http://www.morningticker.com/2016/07/stunning-discovery-marijuana-may-be-harmful/
Bad news, marijuana users: a new study claims that the drug isn’t as safe as you might think it is — and in one very key way is just as bad as tobacco smoke. The study, published in the Journal of the American Heart Association, states that second hand marijuana smoke is just as harmful as tobacco smoke on blood vessels, so you might want to think twice before you toke up.
In fact, it was actually a lot worse. Scientists exposed rats to both pot and tobacco smoke for one minute. Their blood vessels narrowed and it took 90 minutes to widen again for rats exposed to tobacco smoke — it took three times as long for rats exposed to marijuana smoke, according to the study.
The researchers decided to conduct this study because of what they felt was a lack of attention on the dangers of the actual smoking of marijuana versus just the drug itself. The study showed that, just like tobacco smoke, chronic marijuana smoking can narrow and harden your arteries which can lead to potentially deadly cardiovascular complications.