A new 'runner's high' (IMAGE) University of Colorado at Boulder Caption Boulder-based ultrarunner Heather Mashhoodi runs on the treadmill in 2021 as part of a study exploring how cannabis influences exercise. First author Laurel Gibson takes notes in the background. Study participants used cannabis on their own at home before being picked up and driven to the lab for testing. Credit: Patrick Campbell/CU Boulder Credit Patrick Campbell/CU Boulder Usage Restrictions Must credit CU Boulder License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.