Every winter, I receive questions about hypothermia and about the dangers and symptoms of both hypothermia and frostbite. Most are from concerned parents of younger children.
We’re certainly not strangers to cold weather. After all, this is the North Country. And winter is the season of snowmobiling, snowshoeing, skiing, snowboarding, ice fishing, ice climbing, winter hiking, winter camping, sledding, tobogganing, tubing, ice skating, snowballs, snowmen, snow forts, snow sculptures, and winter carnival parades.
Many of us work outdoors or have family members, friends, or neighbors that work outdoors. Others travel considerable distances to and from work.
Most of us recognize that prolonged exposure to cold and wind can be extremely dangerous; even more so if we’re not prepared, but many don’t realize that the danger of cold-related injuries can be compounded when you have poor circulation, are tired, or have been drinking. Age, physical condition, smoking, and the use of certain medications are also factors that can increase risk.
To understand how and why cold injuries occur, we must first recognize that the body’s ability to generate heat and prevent heat loss is very limited. Core temperature (97.7 to 99.5 F) is maintained by the hypothalamus in the brain, which makes physiological adjustments in response to temperature receptors in the body’s shell. Cold injury occurs when the body’s ability to thermo-regulate becomes compromised.
Essentially, hypothermia is injury to the body’s core; systemic injury. Frostbite is injury to the shell; localized injury to a body part or parts. They often occur together and both are preventable. Knowing what to look for, and what to do should either of these conditions develop, is critical.
Hypothermia occurs when the body is losing heat faster than it can generate it. Shivering is often the first sign; a warning. Slow or slurred speech, lethargy, and drowsiness may follow. As the condition worsens, victims will often become disorientated and / or incoherent. Exhaustion will set in. Breathing will become reduced and heart rate will be lowered. In severe cases, the sufferer may lapse into a coma and / or die. Sweating or getting wet can increase the risk of hypothermia and accelerate the onset of advanced stages.
First aid for hypothermia includes getting the victim out of the cold; inside if possible, and replacing cold or wet clothing with clothing that is warm and dry. You can use warm blankets (electric blankets work well), a sleeping bag, and / or body-to-body contact to provide additional warmth. Be sure to insulate the victim’s head and neck. 50% of the body’s heat loss is through the head.
Do not massage the victim’s arms or legs. It will push cold blood toward the heart, possibly causing heart failure to occur. Elevating the feet and lowering the head will safely promote increased circulation to the chest.
A hypothermia sufferer that is fully conscious and able to sit upright on his or her own should drink warm, non-alcoholic, caffeine-free beverages.
Frostbite occurs when a part of the body actually freezes. It most commonly affects the extremities; fingers, toes, ears, nose, and cheeks. Mild or superficial frostbite injury entails the freezing of skin and subcutaneous tissue. There is often, but not always, some discomfort or mild pain. Skin may become slightly discolored. Some numbing may follow. Blisters may develop as fluids freeze and ice crystals form in the tissue.
Mildly frostbitten skin should be warmed slowly. One method is to blow on or hold warm hands against the affected area. Warm water may also be used, but never use hot water or excessive heat and do not rub or massage traumatized tissue. Once the injured tissue has been warmed, be extremely careful to avoid refreezing the area.
While mild frostbite seldom results in any lasting damage, immediate medical attention is recommended for deep or severe frostbite injuries, which can affect muscles, tendons, nerves, even bone.
If a victim is showing signs of both hypothermia and frostbite, treat the hypothermia first.
You and your loved ones can avoid cold injury completely by wearing loose fitting, lightweight, layered clothing that will keep you warm and dry. The innermost garment should be made of a material that wicks moisture away from the body. The outermost layer should offer protection from the wind. In between layers should be made of wool or other warm materials. Wear wool socks, too. In fact, wear multiple layers of socks. And put on warm boots that fit properly. Be sure to protect your head and neck with a hat, scarf and / or a hood. And keep in mind that mittens will offer better hand protection than gloves. Stay dry.
Bear in mind that children are extremely vulnerable to frostbite and hypothermia because they don’t often recognize just how dangerous extreme winter weather can be. And don’t forget that pets are susceptible to cold weather injury, too.
Photo: Wind Chill Chart, courtesy University of Minnesota Duluth.
Good advice except the old myth is repeated that we lose a large portion of our body heat via the head. We lose the same amount of heat in all parts of the body. If we completely covered our head in cold weather but wore shorts the perception would be we lost most of our heat through the legs.
Please explain. Most of our blood supply is in our cranium, as the brain requires a steady flow of highly oxygenated blood to function correctly. There is virtually no insulation there anywhere on the head unless you have a lot of hair. Vasoconstriction that reduces heat loss in cold temps is not possible in the brain, or we pass out. The head is one of our biggest radiators. Hands are another.
Ever see infrared pictures of a body at different ambient temperatures? At high temps more blood (heat) is sent to the extremities to help us cool. But at low temps, the blood is pushed back into the core by vasoconstriction to maintain organ function (hence sacrificial extremity loss as in frostbite). The head is part of this core, but has no means of keeping the heat in other than hair. I am bald and can speak from experience. So I guess it depends on the amount of head and facial hair one has.
The extreme heat loss by head myth according to my investigation started many decades ago from a British study and was not challenged until recently. Here is a link, among many, that cite the recent thinking.
The subtitle of the article/link reads “Only if we’re wearing clothes on the rest of our body, says this expert in wilderness medicine.”
I would say this would include most outdoor enthusiasts – especially in winter. I don’t think we should be downplaying the benefits of hats & gloves in a hypothermia/frostbite discussion.
Nice article, however, I agree it’s time we dispense with the commonly held notion we lose so much heat from our head. It’s a myth, much like the one where it’s claimed we can only use 10 percent or our brains.
Very good, detailed info from Richard, George, and Boreas….Perhaps, as CPR instructions are posted at/in food venues, these strong recommendations should be posted at/near all outdoor recreational venues and businesses!
There is a lot to learn. People may lose a digit or two while reading through the recommendations at a trailhead!
Richard would probably be a-gast to hear that head heat loss is directly proportional to head hair loss.
Makes sense to me.