<i>One possible if slightly disheartening lesson of the study could be, in fact, that we may need to cover considerable mileage in order to experience a runner’s high; the mice in the study, small as they are, averaged more than three miles every day on their wheels.</i><p>I&#x27;m on track for 3000 miles this year. I ran over 2000 miles last year. My shortest run in the last few months is 4 miles, and that&#x27;s on days when I double with a 6 mile run. I&#x27;ve raced almost a dozen marathons and I run the half-marathon distance a couple times a week. So I think it&#x27;s fair to say that I &quot;cover considerable mileage.&quot; This isn&#x27;t all just slow miles either. As any runner trying to improve, I also run intervals of varying distances and tempos (where you run about as fast as you could race for an hour, but for about 30-45 minutes).<p>So I enjoy running. There are runs where I&#x27;m relaxed and in the groove and the miles just click by. But that&#x27;s just an enjoyable experiece, like relaxing at the beach. It&#x27;s nothing like the high from smoking marijuana. Or the exhileration from something like sky diving that first time. Or post-orgasm bliss.<p>I&#x27;ve also spoken with a few ultra-marathoners, runners that cover 50-100 miles or run for 24 hours straight. None of us have experienced a &quot;high&quot; from running. Have we all been duped? Maybe we&#x27;re all expecting the wrong thing?<p>I&#x27;m envious of those mice... :-)