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  • Winter is coming and we've all been told to put a jacket on outside, or you'll catch a cold!

  • Of course, the common response to today has become, "Don't be silly, being cold can't give you a cold!"

  • Or can it? Who wins in this battle of the beliefs?

  • The correlation between cold weather and sickness does stand out.

  • Between 5 to 20 percent of Americans catch a cold or flu every year around late fall and winter.

  • Not to mention, it's called a cold. But there are some important things to consider.

  • First and foremost: colds and the flu are caused by viruses. If there aren't any around, you won't catch a cold, no matter how cold you get. It's as simple as that.

  • So why the correlation with decreasing temperatures? Well, for one, people tend to stay indoors much more often during the winter, which in turn, puts them in contact with more people.

  • More people, means more exposure opportunities for the pathogens to spread.

  • On top of this, humidity plays a role in the spread of some viruses.

  • As the humidity decreases in the winter, not only does the virus spread more readily, but the mucus in your nose dries out.

  • Mucus which would otherwise act as a protective barrier to pathogens.

  • Finally, the lack of Vitamin D, which we get from the sun, can affect our immune system adversely.

  • Both being inside more often, and the fact that winter has shorter days makes this a big factor for your health.

  • So you've proven your parents wrong... right? Not so fast!

  • While some past studies have shown no correlation to temperature, recent evidence suggests otherwise.

  • One study which put test subjects feet into ice water found that they were, indeed, more likely to develop common cold symptoms in the following days than those who didn't.

  • The developing hypothesis behind these results is that cold temperatures cause blood vessel constriction,

  • which slows the white blood cells from reaching the virus, ultimately inhibiting the immune response.

  • Cortisol levels, which suppress the immune system, are also increased with temperature and induce stress.

  • Furthermore, studies on both mice and human airway cells found that immune reaction to the common cold virus is in fact, temperature dependent.

  • Warm-infected cells are more likely to undergo programmed cell death to limit the spread of infection.

  • Finally, studies of the virus itself have revealed a secret weapon of sorts.

  • In winter temperatures, the virus' outer layer or envelope becomes much harder and acts like a shield.

  • This allows it to spread from person to person much more easily.

  • But at warm temperatures, this layer is more of a gel, which is not quite tough enough to protect the virus against the elements.

  • As a result, its spreading ability is compromised.

  • So, maybe your parents weren't so wrong after all. A happy compromise of going outside more often, bundled up, is likely to get you through the winter unscathed.

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Winter is coming and we've all been told to put a jacket on outside, or you'll catch a cold!

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