Diet and Health

• Aerobic endurance
• Muscular strength
• Body composition
• Flexibility

Aerobic Endurance

This is a simple measure of how long you can keep up an activity that requires oxygen, such as running, brisk walking, cycling, rowing, dancing, cross­country skiing, stair climbing, swimming, or hiking. Aerobic exercises should be performed at a moderate intensity, enough so that the heart rate speeds up, but not so much as to fatigue the muscles before oxygen has a chance to reach them.

Some exercises are too intense to be aerobic. These “anaerobic” exercises demand more oxygen than can readily get to the working muscles. This type of exercise can be performed for only a short period of time before muscles begin to “burn” and tire out. Anaerobic exercise includes weight­lifting, sprinting, and spurts of activity during football, basketball, tennis, or soccer.

For those interested in shedding pounds, aerobic exercise is the way to go. It supplies the oxygen needed to burn off fat. If you have a choice between a high­intensity workout for a shorter period of time or a low­ to medium­intensity workout for a longer period, opt for the latter. Low­ to medium­intensity workouts strengthen your heart, lungs, and circulatory system, but inflict fewer exercise­related injuries to muscles and joints. You are more likely to stick with this kind of workout program, too.

How often should you work out? The American College of Sports Medicine recommends some form of aerobic activity 3 to 5 times a week. Exercising more often increases the risk of injury without providing much extra benefit. Each workout should last 20 to 60 minutes, depending on intensity (30 minutes of jogging versus 60 minutes of walking). Always include 5­ to 10­minute warm­up and cool­down periods.

How do you know if you are working hard enough? Your heart rate can tell you. The target heart rate for an aerobic activity is between 60 and 90 percent of your ideal maximum heart rate. To calculate what that range is for you (let's assume that you are 40 years old), do the following:

• Subtract your age (40) from 220 to determine the maximum heart rate, in beats per minute, that's right for your age. Example: 220 ­ 40 = 180 beats per minute.
• Multiply this number by 0.60. Example: 180 X 0.60 = 108 beats per minute
• Then multiply the number again by 0.90. Example: 180 X 0.90 = 162 beats per minute
  These results represent your target heart rate at 60 to 90 percent of maximum. Because it's easier to check your pulse for a 10­second period, take these two numbers and divide each by 6 (there are six 10­second periods in a minute):
  108 divided by 6 = 18
  162 divided by 6 = 27

Thus, a 10­second check of your heart rate, taken on your wrist or neck, should be between 18 and 27 beats. If it is lower, pick up the pace. If it's higher, slow down.

Muscular Strength

To increase muscular strength as opposed to aerobic endurance, you need to undertake resistance training using free weights or weight/resistance machines. Lifting heavy weights or working against a heavy resistance until the muscle is fatigued (usually only a few repetitions) improves muscle strength. Lifting lighter weights and repeating it more frequently increases muscle endurance. Exercises should work all major muscle groups.

As a supplement to aerobic exercise, fitness experts recommend about 20 minutes of strength training at least 2, but no more than 3 times a week. Each session should include 8 to 12 repetitions of 8 to 10 different exercises. Because lifting heavy weights can rapidly increase blood pressure, check with your physician before starting a strength­training program if you have any form of heart disease.

When you plan your exercise program, keep in mind that any amount of exercise is better than nothing at all. Even if you do not exercise enough to improve aerobic conditioning, you may still be doing enough to burn calories, strengthen bones, raise your HDL cholesterol, and reduce your risk of cardiovascular disease.

Body Composition and Flexibility

No matter what your age, you can get the exercise you need. Older women may have to ease into an exercise program more gradually, but they can still reap the benefits. With age, we lose muscle because of inactivity. Unless checked, the result is gradual weight gain due to loss of metabolically active tissue. We call muscle “metabolically active” because even at rest it is burning calories. Regular exercise helps to maintain muscle and burn calories, thus controlling weight. Quick­weight­loss diets without exercise cause loss of muscle as well as fat and almost guarantee that the pounds will return. Keeping muscles toned also keeps the tasks of daily living easier as we get older. Stretching exercises help maintain both flexibility and mobility.

The psychological benefits of exercise are worth remembering, too. Exercise is a great stress reducer. Women who exercise regularly report improved mental capacity and outlook, better self­image and self­confidence, higher energy levels, and more restful sleep. Exercise conditions not only the body, but the mind.