Drugs Physical Activity Surgery and Other Treatment for Overweight and Obesity - Physical Activity

In sharp contrast to the Amish farmers, many Americans in the early twenty-first century are not physically active. The Centers for Disease Control defines the minimum recommended physical activity level for adults as "moderate-intensity activity at least thirty minutes per day, five or more days per week, or vigorous-intensity activity at least twenty minutes per day, three or more days per week—in 2003 about 54% of adults age eighteen or older did not engage in the minimum recommended physical activity. The percent of men and women that are physically inactive during leisure time increases with age and income. According to the CDC in Health, United States, 2005, more than half of adults age sixty-five and older said they were physically inactive during leisure time compared with about one-third of adults aged eighteen to forty-four. Women were more physically inactive than men of the same age across all age groups. This pattern begins early—among high school students at every grade level, significantly fewer female students reported engaging in moderate or vigorous physical activity.

The 2004 National Health Interview Survey data revealed that even fewer adults age eighteen and over engaged in regular leisure-time physical activity than did in 2003. (See Figure 6.1.) Figure 6.2 shows that non-Hispanic white adults were more likely than Hispanic adults and non-Hispanic black adults to participate in FIGURE 6.1 Percent of adults aged 18 years and over who engaged in regular leisure-time physical activity, 1997–2004 "Figure 7.1. Percent of Adults Aged 18 Years and Over Who Engaged in Regular Leisure-Time Physical Activity: United States, 1997–2004," in Sample Adult Core Component of the National Health Interview Survey, Centers for Disease Control and Prevention, National Center for Health Statistics, 2005, http://www.cdc.gov/nchs/data/nhis/earlyrelease/200506_07.pdf (accessed January 12, 2006)regular leisure-time physical activity. In 2004 poor and near-poor adults were less likely than those who were not poor to obtain leisure-time physical activity and were more likely to be inactive. (See Figure 6.3.)

Physical Activity and Weight Loss

Increasing physical activity and exercise is an important element of regimens intended to produce weight loss, even though the addition of exercise to a diet program generally does not produce substantially greater weight loss—the majority of weight lost is attributable to decreased caloric intake. By favorably affecting blood lipids, increased and sustained physical activity does offer many direct and indirect health benefits including reducing risks for cardiovascular heart disease and Type 2 diabetes beyond the risk reduction possible through diet alone. Physical activity lowers LDL cholesterol and triglycerides, increases HDL cholesterol, reduces abdominal fat as measured by waist circumference, and may protect against a decrease in muscle mass during weight loss.

Health professionals deem physical activity important for people who are overweight because it leads to increased expenditure of energy and may serve to inhibit food consumption by reducing appetite. Although it generates only very modest weight loss—a 2% to 3% decrease in body FIGURE 6.2 Age-sex-adjusted percent of adults aged 18 years and over who engaged in regular leisure-time physical activity, by race/ethnicity, 2004 "Figure 7.3. Age-Sex-Adjusted Percent of Adults Aged 18 Years and Over Who Engaged in Regular Leisure-Time Physical Activity: United States, 2004," in Sample Adult Core Component of the National Health Interview Survey, Centers for Disease Control and Prevention, National Center for Health Statistics, 2005, http://www.cdc.gov/nchs/data/nhis/earlyrelease/200506_07.pdf (accessed January 12, 2006)weight or body mass index (BMI)—physical activity is helpful for preventing regain of lost weight.

