Some winter wisdom is about as factual as Frosty the Snowman. Problem is, these fictions don't just give you the warm and fuzzies: They can pack on the pounds, stuff up your nose and even increase your risk of cancer. This season, don't let these winter health myths get the best of you.David Lees/Getty Images
Myth: Cold air can make you sick.
It's called the common "cold," but lower temperatures alone won't make you sick. In fact, the exact opposite is true. "Cells that fight infection in body actually increase if you go out into the cold," said Dr. Rachel C. Vreeman, co-author of "Don't Swallow Your Gum! Myths, Half-Truths, and Outright Lies About Your Body and Health." It's your body's way of combating the stress of freezing temps.
Plus, according to the National Institute of Allergy and Infectious Diseases, cold viruses grow best at about 91 degrees; if you're outside in the cold, your nostrils are surely colder than that.
Get ready to crawl out from under your comforter and run into the great (and yes, cold) outdoors. According to research published in Medicine & Science in Sports and Exercise, in cold temperatures, race times are actually faster, and quicker paces burn more calories in less time. Plus, that harder, faster workout can spike your endorphin levels -- which, according to a review in Environmental Science and Technology, are already increased just by you being outside.
Allergies might be the real source behind your stuffy nose and scratchy throat this season. According to the Asthma and Allergy Foundation of America, one in five people suffers from indoor/outdoor allergies, and the indoor variety can actually be worse in the winter. Pets don't spend as much time outdoors, shut windows seal in poor air quality, and many molds even thrive in the winter, Vreeman says.
If your symptoms last longer than 10 days or ease up after taking an antihistamine, it might be time to visit an allergist.
Forget bathing suits. Department stores should stock sunscreen with the toboggan hats. "Because the Earth's surface is closer to the sun during the winter months, we are actually exposed to more harmful rays without even realizing it," said Dr. Robert Guida, a board-certified plastic surgeon in New York.
What's more, snow and ice can both reflect up to 80% of harmful UV rays so that they can hit the skin twice, according to the Skin Cancer Foundation. So even in winter, keep in mind these five ways to protect against skin cancer. Stuart Stevenson photography/Getty Images
Myth: You lose most of your body heat through your head.
Contrary to the findings from one 1950s Army study, most of your body heat doesn't escape through your noggin, according to Vreeman. "In the now-infamous study, volunteers visited the Arctic with their heads exposed. However, the rest of them was outfitted in gear designed to protect against the cold, so it's logical that they lost most of their body heat from their heads," she said.
If you go outside without gloves, you'll lose a disproportionate amount of heat through your hands.
Although dark days certainly don't help, there are many other factors besides seasonal affective disorder that can contribute to winter depression -- especially around the holidays.
Busy schedules, family stress and worries about holiday spending are more likely to trigger the blues than true SAD, which affects just 5% of Americans. Learn more about surprising causes of winter depression. Marisa/Getty Images
Myth: Women gain 10 pounds over the winter.
Between comfort foods, dreary days and cozy blankets, it's not hard to imagine why women put on winter weight. But it turns out that the average woman gains only one or two pounds over the winter.
Still, one Nutrition Reviews study shows that weight gain during the six-week holiday season accounts for 51% of annual gain. And, according to research published in the New England Journal of Medicine, most women don't shed that extra layer of insulation come springtime, so over the years, the weight can really add up.
OK, this might be more of a half-myth. Meeting your 75-milligram recommended daily allowance of vitamin C is important in maintaining a healthy immune system to prevent and even fight off colds, according to one 2013 study from the University of Helsinki. Other studies have shown that taking a large dose of vitamin C at the first sign of sniffles may help shorten the length and reduce the severity of a cold.
Chilly weather might actually help you hold onto your hair. In one University Hospital of Zurich study, researchers followed 823 women for six years and found that they lost the most hair in the summer and the least in the winter.
It might be evolutionary; just think how thick your dog's fur gets in the winter. Still, dry scalps grow unhealthy, brittle and breakable hair, so if your head gets itchy on cold, dry days, you might need to invest in a scalp-protecting shampoo for the season, Vreeman says.
Alcohol makes you feel toasty on the inside, but that's because it causes your blood to rush toward your rosy-red skin and away from your internal organs. That means your core body temperature actually drops post-sip, Vreeman says. What's more, alcohol impairs your body's ability to shiver and create extra heat.