Introduction
To survive a sustained period of cold the most important thing is to know how
to pick the right clothing and utilize the clothes to its fullest extent. This
means understanding the body`s heat production and how choosing the right
clothing can regulate and maintain warmth depending on what kind of activities
one does. Clothing in itself does not produce any heat, but they retain more
or less the heat that the body produces depending on their material. Fabrics
that are lose and fluffy feels warmer than hard fabrics because the fibers
contains more air. Another important point, is to be aware of the formidable
loss of fluids that stems from undertaking physical tasks. This moisture will
be caught in the
clothing without our notice.
A The body`s heat loss happens mainly due to the following four reasons:
1.) By Circulation
The heated air closest to the skin, is driven off and is replaced with cold
air (convection), this is most noticeable in strong, cold wind.
2.) By Transfer
Contact between the body and the ground you lay of sit upon. Cold soles steal
warmth from the body (Conduction).
3.) By Radiation
The body gives off heat to the surrounding area when these are colder than
the body, this has little effect for a fully clothed person during the winter.
4.) By Vaporization
When sweat on the body and in the clothes vaporizes
To assure that the body has the right working temperature (+37 degrees Celsius/98.6
degrees F) the loss of heat and the heat production, needs to be balanced.
The key to balancing is found in the clothing and the regulating this.
Overly Exposed Body Parts
About fifty percent of the body’s heat production draws off from
the head and the neck. Those parts is therefore key elements when
it comes to regulating surplus body heat, bare headed, open in the neck to
get rid of the excess heat
or conversely maintaining it by means of a cap and/ or a scarf.
It’s the so called extremities, hands, feet, ears and nose that’s
most exposed to the cold. Small cylindrical body parts, for example the fingers
has a major heat loss because of large surface in relationship to volume. By
using mittens instead of gloves the total surface will be less and it will
be easier to keep the hand warm.
The Task of Clothing
Clothing's task is to help us keep the body temperature correct. The clothing
shall isolate against the cold and give protection against wind and rain. It
shall also provide the possibilities for ventilation so that hot air may
be drawn off together with body moisture. Dry air has small capacity for heat
transfer.
More thin layers of clothing traps more air and will give better insulation
than one thick layer of clothes. Protection against wind is accomplished
by using a dense outer layer, waterproofs or impregnated cloth as a outer layer
protects against wet weather, but the biggest problem in the winter will be
heat regulation. Its important that one can vary the clothes and the amount
of clothes, so that you don’t becomes overheated. Its therefore important
that you utilize the layering principle as to using several thin layers of
clothing where each garment is of proper size and used correctly and that the
materials
in the garments is chosen with care.
Ventilation
The body will always give off moisture in the form of perspiration. In the
winter most of the sweat will be contained in the clothes and the clothing
should
therefore be made out of fabrics that will allow the humidity to escape through
it. If we hinder this process by using for example waterproofs as an outside
layer the humidity will be gathered on the inside of the clothing in the form
of rime or ice. The moisture is therefore one of the bigger adversaries
in winter time, not only from the outside but also from the inside.
The clothes should with this in mind be of a kind that facilitates temperature
regulation by opening and closing at the following points: Wrists, ankles,
neck, front, under arms and at the waist. This is what is called "chimney
ventilation." For proper use, the clothing should be loose fitting
and give the
possibility to facilitate ventilation. Trousers that sit tight around
the waist or clothes that are held together by belts or straps will hinder
the ventilation for winter use. Braces (suspenders) are recommended instead
of
belts.
Principles for Layering
The clothing is normally to be divided into three main layers :
- Isolating layer
- Windproof layer
- Waterproof layer
The isolating layer is closest to the skin and is made up of underwear (both
long and short) shirt, sweater and socks etcetera after circumstances. Wool
is by far the best material for the isolating layer and it retains its isolating
capability with 80% even if soaking wet and is reasonable fireproof to boot.
None other natural or man-made fabric comes close to the capabilities of wool.
The negative sides of it is that its expensive, its not as durable as other
fabrics and it may itch if its of a lower quality.
The windproof layer's primary function is to keep the warmed up air in the
isolating layers. The fabric should be windproof but it should also let through
as much
as the humidity as possible. The waterproof layer is used in sleet and rain,
if outside humidity was the only thing to consider the requirement of the clothes
would be that they was
100% waterproof . Things are not so easy because we also has to take into consideration
that we must “bleed off" excess humidity from the body – the
main thing to take under consideration is then to find out what is the worst:
being wet from the inside out or vice versa.
Most people are most likely to dress once in the day regardless of what that
day may bring - putting on everything that’s needed for that days coldest
possibility before leaving the house, sweating, enter ones car going full blast
on the heater, more sweating, drive to the destination of that days undertaking
and step outside and instantly begin freezing because of heat transfer due
to vaporization and heat transfer. Taking one's time to regulate and utilize
the clothing in a proper manner will ensure that you’re able to keep
comfortable for longer periods of time when you’re exposed to the cold.