January 9, 2007

Three healthy, athletic young men were climbing on Mount Hood in Oregon last month when a severe snowstorm hit. One died of hypothermia from exposure; the search was ultimately called off for the other two. 

Also in Oregon last month, James Kim, a 35-year-old father of two young children, died of hypothermia during a fruitless search for help after he made a wrong turn onto an unsecured logging road and the family became stranded in their car in rain and snow. 

These highly publicized cases are but two of what health officials believe are well over 1,000 deaths recorded annually in this country among people who become overexposed to cold air or water.

Hypothermia, a condition in which the body’s core temperature drops below 95 degrees, is the No. 1 killer of outdoor recreationists. It is also an often unrecognized killer of infants and the elderly, although the most frequent victims are homeless people, alcoholics and drug addicts.

And while the weather has been unusually warm thus far in much of the country, temperatures need not be at freezing, or even very low, for hypothermia to occur. Most cases occur in air temperatures of 30 to 50 degrees. But people can succumb to overexposure even at 60 or 70 degrees. This is especially true when it is windy, because wind can carry away more heat than the body can generate, or when people get wet or land in water, because cold water accelerates heat loss 25-fold. 

So it is crucial to know how to prevent a life-threatening loss of body heat and how to recognize the symptoms of hypothermia, preferably in its early stages, and safely reverse them.

Detecting Symptoms
People are warm-blooded animals that must generate their own body heat and, unless something goes wrong, maintain a core temperature of about 98 degrees. But when the body begins to lose heat faster than it can be produced, the risk of hypothermia sets in. Even a drop in core temperature of two or three degrees can have devastating consequences.

There are two types of hypothermia: primary and secondary. In primary hypothermia, the body’s heat-producing mechanisms are working well but can be overwhelmed by environmental exposure to cold air and wind or water. In secondary hypothermia, underlying conditions like strokes, diabetes, malnutrition, bacterial infection, thyroid diseases, spinal cord injuries, alcohol or other drugs interfere with the body’s heat-balancing abilities.

Babies are particularly vulnerable because they have a high ratio of body surface to mass and are unable to shiver to create more heat. The elderly, too, are vulnerable because people gradually lose some defenses against cold as they age, including the ability to move, shiver and contract blood vessels along the body’s periphery. In addition, many older people are malnourished, are taking medications or have chronic illnesses that affect their ability to conserve body heat.

Skiers, hikers and fishermen are among those most at risk, even in relatively mild weather — if their clothes get wet, if there’s a brisk breeze, if they are tired and hungry or if they have been drinking alcohol. And hypothermia can occur in a few hours in water as warm as 60 or 70 degrees.

The first sign of hypothermia is usually violent shivering and cold, pale skin. As body temperature drops, coordination and mental activity are affected. The National Institute on Aging warns that older victims may not be aware of how cold they are or may not want to complain. The institute suggests watching for the “umbles”: stumbles, mumbles, fumbles and grumbles, which indicate that the person’s nerves and muscles are working poorly.

Other common symptoms of hypothermia are confusion or sleepiness; slowed, slurred speech; shallow breathing; weak pulse; stiffness of the arms or legs; poor control of body movements; and slowed reactions.

As hypothermia progresses, the person becomes disoriented. Mr. Kim trekked through 10 miles of wilderness but ended up just a mile from his starting point.

Aiding Recovery
A person suffering from hypothermia must be gradually rewarmed, essentially from the inside out. If possible, call immediately for emergency medical assistance. Meanwhile, remove the victim’s wet or cold clothing and wrap the person in layers of dry, warm clothes or blankets. Apply warm (not hot) compresses to the neck, chest wall and groin area.

If nothing else is available, try transferring your body’s heat to the victim: remove your clothes and lie naked against the naked victim, covering both of you with whatever is available. Be sure to cover the victim’s head.

Do not use direct heat, like hot water, a heating pad or heat lamp, to warm the victim. Do not rub the victim’s arms or legs, which can send cold blood to vital organs and make matters worse. If the person is conscious and able to swallow, provide something warm to drink. But never give beverages containing alcohol or caffeine, which can increase heat loss.

Keep the victim awake and handle the person gently. Avoid moving the victim except for safety reasons or to gain shelter.

And don’t assume someone found motionless in the cold is already dead. Many victims of hypothermia can be revived. 

Taking Precautions
If you are planning an outing, check the weather report (especially wind chill) and travel advisories before going out in a boat, hiking up a mountain or into the wilderness, skiing or even driving in cold weather. 

Dress appropriately in loose layers that trap body heat. Avoid cotton. Wool and polypropylene garments are the best inner layers for capturing heat and allowing moisture to escape. Wet down is a useless insulator. Your outer layer should be wind-resistant (nylon or Gore-Tex do the best job) and waterproof (Gore-Tex or its imitators, or take along rain gear). Wear a hat and neck covering, and if the wind and cold dictate, cover your face with a scarf or mask. Mittens will keep your hands warmer than gloves. 
Eat a nutritious meal and drink plenty of water beforehand. Take along water and snacks like nuts and raisins and consume them frequently. If you get wet, change into dry clothes.

Equip your car for the possibility of becoming stranded. Carry a folding shovel, booster cables, a first aid kit, a flashlight with extra batteries, safety flares and a brightly colored scarf that can be tied to the antenna. Take along blankets, dry clothing, nonperishable food and drinks, and a fully charged cellphone. 

If you get stuck, remove anything you might need from the trunk and get back in the vehicle. While seated, move your arms and legs often to maintain circulation and generate warmth. Run the motor with the heater on for 10 minutes once every hour, leaving one window open slightly (but first make sure the exhaust pipe is not blocked).

If you are outdoors with a baby, make sure that the baby’s head, feet and hands are covered and that the baby is protected from wind, rain or snow. Indoors, never put a baby to sleep in a cold room. People over 65 also need a warmer environment — a daytime indoor temperature of at least 70 degrees, lowered to perhaps 65 at night.

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