Getting Fit And Staying There
Bradley A. Radwaner, M.D., F.A.C.C.
Of all the changeable factors influencing health, physical fitness may be the most important. Even though that view is widely publicized, the majority of Americans would admit that, for one reason or another, fitness has eluded them.
Resolutions simply to "get a little more exercise" usually get buried in the face of other obligations. Any activity is better than none at all, but fitness involves more than an afternoon of softball at the company picnic or an occasional golf outing. As defined by the American College of Sports Medicine, it includes not just an increased capacity of the heart and lungs but muscular strength and endurance, flexibility and a favorable percentage of lean body mass to fat. While that ideal may sound intimidating, it can be achieved by anyone with a little persistence.
Fitness does not require any special athletic talents. You don't have to look like the Fitness Pros or be able to run and jump like Michael Jordan. But you do have to be willing to work up a sweat several days a week…and do it on a regular basis.
FIRST STEP: GET A PHYSICAL
The first step, particularly if you're over 40 or have been inactive for a number of years, is a physical examination. If you have heart disease, diabetes or arthritis, your doctor will give you an exercise prescription appropriate to your condition; otherwise, the task is up to you.
The principles are fairly simple: 1) gradually build a base of muscular strength and endurance; 2) keep your muscles and joints supple with regular warm-ups and stretching; and 3) develop cardiovascular fitness through activities vigorous enough to elevate your heart rate for an extended period three to five days a week. Eventually your body composition will begin to reflect your efforts, but if you're overweight, you also need to adjust your eating habits. Athletes thrive on a diet that's low in fats and high in complex carbohydrates such as fruits and vegetables.
No matter what activities you ultimately choose, brisk walking or jogging may be a good starting point. At least keep the intensity of your workout low at first while you gradually increase the duration. This allows the body to lay down supply lines to feed the muscles and prepare them for handling the increased work load. It also encourages some early weight loss that helps reduce stress on joints and muscles.
It's important to stretch the muscles you use both before and after exercise. As muscles get stronger, they tend to contract; stretching relaxes and lengthens them, preventing injuries and reducing next-day muscle soreness. Warm-ups also help loosen muscles and prevent injury by slowly increasing body and muscle temperature.
For total fitness, muscles ordinarily not used in the chosen activity (such as those in the upper body) should be strengthened through weight training.
Strong, supple muscles are essential, but the ultimate goal of a fitness program is to strengthen the heart and improve the efficiency of the cardiovascular and respiratory systems. To accomplish cardiorespiratory fitness, the American College of Sports Medicine recommends 20 to 60 minutes of aerobic exercise three to five times a week. An aerobic activity is one that produces rhythmic contractions of large muscle groups for 20 to 40 minutes at a time with sufficient supplies of oxygen present. Exercise should be vigorous enough to make you breathe harder (a heart rate 60 to 90 percent of maximum is recommended) but not so much that you have to stop to catch your breath.
The stop and go action of softball is not vigorous or extended enough to be aerobic. Other competitive sports such as basketball and hockey are aerobic but can be risky for those who do not maintain proper conditioning. Activities most commonly recommended are those that can be performed regularly at a controlled level of intensity: walking, running, cycling, stair climbing, skating, aerobic dance and cross country skiing.
Fitness develops gradually over six weeks or more relative to the frequency, intensity and duration of the exercise. Increased intensity will bring about impressive results…but with an increased risk of injury. For most individuals, I recommend exercise of low to moderate intensity with an emphasis on total calories expended. Mileage or duration should be increased by no more than about 10 percent every few weeks up to an expenditure of about 2000 to 3500 calories a week (20 to 35 miles of running or walking).
Rest is an important part of any fitness program. Sessions of high intensity or long duration should be alternated with relatively easy sessions, and at least one or two rest days each week are required to allow muscles to recover fully.
As the body adapts to training, the changes that take place are dramatic: the heart becomes stronger and pumps blood more efficiently to all parts of the body. Blood pressure usually declines, and the heart beats more slowly but the greater force, allowing greater force, allowing greater capacity for work with less effort. The body also becomes more efficient at metabolizing fuel and eventually reshapes itself with a reduced proportion of body fat.
Even the most dedicated person faces the challenge of maintaining fitness through illness, injury, vacations, family upheavals and exercise burnout. Generally speaking, three sessions a week are needed to maintain a fitness level. Four or five sessions will likely bring about improvement while one or two sessions may lead to a slight decline. Muscle strength, on the other hand, can be maintained with only one day a week of resistance training.
Many individuals become obsessive about not missing an exercise session, and that may not be all bad. For the sake of mental as well as physical health, however, it's wiser to be concerned about the overall trend rather than short-term ups and downs. If you find yourself cutting back to one session a week over a month or so, you should realize that your fitness level is eroding and that you cannot immediately go back to the intensity and duration that was previously comfortable. It's also important to watch what you eat whenever you slack off a bit on your exercise program. Even a few extra pounds will put an extra burden on the body when you resume.
Two consecutive weeks of inactivity will result in a reduction of some aspects of your cardiovascular fitness. It takes several months of inaction, however, to reverse all you've accomplished, and even after eight months you won't be totally back to square one…although nearly so. Sometimes a prolonged rest is necessary, but it's important not to jump back into vigorous activity without undergoing the long, slow process of re-training.
To prevent burn-out, runners may turn to cross country skiing during the winter; walkers occasionally switch to swimming or cycling. Many fitness athletes choose a regular program of cross training, not just to prevent boredom but to avoid overuse injuries and keep all parts of the body conditioned.