Getting a second high might be wishful thinking. But a new study out of the University of Sydney suggests exercise could cause a positive blood-based drug test in pot smokers who’ve laid off the ganja for at least a day.
To conduct the study, published in the journal Drug and alcohol dependence, researchers recruited cannabis users who smoked an average of one joint per day. Those 14 subjects exercised for 35 minutes on a stationary bike after abstaining from weed for at least 24 hours.
Researchers checked the users levels of THC, the major psychoactive ingredient in pot, before, directly after, and two hours after exercise. What they found: exercise increased the levels of THC in the users blood by an average of 15 percent directly after exercise.
As lead researcher Iain McGregor told TIME, it’s not clear whether that increase in THC was enough to cause a second high. But researchers did find that the amount of THC released during exercise was directly related to each user’s body mass index; the higher the BMI, the more THC concentration increases after exercise.
That makes sense because THC is stored in fat cells, then is slowly released and cleared from the body. How long it stays in your fat depends on several things, including how much and how often you smoke, your metabolism, and the concentration of THC in the marijuana you’re smoking.
According to Columbia University’s health resource Go Ask Alice, THC should not be detectible in a blood test four to eight hours after smoking. Exercise, however, clearly changes that. And the byproduct of THC, which is what most drug tests check for, can be detected in urine for up to 21 days after the last joint smoked, exercise nonwithstanding.
The bottom line: Exercise can increase the level of THC in your bloodstream if you’ve recently smoked pot, and you’re a regular user. However, it’s currently unclear whether or not that release can induce a second high.