When asked about the importance of exercise in an overall wellness program, Dr. Robert N. Butler, director of the National Institute on Aging, said, "If exercise could be packed into a pill, it would be the single most widely prescribed and beneficial medicine in the nation."

Countless studies have shown that regular physical activity is the closest thing to a fountain of youth known to humankind. Researchers say exercise is the key to living well and that it will improve your health regardless of your age. But for older adults exercise is considered so important that it has been dubbed the "anti-aging drug with no side effects."

"As we age, the risk of diseases such as hypertension [high blood pressure], heart disease and diabetes increases. One of the best things you can do to protect yourself against the diseases of aging is to be physically active," said Janie Clark, president of the Florida-based American Senior Fitness Association.

Does this mean you have to join a gym and start working out if you want to stay healthy? While many fitness centers and programs such as Jazzercise offer special classes for older folks, it's not necessary to become part of a formal exercise program to reap the benefits of being physically active.

"There are many ways to build physical activity into your daily living routine. Gardening, housework, washing windows, stair climbing, walking around the supermarket or mall while shopping, walking around to look at the sights while on a trip, traipsing around the local flea market, walking around art galleries and museums, walking from your car to your destination, walking the dog, visiting the county fair and playing with your grandchildren or taking them to theme parks are all activities that can add up to the 30 minutes of physical activity per day recommended by the American College of Sports Medicine and it doesn't even seem like exercise," Clark said.

Ballroom dancing, square dancing and line dancing, and recreational activities such as golf are also excellent forms of exercise that don't seem like a workout.

Clark sees building physical activity into daily life as a bridge to embracing a more conscious exercise program such as walking for 30 minutes a day either outdoors or in the safe, climate-controlled environment of a mall. (Many malls have regular walking groups that meet before stores open.)

Walking is the easiest, most user-friendly kind of exercise program. It requires no special skills or equipment and if you walk with a friend or a group it has added social benefits. "Plus walking with a buddy or a group is a good way to stay motivated and stick with your program," said Clark, who advises starting off with short walks at a moderate pace.

"If you've been inactive, it's important to start slowly so you can succeed. Don't try too much too soon and don't quit before you have a chance to experience the benefits of improved fitness. Build on your success by adding distance and increasing pace in a way that feels comfortable," she continued. "It's also important to know that it's never too late to start exercising."

The price of not being physically active is a high one, according to IDEA (International Dance Exercise Association) spokeswoman Peggy Buchanan, program director of a fitness facility for older adults in Santa Barbara.

"If you don't exercise, you gradually lose flexibility, mobility, strength, endurance, balance, coordination and your ability to move easily and comfortably, which can alter your life dramatically," Buchanan said. "Climbing stairs, hauling groceries, traveling and enjoying activities with friends and family can become difficult, if not impossible."

The proven benefits of regular exercise include strengthening heart and lungs, lowering blood pressure, helping to protect against the start of adult-onset diabetes, helping to maintain healthy weight, keeping joints, tendons and ligaments more flexible and helping to stimulate bone growth.

"Exercise also improves your appearance and self-confidence, helps you sleep better, contributes to good mental health by keeping you socially active and promotes a sense of well-being," Buchanan said.

Aerobic exercise (such as brisk walking, cycling, swimming or cross-country skiing) for 30 minutes a day six times a week contributes to lower blood pressure, increased cardiac and pulmonary function, lower resting heart rate, decreased fat weight, reduced cholesterol levels and increased insulin sensitivity, according to a report from IDEA. Regular exercise helps fight depression and anxiety and may even make you feel more alert, according to some studies.

Resistance and weight-bearing exercise is helpful to those with osteoporosis because it helps decrease bone loss associated with aging, which in turn results in fewer musculoskeletal injuries. For those with osteoarthritis, weight-bearing exercise helps improve range of motion and coordination and improves muscle strength.

"Strength training may be one of the most important steps in slowing the aging process," Buchanan said.

While the thought of going to a gym may seem intimidating at first, Clark points out that many fitness centers and YMCAs have special classes just for seniors, including chair aerobics and other exercises that can be performed while seated. Many senior centers also offer fitness classes that range from aerobic dancing to tai chi. Fitness programs such as Jazzercise also have special "light" classes that are suitable for seniors. (Jazzercise founder Judi Shepard Missett, now in her 60s, still teaches classes at Jazzercise headquarters in Carlsbad.)

"One of the advantages of going to a class is the socialization factor," Clark said. "For seniors who may be alone and isolated, going to a gym or a class is a good way to get out of the house and into a situation where it's possible to make new friends."

Before beginning an exercise program, consult your doctor. Always start an exercise session with warm-up exercises and end up with a cool-down. If joints are stiff, use moist heat on them before exercising. Don't exercise when you are injured, sick or running a temperature. Drink plenty of water before, during and after exercising.