A few weeks ago, I was chatting with a friend over dinner about his work-out routine.

He told me,

I just smoke a little bit before I head to the gym. It gets me in the zone. It's awesome.

I sat back in my chair, perplexed. I'm not big on marijuana. The few times I have smoked weed, it's left me unable to leave my apartment and in a state of giggly paranoia with my lungs burning. In what universe could I go to a gym full of people?

This wasn't the first time I heard of people smoking a bowl pre-workout, though. I remembered a friend in college telling me he biked around campus a lot faster when he smoked prior to his ride.

So, I started asking around. As it turns out, these friends of mine weren't just freak cases.

Karen Nuccio, a fitness and spin instructor in New York City, told me a funny story:

While waiting in my car before teaching an evening spin class one night, I spotted one of my students. He tapped on my window and got in my car to chat. This was one of my all-star spin students -- a ripped, shredded dude with tattoos and attitude. He would spin faster and harder than anyone. He gets in a car, we start talking about the playlist for the class and then he goes, 'Do you mind?' before pulling out a joint. Yep, my best spin student to date was high during every class. Moral of the story? Not every pot smoker sits on the couch and orders Domino's. Some of them are dominating your spin class. We are all very specialized animals. Do I promote mixing drugs and fitness class? No. But I think we all need to find our way and for some people, the road to health is not a typical one.

OK, so a fitness instructor I know well and respect confirmed marijuana can be extremely effective in athletic performance. Upon further digging, I found some long-distance runners use it before running races, and yogis use it to get a better stretch in.

In more weed-friendly states, there are even yoga classes specifically designed to incorporate marijuana, like Ganja Yoga in San Francisco.

So, what's the science behind all this? Truth be told, there's not a lot. The drug is only slowly becoming legal, after all, and many researchers hesitate to study it.

From the limited studies done, here's what we know about marijuana and exercise.

It distracts you from your pain.

Need something to take your mind off the pain of exercise? Try smoking.

San Millán, the director of sports performance at the University of Colorado, Boulder, told Shape magazine weed can act as a distraction.

He explained,

Obviously your mental state plays a role in how well you perform. And in certain situations when reducing anxiety or pain is beneficial, marijuana may be helpful despite its ergolytic properties.

Marijuana has long been prescribed to cancer patients to treat nausea or vomiting from chemotherapy and is proven to improve food intake in HIV patients, according to the American Cancer Society.

It's prescribed to people in pain because it works. So, it only makes sense it would help with the pain of a super intense workout as well.

It gets you "in the zone."

Say you're someone who gets easily bored by exercise. While it's hard for me to get bored during a long run outside when I'm somewhere between a runner's high and thinking about when the pain will end, I can certainly relate to getting sick of the elliptical or stationary bike.

A blog post on Wellspring Collective explains many long-distance runners used edibles or vaporizers before a long run to promote a "steady rhythmic zone for keeping at a competitive running speed."

In other words, for some people, a marijuana high can seriously improve focus and keep them "in the zone." If you've ever smoked marijuana and watched the same YouTube video on repeat, you can probably relate.

Don't forget to take care of your lungs.

Marijuana may boost your athletic performance, but it goes without saying lungs filled with smoke are never a good thing.

Although there isn't quite as much research on marijuana and lung cancer as there is with cigarettes, smoke is harmful to your lungs no matter what.

So if you do choose to work out while high, it's safer to opt for a vaporizer or edible (be careful with edibles, though -- they can get you way too high if you eat too much).

I'm not saying you should absolutely light up before your next spin class, and research on this subject is still very limited, but it's certainly interesting to know for some, marijuana use is the key to exercise success.