Cooler air — both inside your nasal cavity and in the air around you — can help the common cold virus replicate thanks to an immune response, a new study from Yale University found. This finding gives some credence to the old wives’ tale that you should bundle up — and cover your nose — to avoid getting sick. It might also help explain why touching your face after contact with a potentially contaminated surface is one of the fastest ways to catch a cold. The study authors examined cells taken from the airways of mice at 37-degrees Celsius (core body temperature) and 33-degrees Celsius (the temperature just inside the nasal cavities). When the virus entered the cells heated to the temperature of the human nose, it replicated faster, and the cells demonstrated a lower immune response.