Will going out with wet hair really give you a cold?

Personal Hygiene Image Gallery Will a sopping-wet head earn you a nasty cold if you go outside? See more personal hygiene pictures.
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"Don't go outside with a wet head or you'll catch your death of cold!" It's a warning that's been passed from one generation of parents to the next, along with the better-founded, "Don't go swimming right after you eat or you'll get a cramp!"

If you're one of those moms (or dads) who still follows the wet head equals head cold line of reasoning, you're not alone. In one survey, 40 percent of mothers said they believed sending their kids out in the cold weather with a wet head would get them sick [source: Pediatrics].


Who started this familiar maternal refrain? Part of the blame may rest with French chemist Louis Pasteur, who in 1878 exposed chickens to anthrax and then dipped their feet in icy water to see how it might affect their odds of catching the disease. The chickens developed anthrax and died. When he repeated the experiment but wrapped the exposed chickens in a warm blanket, they survived.

Human studies in the early 20th century seemed to confirm Pasteur's research. A German scientist discovered during World War I that soldiers who slept in cold, wet trenches were four times more likely to get colds than those who rested in dry barracks [source: Zuger]. Somewhere along the line, a few mothers must have caught wind of these studies and began forbidding their children to step foot outside until their heads were bone-dry.

It's also possible that people who believe that a wet head will lead to a cold have heard that a good percentage of the body's heat escapes through the head. That is a myth. In actuality, you lose just as much, if not more heat through a bare arm or leg as you do through your noggin.

The idea that going out with a wet head will lead to a cold is, like so many of those other old warnings, just an old wives' tale. So, if going outside with a wet head won't give you a cold, what will? Read on to find out.


What Causes Colds?

Luckily for wet-haired adventurers, viruses cause colds, not wet heads.
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Being cold and wet does not cause colds. You also won't catch a cold from going outside without your coat (another warning your mother may have issued when you were young), although you'll probably feel very chilly. And you won't catch cold from going to bed with a wet head -- even if the air conditioner is running at full blast (though you might wake up with a pretty funky hairdo).

Colds are actually caused by viruses. You need to be exposed to the cold virus in order to get sick. More than 200 different viruses can cause colds, but the biggest culprit is the rhinovirus [source: NIAID].


When someone sneezes or coughs and isn't kind enough to cover his or her mouth and nose, droplets containing the cold virus escape out into the air. If you're close enough to some of these droplets, there's a good chance you'll soon be coming down with a cold. Viruses also can live on sinks, counters and other surfaces, which means you can catch a cold if you touch an object that was recently handled by someone with a cold, and then put your hands on your nose or mouth.

Going outside with a wet head in winter won't make you sick, but cold weather can make you more susceptible to catching a bug. However, it's not the temperature, but the humidity (or lack thereof) that's to blame. Scientists have shown that cold winter air (which is less humid than warm summer air) can dry out the mucus lining of your nasal passages, making it easier for viruses to get in and make you sick.

Kids are also more likely to catch colds during the fall and winter, simply because that's when they're at school. Classrooms are close quarters, which make them breeding grounds for all sorts of germs.


Lots More Information

Related HowStuffWorks Articles

  • Go Ask Alice!http://www.goaskalice.columbia.edu/2351.html
  • Lee, GM, et al. Misconceptions about colds and predictors of health service utilization. Pediatrics. 2003;111:231-236.
  • NIAID. Common Cold. Cause. http://www3.niaid.nih.gov/topics/commonCold/cause.htm
  • O'Connor, Anahad. "The Claim: You Lose Most of Your Body Heat Through Your Head." The New York Times, Oct. 26, 2004. http://www.nytimes.com/2004/10/26/health/26real.html
  • WebMD. "Cold Wars -- Chicken Soup and Beyond." Jan. 12, 2007.http://blogs.webmd.com/all-ears/2007/01/cold-wars-chicken-soup-and-beyond.html
  • Zuger, Abigail. "'You'll Catch Your Death!' An Old Wives' Tale? Well…" The New York Times. March 4, 2003. http://www.nytimes.com/2003/03/04/science/you-ll-catch-your-death-an-old-wives-tale-well.html?sec=&spon=&pagewanted=all