Normal 0 > Exercising in your 40's, 50's and 60's is like saving for your retirement, experts say. Starting early is money in the bank, but even late bloomers can reap astonishing benefits. "The game isn't over, even if you haven't been active," said Dr. Angela Smith, past president of the American College of Sports Medicine. "Aerobic fitness, bone health, agility, you may be able to catch up. It's remarkable to see the things people can actually do." Smith, a physician at Philadelphia Children's Hospital, said studies have shown that even octogenarians can double their strength with weight training. "There's good evidence that among people who have arthritis, the stronger have less pain, and that getting fit decreases the chance of having cancer," she said. But if you're a former high school athlete who became sedentary as your temples grayed, don't expect your history to save you. "Some of the benefits you built up aren't going to maintain themselves if you become a couch potato," Smith said. "That wonderful bone strength you built in your 20's will melt away a lot faster if you don't stay active." Smith said logic dictates that 40-, 50- and 60-year olds need to pay attention to all components of fitness. "Make certain to do flexibility, strength and aerobic training, even if you have to decrease the amount of impact. A jumping sport may be difficult. But many of the non-sport activities, swimming, weight training, yoga, people can do just fine in 40's, 50's, 60's."