View all slides | Contents of this slide

Lecture Notes

The fourth possible mechanism is called the endorphin hypothesis, and this is probably one of the most popular things that you hear in the media, and the endorphins are simply body chemicals that are responsible for enhancing euphoria and providing pain relief. We know that there is this neurochemical reaction that occurs that increases about 20 minutes after physical activity has been participated in, but there's not much support for this theory because no one has ever shown a change in mood with the increase in endorphins. So yes, the endorphins increase, but we don't know if those endorphins are actually improving mood, and in fact some research shows that when you block the endorphin receptors—so you don't allow those endorphins to work—people still feel better after exercise, so this is probably not the most plausible explanation. And the final explanation here for the relationship between physical activity and mental health is the thermogenic hypothesis, and this is really all about body temperature and muscle tension, or muscle tension relief or relaxation, and this is the idea that the warming effect on the body reduces muscle tension. So by being physically active we're warming up our muscles, we're reducing muscle tension, and hence that's where the relaxation comes from to improve mental health. And so these are just five possible explanations for the reason that we see the relationship between physical activity and mental health.