Smoking marijuana has just got to be bad for the lungs, since it's been made abundantly clear that cigarettes wreak havoc. Or so it would seem.
But the record on marijuana and lung health has been confusing at best. The latest study is typical: It shows that pot smokers' lung function actually improves, at least if they're not smoking a lot.
Smoking a joint a week for up to seven years doesn't hurt lung function, according to researchers at the University of California, San Francisco. They came up with that number after following more than 5,000 people for 20 years. The results were just published in JAMA, the Journal of the American Medical Association.