High-intensity interval training may be better at producing endorphin-associated euphoria from exercise than traditional lower intensity exercise
www.sciencedaily.com
From the article:
In the study, HIIT significantly increased the release of endorphins and other opioid peptides in the brain areas controlling pain and emotions. In addition, HIIT induced negative feelings in the test subjects, which was associated with higher endorphin release. Although one-hour aerobic exercise did not induce significant release of endorphins, it increased pleasurable feelings and euphoria, which correlated with endorphin release.