More athletes now turn to weed for the best performance

The avid runner and cyclist, typically lights up immediately before his athletic activities and usually within an hour or two post-sweat session.

Andrew isn’t alone in his habit of combining cannabis and sport. In fact, it's become an underground trend in distance-running culture.

Ultra runners like Avery Collins and Jen Shelton have admitted to running under the influence of marijuana and former professional runner, Chris Barnicle, a cannabis advocate living in Los Angeles, calls himself the “world’s fastest stoner” on Twitter.

Pro-cannabis running groups, like Run on Grass in Denver, are dedicated to staying fit and educating others about cannabis, while online communities like Cannafit and NORML Athletics also promote cannabis' association with healthy living.

Andrew didn't smoke up before a workout.

“But as I started getting into longer distances like marathons, I noticed my mindset was very similar when I’m running and when I’m high,“ he says. “If I don’t smoke before a run, I’m constantly thinking about the miles and how much further I have to go, rather than just enjoying the experience.”

Science backs up this sensation.

When you ingest marijuana, whether via smoke, vape, or edibles, its chemical compounds, or cannabinoids, combine with your brain and body’s receptors that regulate pain, emotions, appetite, and memory.

One compound, cannabidiol (CBD), is non-psychoactive and brings about that calm and relaxed feeling.

The other main compound is tetrahydrocannabinol (THC), a psychoactive chemical that generates feelings of euphoria, relaxed inhibitions, lack of focus, and sometimes drowsiness.

While weed may not sound like an ideal substance to ingest before lacing up your sneakers, it turns out our bodies naturally produce similar compounds after exercise.

Research has shown high levels of anandamide, a cannabinoid naturally produced in the body, in the bloodstream of individuals after running and cycling.

So, ingesting cannabis mimics the very natural process of increasing exercise-induced endocannabinoids, explains Gregory Gerdeman, an assistant professor of biology at Eckerd College.

“That runner’s joy, whether natural or marijuana-induced, can minimize distraction and help exercise be not just a means to an end, but an enjoyment.”

Studies on the effects of cannabis on athletes are very limited, and the studies that are available tend to focus on the negative effects, says Amanda Feilding, director of The Beckley Foundation, a non-profit in the U.K. devoted to consciousness and drug policy research.

These positive effects are mostly indirectly related to the sport itself, explains Feilding, such as helping people relax before or after a competition.

Athletes seem motivated to use cannabis due to its effects on anxiety, well-being, and its promotion of better sleep before a race, research finds .

Since coordination can be affected, Feilding notes that it might be better to avoid cannabis immediatelybefore a competition.

Cannabis can also increase impulsive responses, leading to more risk-taking behavior, without affecting decision-making, which can be beneficial in competitions.

Studies also suggest that cannabis can increase oxygenation of tissues, improve vision and concentration, help athletes forget previous traumatic experiences related to the activity (like falls or injuries), reduce muscle spasms, and aid in pain relief.

Still, researchers say much more scientific research is needed to determine the performance-enhancing effects.

Plus, inhaling smoke is not exactly an ideal delivery method, explains Dustin Sulak, a licensed osteopathic physician and advocate of integrative medicine.

Instead, runners can turn to edibles, vaporizers, and oral medicine.

These alternatives won't harm your lungs or expose you to toxic substances that are in smoke—"vaping" in particular has been touted as the healthiest way to ingest cannabis, but they can also hit your system harder and last longer up to 10 hours than smoked THC.

Though the verdict is still out on the benefits of weed for runners, there's plenty of anecdotal evidence from pro-ganja athletes.

Tyler Hurst, a writer, runner, and cannabis enthusiast in Phoenix, has been using cannabis regularly for about five years. He typically ingests a Squib, a small, easily-stashable edible, before long weekend runs.

“It’s pretty great to run through a field, across a bridge, in a forest, or up a mountain while being hyper-aware of your environment,” Hurst says. “I’ve recovered faster in the past year than I ever have before, all while running longer and eating the same.”

He says cannabis helps relax his muscles once they become fatigued, making it easier to foam roll and stretch post-run.

Even with all these research, it still isn't exactly safe.

More research is needed to fully understand the effects of cannabis on running and in general, so there’s the risk of the unknown, Feilding says.

Cannabis also increases the heart rate, so runners might reach their limits more quickly after smoking or ingesting cannabis, she explains.

Then, there's what we’ll call “the stuff our parents warned us about.”

Studies show that consistent cannabis use can impair short-term memory, decrease alertness, lower reaction time, accelerate muscle fatigue leading to a shorter exercise sessions, or even cause cardiovascular disease.

It's also been associated with a declining IQ. Plus, some people experience paranoia or extreme anxiety while high.

Finally, we’re all familiar with the fact that smoking can damage your lungs. Although smoking pot has lower risks of lung disease compared to tobacco, marijuana smoke does contain a number of carcinogens and has been associated with an increased likelihood of chronic bronchitis .

Edibles aren't a 100-percent safe bet either; "Eating cannabis can change the quality of the effects, which come on much more slowly, and edibles can vary greatly in strength, making it difficult to measure or gage how much you should take," says Feilding. “Taken in ignorance, people often over do it."

Medical marijuana is also only legal in 23 states and Washington, D.C. so far, and only four states Washington, Oregon, Colorado, and Alaska allow legal use today.

Cannabis is also banned by the World Anti-Doping Agency for all individuals competing in professional sports.