Original Article
The air is crisp, crystalizing around you
with each breath. A twig snaps under the pressure of your foot, echoing
off the surrounding trees. It’s a brisk, beautiful late autumn morning.
It’s great to be in God’s creation.
But for the ill-equipped traveler thrust into
survival mode due to mechanical issues with his vehicle, the same
picturesque morning can be cold, hard, unforgiving, and even
life-threatening.
The right gear makes a world of difference. So what’s the right gear? In previous article, I’ve written about the best way to dress for cold weather. In
this post, I’ll share the 5 ways your body looses heat. Understanding
these methods can help you to reduce your heat loss and stay warm
longer.
Heat Loss Through Radiation
As warm blooded beings, people produce their
own heat. By just being alive, we create a normal body temperature of
98.6F. Most the time that’s warmer than our surrounding environment, so
the two try to equalize. Our body gives off heat through radiation.
That’s when the warmer of the two areas gives off heat to the cooler
area.
To control heat loss through radiation, we
need to insulate the ourselves from the surrounding environment. We can
do this through warm clothing.
A down jacket, for instance, uses our body
heat to warm the pockets of air trapped in the down. That helps keep the
heat inside the jacket and thus keep us warm.
Your head is a major source of heat loss. Keeping your head covered, and the area around your neck can help preserve your heat.
Heat Loss Through Conduction
Another way our bodies loose heat is by
coming into direct contact with another surface that is at a lower
temperature. It’s similar to radiation except rather than loosing heat
to the environment, the heat is transferred to another object or
surface.
Solid objects such as a metal pole or the
ground can steal heat from your body much more effectively than air. In
fact, you loose heat about 30 times faster when submerged in water than
standing in air. 75F in air feels comfortable; 75F in water is feels
cold and can cause hypothermia.
Conduction is why it’s important to insulate
yourself from the ground when sleeping. Body heat will seep into the
cold ground, leaving you cold and miserable. Sleeping on evergreen
boughs will help lift you off the ground and preserve your body
temperature.
Heat Loss Through Convection
As with radiation, convection is when your
body looses heat to the surrounding environment. However, with
convection, the heat loss is through the stirring of the air.
Consider a fan. When you are sitting in your
home and you’re a little warm, you may turn on a fan to help circulate
the air. The moving air brushes by your skin. When it does, it takes a
little bit of your heat with it. Then, having moved along, more air
brushes by, taking more of your heat. The more air, or wind, the more
heat loss.
This is sometimes called “wind chill” and it can be devastating for the survivor in colder climates.
When dressing during cold weather, it’s
important to keep in mind that your outer layer of clothing should
protect you from the wind.
Heat Loss Through Evaporation
Our bodies have a built in system to help
regulate excess heat. When we exert ourselves and our core body
temperature rises, we begin to sweat. On a hot summer day, sweating is a
good thing. In fact when you stop sweating, you should be worried about
overheating.
However in the winter, sweating is bad. In fact it can be deadly. As renowned survivalist Les Stroud
has said, “In cold weather if you sweat, you die.” But the threat is
not limited to sweating. In cold weather survival situations, you must
stay dry. Rain, mist, snow, and other forms of liquid will have the same
effect is sweating.
When water, including sweat, evaporates it
cools the adjacent surface. When that surface is your skin, it removes
much needed heat from your body and makes it harder to stay warm.
In cold weather, you must stay dry. Having
the proper clothing is important. Avoid overexertion. Regulate your body
temperature to avoid sweating by removing layers of clothing when you
do strenuous activities. Stay dry.
Heat Loss Through Respiration
When you breathe, you were bringing in cold
air from the outside into your lungs. As oxygen is transferred to your
bloodstream and carbon dioxide is transferred out, your body warms the
air. When you exhale, you’re releasing the warmed air into the
surrounding environment. That is heat loss through respiration.
Compared to the first four sources, heat loss
through respiration is relatively minor. But still you should be aware
of it. A light covering over your face will help pre-warm some of the
air before bringing it into your lungs.
Summary
As fall is giving way to winter, it’s important to understand how our bodies can lose heat and how to avoid it. Hopefully if you’re thrust into a survival situation, you’ll have the proper clothing and gear. But being prepared is as much about knowledge and skills as it is about gear.Related Posts
- Winter Driving: Be Prepared for the Unexpected
- Why Garbage Bags Should Be in Your Survival Kit
- Is Anything More Important than Fire?
- 5 Tips to Improve Your Cold Weather Survival Shelter
a rehash of what I already know, but well said in your article for those who haven't experienced it...
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