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.
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.