followed by collapse so the sooner you sort it out the sooner you can deal with the problem… A problem that should have been avoided in the first place.

Problems such as this often occur through the reluctance to tell someone that you are feeling cold and have to stop for a moment and sort it out; this is more often encountered in a group that does not know each other very well. A good navigator/guide will be on the lookout for this constantly and often make adjustments to the route to ensure the availability of natural shelter as much as possible should the need arise. Among an experienced group that know each other well, the problem is unlikely to occur as the others are aware of its importance. In this instance it is normal to receive an endless torrent of personal abuse from the others that you will no doubt find great pleasure in passing on to someone else further up the mountain; it is this ‘banter’ that keeps everything as it should be and ensures that everyone in the group are very comfortable with each other. Never, ever be concerned that you will be considered a ‘wus’ if you say that you’re cold; everyone has different thresholds.

Hypothermia is a very complex problem that is far better avoided; this article has only scratched the surface. That said, don’t be frightened of the cold, just give it a healthy respect.

Many dangers are reduced substantially by nothing more than acknowledging that a problem may exist.

Safe & happy adventures.

Read about my article on Hyperthermia here.

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