Many of you will recognize that lovely runner’s high that propels myriads of limber bodies across finish lines around the world! But what’s behind this phenomenon besides an enormous blast of dopamine to the head?

In a recent study, researchers found that a hormone, Leptin, is not only a key factor in metabolism, but may also determine whether or not you feel “the high.” Because it regulates the release of dopamine and the feeling of being satisfied, when we have higher levels of Leptin (aka higher fat levels), our body tells us that we’re satisfied and doesn’t need to push us towards a reward, hence no runner’s high.

In the study, the scientists observed two groups of mice. One group was modified to suppress a molecule, activated by Leptin, called STAT3. They found that these mice ran a significantly greater distance: “Our study on mice suggests that this molecule is also involved in the rewarding effects experienced when we do physical exercise. We speculate that for humans, low leptin levels increase motivation to exercise and make it easier to get a runner’s high.”

So, basically, the more you run, the lower your leptin levels, the closer you are to feeling a runner’s bliss! These tips on How to Run Faster and Longer will get you there in no time.

READ MORE: What Should I Eat Before Running a Half-Marathon?