A study published in the Journal of Public Health Nutrition was conducted on 3,882 heart attack sufferers, 124 of which have used marijuana. Of these 124, 37 had used marijuana within 24 hours of having a heart attack and 9 said they used it within an hour.  Researchers reported that the risk of heart attack was slightly increased during the first hour after smoking, but slowly dissipated afterwards.  It was concluded but not completely proven that marijuana has little to no effect on heart attacks and posed less of a threat than air pollution.

For further reading on this study please visit: