This is not what I was expecting. I figured I'd call doctors and athletes, ask this question, listen to them say, "No, what's wrong with you?" and go home. Turns out the answer is far cloudier.
In terms of the science, we just don't know enough about it. One person's anxiety medicine can make somebody else sluggish. That said, we also don't have enough long-term evidence to say it's not problematic.
In short, we're not sure what pot does to your workout. The same doobie that eases the relentless trauma on an ultramarathoner's joints can make someone else put on 35 bracelets and listen to three uninterrupted hours of Rusted Root. It's a highly personal response. If someone tells me it relaxes them so they run more smoothly, who am I to say that isn't true?
Here's how that response works: Marijuana's chemical compounds, called cannabinoids, bind with the receptors that regulate mood, appetite, pain, memory, and interest in The Big Lebowski. Such effects make it an interesting option for endurance athletes, whose grueling superhero feats are accomplished during periods of heightened stress and, weird as it sounds, boredom. (Next time you ride your bike a hundred miles, see if you don't get just a little bored.) Marijuana also has an anti-inflammatory effect and can mimic your body's endorphins—which could, in theory, help push you through one more mile or make you feel braver about the fencing championships/water polo gold medal match/NBA playoffs.
Trouble is, there's little actual research about exercise and pot, what with how it's still a Schedule 1 banned substance you can't take across state lines. What we know is anecdotal, so while we can read about Rob Van Dam and listen to our friends who say they run while pleasantly baked, their reports are less "based in science" and more "stuff my buddy said."
Obviously, there are people who are all into this , including athletes in the snowboard, MMA and pro wrestling realms. (Also apparently all of the UFC.) There are, not surprisingly, pro-pot gyms in Denver. A San Francisco gym will soon let members smoke during workouts, which is curious until you learn it's being run by Ricky Williams and a snowboard company executive who runs the 420 Games. A number of ultra-marathoners are on record as being into it (though rarely if ever during competition). So it can be done.
However, and it's a big however, joints pull all those chemicals into the body at once, in unknown amounts. If you're puffing away at a joint, you're taking a good chance of impaired performance. This makes sense, and is also generally the point of puffing away at a joint.
If you're reading this, and/or if you've ever been to Colorado, you probably know what he means by impaired performance: decreased reaction time, poorer hand-eye coordination, scattered attention. Weed can also jack up your heart rate by 20 percent or more for up to three hours—not great for athletes or people with heart conditions. It's not right to write an endorsement. I'd never say that. I'd ask, 'What's your experience of it? How does it affect you? What are your goals?' And we'd try to figure out from there whether there was a problem or not.