"Exercise produces the growth signals that overcome the signals to atrophy, so your body turns on the machinery to build up muscles, nerves, capillaries, tendons, bones, and so on," says Henry S. Lodge, MD, who cowrote Younger Next Year for Women with Chris Crowley. "Movement is the anti-aging magic you’re after."Do the nine strength-training moves here (or your own weight routine), and follow these tips.Do Cardio Exercise at Least Four Days a Week Not only will you increase your muscular endurance, you’ll also improve your circulation. Circulation controls your capacity to get fuel to cells as well as to remove waste products. "The greater your circulation, the greater the amount of growth and repair," Lodge notes.Train at All Cardio Levels Vary your workouts from long, slow endurance sessions to faster-clip cardio with a few full-tilt sprints thrown in for good measure. "It’s both the duration and the intensity of workouts that create these growth signals," Lodge says.Take Up a Healing Sport Not all cardio workouts have to be pounding or punishing. You get plenty of benefit by swapping in a lower impact "healing" activity (cycling, Spinning, rowing, swimming, cross-country skiing), because these also promote endurance. In fact, varying your workouts by cross-training prevents injury and burnout, so you can stick to exercise long-term.Originally published in MORE magazine, May 2006.