Earlier today, there was a slow jogger at the track I go to. My plan was to do some intermittent running - run fast for a bit, then walk a bit. I have gone back to more intermittent running and less continuous running lately.
What surprised me was that I almost kept pace with the jogger, even though I was essentially running half a lap and walking half a lap. I noticed this after the second lap, when I caught up to him right when I was finishing a run segment. This continued for most of the workout.
Just in terms of pure fitness gains, you would have to say that the interval running would produce more benefits than the slow jogging I witnessed. If you run faster than normal, your body will attempt to adapt. Further, the higher intensity of running releases more growth hormone and other key hormones.
I'm sure that over a long distance this jogger could outlast me, just like the old tale about the tortoise and the hare. The fable is sort of deceiving however, because it only measures one outcome - a long distance to cover. I think most people would want to live their life more like a hare - springy, energetic, and capable of high intensity on occassion. Even if this means not being the best at extended endurance tasks.
