Exercise Intensity & Endorphins
Exercise is known to cause a release of endorphins. New research suggests that some forms of exercise are more effective at triggering a flood of the happy hormones than others.
This small study included 22 recreationally active men aged 21–36 years who completed three different protocols on separate days: a 60-minute moderate-intensity aerobic session, a high-intensity interval training (HIIT) session and a period of rest. The men underwent positron emission tomography, which measures endorphin release. They also reported on their moods throughout the intervention.
The HIIT workout caused a significant increase in endorphin release. The effect was less prominent after the moderate-intensity exercise. Interestingly, the men expressed negative feelings in response to HIIT; however, they had the opposite response after completing the moderate-intensity aerobic session.
Tiina Saanijoki, lead researcher and PhD candidate at the University of Turku in Finland, interpreted the results this way:
“Exercise-induced endorphin release may be an important mechanism which supports exercise motivation and maintenance of regular exercise,” she said in a press release. “At moderate training intensities, the pleasurable sensations caused by the possible release of endorphins may promote habitual exercise. At very high exercise intensities the release of endorphins appears to be linked to increased negative feelings and pain, and may be needed to manage the emotionally and physically demanding challenge. However, such negative feelings may discourage further exercise. Exercise intensity should be taken into account when starting new exercise routines.”