Your mom certainly meant well when she said, “Don’t go outside with a wet head, or you’ll get sick!” But was she right? Here’s what Columbia University epidemiologist Dr. Stephen Morse has to say about it: 

  • First, there’s absolutely no clinical evidence that wet hair makes us more susceptible to viruses or bacterial infections. Plus it’s exposure to viruses, not cold air, that causes colds and flu. To prove it, researchers squirted cold viruses into the noses of volunteers, and those who were exposed to cold, wet conditions were no more likely to get sick than those stayed warm and dry.

  • And at one time, there was anecdotal evidence that being cold and wet caused illness. During the First World War, millions of soldiers died from diseases they caught living in wet trenches. But today’s scientists know that those illnesses had less to do with wet heads, and more to do with unsanitary conditions.

Bottom line: The only hair that has an effect on viruses is nose hair. It acts as a filter, by catching the viruses you breathe in, and keeping them from getting inside your body. That means nose hair is our first line of defense against airborne illnesses. But Mom was right about washing your hands, covering your mouth when you sneeze, and avoiding people with the sniffles. All of those things really do prevent colds.