The first principle is to maintain proper posture. Run tall. Think of your body as a straight, vertical line. Keep your neck straight and your head from drooping forward. Look straight ahead, toward the horizon. Plant your feet flat on the ground. This is your neutral posture—the position of balance and strength.

A recent meta-analysis, extracted from multiple studies and pooled data, showed that even rigorous daily exercise doesn’t mitigate the negative health effects of sitting, even for those who exercise regularly and are physically active (including marathon runners). This “active couch potato syndrome” came as a surprise to me because, like many of us

If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health. —HIPPOCRATES

For car and airplane seats, I use a product called Backjoy, which better positions the pelvis and lower spine.)

You are not training to run an event. What you are training for is to live a long and productive life and maintain health optimally. For that there is no question that whatever is sustainable is the best type of training. —DR. TIM NOAKES

By some measures, average functional life spans in the United States have started to decline. This refers to the length of one’s healthy, active life, in contrast to the total number of years that one has been alive. In light of this, Orville Rogers, a one-hundred-year-old Masters record holder in the 200-meter run, quipped that our goal should be