Dr Kat Arney, Naked Scientist
Kat - ďDry your hair before you go out, or youíll catch your death of cold!Ē How many of us, particularly those blessed with luxuriant, flowing locks, have heard this at some point in our lives? With high winds and rainstorms lashing many parts of the UK over the past month or so, long-haired lovelies with busy lives or a low boredom threshold might be wondering if itís really worth drying off our locks before tackling the outside world. But is there any scientific truth to the idea that going outside in the winter chill with wet hair will literally give you a chill?
Itís not entirely clear where this myth has come from, but in a snub to concerned parents everywhere, itís not true. The suspected link between cold temperature and catching a cold goes back a long way, from German scientists studying unfortunate soldiers stuck in cold wet trenches in the First World War to sturdy Canadian Mounties stuck up in the Arctic, who were more likely to get colds if they over-exerted themselves in the nippy conditions.
And in 2005, researchers at the Common Cold Centre in Cardiff - yes, there is a common cold research centre - published the results of a fairly small study showing that a small proportion of volunteers who had their feet dunked in cold water were more likely to develop cold-type symptoms a few days later. But that was 13 out of 90 people who got the cold foot bath, compared with 5 out of 90 who managed to avoid that unpleasant experience.
But while going out in the cold with wet hair will probably make you feel more chilly, and thereís some evidence that it can lower your body temperature, thatís not what gives you a cold. That task comes down to microscopic viruses, such as rhinovirus, adenovirus, and the daddy of them all - influenza - and you still need to be infected with cold viruses to catch a cold. And these are spread by horrible germy people coughing and sneezing and snuffling all over the place, rather than by the dampness of your hairdo. Although if you go out with wet hair in sub-zero temperatures, thereís a good chance that the water in it will freeze, which could make your hair more brittle and susceptible to breaking. I guess it depends whether you think scruffy hair is worse than a horrible cold...
Thatís not to say that temperature is completely irrelevant - after all, itís well documented that colds and flu are more prevalent in the miserable winter months. By way of explanation, a paper published in 2015 showed that cold viruses do thrive in cold weather, because sensors in the immune system are a bit more sluggish when the temperature drops. But having wet hair and feeling cold wonít make you catch them - getting the little beggars inside your body will.
So at this time of year when snuffles and sneezes are generally more prevalent, itís much more important to wash your hands regularly and avoid touching your face than worry about whether youíve washed and dried your hair.