Many people assume that cold weather brings on the common cold, because it is during the wintertime that people get sick more frequently. It’s a common myth that has been disproven in the medical field — colds are more common in the wintertime because people often stay indoors in close quarters, thereby allowing germs to thrive and move more freely from person to person. It is a virus, not cold weather, than causes someone to get sick.
Just as this is true for cold weather, so it is the case for rooms cooled with air conditioning. So why do some people believe that going in and out air conditioning can give you a cold? Because like cold weather, cold air can definitely contribute to someone getting sick, but only if they’ve been exposed to a virus in the first place.
In the summertime, when you often go from the summer heat outdoors to an air-conditioned space indoors multiple times during the day, it causes your body to do some interesting things in response. Since we are warm-blooded, our bodies will do whatever it takes to keep us at a comfortable 98.6 degrees. When we go into a cold building after being in a heated environment, the skin sends a cold message to the brain which in turn sends a message back to the skin causing blood vessels to constrict, helping us to stay warm. You can see this happening — a person will often go very pale right after entering an air-conditioned building from outside. The next stage is shivering, which also generates heat.
The blood vessels located in our nose and throat also constrict, causing the infection-fighting white blood cells there to be diminished also, making us more vulnerable to a virus. Again, the virus has to already be present in our system, but going in and out of air conditioning can make that virus more likely to take hold of our system since we can’t fight it off as well.
Going from cold to the heat outside doesn’t pose the same issues, since even more blood flows to our nose and throat during that process, making the white blood cells plentiful.
Though air conditioning can help to relieve asthma and other respiratory symptoms, it is important to maintain your unit properly to avoid excess moisture around the unit itself, which can harbor bacteria and fungi. A poorly maintained air-conditioning unit, or an old one, can send those bacteria and fungi right into your airways.
What can you do to lessen your risk of getting sick? Make sure to drink plenty of fluids to keep your nasal passages and throat moist, wash your hands often at work to keep viruses at bay, and open up your windows when you can and take a nice deep breath of fresh air.