A study published today in the Journal of the American Medical Association found that smoking marijuana does not negatively affect lung capacity.
The long-term study analyzed the lung function of cigarette smokers, marijuana smokers and non-smokers over a 20-year period beginning in 1985. Incredibly, it found that casual marijuana smokers performed better on certain tests than non-smokers. From Time:
While tobacco smokers showed the expected drop in lung function over time, the new research found that marijuana smoke had unexpected and apparently positive effects. Low to moderate users actually showed increased lung capacity compared to nonsmokers on two tests, known as FEV1 and FVC. FEV1 is the amount of air someone breathes out in the first second after taking the deepest possible breath; FVC is the total volume of air exhaled after the deepest inhalation.
Heavy pot smokers, defined as people who smoke more than 20 times a month, did not see the same pulmonary benefits. As to why the casual smoker sees improved lung function, researchers surmise it is because smoking pot is a form of exercise.
Unlike cigarette smokers, cannabis users usually draw deeply on the joint or pipe— and hold each puff in, typically for as long as physically possible.
“In some ways, marijuana smoking is really a lot like doing a pulmonary function test,” Pletcher says. This “practice” or “exercise” might expand lung capacity and account for the unusual results.
THC, it might turn out, could also benefit cigarette smokers.
But Tashkin argues that specific properties of marijuana also matter. He says that THC has anti-inflammatory and immune suppressing properties, which may prevent lung irritation from developing into chronic obstructive pulmonary disease (COPD), a devastating lung disorder frequently caused by tobacco smoking.
So, cig rippers, toke away! But not too much.
[Marijuana smoker via Shutterstock]