sometimes, people feel euphoria when exercising. a well-known example is "runner's high," a state of euphoria and high energy that runners sometimes experience, especially during intense workouts. according to recent studies, intense exercise can cause the brain to release endorphins. these endorphins attach to the same brain receptors as opioid drugs, so they can cause the same euphoric effects as those drugs do. unfortunately, this means that a person could get chemically addicted to consistent exercise, just as he or she might get addicted to opiates.