My parents are from Russia and have some crazy superstitions because of it. The most annoying thing they always nag me with is not going outside when it’s cold with wet hair because they say that I’ll get sick. I’m not sure if this is just a superstition, or if it actually holds some truth. A part of me thinks it makes sense; maybe wet hair makes your head colder, and I’ve always been told that most body heat is lost through your head (hence why we wear hats), and if your body is super cold maybe that lowers the strength of your immune system? And the other part of me thinks that our intuition is lousy and that this is just another weird superstition like no whistling or open umbrellas inside or you’ll get bad luck.
I first decided to see how this theory even began, and found that back in the 1800’s Louis Pasteur saw that chickens were immune to anthrax and believed it was due to their high body temperature, so he decided to experiment. He found that when he put the chickens’ feet into cold water and exposed them to the disease, they contracted anthrax and died. He then did the same experiment, let the chickens get anthrax, and then warmed them back up and they survived. This is most likely where the theory that cold temperatures cause colds came from. (More on that in my next article)
In this experiment, you can rule out reverse causation because clearly anthrax didn’t cause a decrease in body temperature as that was manipulated. And Pasteur even tested what happens when you bring the temperature back up and found that they chickens lived. However, bigger trials are needed for this, (although it has been found that cold monkeys are more susceptible to polio, and cold mice are more susceptible to pneumonia), more evidence is needed on what exactly causes this, and animals are not humans.
I found another experiment in Salisbury, England where thousands of volunteers were given a drop of infected mucus into their noses to see what happens. There was a variable group who were “assigned to bathe and then wander around cold corridors in wet socks and bathing suits ‘for half an hour or as long as they could bear it’”. Source
The control group did not have to subject themselves to the cold. The results showed that the variable group “showed a drop of several degrees in body temperature and felt rather chilly and unhappy for a time, but were no more likely to catch cold than their warmer colleagues”. Source
This seems to be a well-done study, however, it does not answer the question if going outside with wet hair leads to higher susceptibility to colds. While hospitals are home to millions of bacteria and such, they are also heavily sterilized unlike the outside world of dirty buildings and public transportation and such. Maybe having a decreased temperature and being surrounded by all of the germs outside can cause a higher risk of catching something.
I’m still not quit convinced as there aren’t many experiments that deal exclusively with wet hair outdoors and the chances of getting a cold, but the information I’ve found shows that scientists are pretty stumped too. There is also a question of why lower temperatures seem to cause higher rates of sickness, which I’ll tackle in my next article.
I’m hoping for more studies to be done on this in the future, as it may help either protect us from sickness, or just save us a little time.