Layering for Comfort and Survival
Layering for Comfort and Survival
Layering refers to a choice of clothing that enables the user to manage their individual pieces to promote comfort and ultimately their survival. Layering is frequently thought of as a method of staying warm in cold temperatures, but in fact it can be used over a wide range of temperatures. In many cases layering is a method of moisture control rather than temperature control. How we put clothing on our bodies can mean the difference between having a good time and being miserable.
Clothing is a good substitute for that outer layer of hair that has been lost in our adaptation to our environment. If we had to depend on the hair on our bodies, we would face a much more limited choice of places to live and we would not be able to do as many things during periods of extreme temperatures. It used to be pretty simple: Put on a little clothing if it is hot and a lot of clothing if it is cold. But as in the evolution of humans to desert environments, we have found that this technique is lacking in sophistication and character. Now, it is not only what clothing you put on, but how you put it on that counts.
The key element in layering is the idea of active management of your clothes before you get too hot or too cold and the role that moisture plays in making us feel hot or cold. In its simplest terms, there are three layers: A wicking layer, an insulating layer, and a protective layer. There is no requirement to wear all three layers except as dictated by the environmental conditions. It does make good sense in an area that experiences rapid, dramatic weather changes to have all three layers available.
The wicking layer is perhaps the most important as it is what you experience next to your skin. This is the foundation of the system and assures that moisture that is constantly being generated by the body is transported away from the skin. If only one layer is being employed because of the temperature, it is usually this one. A good wicking layer will consist of synthetic fabric that is highly hydrophobic. This property will cause body moisture to be drawn away from the skin to be exposed to evaporation. If evaporation takes place on the skin, it causes a drop in the sensible temperature of the skin. It is the body’s way of cooling. Unfortunately, in the absence of warm temperatures, this cooling can be detrimental. The wicking layer should be capable of covering all the areas of the body including feet, legs, torso, head and hands. Every item of potential clothing next to your skin should be a wicking layer.
Insulation is an idea most people understand. The more dead airspace you create, the more heat can be trapped and the warmer you stay. To say that the next layer is an insulation layer does not completely communicate the idea because this layer may be several garments. But in the end, the idea is to create dead airspace that is not too great to be warmed by the body. The issue here is the right amount of dead airspace: Too little and the body is still cool or cold, too much and the body is too warm and begins to actively perspire. The creation of water necessitates a system that will transport it away from the skin and out to evaporate. This process of evaporation has to take place through the insulation layer where it may be absorbed, so this layer too needs to be hydrophobic. It needs to continue to move the water out. In the absence of a hydrophobic layer, it is important to not get this layer wet. This is where active management is important. If you start to perspire, it is time to remove layers to the point where you are no longer doing so. Remove layers before you get wet to remain dry and comfortable. The ability of the body to heat the dead airspace is also important as the lack of activity or calories to burn may hamper the ability to stay warm.
The protective layer will do just that, protect you. If the fabric is durable enough, it will even protect you from underbrush, willows or rocks, but the important function is to protect you from wind and precipitation. The two conflicting properties of this layer are breathability and waterproofness. They are in conflict because usually the more breathable the layer is, the less waterproof it is. Both of these properties are defined by the manufacturers of these products and what may be waterproof to one may not be waterproof to another. The usual criteria involve the pressure at which the water passes through the fabric. Some consider it waterproof at 2 PSI and other not until it resists water penetration at 6 PSI. Conversely, what allows perspiration vapor through a little may not be enough to allow all vapor created by the body to pass out for evaporation. Protective layers can range from coated nylon that is completely waterproof but does not breathe at all, to softshells that breathe well but are only water resistant, to Gore-Tex that is waterproof and breathes well. The level of activity should determine the choice of garment. The purchase of this layer is a significant investment. If the need is temporary and the situation is not critical, almost any protective garment will do. If the use will be continuing and long term and the situation may involve critical, life-threatening environments, it is important to choose wisely and get a good garment.
As stated earlier, the key to this system is active management. In an inactive situation, a combination insulation and protective layer will suffice. But in the absence of a conscious decision to remove the insulation layer when the weather gets warmer, this piece will not do for active situations. The important concept here is that you have enough layers to allow easy changes that will accommodate numerous environmental conditions. If it is warm out, the wicking layer is all you need to wear while carrying the others. In the absence of active wind or precipitation, it is not necessary to wear the protective layer. If this layer is worn without the presence of wind or rain, it will create a barrier to the transport of perspiration. The easiest way to accommodate temperature changes is by varying the insulation layer. In warm temperatures it is still smart to carry a light insulation layer. In cold temperatures it may be necessary to wear one layer and carry another. If it is still not raining but only windy, a wind barrier layer can act as insulation and a protective layer. If it begins snowing, a softshell that is water resistant may be enough to keep the water out while allowing perspiration to evaporate. If it is thunder storming, wear it all.
Most of us want to be warm and comfortable. We start out the day that way. We put on all the clothes that we think we will need to stay warm and then we get out of the house or car and begin some activity. It should quickly become apparent that we have over-dressed for the situation. Take something off before you start to get wet. Better yet, start out with just a little less than you think will keep you warm and let the body heat of the activity bring you up to comfortable.
One of the most frequently overlooked parts of dressing for the cold is that we lose about 70% of our body heat from the neck up. That makes the wicking, insulating and protecting layers for the head one of the most important areas to consider. Varying clothing in this area will quickly provide results. As grandmother once said, “If your feet are cold, put a hat on.” Conversely, if you are starting to get hot, take your hat off. The back of the neck and head are a good place to gain or lose heat and make a good argument for a well-fitting hood on your protective layer.
If you think of your clothing as an extension of yourself and the creation of a shelter from the environment, you will go a long way toward choosing the right stuff. In our urban environment looking good may be important, but in the wilderness what we choose to wear may make the difference between life and death. This is an investment in your life. Take the time to evaluate and choose wisely and your clothing will provide many days of happiness in the wilderness.
– Bill Houghton