Earlier this month, researchers discovered that at least part of the euphoria that comes after a strenuous workout — runner's high — is due to endocannabinoids, the body’s self-produced counterparts to some of marijuana’s mood-enhancing chemicals. The finding overturned decades of conventional wisdom claiming that natural highs come from endorphins, the chemicals that became famous in the 1980s for their euphoric effects. While endorphins seem to help numb our muscles during a workout, their molecules are too large to cross the blood-brain barrier and trigger a “high” like endocannabinoids can. Although endocannabinoids may deserve more credit for rewarding your workout, media coverage around the discovery tended to blow the findings a bit out of proportion — giving endocannabinoids all the credit. The study authors' actual claim was that endocannabinoids in addition to endorphins may play a role in runner's high. Endocannabinoids, though, are far from the only intoxicating chemicals our bodies produce – and they don't work alone. The bewildering variety of highs we can give ourselves – and the ways they work together – reveal some intriguing truths about the responses we’ve evolved to soothe our pain and get the good vibes flowing. Here’s a quick look at the usual suspects.