It’s the season for fuzzy sweaters and heavy coats, as well as colds and flu. But what does cold weather have to do with catching a cold? For generations, mothers worldwide have advised bundling up to avoid getting sick. Yet medical experts call the association an old wives’ tale. Despite the prevalence of coughs and runny noses during the cold months of the year, scientists assert that a drop in temperature is not responsible for the rise in respiratory infections. It is viruses that cause illness, they contend. Cold is just a coincidence. One explanation for the higher number of colds during fall and winter is that we spend more time indoors. People are packed inside with the windows closed. As the same old air circulates in a well-populated room, we get more exposure to pathogens, and thus more illness. However, recent discoveries suggest cold plays more of a role in making us sick than …