At least a few times a month, decide what route you’re going to run, and then leave your watch at home. Other days, run wherever, guided by total time on your watch. The thing to mostly avoid is timing yourself over the same courses day after day. That way lies the madness of beating yourself up for running slower than you “should”

The time spent warming up and cooling down should be included as part of your total workout—it is a very important portion. So, if you plan on doing a “one-hour aerobic run,” spend fifteen minutes warming up, fifteen cooling down, and a half hour in your aerobic training zone.

What does all this mean for today’s recreational exerciser? For one thing, it suggests that the key to unlocking the runner’s high is not the physical action of running itself, but its continuous moderate intensity.

Secret Source of Energy

When you're feeling flat, a little fast running is often the best cure. A slow 5 miles might leave you feeling more lethargic. Instead, throw in some random, short pick-ups, or do a set of striders on your street once you've done your normal loop. Little bursts of fast running can help you surpass sluggishness.