Exercise: A healthy habit

Pay attention to your body's messages. Severe muscle soreness, pain, problems breathing, dizziness and nausea are all signs that you are pushing your body too hard.

There's no denying it. Not only does exercise make you look and feel great , it's also good for your health.

Fitness: you're bombarded with the word in magazines and commercials. "Get fit and lose weight." "Get fit and improve your sex life." But the real reason you should get and stay fit is less visible: Regular physical activity–some exercise done on most days of the week–can help prevent or control diseases that are the leading causes of death among women: heart disease, some cancers, diabetes, high blood pressure, and stroke.

Be inspired

Women who do little physical activity–no matter what they weigh–have a higher risk of developing certain life-threatening diseases. Active overweight women tend to be healthier than inactive normal-weight women. Being active can help:

• Strengthen your heart
• Lower your cholesterol levels
• Reduce your blood pressure
• Strengthen your muscles
• Build and maintain strong bones
• Increase your flexibility
• Give you more energy
• Improve focus and concentration
• Relieve stress
• Make you sleep better

And being active helps control weight. That's an impressive list! The bottom line: exercise is key to a healthy lifestyle.

Be well-rounded

Distinct kinds of exercise have specific benefits. It's best to do some of all three: aerobic to increase cardiovascular fitness, resistance to build strength, and stretching to promote flexibility.

Exercise that builds your endurance–cardiovascular or aerobic training–can be as simple as a daily walk or as challenging as a triathlon. It strengthens your heart and lungs and makes your body use oxygen better. Swimming, running, biking and cross-country skiing are examples. Aerobic dance, step classes and water aerobics are other options.

Exercise that builds your strength–resistance training–need not mean slinging weights in a gym. You can swing a child up in the air or do push-ups and sit-ups. Resistance training helps build stronger bones. It also helps support joints that weaken with age.

Exercise that improves your flexibility–stretching, yoga, pilates–should be part of every fitness routine. It can improve your range of motion and keep your joints supple. Try doing it when you wake up or before you go to bed, to ease into or out of the day.

Be kind to your body

Warm up for about five minutes before starting any activity: circle your arms, lift your knees, twist at the waist, jog in place. Doing so prepares your heart and muscles for more intense activity. It also helps prevent injuries.

Cool down after exercise: walk briskly, do the activity at a slower pace or less intensely, or stretch the muscles you have been using. Doing so helps your heart rate return to near normal. Stretching also helps prevent muscle soreness.

Be alert

Use good form in any activity. If you're walking, stand tall, swing your arms easily, and roll your foot from heel to toe. If you're biking, make sure your bike fits you. The seat needs to be high enough to leave your leg almost straight at the bottom of the pedal stroke. The handlebars need to be the right distance from the seat so you don't hunch your shoulders. If you're lifting weights, keep your body aligned correctly. If you're doing yoga, learn the correct form for each pose. If you're stretching, hold each stretch for 20-30 seconds and breathe normally. No bouncing! Poor form can prevent you from benefiting from any exercise.

Be a smart dresser

Wear the right kinds of shoes for the activity. Tennis shoes support side-to-side foot movements.

Running shoes support your heels as they strike the ground. Aerobic shoes provide side-to-side support and cushioning. Yoga is best done barefoot for balance and better grip on the mat.

Be serious

"Target heart rate" denotes the level of exercise that gives your heart the best workout. Simply put, it is 60-80% of your maximum heart rate, which is the fastest your heart can beat. You can estimate it by subtracting your age from 220 then figuring what 60-80% of that is. Or you can use a simple gauge: Can you talk easily? Then your heart is probably not working hard enough. Are you gasping for breath? Then your heart is probably working too hard. As you exercise more and your heart gets stronger, you'll find that you can go longer or work harder.

Be careful

Pay attention to your body's messages. Severe muscle soreness, pain, problems breathing, dizziness and nausea are all signs that you are pushing your body too hard. If you aren't sweating, you're probably not pushing hard enough. One way to avoid injury is to rest on some days. You can also alternate between vigorous and lighter exercise. Or you can cross-train: do different kinds of activities on alternate days. Try swimming and tennis, for example, or yoga and running.

Be regular

How often should you exercise? The answer depends on your goals. If you want to reduce your risk of disease, you should exercise at least 30 minutes on most days of the week. If you want to maintain your weight, you should exercise about 60 minutes on most days. If you want to lose weight, you should exercise 60-90 minutes on most days.

The bad news is that you can't store up exercise, doing a lot one week and none the next. The good news is that you don't have to block off big chunks of your day. Doing physical activity throughout the day in small stints that add up to at least 30 minutes can be nearly as effective as doing the same activity for 30 minutes in a row.