The leaves have fallen from the trees, the clocks have changed and the days are getting even shorter still. As winter slowly slides in I can’t help but over hear the weather reports. -22’C in Edmonton, -25’C in Yellowknife, I feel somewhat blessed to be sitting here in Ontario with temperatures in the low single digits. Most outdoors people are not scared off by our current local temperatures, but most do not realize there is a silent enemy awaiting them between the bare trees and the November winds, an enemy that will strike should they let their guard down, or be unprepared. The enemy is Hypothermia.

Every year there is usually one or two stories that make the news about a hunter or wilderness adventurer that becomes stranded in the bush for a night, be it from an injury or from getting lost. The story usually ends with a report of the individual being found but suffering from the elements.
So what is this deadly condition that can sneak up on us when things go awry?
It is called Hypothermia:

Hypothermia is defined as ~ Hypothermia, a potentially fatal condition, occurs when body temperature falls below 95°F (35°C).

When someone says the word hypothermia most people conjure up an image of a mountain climber or arctic explorer who is nearly frozen solid. Although these types of incidents do happen, often the story is not as drastic. Often an average individual with good intentions finds themselves in the middle of a hypothermia scenario.
The individual is usually dressed in clothing that is light weight or made of cotton. Although the weather maybe nice by day as the evening hour’s role around and the sun sets the person will often “catch a chill”. Hard work or travel during the day has caused perspiration which in turn has made the individuals clothes damp. A light breeze or failing to insulate one’s self from the ground adequately while taking a break is all that is required to start the cooling process.

The body has a built in defence mechanism whereby it shunts blood from the extremities towards the core of the body in an attempt to protect the vital organs. The individual will start to suffer from cold hands and feet (which can cause a cascade leading to an increased risk for frostbite). As the body’s core temperature begins to slide downward the individual will begin to shiver. This is the body’s way of telling us we are not moving around enough, so it tries to move for us. When we utilize our muscles, they produce heat which helps raise our core body temperature. So... if you start shivering start moving, go for a quick jog, do some jumping jacks or in a survival situation now would be a good time to gather some fire wood.
If we ignore this warning sign or we are unable to move perhaps do to an injury our core temperature continues to drop. We actually will reach a point where we stop shivering, this is not because we have warmed up but because they body has decided that the shivering defence is not working and does not want to expend anymore energy on a method of warming that is not working.

When the shivering stops, the pilot light in our furnace has basically gone out. The body now requires heat to be put back into it from an outside source. I.e. Heat packs and or slow re-warming in a controlled environment, etc... Notice I said a slowly controlled re-warming, as rapid re-warming can cause an influx of cold blood from the extremities to rush back to the heart, this rush can bring on cardiac abnormalities such as heart arrhythmias.
Individuals will start to show the warning signs of Hypothermia, The Umbles, Mumbles and Stumbles. Their fine motor co-ordination will begin to fail (Umbles) this can complicate simple tasks such as working buttons and zippers on clothing. They will start to slur their speech and have trouble annunciating their words (Mumbles). And lastly they will often have trouble co-ordinating gross motor skills such as walking (Stumbles). It is not unusual for victims of hypothermia to act in irrational ways, for example taking all of their clothes off while claiming they feel hot, when in actuality they are freezing to death. An individual who can’t answer simple questions like what is 2+2 in a reasonable time should have the warming process started on them ASAP.

In my next post we will talk about some ways that a person can be effectively rewarmed under field conditions and what some of the predisposing factors to hypothermia are.

Tags: Wilderness First Aid Training , Safety Topics