A "runners high" is an endocannabinoid high. The high from a rollercoaster is an endocannabinoid high. A scary movie is an endocannabioid high.
Out here on the perimeter there are no stars. Out here we is stoned. Immaculate.
It's funny what high is deemed acceptable by society, eh? I like the runners high. You get that after a really good workout session at the gym too. But the method of attaining that can be just as bad for your body. I know a gentleman who was a runner and at the age of 43 had to have his hips replaced because of running. He's not the only person who's been seriously injured by doing something that is good for you, but can be bad for you.
There are a good portion of people out there who do not know how to run correctly. Which sounds absurd, but there IS proper technique and if you don't practice it, you'll destroy your knees, your hips, your back, your shins, your feet. The important bits that get your mobile.