Smoking marijuanaSecondhand marijuana smoke may damage your blood vessels even more than tobacco smoke.

In a new study, arteries in rats that inhaled secondhand marijuana smoke for one minute carried blood less efficiently for at least 90 minutes. Similar exposure to secondhand tobacco smoke caused blood vessel impairment for 30 minutes.

“While the effect is temporary for both cigarette and marijuana smoke, these temporary problems can turn into long-term problems if exposures occur often enough and may increase the chances of developing hardened and clogged arteries,” said Matthew Springer, Ph.D., study senior author and professor of medicine at the University of California, San Francisco’s Division of Cardiology.

Researchers examined blood vessel function in rats before and after exposure to secondhand marijuana and tobacco smoke similar to real-world levels.

“Arteries of rats and humans are similar in how they respond to secondhand tobacco smoke, so the response of rat arteries to secondhand marijuana smoke is likely to reflect how human arteries might respond,” Springer said.