Question

Cold and Flu

How true is it that going out in the cold will make me sick?

A Answers (2)

  • AMehmet Oz, MD, Cardiology, answered

    You can hear mothers everywhere calling their kids back inside from playing outdoors in the cold, shouting that they will catch their death. Being wet and cold can certainly make you feel lousy, but it doesn't make you sick. Even when scientists put cold viruses directly into people's noses, people who were chilled were no more likely to become ill than those who were warm and comfortable. We may get sicker during the winter months, but that's not because we are out in the cold.

    Cold and flu viruses are transmitted from person to person through close contact and we all tend to congregate more indoors when it's cold or rainy outside. Close up the house and crank up the heat (or air-conditioning) and you dry out the natural protective mucous in the nasal passages making it more conducive for viruses to sneak into the bloodstream. 

    Actually being a little cold might provide some benefits. One study found that cooler temperatures actually stimulated parts of the immune system.

  • AAnthony Komaroff, MD, Internal Medicine, answered
    Almost every mother has said it: "Wear a jacket or you'll catch a cold!" Is she right? So far, researchers who are studying this question think that normal exposure to moderate cold doesn't increase your susceptibility to infection. Most health experts agree that the reason winter is "cold and flu season" is not that people are cold, but that they spend more time indoors, in closer contact with other people who can pass on their germs.

    But researchers remain interested in this question in different populations. Some experiments with mice suggest that cold exposure might reduce the ability to cope with infection. But what about humans? Scientists have dunked people in cold water and asked others to sit nude in subfreezing temperatures. They've studied people who lived in Antarctica and those on expeditions in the Canadian Rockies. The results have been mixed. For example, researchers documented an increase in upper respiratory infections in competitive cross-country skiers who exercise vigorously in the cold, but whether these infections are due to the cold or other factors -- such as the intense exercise or the dryness of the air -- is not known. They've found that exposure to cold does increase levels of some cytokines, the proteins and hormones that act as messengers in the immune system, but how this affects health isn't clear.

    A 2009 study suggested that the cold virus travels more easily in cold dry air. That might help explain why people contract colds more often in winter. A separate group of Canadian researchers that has reviewed hundreds of medical studies on the subject and conducted some of its own research concludes that there's no need to worry about moderate cold exposure -- it has no detrimental effect on the human immune system.
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