One way to judge what is moderate activity for you is to measure your heart rate. Although this is perhaps a more accurate approach to gauging your effort, it's also more of a nuisance if you happen to be one of those who has a hard time finding a pulse to count. In any case, moderate activity is activity intense enough to elevate your heart rate to at least 50 percent of your maximum heart rate (60 to 70 percent is better). You can calculate your rough maximum heart rate by subtracting your age from 220. Thus, if you're 55, your theoretical maximum heart rate will be 165. Seventy percent of this would be 115 beats per minute. (While exercising, stop and count your pulse for 10 seconds, then multiply by six.) You should measure your heart rate during the sustained effort portion of your workout, not during the beginning warm-up period or the later cool-down, as these measurements won't be as indicative of your true sustained effort. Also, if you're very out of shape, counting your heart rate won't give you an indication of the intensity of your effort.

During wour workouts, periodically check your heart rate. If you have a heart rate monitor (a device worn on your chest and wrist that can detect and track your heart rate while you are being active), you can set the alarm limits around your target heart range.

If you do not have a monitor, you can get a rough estimate of your heart rate by counting your pulse for six seconds and adding a zero. You can check your pulse by placing your index and middle fingers lightly on your radial pulse. This is the pulse on the thumb side of your wrist. Press lightly because pressing too heavily will cut off the flow of blood through the vessel, and you will be unable to count. You can also place your fingers lightly on either side of your windpipe (the hard tube you feel in the very center of your throat) to feel your carotid pulse. Do not press too hard or massage this area since this can affect your heart rate. Practice taking your pulse before you start to exercise so you know what you are feeling for before you exercise. If your heart rate is too slow, pick up your pace; if it is too high, then slow down a bit.