Image Source: Stock.Xchng. By: Chendra.

Do you or someone you know have breathing problems while sleeping? If so, you may be surprised to learn that a recent study shows a link between air pollution exposure and breathing troubles during sleep.

Air pollution is already known to irritate the respiratory system, so, researchers tried to figure out if this irritation has anything to do with sleeping trouble, too. First, they studied data from the Sleep Heart Health Study, which examined links between heart health and sleeping patterns of more than 6,000 people between 1995 and 1998.

Then, they compared that data to EPA air pollution data in 7 cities: Framingham (Mass.), Minneapolis, New York City, Phoenix, Pittsburgh, Sacramento, and Tucson. All in all, they studied more than 3,000 people, making sure to adjust for different factors, such as age, gender and smoking habits.

What they found is incidents of sleep apnea and low levels of oxygen during sleep increase as the temperature increases during all seasons of the year. Breathing troubles during sleep also increased in the summer as air pollution increased, too. Sleep apnea is the most well-known form of breathing-related sleep disorders. It causes those affected to wake up repeatedly when their airways constrict and breathing is cut off.

The study—a first of its kind—was conducted by the Harvard School of Public Health and Brigham & Women’s Hospital, and it was funded by the EPA, US National Heart Lung and Blood Institute, and the US National Institute of Environmental Health Sciences. You can read a full report in the American Journal of Respiratory and Critical Care Medicine.