In New England we are fortunate enough to experience four distinct seasons- however, each one has its good and bad sides. One that we often think of as the least enjoyable is winter. Most people also don't bear in mind, how easily our bodies can lose heat in winter months. The same mechanisms that help us to endure very hot summer weather can be our undoing in very cold winter weather. Here are some helpful tips on how our bodies lose heat in the winter, what can happen and how to avoid such situations.
How Our Bodies Loose Heat
- Radiation of Heat- this occurs when surfaces surrounding us are cooler and heat energy leaves our bodies.
- Conduction- which occurs by heat loss through direct contact with a surface that is cooler than we are.
- Convection- which occurs when moving air carries heat away from the body’s surface.
- Evaporation- which occurs when water is lost from the skin (sweat) causing body heat to be lost during this process.
In cold weather, radiation and convection are the two main ways that we lose heat. Sweating, occurring during heavy exertion, can also be a significant issue in so far as the sweat does not evaporate, but remains on the skin and becomes a very efficient conductor of heat away from the body- as well as being able to be frozen. Unless you are sitting for a prolonged period on a cold surface, conduction is much less of an issue.
Cold Weather Dangers & How Easily They Can Occur
Frostbite is an injury to the body that is caused by an actual freezing of body tissues. The parts of the body most at risk for frostbite are the ears, nose, cheeks, chin as well as toes and fingers. In fact, any part of the body that is in prolonged contact with a cold surface (remember conduction) can also be affected. As a result of this condition, a person can suffer permanent injury. In cases that are severe, a person may even end up with an amputation of the affected part.
- The elderly
- The very young
- Anyone who may have a condition associated with “poor circulation”
- People (or pets) outdoors for prolonged periods of time
Of, course, those who don’t dress properly in very cold weather are also at risk. Sorry, but wearing shorts or light shoes in very cold January or February weather is like dipping your toes in a piranha tank- you’re asking for trouble!
"Don't ignore the early signs of frostbite including: redness of the skin, and a tingling or a burning sensation. These may indicate that frostbite is beginning and if one doesn’t get out of the cold, it may progress. Don't forget your pets. They can also suffer from cold weather injuries"
If no action is taken, the skin may begin to appear white to a slight yellow in color, numbness may set in, and the skin may then take on a waxy to firm character. In some cases, because of the numbness, a person is not aware until someone else points out the color changes! Unfortunately, as skin tissues freeze, they become numb and less sensitive.
In the early stages of frostbite, getting out of the cold and into a warm room is the first step. The affected body part can be warmed gently- usually by immersing in warm water. Note that I say “warm”, not “hot”. A good rule of thumb is that anything that is not comfortable for an uninjured body part is not appropriate for a potentially injured body part!
Another way to gently warm an area is by body heat -in other words, against the body such as in the armpit, between warm hands, etc. If there is already numbness or skin texture changes, then one is going to need medical attention. A person should never walk on toes or feet that are frostbitten, since more damage can be done to the already injured tissues. Other mistakes are massaging a frostbitten area ( since vigorous rubbing of injured tissues may increase swelling and damage), or the “Old Wife’s Tale” of rubbing it with snow.
Because a frostbitten area can be numb, you should never warm it by the heat of a stove, fireplace or against a radiator. There is the likelihood that an early cold injury can be converted to a heat injury!
Remember, however, that if there is the suspicion that frostbite has occurred, you need to seek medical attention, and only use the above methods if immediate medical attention is not available and until you can get it!
Hypothermia is a condition where one develops an abnormally low body temperature. This is the result of having reached a point where your body’s production of heat is surpassed by its loss of heat. The problem with this situation is that the brain is sensitive to low body temperatures and it begins to function less effectively. In fact, its metabolism slows down. That is why in some medical situations a medically-induced state of hypothermia may be used to protect the brain. Usually, when hypothermia sets in, a person’s judgment may be sufficiently impaired so that they don’t know what is happening.
Warning Signs of Hypothermia and What to Look Out For:
- In Adults: shivering, particularly when intense and prolonged, should never be ignored. When we shiver, we rapidly contract muscles as a way to produce additional heat. However, this is a metabolically intense action that cannot be sustained for long. As time progresses –which can be very short in extreme conditions- confusion starts to set in. Along with this may be clumsiness, then slurring of the speech, and trouble thinking. Drowsiness is a dangerous sign.
- In Young Children: particularly infants, their skin may take on a bright red color yet it may feel very cool to the touch. They may also seem sluggish and difficult to arouse.
Who is most at risk of hypothermia?
Clearly, anyone remaining outdoors for extended periods of time is at risk. This can include those working outdoors as well as people participating in recreational activities outdoors. Hypothermia can occur at both very cold temperatures and even cool temperatures- such as above 40 degrees! Remember, convection (strong winds), radiational loss and conduction (through cold surfaces or cold water) are the major factors.
The elderly are at particular risk of hypothermia; even at “ just slightly cooler” temperatures.
This is because they often have little body fat; their skin is thinner and more conductive; they may have other underlying medical conditions; or they may be taking certain medications that place them at risk. In situations where one may not have adequate indoor heat and poor nutrition, the threshold for hypothermia is even lower. It is always a good idea to check on your elderly relatives and neighbors when the weather is very cold, since few people can say or even realize they are becoming hypothermic. Infants, for many of the same reasons, are also at risk.
Increasing Your Risk For Hypothermia
Drinking alcohol can also increase one’s risk for hypothermia. Alcohol does not warm a person; in fact, it increases heat loss from the body. The image of a St. Bernard dog with a keg of brandy around its neck is one that needs to be forgotten! Alcohol dilates blood vessels.
Henry R. Vaillancourt MD, MPH, a Truesdale Health member and specialist in Public Health and Prevention.