Lighting up outside the gym might just equal foggy workouts inside.
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Many avid marijuana users love to tout the "no negative side effects" claim about smoking pot-and they argue that if people are using it for medicine, it's got to be good for you, right? (Women are even putting pot in their vaginas.) And now that more states are legalizing the green stuff (looking at you, California and Massachusetts), more recreational smokers are bound to start popping up.

But the latest research suggests that there might be more to think about before you light up to ~let go~. Cannabis users may experience impairments in motor function and learning, according to a review published in Current Opinion in Behavioral Sciences.

For one, the researchers found that a number of studies suggested negative mental effects for both long- and short-term marijuana users, including impaired memory, associative learning, vocabulary, episodic memory, attention, cognitive flexibility (task switching), and immediate and delayed recall. (Here's more about your brain on marijuana.) Before you swear off the stuff forever, just know that some other studies showed no effects in chronic users. (Repeat after us: more. research. needed.) And there was even less research done on the physical effects; some studies showed impairments in reaction time or simple motor responses.

However, because mental processes play such an important role in physical performance, the researchers concluded that, together with the possible physical effects, it's likely that marijuana use can impact motor control and learning (aka your ability to perform complex movements, like in a workout).

"We have hypothesized that because the same brain networks are involved in movement production and addiction, cannabis use may result in motor impairments," says Shikha Prashad, Ph.D., one of the review authors and a postdoctoral research scientist at the Center for BrainHealth, at the University of Texas at Dallas.

Still, the ultimate takeaway is that we need more research on this, stat, especially as marijuana becomes easier to access. For now, keep in mind that there's a lot we still need to know about how pot affects our bodies, despite what you may have heard around the dorm. (And if you're worried about weight gain, don't forget to factor in the munchies.)