Naturally, the fastest way to get a distance-based task such as a five-mile run over with is to treat it as a race and go all out. Maximal efforts come with a good deal of suffering, however, and humans have a natural aversion to suffering that is at least as powerful as our natural inclination to “get ’er done.” So what do we do? We compromise between the desire to get the workout over with quickly and the desire not to suffer inordinately, and we end up doing the run (or the bike ride or the stair climb or whatever) at a moderate intensity.
