The endorphin thing is a myth: https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-truth-behind-runners-high-and-other-mental-benefits-of-running

The endorphin thing is a myth: https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-truth-behind-runners-high-and-other-mental-benefits-of-running https://www.hopkinsmedicine.org/health/wellness-and-preventi... Nothing in human biology is simple.