Is it true that … going out when it is chilly can make you catch a cold? | Life and style
IIs spending too much time outside on cold days responsible for coughs and runny noses? Not exactly. “Colds are more common in winter, but this is almost certainly a correlation, not a causation,” says John Tregoning, professor of vaccine immunology at Imperial College London.
A marginal factor is that UV light can kill viruses. Sneezing outside in the summer, for example, can expose viral droplets to sunlight, which can deactivate the virus, while faster evaporation dries it out. But the main factor is behavioral: during the colder months, we spend more time indoors, with less ventilation and in closer contact with others.
“Different cold and flu viruses peak at different times during winter,” says Tregoning, the author of Live Forever? A Curious Scientist’s Guide to Well-Being, Aging, and Death. “Rhinovirus increases as children return to school and spreads germs in small classrooms. RSV – another cold virus that is serious in older people and babies – peaks around the New Year.”
Data from the Covid-19 pandemic shows how important human contact is: many other viruses largely disappeared during lockdown because people didn’t interact. A strain of flu has even disappeared due to lack of spread.
That said, extreme cold can affect your susceptibility to viruses. “If you were cold all the time, wasting calories and exhausted, you would be more prone to infections,” says Tregoning. Studies also show that rhinoviruses grow slightly better in cooler temperatures and that the body’s ability to defend itself against viruses is slightly reduced in colder air.
The most effective protection? Vaccination against winter viruses such as influenza and RSV. “Vaccines not only prevent infection: they also have broader benefits, such as reducing the risk of heart attacks,” he says.
