How hard do I have to exercise?

Even small amounts of exercise are better than none at all. Start with an activity you can do comfortably. As you become more used to exercising, try to keep your heart rate at about 60 to 85% of your "maximum heart rate." To figure out your target heart rate, subtract your age in years from 220 (which gives your maximum heart rate), and then multiply that number by 0.60 or 0.85. For example, if you are 40 years old, you would subtract 40 from 220, which would give you 180 (220 - 40=180). Then you would multiply this number by either 0.60 or 0.85, which would give you 108 or 153 (180 x 0.60=108 and 180 x 0.85=153).

When you first start your exercise program, you may want to use the lower number (0.60) to calculate your target heart rate. Then, as your conditioning gradually increases, you may want to use the higher number (0.85) to calculate your target heart rate. Check your pulse by gently resting 2 fingers on the side of your neck and counting the beats for 1 minute. Use a watch with a second hand to time the minute.

How do I avoid injuring myself? The safest way to keep from injuring yourself during exercise is to avoid trying to do too much too soon. Start with an activity that is fairly easy for you, such as walking. Do it for a few minutes a day or several times a day. Then slowly increase the time and level of activity. For example, increase how fast you walk over several weeks. If you feel tired or sore, ease up somewhat on the level of exercise, or take a day off to rest. Try not to give up entirely even if you don't feel great right away! Talk with your doctor if you have questions or think you have injured yourself seriously.

What about strength training?

Most kinds of exercise will help both your heart and your other muscles. Resistance training is exercise that develops the strength and endurance of large muscle groups. Weight lifting is an example of this type of exercise. Exercise machines can also provide resistance training. Your doctor or a trainer at a gym can give you more information about exercising safely with weights or machines.