More on Marijuana

Within an hour of snorting cocaine, for example, the risk of having a heart attack goes up more than 20-fold. That's about five times more than after smoking pot. The hour after you smoke marijuana, your heart attack risk does appear to nearly quintuple, but only for that hour, then your risk drops down to normal.

Smoking marijuana leads to nearly five times more carbon monoxide in your bloodstream than smoking tobacco. This is because pot smokers inhale deeper and then hold the smoke in, allowing more carbon monoxide into your system.

Cannabis users do seem to have relatively stiffer arteries for their age, suggesting an acceleration of the aging process—and we are only as old as our arteries.

Roughly 20-30% of traffic crashes involving cannabis use occur because of the cannabis use. To put that in perspective, though, that number is more like 85% when it comes to alcohol.

We've known for nearly 40 years that within 15 minutes of lighting up, your metabolic rate goes up by about 25% and stays there for at least an hour.

There have been case reports of artery damage due to the vasoconstrictor effect of cannabis, something that's been well documented. One study found cannabis users had a hundred times greater odds of suffering from something called multifocal intracranial stenosis where the arteries inside your brain clamp down at multiple points, but that's a rare condition.

Recreational marijuana use did seem to be associated with an increased risk of being hospitalized with an acute ischemic stroke.