The first, and easiest, change to make on your journey to fitness is to add "lifestyle physical activity" to your day. This means being more physically active as you carry out your usual daily activities. You can:

• park in a faraway spot and briskly walk to your destination;
• take the stairs instead of an elevator;
• rake leaves instead of using the blower;
• play tag with the kids instead of computer games;
• go golfing, bowling or dancing for fun;
• walk down the hall instead of using the phone or e-mail to discuss an issue with a colleague;
• take a walk during a morning or afternoon break — and ask a friend to go with you;
• do indoor chores — wash the windows, scrub the bathtub or reorganize your closet, for example; and
• do some active outdoor chores — mow the grass, work in the garden or wash the car.

Making these changes is an easy way to improve heart and respiratory fitness, mood and muscular fitness and to reduce body fat.

However, for women who need to make more dramatic gains in fitness or would like to lose weight, a more formal exercise program, in addition to lifestyle physical activity, may be necessary. Your program should include the main components of fitness:

• Aerobic activities, which involve using the large muscles of your body in rhythmic, continuous motion, improve cardiovascular conditioning and help reduce body fat. Aerobic exercises include walking, jogging, bicycling, swimming and aerobics or exercise classes or videos.

• Strength training, such as weight lifting, improves muscular strength and endurance, helps maintain bone density, and raises metabolism, causing you to burn more calories

• Stretching exercises, which include slow, gentle movements that elongate your muscles, improve flexibility. These exercises are often worked into exercise classes or videos and also are a part of yoga.

How Much Exercise Is Enough?
One of the most common questions is, "How much do I need to exercise?" The U.S. Centers for Disease Control and Prevention and other professional groups recommend that healthy women do some sort of aerobic exercise on most or all days of the week for 30 to 45 minutes. These minutes can be accumulated — 15 minutes of an aerobics video in the morning and 15 minutes of brisk walking in the evening, for example. Intermittent exercise can be part of a good weight-loss strategy because your metabolism is elevated following each bout of exercise.

If you have been inactive, you need to work up slowly to this amount. Start with five or 10 minutes — or whatever you're comfortable with — every other day, and add one minute every other session. If you do too much too soon, you can become injured, fatigued and discouraged. At the top end, professionals recommend experienced exercisers do no more than 200 minutes per week of aerobic exercise with no more than 60 minutes per session.

Similarly, strength training should not be overdone. Start slowly, with lighter weights, and work up to heavier weights and more repetitions or sets of repetitions. You don't need to strength-train more than three days per week; and always wait at least 48 hours before exercising the same muscle group to give those muscles adequate time to recover between sessions.

Stretching and flexibility exercises should be done for 10 to 12 minutes three times a week. They can follow an exercise session. Some lighter stretches can even be done at your desk or while you watch TV. Examples of stretching exercises include shoulder or arm circles. There are also a number of stretches specifically targeted to arm, back, chest, thigh and calf muscles.

How Hard Should You Exercise?
The second question is, "How hard do I need to exercise?" As you work on increasing the length of your exercise sessions, you also need to work on increasing their intensity. Low-intensity aerobic exercise, like housework, gardening and walking the dog, provides a great deal of general health benefits, but to truly enhance fitness, especially if weight loss is one of your goals, you need to up the ante and exercise at a moderate or higher intensity with vigorous activities like brisk walking or jogging, singles tennis, aerobics classes or cycling.