As winter approaches, many of us are switching to indoor exercise. However, a recent study in gyms raised some questions about the cleanness and safety of the air we breathe while exercising. Few studies have examines the air quality in gyms, so these findings are quite interesting.

Researchers at the University of Lisbon in Portugal went as far as placing air-monitoring devices in certain gyms to examine its quality. Portuguese gymnasiums are similar to those in the United States, so this may be a concern for gym goers in the U.S. as well. The machines installed were set to measure the amount of indoor pollutants (carbon monoxide, carbon dioxide, ozone, airborne particulates, etc.) in gyms during the afternoon hours when they were most crowded. The device monitored air at each gym for about two hours and revealed that the gyms showed concerning levels of airborne dust, formaldehyde and carbon dioxide.

These levels were especially high during evening aerobics classes when dust particles were stirred up by movement. In large quantities, the dust and formaldehyde may contribute to asthma and other respiratory problems. High concentrations of carbon dioxide can also contribute to fatigue and fogginess which is not desirable during levels of high physical activity.

We consider that the gymnasiums meet the criteria for a poor indoor quality.”When we exercise, we take in more air with each breath and most of that air goes through the mouth, bypassing the natural filtration system in the nostrils,” Ms. Ramos said. “The pollutants go deeper into the lungs compared to resting situations.”

Fortunately, none of the gyms examined showed dangerously high levels of indoor pollutants. These findings should not discourage anyone from visiting the gym. However, this information may encourage you to be more aware of whether you notice chemical or stale smells at your local gym. Additionally, you may consider inquiring about what cleaning products the gym uses and whether they sweep or mop their floors (mopping is more effective at reducing air pollutants).

Read more here – “The Bad Air in Our Gyms,” (Gretchen Reynolds, New York Times).