How hard should you exercise?

Build up slowly If you've been inactive for a long while, remember it will take time to get into shape. Start with low- to moderate-level activities for at least several minutes each day. See the sample walking program, for example. You can slowly increase your time or pace as you become more fit. And you will feel more fit after a few weeks than when you first started.

It's important to exercise at a comfortable pace. For example, when jogging or walking briskly you should be able to keep up a conversation comfortably. If you do not feel normal again within 10 minutes of stopping exercise, you are pushing yourself too much. Also, if you have difficulty breathing, experience faintness or prolonged weakness during or after exercising, you are exercising too hard. Simply cut back.

Length of sessions

That depends on your age, your level of physical fitness, and the level of intensity of your exercise. If you are inactive now, you might begin slowly with a 10-15 minute walk or other short session, three times a week. As you become more fit, you can do longer sessions or short sessions more often.

If you're active already and your goal is to condition your heart and lungs, try for a minimum of 30 minutes. Each exercise session should include:

1. Five minute warm-up

Begin exercising slowly to give your body a chance to limber up and get ready for more vigorous exercise. Start at a medium pace and gradually increase it by the end of the five minute warm-up period.

Note: With especially vigorous activities such as jumping rope, jogging or stationary cycling, warm up for 5-10 minutes by jumping rope or jogging slowly, warming up to your target zone. It is often a good idea to do stretching exercises after your warm-up period and after your exercise period. Many of these stretching exercises can be found in books on sports medicine and running. Below are three stretches you can use in your warm-up period and after your cool down period. Each of these exercises help stretch different parts of your body. Do stretching exercises slowly and steadily, and don't bounce when you stretch.

Wall push: Stand about 1 1/2 feet away from the wall. Then lean forward pushing against the wall, keeping heels flat. Count to 10 (or 20 for a longer stretch), then rest. Repeat one to two times.

Palm touch: Stand with your knees slightly bent. Then bend from the waist and try to touch your palms to the floor. Count to 10 or 20, then rest. Repeat one to two times. If you have lower back problems, do this exercise with your legs crossed.

Toe touch: Place your right leg level on a stair, chair, or other object. With your other leg slightly bent, lean forward and slowly try to touch your right toe with right hand. Hold and count to 10 or 20, then repeat with left hand. Do not bounce. Then switch legs and repeat with each hand. Repeat entire exercise one to two times.

2. Exercising for 30-60 minutes

Build up your exercising time gradually over the weeks ahead until you reach your goal of 30-60 minutes. Once you get in shape, your exercising will last from 30 to 60 minutes depending on the type of exercise you are doing and how briskly you do it. For example - for a given amount of time, jogging requires more energy than a brisk walk. Jogging will thus take less time than walking to achieve the same conditioning effect.

3. Cool down 5 minutes

After exercising within your target zone, slow down gradually. For example, swim more slowly or change to a more leisurely stroke. You can also cool down by changing to a less vigorous exercise, such as changing from running to walking. This allows your body to relax gradually. Abrupt stopping can cause dizziness. If you have been running, walking briskly, or jumping rope, repeat your stretching and limbering exercises to loosen up your muscles.

Frequency of exercise

If you are exercising in your target zone, exercise at least three or four times per week (every other day). If you are starting with less intense exercise, you should try to do at least something every day. Exercising regularly is one of the most important aspects of your exercise program. If you don't exercise at least three times a week, you won't experience as many of the benefits of regular physical activity as you could or make as much progress. Try to spread your exercise sessions throughout the week to maximize the benefits. An every-other-day schedule is recommended and may work well for you.

Missed sessions

Whenever you miss a few sessions (more than a week), you may need to resume exercising at a lower level than before. If you miss a few sessions because of a temporary, minor illness such as a cold, wait until you feel normal before you resume exercising. If you have a minor injury, wait until the pain disappears. When you resume exercising, start at one-half to two-thirds your normal level, depending on the number of days you missed and how you feel while exercising. Whatever the reasons for missing sessions, don't worry about the missed days. Just get back into your routine and think about the progress you will be making toward your exercise goal.

Know your limits

Is there a top limit to exercising? That depends on the benefits you are seeking. Anything beyond 60 minutes daily of a vigorous or moderately vigorous activity will result in little added conditioning of your heart and lungs. And it may increase your risk of injury. If you want to lose extra pounds or control your present weight, there is no upper limit in that the longer you exercise, the more calories you burn off. But remember that the most effective weight loss program includes cutting down on calories in addition to exercise. Remember: How you exercise is just as important as the kind of activity you do. Your activity should be brisk, sustained and regular - but you can do it in gradual steps. Common sense and your body will tell you when you are exercising too long or too hard. Don't push yourself to the point where exercise stops being enjoyable.