Welcome to brain stuff from how stuff works. Hey, brain stuff, Lauren vocal bomb here, raise your hand. If a parent, grandparent, or an older, wiser caretaker of any kind has scolded you for not bundling up when the temperatures drop, if you're waving your arm frantically, you're far from alone. Across cultures and geographical boundaries. There seems to be a long held, pervasive belief that sudden meteorological changes automatically trigger colds and flus.
But does the theory really pan out well, Yes and no. According to health experts, weather driven sickness is a thing, but the temperature itself is more of an indirect cause of the resulting illness. In other words, it's not the cold itself that makes you sick, but the environmental factors related to it. A two thou two meta analysis found that exposing your skin too chilly temperatures doesn't automatically make
you more susceptible to the common cold. What does likely set you up for sickness is the drop in humidity.
Associate did with that sudden drop in temperature, The mucus membranes in your eyes, nose, and lungs all dry out those mucus membranes are your first, gooeyest line of defense against bacteria and viruses, so losing the goo makes you more susceptible to sickness, and because viruses are more likely to survive and replicate in cold than in heat, you're more likely to get sick when the weather turns frigid. Study Columbia Universities Jeffrey Shaman and his colleagues compared thirty
years worth of climate records to health records. They determined that flu epidemics almost always followed a drop in air humidity. Their evidence was reviewed in a study and replicated again in a two thousand nine analysis of the swine flu pandemic. The research paints a pretty compelling picture of why and how dry air fosters this kind of cold and flu
free for all. When there's moisture in the air, the particles we release from our noses and mouths when we cough and sneeze stay large, but in dry air they break into tiny pieces that can stay suspended in the environment for hours or even days, creating a virus filled cloud for us to inhale. Furthermore, when it starts getting cold or more likely to stay indoors for more of the time, exposing ourselves to that virus soup. One easy trick to lowering your risk for illness during the colder
months is to run an air humidifier. Study found that doing so for just an hour a day could kill thirty of the airborne viruses in schools. But, like everything else in life, balance appears to be key since some pathogens like mold actually thrive in human environments, and of course, relying on good old standbys like vaccines and hand washing is always a good idea to reduce your risk, whether
you bundle up in cold weather or not. Today's episode was written by Michelle Kunstantinovski and produced by Tyler Clang. For more on this and lots of other bundled topics, visit our home planet, how stuff Works dot com.