We’ve probably all heard someone exclaim, “Ah, my endorphins are kicking in!” at the end of a good run. Endorphins are famous for supposedly producing “runner’s high,” that fleeting sense of calm and euphoria that engulfs many of us after a satisfying workout. But in fact, endorphins may be unfairly hogging the credit for making workouts enjoyable, according to an enlightening new experiment with animals. http://well.blogs.nytimes.com/2015/10/07/homing-in-on-the-source-of-runners-high/