Riding on the runner's high

Ever get "runner's high?"

That feeling where you feel like your body is numb to any soreness or pain you may be feeling on those last miles? Or that euphoric feeling that all is well in the world (I mean, who cares if there's that looming deadline?).

Alone to your thoughts (photo courtesy of Alias0591)

Whether you just ran a massively long distance, hiked up a tall hill, or have been biking a long stretch, long endurance exercise has a way of producing this great boost of energy that many categorize as "runner's high." It doesn't happen all the time, but when it does, you feel on top of the world. I call it "second wind" or "autopilot," because my runner's high entails either feeling a speed of energy or just going through the motions.

It turns out there's an actual scientific reason why you're feeling so good during your runner's high - your body is releasing lots of feel-good hormones that are triggering pleasure centers in your brain. Specifically, chemical compounds called endocannibinoids (eCBs) are released in your brain, which act to relieve inhibition of the hormone dopamine. In doing so, more dopamine can be released to have an effect on different brain regions, giving you that fuzzy, happy-go-lucky, not-a-care-in-the-world feeling!

Endurance exercise stimulates release of eCBs that eventually lead to release of happy-go-lucky dopamine

But human aren't the only ones who run for leisure - some other animals do long distance running as well (known as cursorial animals). In a study conducted in 2011, researchers found that other animals that do endurance activities (dogs, horses, etc.), also have the same physiological after-effects. In this study, blood levels compared eCB from treadmill runners versus treadmill walkers within three groups (people, dogs, and ferrets). Researchers found that while dogs and humans both had increased levels of eCB in their blood, the non cursorial ferret (animals that do not do long distance running) did not have eCB release.

This study shows the physiological rewards that humans and other animals have when they engage in endurance exercise and points to why certain animals are willing to do more high risk, injury-prone exercise (running) over the safer, less injury-prone exercise (walking). There's just something so addicting about getting out there and going on a run. The day may have been long, your legs might be too tired to hold your body up, and the sun might just be a little too bright for your liking, but nothing can beat the chance to hit that rush. You just hit the pavement running, leaving everything behind.


References:

Raichlen DA, Foster AD, Gerdeman GL, Seillier A and Giuffrida A. Wired to run: exercise-induces endocannabinoid signaling in humans and cursorial mammals with implications for the 'runner's high'. 2011. Journal of Experimental Biology.