Q. When I start an exercise plan, I always stop after a few days. How can I stick with it?

A. By now nearly everyone knows it's healthy to exercise at least 30 minutes each day, five days a week. Congratulations if you are among the 3.5 percent of Americans who get enough exercise! Don't feel badly if you are among the majority of people who don't get enough physical activity. You may have started a fitness program before and failed to keep going. If you're ready to try one again, here are four simple ways to start and stick with an exercise program. Make sure to check with your health care provider before starting one.

1. A good match

Find something that fits your interests and strengths. What do you like doing? Walking, yoga, biking, tennis and dancing are all great ways to revisit what makes you feel good. Your exercise program might be different today from what you did as a youngster. I used to run track in college. A few years ago I tried to add running to my exercise program, and my knee swelled and hurt for weeks. Every few weeks I tried to run, with the same painful result. Finally I quit, discouraged. It took me years to accept that walking is an acceptable and enjoyable alternative to running.

2. Strength in numbers

If you get energy from being around others, consider joining a team sport (many leagues have seniors only divisions) or sign up for one of the SilverSneakers classes available at a participating fitness center. You might enjoy a spin class for the physical and social aspects, or if you prefer solo activities, you can find many different cardio, strength and conditioning activities at a SilverSneakers fitness center.

Summer is a great time to walk on a nature trail or on a quiet street in your neighborhood. In bad or extremely hot and humid weather, you can get in your 10,000 steps a day at a local mall. Watching TV can be combined with marching in place, stepping off and on a platform, or walking on a treadmill. A used treadmill is not that expensive and is often in like new condition because the owner stopped using it!

3. Make it fun

No matter what your chosen activity, getting in your 30 minutes a day is easier when you use tricks to distract you from the task at hand. Walking or dancing to your favorite music, reading a book or magazine while on a stationary bike or treadmill, or just enjoying the beauty of nature can make the time pass more quickly.

Many people stop exercising right when they are on the verge of success. Sweating, slightly sore muscles, heavy breathing, increased heart rate and feeling short of breath are a normal part of exercise. Active muscle movement produces more carbon dioxide for your lungs to expel. You may feel short of breath because you are exhaling more carbon dioxide, which can reduce the amount of oxygen you take in. This is exercise! Keep going.

4. Ease into it

The key to starting and sticking to an exercise program is to start low and go slow. "Many sedentary people push beyond their usual range when they try to exercise too quickly or intensely," according to The Wall Street Journal article "Hard Wired to Hate Exercise." Even walking can be too much for someone who's been sedentary for years. You may need to build your confidence and stamina as you work to improve your health. Cooking, gardening and housework are activities that can build your tolerance for exercise. You can even break up the recommended 30 minutes of daily exercise into three 10-minute increments--you'll still benefit from the increased activity if it's done in segments.

No matter what your activity level, you should be careful to avoid overdoing it. Save the 20-mile charity walk or the extra 18 holes of golf until you've worked up to it.

Robert Herr, M.D., MBA

Robert Herr, M.D., MBA, practiced internal medicine and emergency medicine for more than 20 years prior to serving as a medical director at Regence. Dr. Herr frequently lectures and writes about health care issues affecting seniors.