Beat Old Man Winter at His Own Game
C > Keep your body and clothing CLEAN
O > Do not OVEREXERT yourself
L > Use LAYERS to control your warmth
D > Keep yourself DRY to maximize warmth
If you are going to stay warm in cold weather, it might sound odd but the acronym C.O.L.D. is the trick to help you remember what to do.
C IS FOR CLEAN
Staying clean has two components, your body and your clothing. When your skin is clean it removes the layers of dead skin cells that can act like an insulator and it keeps the pores clear so they can do their job of creating and releasing sweat. Keeping your clothing clean helps it perform as it was designed. Most insulating clothing needs to let moisture in the form of vapor escape through the fabric to avoid becoming damp, which will reduce its ability to trap warm air in its insulation. Dirty or wet clothing also reduces the insulation’s ability to trap and hold warm air next to the body.
The “C” can also stand for Cover. The majority of the heat radiated by your body goes out from your head, hands, and feet. You have probably felt how putting on a hat on a cold windy day very quickly makes you feel warmer. That is because you are trapping the warmth escaping from your scalp. Your best head covering is both windproof and will trap air either in the fabric or in the empty space above your head. For your hands, mittens are warmer than gloves as gloves expose more surface area to the air you are trying to warm up. Keeping fingers together in a single space to keep them warm is more efficient than separating them. For your feet, use wool socks or a wicking liner sock and a synthetic insulating sock.
O IS FOR OVERHEATING OR OVEREXERTION
If you exercise too much, or don’t let enough heat escape from your body, you will sweat more than usual. This will cause several problems. Your skin will get wet and can cool by evaporation while still active, or by conduction if your body temperature drops enough that the heat of the water goes back into the skin. Significant perspiration will also inhibit your clothing’s ability to keep you warm and it increases the risk of dehydration. So, avoid overheating by either keeping your activity level moderate or vent the heat from your body by opening layers.
L IS FOR LAYERS
The best way to control your body temperature, and to create effective pockets of trapped air in your insulation, is to use a layering system for your clothing. It will trap more warm air than just one heavy coat. You can also add or remove layers as you start to feel cooler or warmer. Your layers should be lightweight and loose fitting; tight fitting clothing reduces circulation and does not insulate well. The most effective approach is to have a light base layer that insulates and transports sweat away from the skin, followed by an insulating layer to trap warmth, and then an outer layer to protect from wind and precipitation. You should also ensure that the parts of your body that radiate the most heat, your hands, feet, and head, have an insulating layer on them. If you keep those three warm you can keep your whole body warm.
D IS FOR DRY
Staying dry is the biggest key to staying warm. If you and your clothing are not dry then the other three aspects of this acronym don’t matter very much. Wet skin will get cold much faster than dry skin will from evaporation and conductive heat loss. Wet clothing can’t do its job of insulating you from the elements and trapping the heat your body is giving off. You also stand the chance that exposed parts of wet clothing will freeze, further complicating your efforts to stay warm and healthy. So, don’t overexert yourself and keep your clothing clean and dry. You should also replace damp clothing like socks, gloves, hats, and any layers that are next to your skin with dry clothing so they can continue to be effective as insulators.
Now that you have an easy mnemonic to remember what to do, keep your body and your clothing dry and use clothing that maximizes the layers of trapped air to keep yourself warm enough, but not too warm.
How the Body Loses Heat
The body loses heat in several ways. The four main mechanisms of heat loss are:
Evaporation — The body’s way of reducing its internal temperature is to sweat. Sweat glands take water from the blood to produce the sweat, and at the same time it moves the heat of the blood to the surface of the skin where it evaporates, reducing body heat in two ways. The first method is by reducing the amount of heat in the blood, and the second method is by cooling the skin through evaporation.
Radiation — Since nature always tries to create a balance, if the body temperature is higher than the air around it, the body will radiate its heat into the air. The greater the difference between body temperature and air temperature, the more heat is lost to the air.
Conduction — Heat moves from the hotter area to the colder adjoining area, and it moves through whatever is there to serve as a conductor. Air is the poorest conductor, since it isn’t very dense, while solids like rock or dirt are better conductors since they are very dense and homogeneous. Water or moisture is a moderate level conductor but the one most commonly encountered when one is outdoors. Keeping your body and clothing dry will inhibit the movement of heat out of your body.
Convection — Your body heats the air around it through conduction, as described above. But if that warm air is moved away from your body by a breeze or other action then your body will heat the air surrounding it again, and again, and again, until there is no cool air to warm. The loss of heat by moving the warm air is called convection. A common example of this is a breeze or wind blowing across your body, this cooling of the body is what we know as wind chill.
EAT RIGHT TO HEAT RIGHT
The food you eat is just like the gasoline you put into your car. The car can have all kinds of great features but if it doesn’t have any fuel, or the right kind of fuel, it won’t do anything for you. In cold weather you want to:
- Keep yourself well hydrated. Without enough water your body cannot digest and metabolize the food that you eat, so keep your water levels up. An easy way to tell if you are starting to get dehydrated is if your urine starts to get a yellowish or straw color to it. The darker yellow it gets the more dehydrated you are becoming.
- Eat a balance of carbohydrates, fats, and proteins. Your body needs all three of these to operate effectively. So make sure you eat a good mix of them and eat them throughout the day, not just at breakfast, lunch, and dinner. A good mix is 50 percent carbohydrates, 20 percent protein, and 30 percent fats.
- Cold weather reduces your hunger and your thirst so drink and eat throughout the day, even if you don’t feel thirsty or hungry.
- “Dirty” soups like beef vegetable are the perfect cold weather food. They help keep you hydrated by providing warmth to your core without having to burn calories, and they have a good mix of fast energy-releasing carbohydrates, slow-releasing proteins, and slower-releasing fats. Plus they tastes great.
Loose is Better than Tight
Insulation traps body heat in pockets of air. The more air you can trap the better the insulation will work. For that reason a knit cap or beanie will work better than a baseball cap made of solid fabric. Tight fitting clothes compress the fabric and reduce the presence of air pockets in the fabric.
Tight fitting clothing also restricts blood flow, which reduces the body’s ability to move warm blood around.
For example, mittens are better than gloves because they trap more warm air and expose more skin surface area to radiate heat into the air pockets. They are also less restrictive, which helps maintain good blood flow. A fleece or knit cap will work much better than a tight beanie or a low-crowned baseball cap that does not have any air space between your head and the top of the hat.
Cotton Kills
The characteristics of cotton fabric make it an excellent fabric for warm or moderate weather. It absorbs moisture easily so you don’t feel sweaty, it is soft to the touch so it feels nice against the skin, and it does not hold in heat like wool or synthetics do. Sadly, these same characteristics can become deadly as the weather turns colder and damper. Cotton will keep your perspiration against your skin and as soon as your activity level drops you have cold liquid against you skin chilling you. This will constantly sap heat from your body and lead to hypothermia which can kill you. So, for cold weather, clothing made from cotton, such as t-shirts, cargo pants or blue jeans or flannel shirts, should be left at home and not worn.
Synthetics, typically knit polyesters, nylons and other blends, are engineered to pull moisture off your skin and move it to the outside surface of the garment where it will evaporate much more quickly than cotton. This keeps you drier, warmer and more comfortable, making for a safer and more enjoyable winter outdoor experience.
Editors Note: A version of this article first appeared in the March 2015 print issue of American Survival Guide.