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Coffee affects cannabis and steroid systems -- ScienceDaily

Blood metabolites of the endocannabinoid system decreased with coffee consumption, particularly with eight cups per day, the study found. The endocannabinoid metabolic pathway is an important regulator of our stress response, Cornelis said, and some endocannabinoids decrease in the presence of chronic stress. "The increased coffee consumption over the two-month span of the trial may have created enough stress to trigger a decrease in metabolites in this system," she said. "It could be our bodies' adaptation to try to get stress levels back to equilibrium." The endocannabinoid system also regulates a wide range of functions: cognition, blood pressure, immunity, addiction, sleep, appetite, energy and glucose metabolism.

Stairs are the new stimulants

"We found, in both the caffeine and the placebo conditions, that there was not much change in how they felt," said Patrick J. O'Connor, a professor in the department of kinesiology who co-authored the study with former graduate student Derek Randolph. "But with exercise they did feel more energetic and vigorous. It was a temporary feeling, felt immediately after the exercise, but with the 50 milligrams of caffeine, we didn't get as big an effect."