Unlike alcohol, which slows down your heart rate, marijuana speeds it up, which could have negative short-term effects on the heart. Still, the largest-ever report on cannabis from the National Academies of Sciences, which was released in January, found insufficient evidence to support or refute the idea that cannabis might increase the overall risk of a heart attack.
On the other hand, low to moderate drinking — about a glass a day — has been linked with a lower risk of heart attack and stroke when compared to complete abstention. Still, James Nicholls, a director at Alcohol Research UK, told the Guardian that those findings should be taken with a grain of salt since "any protective effects tend to be cancelled out by even occasional bouts of heavier drinking."