Have you tried exercising many, many times, only to find it difficult to stick with the program? You just can't seem to get the motivation to make it a routine habit? You're not alone. Research has found that about 50 percent of people who start an exercise program drop out within the first six months. Usually excuses are tossed around, from "I'm too busy" to "I'm too tired."

So, what is it that keeps longtime exercisers committed? People who have been exercising regularly for at least five years were asked what motivates them. You might be surprised by the answers. There was no mention of awesome abs, or even losing weight. The four main reasons they gave: maintaining or improving bone density, having more energy, feeling good and feeling younger.

Whatever your reason to make exercise a regular part of your life, it must offer a combination of fun and fitness. Here are some tips on how to do that.

• Select an activity that you feel both you and your body would be happy with. If you are dealing with arthritic joints, you might want to head to the water to try swimming or water aerobics. Or you might want to work with a certified trainer who has experience in the pool.

• Select days and a time of day that will work with your schedule and help you stay on track. Make appointments for yourself on your calendar and check them off.

• Ignore the fitness myth "no pain, no gain.'' That saying alone is enough to discourage some people from even giving exercise a try.

• Fight off the "I'm too tired" excuse. Exercise can energize you. That's just one of its many delights.

• Shorten your workouts: Studies have shown that people starting an exercise program remained more committed when they worked out for 10 minutes a day, rather than 30 or 40 minutes.

• Keep walking shoes in your car, for a "just in case" moment. If you enjoy walking and want to take things up a notch, add a few good body weight exercises for a strength workout on days you are not walking. For a little more cardio action, pretend you are jumping rope.

As always, check with your doctor before starting a new exercise program.