A study that was recently published in the Journal of the American Medical Association set out to analyze the connection between marijuana exposure and pulmonary function. The study was conducted to see if marijuana has the same effects on the lungs as tobacco, as smoke from both contains many of the same aspects.
The study was named the Coronary Artery Risk Development in Young Adults study, which collected numerous measurements of lung function and smoking over the 20 year span between March 1985 and August 2006. Over 5,000 men and women were studied in 4 different US cities.
The study showed that marijuana smoke does not impair performance on a lung function test. Tobacco smoke, on the other hand, caused a decrease in performance on the same lung function test.
Dr. Kertesz, one of the co-authors of the research, explains that “at lower or moderate levels of use [of marijuana]… there’s no real evidence of harm to air flow rate or to lung capacity.” This study defines moderate use as smoking up to a joint per day for seven years.
The researchers “suspect some kind of training effect from repeated deep inhalations” of marijuana smoke. Other doctors have hypothesized that the anti-inflammatory effects of THC could contribute to the lack of a deficit in performance for marijuana smokers.