Daily exercise dosage: thirty minutes of elevated heart rate, taken daily, a magic bullet against the ills of modern life. That's actually how running starts for most of us. If we progress beyond that formula, it is because we discover an appetite that turns running into something more: a challenge, a security blanket, a fulfillment unavailable in otherwise sedentary lives. Dr. Kenneth Cooper has said that if you're running more than fifteen miles a week, you're running for something other than cardiovascular health. Yes. Exactly.