Few fields have changed as rapidly as the science of exercise. New research suggests that exercise can increase your life expectancy and stave off cognitive decline more than anything else you do. The best part? You may not need to do as much of it as experts once thought. In this TIME special edition, readers will learn:exactly why exercise is the best anti-ager-and how it changes nearly every part of the bodyeffective ways to squeeze tiny amounts of exercise into your daystrategies for lasting weight loss through exercise in conjunction with the right dietthe best exercises for every goal, whether it's stress reduction, better skin, a stronger stomach or a healthier heart