ASI OUTINGS - ADVENTURE TIPS
FUNCTIONAL CLOTHING
Introduction
In the out-of-doors, your clothing is all that stands between your
body and a changeable, often inhospitable environment.
As your body's main defense against the elements, your clothing is
the most important equipment you can carry with you into the
wilderness. Therefore, it must be chosen with care.
Understanding the basics of the body/clothing/environment relationship
will enable you to choose the best clothing for comfort, safety, and
high performance in the outdoors. This handout covers the fundamentals
of homeostasis, insulation properties and functional outdoor clothing.
Homeostasis
Homeostasis is the medical term for the process wich controls the
equilibrium of your body's temperature.
In order to function properly, your body must maintain an even temperature
of 98.6º F around the vital organs within your torso.
The homeostasis process functions like your body's thermostat, using
your arms and legs like the cooling vanes on an automobile radiator.
When cold threatens your body temperature's equilibrium, the homeostasis
process decreases blood flow to your extremeties and constricts the
blood vessels in your arms, legs, hands and feet.
Warm blood flow to your fingers and toes can be cut back as much
as 99% or more.
Insulation
Some types of garment materials such as wool and synthetics
maintain more of thier insulating abilities than others when
they become wet such as cotton and down.
Cotton: Cotton clothing is an exceptionally poor insulator
when wet and should be avoided in inclement weather which may occur
at any time in the outdoors!
Down: Down is the finest insulating material available today. It
has a greater "loft" and comfort range than any other insulation for
an equal amount of weight. It creates innumerable tiny dead air pockets
which provide a barrier between body heat and the outside cold. While
down is the best insulation for cold, dry conditions, it is virtually
worthless when it becomes wet.
Wool: A strand of wool is covered with many, many little furry
projections. Each one of these furry projections traps its own
boundary layer of air. This entrapped air keeps you warm. Wool fibers
can absorb quite a bit of moisture without losing thier "furriness."
This is why wool maintains its ability to insulate, even when wet.
Synthetics: All of the sythetics currently on the market
maintain most of thier original loft even when saturated, thereby
keeping you warm and relatively comfortable even when wet. Brand
names include Polarguard, Thinsulate, Hollofil, Polypropylene and
Fiberpile. These synthetic fibers give the material more bulk for
the weight than down, but still maintain dead air space when wet
which improves the insulating qualities of the material.
Problem Areas
Your Head: Up to 50% of your body's total heat production can
be lost through an uncovered head. A hat will greatly slow this
body heat loss, especially a knit WOOL cap or "balaclava."
Your Hands: Your hands will often be the first to feel the effects
of body heat loss. Make sure that the rest of the body (especially
the head) is well insulated. Mittens will provide more warmth
than gloves because the fingers can help to warm each other.
Your Feet: Feet are often cold because a person is not wearing
a hat, has too many pairs of socks on, or has boots that are
often too tight and restrict circulation. Damp socks, especially
cotton ones, will cause feet to be uncomfortable and cold. Wool
socks work well in cold, wet situations.
Your Ears: Protection provided by a wool cap or ear band is usually
all that is needed when exposed to wind and low temperatures.
Drugs
Many prescription drugs may adverse affect your ability to stay warm
in a cold environment. Check with your druggist or physician. Alcohol,
while increasing circulation of warm blood to the extremities and
making you feel warmer, actually depresses the whole body system and
speeds the cooling of your internal body temperature, making you
end up colder. Nicotune can slow down circulation to the extremities
making your hands and feet colder.
Note: Smoking and drinking together do not counteract each other,
you actually get the worst effects of both.
Layer System
Many thin layers of clothes are more versatile than a few heavy layers.
A number of easy to put on and take off layers will allow you to
easily regulate your heat build up or loss so that you can maintain
a comfortable temperature, neither too hot, not too cold.
Wind Chill
If cool air comes into contact with the skin, it absorbs heat from
the body. The faster this happens, the more heat is lost and the colder
the body will get. This is how WIND CHILL works to drastically speed
the loss of body heat. If the skin is wet from rain, perspiration
or condensation, this cooling process is greatly accelerated.
Hypothermia
Hypothermia is simply lowered body temperature caused by the loss of heat
at a rate that is faster than the rate of heat production by your
body. Commonly but incorrectly called "exposure", hypothermia
is a major outdoor killer. You can prevent hypothermia by eating
and exercising to produce body heat, and by conserving that body
heat with the right clothing. Your clothing must be adaptable
to changing weather and activity levels and must allow body moisture
to breathe away while preventing rain and snow from entering.
Editor:
Michael Swiderski, PhD