It starts out with a cool rush of euphoria felt in the head and behind the eyes, which quickly spreads to the extremities and blankets any perpetual pain/discomfort, replacing it with a weightlessness, like every tendon and muscle in your body has been renewed. It's a pure, cool, iron-like high that allows me to cut 30-60 seconds off the next 1-2 miles once it kicks in.
I don't think it's a distance thing - it's more of a pushing yourself to the point where your brain feels the need to intervene. I expect that if I had a disciplined training schedule and ran long distances regularly, my brain would get used to the idea of running and stop getting me high.
I also lift weights 3 times a week, but I never experience a high while deadlifting, bench pressing, running sleds, etc. I'm fairly certain it has to be biking/running where you have no rest in between sets in order for your brain to flip out and turn on whatever chemical switch it is that produces the effect.
I've seen others commenting that they think runner's high is akin to a state of flow - it's not. I flow occasionally when I play tennis and write, and it's a completely different feeling - one of non-feeling, simply being and doing which allows me to lose my ego for a short while. I'm acutely aware of myself, my body, and my senses when I feel the runner's high.
I am in my mid-thirties though and I can't recollect having run more than a mile before in my life. Maybe I will get used to this high and stop feeling the difference. Maybe I am feeling the kick because it is novel to me. But yes, it is nothing like the high you get from smoking marijuana :)
What I actually experienced felt more like what we now call Flow, which is a pretty good experience by itself. Programmers seek it out almost habitually, like an addiction. I've also experienced the same thing once doing restorative Yoga (the teacher was experimenting at the end of a quarter, but I moved across town after), and maybe while doing meditation but it felt different.
I'm really curious if this is the high people mean, and those who rave about it just have a really hard time entering a flow state. If that's so then I pity them.
Thanksgiving before last this really gelled for me. I had potatoes cooling on the stove and the dog was begging for a walk so I went out with him at like 10:15 am. Runners. Everywhere runners. Then it hit me like a brick. They were all out meditating, trying to mentally prepare for the onslaught of relatives and poorly behaved nieces and nephews that were about to descend on them.
I think, in each case there were a couple of prevailing influences to the sensation:
1.) Feeling alone. Even during my mile, surrounded by 10 other racers, I felt pleasantly alone. Everything was quiet, non-distracting, sublime even.
2.) I was also on the verge of a major breakthrough in my training. My first year running, my 5K went from 22:09 to 17:21, and that first high was probably two weeks before that new PR. Same for the run in Lexington. Luckily it came in the MIDDLE of my mile, because I'd run the exact same time the past 4 races in a row.
3.) The weather. In each case, the weather was extremely mild - cool, brisk, gentle breeze, but no wind.
I'm probably over-analyzing it. Also TONS of nostalgia. But still, I want to make that feeling a more regular part of my life as time ticks on :)
EDIT: There's a fourth.
4.) Running was joyful. Not something I was doing to rack up mileage, or beat a competitor, or "push myself to the edge." Yeah, those things happened as a consequence of training, but they weren't the goal. The goal was to enjoy going fast. And yeah, I got high from it. It's when the focus became about those other things that the best I could do was get in a groove.
[1] http://www.newyorker.com/news/sporting-scene/complexity-and-...
The trick is to train enough (enough miles and the right kinds) to meet your goals. And figure out how to do so w/o getting injured. (Hint: go see a PT, have them evaluate you for imbalances and weaknesses. Do the exercises they prescribe. Then build your mileage, slowly and methodically. And you'll get there. Running well takes years for most people. Don't rush it.)
[1] http://www.bunnhill.com/BobHodge/Rodgers/TrainingLogs/br75tr...
The closest I come to "runners high" is usually on those days where it's been a bit hot for long periods and then a cool front blows in. I'm practically giddy for the whole run and feel amazing. And I run races from 5k to 100 miles. I really, really enjoy racing, but I think it's the competitive aspect of it and not from some runners high.
I'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's on days when I double with a 6 mile run. I've raced almost a dozen marathons and I run the half-marathon distance a couple times a week. So I think it's fair to say that I "cover considerable mileage." This isn'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).
So I enjoy running. There are runs where I'm relaxed and in the groove and the miles just click by. But that's just an enjoyable experiece, like relaxing at the beach. It's nothing like the high from smoking marijuana. Or the exhileration from something like sky diving that first time. Or post-orgasm bliss.
I'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 "high" from running. Have we all been duped? Maybe we're all expecting the wrong thing?
I'm envious of those mice... :-)