So swimming is an excellent way to lose weight. But simply losing weight does not mean getting fit. You can be thin and still be unhealthy. The key is reducing body fat. Here swimming’s credentials are even more impressive, for, contrary to Bailey’s contention, Olympic swimmers have close to the lowest body-fat percentages of any athletes: about 6 percent for men and 12 percent for women.
But what about ordinary folk like you and me? Medical experts agree that to be fit, a man should have 15 percent body fat or less; a woman 22 percent or less. In general, women have a higher percentage of body fat than men because women’s breasts are composed of fatty tissue and women have more internal fat to protect their reproductive organs.
If you are above these levels, you must consider yourself overweight even though you may be within normal limits on an insurance company chart. According to the most recent health statistics, at age thirty-five the average American male carries 25 percent of his weight in fat, the average female 33 percent. These figures are perilously close to those that place your health in serious jeopardy.
Without exercise, people lose muscle and add fat as they grow older. Their weight may stay the same, but by middle age the average American is carrying far too much fat. Excessive levels of body fat are strongly correlated with heart disease, diabetes, cancer, and many other diseases.
People who exercise regularly add body fat much more slowly as they age. The typical man in an exercise program carries 16 percent of his body weight in fat at age twenty-five and 23 percent at age fifty-five. For women, the figures are 19 percent at age twenty-five and 29 percent thirty years later.
As mentioned, numerous studies have shown that regular swimming results in significant weight loss. More important, it leads to a decrease in body fat. In one study, overweight middle-aged men lost twelve to fifteen pounds of body fat during just twelve weeks of swim training. In another, overweight women lost fifteen to twenty pounds after swimming for ten weeks. Masters swimmers who train a minimum of forty-five minutes a day, three or more times a week, fare even better.
Forty-six-year-old Bill Purdin was horrified when he weighed in at 194 pounds, more than 30 pounds above his college weight. A body-fat analysis showed that at 22 percent he was lugging around almost 43 pounds of fat. The busy Boston-area advertising executive had tried working out over the years but had never stuck to a program. His imminent encroachment on 200 pounds must have provided special motivation, for this time he did. As a result of training six hours a week, Bill’s weight dropped to 164 in less than six months. More important, his body fat percentage dropped to just over 16 percent. His goal is to reach 12 percent and stay there.
My own experience is similar. In 1971 I was a twenty-eight-year-old hotshot, several years into a promising publishing career and probably a bit more active than most guys my age. I had been a competitive swimmer in college and had continued to work out on and off while in graduate school. Although I no longer exercised in any sort of program, I did go for a bike ride once or twice a week and tried to squeeze in an occasional game of touch football or a set or two of tennis. I even got into the pool every now and then. On top of that, as a single father I was kept hopping by my then three-year-old son, Russell.
But clearly I was on the road of ever-decreasing activity that ultimately would lead to serious health problems. I already weighed in at 188 pounds, 10 pounds above my competitive weight in college. And my waist had expanded five inches, to a nice round girth of thirty-six inches. My body fat was 17.6 percent, not terrible but well above the 15.0 percent that defines fitness for a man and less than 2.0 percent from the point at which coronary risk begins.
In December 1971 I began swimming again, and I have been doing it ever since. Now, at the age of fifty, I am in far better shape than I was twenty-two years ago. My weight is back down to the 180 pounds I weighed as a college freshman, my waist is a trim 32 1/4 inches, and my body fat is 9.8 percent. (See Table 4.1 for a more detailed comparison.)
I have lost over seventeen pounds of fat while gaining seven pounds of muscle. And I have never been healthier.
There is nothing unique about my experience. In 1991-92, I tested the body fat of over 700 Masters swimmers from throughout the United States and several other countries. The results are shown in Table 4.2.
These dramatic figures demonstrate that losing muscle mass and increasing fat are not inevitable parts of the aging process. In fact, it seems crystal clear that if you swim regularly, you can remain fit and trim, with little increase in body fat.
Table 4.3 illustrates this point by comparing Masters swimmers with people in an exercise program and with sedentary individuals to illustrate how body fat changes with age.
