I recently returned from an extended vacation with family with lots of time in air conditioned planes, trains and automobiles. In the week since we returned, three of the five of us developed full on cold symptoms including sore throat, chills, sinus infection and one was even diagnosed with strep throat. In the past, I’ve written about the wintertime cold and flu season, where I discussed reasons why more people experience colds in the cold dry air of winter. But it got me thinking about the summertime cold.
Researchers at Cardiff University in Wales write about the many factors that my family and I likely experienced, including long-haul jet flights, traveling in foreign countries and the stress accompanied with taking a vacation. There are some 200 varieties of common cold virus world wide. When we pack ourselves onto an airplane for several hours, we are in constant exposure to a plane load of potential sources of infection. Add to that travel to a foreign country, and you are exposing yourself to strains of virus for which you likely have not built immunity. Heap on the stresses of travel, which compromises the immune system and you have a recipe for a cold.
The one factor that seems to be most significant and consistent to the summer time cold, regardless of whether you are vacationing, is air conditioning. Conditioned air is significantly dryer than non-conditioned air. This dries out the mucus that lines the nasal passage, which is the first line of defense from airborne virus. This dry air is typically the same relative humidity of cold winter air.
Several studies correlate a higher incidence of contracting a cold by workers in air conditioned offices than workers in a non air conditioned environment. One study of over 900 French women revealed a 38% increase in the incidence of doctor visits from cold symptoms over women who worked with out air conditioning. Another study found that workers in air conditioned offices reported more symptoms of cold and flu than those in naturally ventilated work places.
So if other factors like stress and exposure are a given and the variable is exposure to dry, conditioned air, then one of the easiest remedies is to ensure that you are properly hydrated at all times to combat the dehydrating effects of air conditioning. Additionally, practicing proper hygiene of washing your hands before eating, or touching your face are important to preventing the spread of cold causing virus. That way, you can enjoy the rest of your summer and hopefully one last vacation with out being laid up on a beautiful summer day with the aches and chills of the flu.