Don't underestimate yourself. If you're a newbie, don't think you can't make giant leaps in your fitness; plenty of age-group champions in running, for example, never laced up a pair of shoes until their 40th birthdays were well in the rearview mirror. And if you've been exercising for years, don't assume your performance is going to fall off a cliff once you exit the MTV demographic. Research that Dr. Wright published last year found that top-flight senior athletes saw their performance edge down only about 3.4 percent a year from age 50 through 75. Only after that do the sharper declines begin. "The bottom line is we can continue to achieve high levels of performance into our eighth decade," she says.
Speed up. That means you are not consigned to a plodding pace. If you're in good health and have built a solid base of fitness, interval training—alternating intense bursts of activity with periods of rest—is a great way to burn more calories in less time. Schafer recommends starting with the stationary bike: Go one minute hard for every four of rest. (Just keep tabs on your heart rate to make sure you're not redlining.) "It's a nice way to break up the monotony," he says.
Get social support if you need it. "This is huge," says Huberty. "If you need it, ask for it." It really helps to get your family and friends on board, in spirit if not in body. And if you don't want to exercise solo—and some of us do relish the time alone spent listening only to AC/DC on the iPod or the sound of our own breath—find companions. Local running, walking, cycling, and swimming clubs offer a chance to do a normally solitary sport with others, while classes at the local Y or gym can give you built-in companionship.
Mind old injuries. "Work within the bounds of your health," advises Dr. Wright. Almost everyone, except the very ill and very frail, can exercise. But if you blew out both knees as a college linebacker, running is perhaps not your best option for a consistent form of exercise. Pick an activity that your body can tolerate, if not embrace. And if you're hellbent on re-creating your high school hoops glory days despite the way it makes your back bark, find a game with folks your own age, do it less often, and cross-train with something that's easier on your bod.
Don't obsess over weight. Here's the thing: Many people start an exercise habit thinking only of the potential for weight loss. When progress on that front is slow or nonexistent—there are 3,500 calories in a pound of fat, and 30 minutes of walking briskly may burn off only 200, so you do the math—they get discouraged and stop working out. Instead, try thinking of exercise in terms of the other, less visible health benefits it's providing, like reducing your risk of type 2 diabetes, heart disease, and some forms of cancer. And there are other bonuses, like helping you get better sleep, feel strong, or enjoy the moment, advises Huberty. If you do need to lose weight, focus on developing healthful eating habits—smaller portions, more nutrition-dense foods—rather than tracking every twitch of the scale dial.