Measuring Body Fat
There are several ways to determine how much body fat you have. The original method, and theoretically the most accurate, is called hydrostatic weighing, or water weighing. Here you are weighed while you hold your breath under water. Then you are weighed again as you duck your head under water and exhale all the air in your lungs.
The skin caliper test is another common method of measuring body fat. A caliper gathers up and measures the thickness of your fat and skin at specific spots on your body, such as your triceps.
A third method, called electrical impedance, is based on the fact that muscle contains more water than fat and thus is a better conductor of electricity. Sensor pads connected to a monitor are placed on your ankle and wrist; then a small current is sent through the sensors. The time it takes the electrical impulse to travel the length of your body reveals how much fat and lean tissue you have.
All these techniques require special equipment and some expertise in its use. But not to worry. According to Jack H. Wilmore, an exercise physiologist at the University of Texas, you can estimate your body-fat percentage fairly accurately using only a scale, a tape measure, and the charts in Figure 4.1. Here’s how:
Men: Weigh yourself, then measure your waist at the belly button. Using a straightedge, line up the two figures on the chart. Your body-fat percentage is where the straightedge crosses the percent body-fat line.
Women: Measure your hips at their widest point. Using a straightedge, draw a line connecting your hip girth with your height. Read your body-fat percentage where the line crosses the percent body-fat line.
A highly accurate method for calculating your body fat involves only slightly more effort. The only tools you need are a scale, a tape measure, and the ability to perform a simple arithmetic calculation.
Body-Fat Calculation for Women
1. Measure your hips at their widest point and your waist at your belly button.
2. Measure your height without shoes.
3. Record these measurements on the work sheet on this page.
4. Find each of these measurements in the table in Appendix D and record the constants on the work sheet.
5. Add Constants A and B, then subtract Constant C from this sum. Round to the nearest whole number. The figure is your percentage body fat.
Let’s say that you are 5 feet 6 inches tall. Your hips are 36 inches, and your waist is 27 inches. Here is how to calculate your body fat:
| Hips: 36 inches | Constant A = 41.86 |
| Waist: 27 inches | Constant B = 19.20 |
| Height: 66 inches | Constant C = 40.23 |
Add Constants A and B:
Now subtract Constant C:
Round out to the nearest whole number, and you get 21 percent.
Some things to keep in mind: Take all your measurements on bare skin, making sure the tape is snug but not too tight. The best procedure is to take each measurement three times, then use the average. When taking your waist measurement, be sure you measure at the belly button and not at the narrowest point.
I have found this simple procedure to be remarkably accurate and a good way to keep a record of your progress as you get into shape. However, it is important to keep in mind that the procedure was developed using averages based on the measurements of thousands of women. My experience is that it tends to overestimate slightly the body-fat percentage of women in excellent shape and women with smaller than average breasts. It also underestimates somewhat the body-fat percentage of women with larger than average breasts.
Your body composition is an important measure of your physical fitness. How do you compare with other women? Table 4.4 lists the body-fat percentages for different reference groups. This list will help put your own body-fat percentage in perspective. It will also allow you to measure your progress as you get into shape.
Body-Fat Calculation for Men
The formula for calculating men’s body fat is even simpler than that for women.
1. Measure your waist at your belly button.
2. Measure your wrist where it bends, at the space between your hand and wrist bone.
3. Record these measurements on the work sheet on this page.
4. Subtract your wrist measurement from your waist measurement and find the resulting value in the table in Appendix D.
5. Find your weight on the left-hand side of the table. Move to the right. Then move down from your waist-minus-wrist figure. At the point where these two intersect, simply read your body-fat percentage.
Let’s say that your waist measures 34 inches, your wrist is 7 inches, and you weigh 165 pounds. Here is how to calculate your body fat:
Waist: 34 inches
Wrist: 7 inches
Subtract your wrist measurement from your waist measurement:
Be sure to take your measurements on bare skin, keeping the tape snug but not too tight. Take each measurement three times, using the average. Remember to measure your waist at the belly button, not the narrowest point.
As with women, a man’s body composition is one of the most significant indicators of his physical fitness. How do you measure up against other men? Table 4.5 lists the body-fat percentages for different reference groups. This list will help put your own body-fat percentage in perspective and allow you to measure your progress as you swim yourself into condition. Note that the athletic groups listed are world-class or professional.
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