Think you get sick from flying? You’re right. A study reported in the Journal of Environmental Research found that aircraft passengers do indeed develop colds with a higher frequency in the week following their flights than non-travelers. But you can’t just blame the sniffling, sneezing guy in the seat next to you. The real culprit is the extremely low cabin humidity at high elevations. At very low levels of humidity, the “natural defense system” of mucus in our noses and throats dries up, creating an extremely germ-friendly environment. What can you do? For one, stay hydrated. Drink water and use a saline nasal mist. Also, keep your hands clean. Lastly, try a well- fitted filter face mask, which helps maintain a more humid breathing environment.