Regulating Body Temperature
It's important to understand how your body reacts to the temperature and various weather conditions in order to plan the right clothing for a trip. The term thermoregulation refers to the process of balancing the heat you lose to the environment with the heat you generate from exercise and absorb from the environment. Thermoregulation, or more simply put body temperature regulation, is important to prevent both hyperthermia and hypothermia, and winning this battle begins by wearing the right clothing and layering properly. Although clothing items should be versatile enough to meet the various seasonal and weather conditions you may encounter on a backpacking trip, it is important to note that each person's body is different, which in turn means that individual requirements are different as well. Finding the exact right clothing to suit your needs might take a little experimentation.
How Your Body Loses Heat
Heat leaves your body in the following ways:
How Your Body Loses Heat
Heat leaves your body in the following ways:
- Conductive Heat Loss This occurs when your body comes in contact with a cooler surface, primarily through your feet via the soles of your boots. When resting, it can be minimized by avoiding situations in which you sit or lay on cold surfaces. Conductive heat loss also occurs 25 times faster with wet clothing than it does with dry clothing. Thick insulation will help prevent conductive heat loss.
- Convective Heat Loss This occurs when your body heat warms the air around you, that air rises and is displaced by by cold, fresh air from the environment. Convective heat loss is increased by the wind, and is measured by the windchill. Wearing windproof garments will help prevent convective heat loss.
- Radiant Heat Loss This occurs by the emission of infrared radiation from the body, and primarily happens on cold, clear nights around sunset (cloudy nights somewhat lessen the effects because the clouds reflect a portion of the radiant heat back to the earth's surface). Wearing thick layers of insulation or fabric that reflects the heat back to the body will help prevent radiant heat loss.
- Evaporative Heat Loss This occurs when liquids on the skin (primarily through perspiration) evaporate and draw heat from the body after intense physical activity. This process (changing water from a liquid to a gas state) takes a lot of energy, and explains why sweating helps cool you off when hot. Evaporative heat loss is very important to cooling down your body to prevent heat illnesses in hot weather. Conversely, it's very important to minimize the amount of perspiration and therefore reduce evaporative heat loss when it's cold. Wearing fabrics that pull moisture from the skin and dry quickly, along with vapor barriers, will help prevent evaporative heat loss.
Trapping Your Body Heat
Clothing insulates you by trapping your body heat and creating pockets of "dead air," which is a layer of static, unmoving air close to your body. This air is warmed by heat given from your body through radiation, conduction, and convection, and helps maintains a warm microclimate around your body. The amount that a particular clothing fabric insulates is based on its thickness or loft, and the greater the amount of loft, the greater amount of dead space within a garment. Furthermore, not all fibers are created equally, and different fibers are better at creating dead air than others. As a backpacker, you're looking for a garment that creates a significant amount of dead air space but does not weigh a lot, referred to as the warmth-to-weight ratio.
Clothing insulates you by trapping your body heat and creating pockets of "dead air," which is a layer of static, unmoving air close to your body. This air is warmed by heat given from your body through radiation, conduction, and convection, and helps maintains a warm microclimate around your body. The amount that a particular clothing fabric insulates is based on its thickness or loft, and the greater the amount of loft, the greater amount of dead space within a garment. Furthermore, not all fibers are created equally, and different fibers are better at creating dead air than others. As a backpacker, you're looking for a garment that creates a significant amount of dead air space but does not weigh a lot, referred to as the warmth-to-weight ratio.