Menu Join now Search

Can Air Conditioning Make You Sick?

Growing up, my mother never allowed air conditioning in our house or the car. It wasn’t that we couldn’t afford AC; my mom was a firm believer that fresh air “killed germs.” I always accused her of subscribing to an old wives’ tale, but it turns out that there may be something to air conditioning making you sick.

AC Makes Buildings “Sick”

People who live and work in buildings with contaminants like asbestos and mold often fall ill because of their toxic environments. But even something as apparently innocuous as air conditioning can create the phenomenon known as “sick building syndrome.” Dr. Dan Teculescu of the European Respiratory Society led a study in 1997 of 770 office staff in both air conditioned and naturally cooled buildings. He found that those in air-conditioned work environments were 2.5 times more likely to suffer frequent respiratory infections than those who breathed fresh air every day. 

There are two theories, probably working in tandem, about why this might be the case. The first is pretty straightforward: dirty air filters lead to germs being re-circulated throughout an enclosed space. One Chinese study of 170 air-conditioned buildings found that 75 percent of filters contained the bacteria that cause Legionnaire’s disease, a severe form of pneumonia. Air conditioning is great at keeping hot, sticky air out, but it also keeps a lot of bad, germy air in. 

The second theory deals with the body’s response to sudden temperature changes. Heat causes pores to open in order to ventilate the skin and keep your insides from boiling. However, it also allows your skin to better absorb bacteria and fungi in the air. In other words, if you walk into an air-conditioned room on a hot day, you soak up all the particulates that aren’t filtered out. Gross. 

Is Your Air Conditioner Making You Fat?
Air conditioning also wreaks havoc on a different health front. In the April 2009 issue of Environmental Health Perspectives, a study entitled, “The Relationship of Housing and Population Health: A 30-Year Retrospective,” connected data from the National Health and Nutrition Examination Survey (NHANES) and the Census Bureau’s American Survey (AHS) and showed a direct correlation between the rise in air conditioning usage and obesity in America. According to the study, in 1972 only 15 percent of U.S. homes had air conditioners. In 2002, that number quadrupled to 60 percent. And during that same period, the average American body mass index (BMI) increased from 24.9 to 27.7 (anything over twenty-five is considered overweight). 

Just a coincidence? Or is there really a relationship between air conditioning and the national obesity epidemic? Of course, there are numerous contributors to the obesity epidemic, but according to the study’s authors, those with cooled houses are heavier because air conditioners create an “incentive for people to remain indoors and thus exercise less.” 

I mean, would you want to go out for a run on a 90° day when it’s a cool 72° in front of the TV? Me neither. 

We need to get outside for more than exercise, too, and air conditioners are a big deterrent to doing so. When we are exposed to air conditioning for long periods, our bodies accustom themselves to the lower indoor temperature and our tolerances for heat decrease when we finally do get outside. That’s a real shame, especially since people who spend more time outdoors exercising have lower stress levels, a greater ability to focus on school and work, and decreased disease incidence. Sort of makes a little heat not seem so bad, doesn’t it? 

Like a Breath of Fresh Air
Of course, air conditioning can be a real saving grace on a boiling summer day. People with certain health conditions and the elderly are generally more susceptible to heat stroke and need to keep themselves cool. But others find air conditioning simply intolerable, like those with arthritis, neuritis, and sinus problems. Allergy and asthma sufferers often claim that air conditioning eases their symptoms, but some researchers aren’t so sure. AC filters may lower exposure to pollen and other outdoor allergens, but they keep dust and other irritants circulating through a room. 

Even those with no pre-existing conditions can be made sick by air conditioning, so it seems that fresh air wins the day. Choose to open windows instead, as my mom would advise, and you may find yourself getting sick less often and heading outdoors more. Of course, there are scorching, breezeless days when nothing else will cut it. Just make sure your filter is clean and that you keep the room temperature to a reasonable level (no more than ten degrees below what it is outside). 

So take advantage of natural breezes and chill out with a lower electricity bill and a healthier, happier you.