Although this posting is focused on improving warmth in the bush, the principle can be applied to other areas as well:
1. Stay Dry
Water conducts heat about 25 times faster than air at the same temperature. The best way to stay warm is to stay dry. Two ways of doing this are to avoid open areas of water that can be absorbed into clothing and avoid overexertion.
Body sweat is a natural process that cannot be avoided. It’s important to regulate body temperature by letting it breathe. Dressing in several layers can assist the wearer with the addition/subtraction of layers as needed. If possible, open air vents in clothing or stop periodically, remove a layer or two to air dry.
It’s a good idea to attempt to keep yourself a little on the cooler side at rest. Don’t put on layers until you’re warm and comfortable. If you do, you’ll start to sweat and become overly warm with exertion. Water is absorbed in the innermost layer of clothing. Until it evaporates, you will become cooler than need be and at the same time, your water demand will increase. Water is one of the most important resources in a survival situation, so water management should include sweat management.
2. Increase/Decrease Loft as needed
Loft is considered to be the airspace that is contained between the outermost garment worn and the distance to the skin. As the loft is increased the airspace (barrier) is increased between you and the outside environment.
Many people have frozen to death (hypothermia) because they didn’t have the correct clothing for the environment in-which they found themselves. Survival requires that you think outside of the box. Perhaps you’ll find yourself needing an extra layer or two that you don’t have. In this case, find something like small spruce boughs to stuff inside your clothing. This will increase the loft and you will be warmer.
3. Dry your Equipment
Air dry any clothing /equipment that gets damp. One area that often gets overlooked is the sleeping bag…
Down bags provide the best loft (and the most warmth per pound). Unfortunately their available warmth diminishes the longer its been worn. A wet down bag offers no warmth and in-fact reduces body heat. For this reason, synthetic bags are generally superior to down, given that synthetic fibers don’t stick together when wet. A good synthetic bag will still offer warmth when wet.
Always use a sleeping bag liner. Cotton is a good choice because it will readily absorb moisture. It should be removed in the morning and dried. In cold weather, the moisture will turn into tiny ice crystals. If this is placed back into the bag, it will quickly turn into water with your body heat and continue to absorb more moisture. Be sure to remove any layer of clothing before you get into the bag, unless you plan on drying it before you put it on for the day. There can be a positive to sleeping naked… 🙂
After three or four nights, people I’ve guided often complain of the cold at night. The morning solution is to let the liner get cold, shake it out and (if necessary) beat it with a stick to dislodge the ice crystals.