By John Casey
WebMD Weight Loss Clinic - Feature
Reviewed By Kathleen Zelman, MPH, RD, LD
Shorter days, longer nights, colder temperatures -- they all signal the coming of winter. For many, the season means spending time in front of the fireplace drinking hot cocoa. But for enthusiasts of outdoor sports, winter can mean interminable months of waiting for the return of spring and a suffocating case of cabin fever.
But whether your sport of choice is kayaking, hiking, biking, or running, experts say that with the proper equipment and clothing, outdoor-loving people don't need to give up their favorite recreations. Just be cautious: Failing to heed good sense or to prepare properly can put life and limb at risk -- even at moderate temperatures.
"Most deaths from hypothermia occur between 30 and 50 degrees Fahrenheit," says William Forgey, MD, former president of the Wilderness Medical Society in Colorado Springs. "If you get below 55 degrees and you have wet cotton on you, you cannot keep up with the heat loss. If you're wearing almost anything else, you'll be OK."
Hypothermia hits when a person's body temperature drops below 95 degrees. Among its signs are slurred speech, mental confusion, slowed breathing and heartbeat, and an inability to walk in a straight line.
"It's very much like being drunk," says Forgey, who notes that most U.S. deaths due to hypothermia occur among the homeless.
Take precautions against frostbite and windburn as well, says Brian Halpern, MD, of the Hospital for Special Surgery in New York City. Halpern explains that sensitive areas, such as the genitals, and exposed areas, like the hands and face, are susceptible to frostbite -- freezing of body parts.
And it doesn't take long to feel the effects of the cold. Skiers should take into account the speed of a downhill run, which can add a wind-chill factor to already low temperatures. Long hikes and other long outdoor activities can lead to a slow, continual loss of body temperature. People who dabble in water sports are especially at risk if they become immersed in cold water, which can lead to rapid cooling.
Clothes: Old-Fashioned and High-Tech
Wearing the right types of clothes can make a big difference. Experienced whitewater kayakers wear synthetic materials such as polypropylene or fleece underneath a dry suit designed to provide a nearly watertight seal around the body. The result is a cozy cocoon, even on icy days.
Forgey advocates the old-fashioned method of layering clothes -- the thinnest layer usually going against the skin. Materials that will pull the sweat away from the skin and let it evaporate are best: high quality wool, polypropylene, and polyester. He advises against wearing silk, acrylic, and cotton, which hold moisture.
Food and Liquids
Cold weather tends to increase your need for calories, says Bruce C. Paton, MD, professor emeritus of surgery at the University of Colorado and past president of the Wilderness Medical Society. But the increase is only significant if you're into the most strenuous activities. Unless you're tackling a mountain, says Paton, "for most people, eating their regular diet is fine."
Stay away from alcoholic fluids. Despite the popular image of alcohol warming the soul on a cold day, doctors advise cold-weather sportspeople to abstain while working out outdoors. Nicholas DiNubile, MD, a member of the American Orthopedic Society for Sports Medicine, says alcohol actually causes the body to lose heat more rapidly. The alcohol opens up the vessels in the skin and extremities, exposing the heat in the blood to the environment.
Drink plenty of non-alcoholic beverages to stay hydrated while out in the cold dry air, advises Paton. Cross-country skiers, for example, can lose about a quart of sweat an hour. Outdoor exercisers should drink four to six liters of water per day. Drink water even if you don't feel thirsty, Paton says -- by the time you're thirsty, you may already be dehydrated.
Originally published October 12, 2001.
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