Certainly, we are aware of the dangers of exercising in hot weather, but do we need to be concerned about cold weather? Well, yes. The temperature does not even need to be below freezing to cause hypothermia. Hypothermia is a decrease in body temperature that occurs when heat loss exceeds heat production. When it is cold, the body loses heat much faster and because cold air is drier (has a lower vapor pressure) moisture evaporates more quickly from the skin, further cooling the body.
It is also important to consider that heat is lost 25 times faster in water than in air of the same temperature because water offers little or no insulation where it meets the skin and heat loss occurs quickly. Furthermore, movement in water (e.g., swimming) accelerates heat loss. A greater percentage of body fat (subcutaneous fat) will better insulate your body and allow you to remain in cold water for longer periods, which is why long-distance swimmers tend to have a higher percentage of body fat than short-distance swimmers (that, combined with the fact that body fat provides more buoyancy, making it easier, less energy expended, swimming those long distances).
If you partake of outdoor activities, dress appropriately, consider all of the factors listed above, and become better educated on how to deal with all environmental-related medical issues.
~Lori Dotson, CPT, CPFT, PES, BA, MS President, DotsoFit, LLC Copyright © 2012
Some of the factors that affect hypothermia include temperature, water vapor pressure, wind, air or water, clothing, and body fat. As discussed previously, the lower the temperature and the lower the water vapor pressure, the greater your chance for hypothermia. Wind and water are two factors that interact with temperature to facilitate heat loss from the body. The wind chill index is the equivalent temperature under calm conditions for any combination of temperature and wind speed. For a chart depicting the chilling effect of wind, see the National Weather Service website6 located at:
It is also important to consider that heat is lost 25 times faster in water than in air of the same temperature because water offers little or no insulation where it meets the skin and heat loss occurs quickly. Furthermore, movement in water (e.g., swimming) accelerates heat loss. A greater percentage of body fat (subcutaneous fat) will better insulate your body and allow you to remain in cold water for longer periods, which is why long-distance swimmers tend to have a higher percentage of body fat than short-distance swimmers (that, combined with the fact that body fat provides more buoyancy, making it easier, less energy expended, swimming those long distances).
If you encounter someone with hypothermia, it is important to act quickly (this is also true of heat-related illnesses). Waiting until the person can be taken to an emergency room can mean death. This is especially true if you do not have immediate access to medical facilities, such as when you are cross-country skiing, camping, etc., in remote locations. It is imperative to get that person out of the cold, wind, and rain, remove their wet clothing and replace it with dry clothing and/or a warm sleeping bag. Give them warm drinks and get them near a heat source. If you are in the wilderness, build a campfire or even have another person hold them to keep them warm. It is also important to keep the person awake.
If you partake of outdoor activities, dress appropriately, consider all of the factors listed above, and become better educated on how to deal with all environmental-related medical issues.
~Lori Dotson, CPT, CPFT, PES, BA, MS President, DotsoFit, LLC Copyright © 2012
