There's quite possibly no better feeling in the world than the feeling of calm and happiness at the completion of a tough run. So what's the reason for this runner's high? You've probably heard that can be chalked up to a rise in something called endorphins.
But it's actually a bit more complicated than that. Recent studies in mice suggest that endorphins may have nothing at all to do with the so-called runner's high. Instead, scientists think the effect could be attributed to other chemicals in the body that produce similar pain-relieving and happy feelings.
(via Miss Cellania)