Like those who have been inactive or sedentary, overweight people are advised to initiate physical activity slowly and gradually. Walking and swimming at a slow pace are ideal activities because they are enjoyable, easy to schedule, and less likely to produce injuries than many competitive sports. Table 6.1 is an example of a walking program that progressively increases physical activity. Further, because amounts of activity and the resulting health benefits are functions of the duration, intensity, and frequency, the same amounts of activity may be obtained in longer sessions of moderately intense activity such as brisk walking than in shorter sessions of more strenuous activities such as running. Table 6.2 shows how a moderate amount of activity—physical activity that uses about 150 calories of energy per day for a total of about 1,000 calories per week—can be obtained in a variety of ways. Table 6.2 also indicates how performing common household chores, and even such self-care activities as using a wheelchair, may be used to fulfill requirements FIGURE 6.3 Leisure-time physical activity among adults 18 years of age and over, by poverty status, 2003 "Figure 14. Leisure-Time Physical Activity among Adults 18 Years of Age and Over, by Poverty Status, United States, 2003," in Health, United States, 2005, Centers for Disease Control and Prevention, National Center for Health Statistics, December 8, 2005, http://www.cdc.gov/nchs/data/hus/hus05.pdf#chartbookontrendsinthe (accessed January 8, 2006)for moderate amounts of physical activity. Changing routines to include walking up stairs rather than taking an elevator or parking farther than usual from work, school, or shopping are ways to increase physical activity incrementally. Even reducing sedentary time, such as hours spent in front of the television, video game system, or computer can serve to increase energy expenditure.

Table 6.2 also shows the relationship between the intensity and duration of physical activities by comparing the amount of time a 154-pound adult must spend performing each activity to expend 150 calories. It is interesting to note that just five additional minutes of walking at a moderate pace expends the same number of calories as walking at a brisk pace.

A study conducted by John Jakicic and his colleagues at the University of Pittsburgh Physical Activity and TABLE 6.1 A sample walking program "A Sample Walking Program," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, October 2000, http://www.nhlbi.nih.gov/guidelines/obesity/practgde.htm (accessed January 12, 2006)

TABLE 6.1
A sample walking program
	Warm up	Exercising	Cool down	Total time
SOURCE: "A Sample Walking Program," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, October 2000, http://www.nhlbi.nih.gov/guidelines/obesity/practgde.htm (accessed January 12, 2006)
Week 1
Session A	Walk 5 min.	Then walk briskly 5 min.	Then walk more slowly 5 min.	15 min.
Session B	Repeat above pattern
Session C	Repeat above pattern
Continue with at least three exercise sessions during each week of the program
Week 2	Walk 5 min.	Walk briskly 7 min.	Walk 5 min.	17 min.
Week 3	Walk 5 min.	Walk briskly 9 min.	Walk 5 min.	19 min.
Week 4	Walk 5 min.	Walk briskly 11 min.	Walk 5 min.	21 min.
Week 5	Walk 5 min.	Walk briskly 13 min.	Walk 5 min.	23 min.
Week 6	Walk 5 min.	Walk briskly 15 min.	Walk 5 min.	25 min.
Week 7	Walk 5 min.	Walk briskly 18 min.	Walk 5 min.	28 min.
Week 8	Walk 5 min.	Walk briskly 20 min.	Walk 5 min.	30 min.
Week 9	Walk 5 min.	Walk briskly 23 min.	Walk 5 min.	33 min.
Week 10	Walk 5 min.	Walk briskly 26 min.	Walk 5 min.	36 min.
Week 11	Walk 5 min.	Walk briskly 28 min.	Walk 5 min.	38 min.
Week 12	Walk 5 min.	Walk briskly 30 min.	Walk 5 min.	40 min.
Week 13 on: Gradually increase your brisk walking time to 30 to 60 minutes, three or four times a week. Remember that your goal is to get the benefits you are seeking and enjoy your activity

Weight Management Center, "Effect of Exercise Duration and Intensity on Weight Loss in Overweight, Sedentary Women: A Randomized Trial" (Journal of the American Medical Association, vol. 290, no. 10, September 10, 2003), confirmed the weight-loss benefits of even moderate exercise. The study divided 201 women aged twenty-one to forty-five into four groups. Two groups of women expended 1,000 calories per week walking at a moderate pace for forty minutes a day. The other two groups expended 2,000 calories per week; one group walked at a moderate pace for sixty minutes a day and the other at a vigorous pace for forty-five minutes a day. All of the study participants reduced their calorie consumption to between 1,200 and 1,500 calories per day. The investigators found no differences based on different exercise durations and intensities—one group of women lost almost as much weight—about thirteen to twenty pounds over twelve months—from walking at a moderate pace as another group did from walking at a brisk pace.

Another study, supported by the National Heart, Lung and Blood Institute and conducted by Cris Slentz, and his colleagues at Duke University Medical Center found a dose-relationship between exercise and weight loss—increasing amounts of exercise yielded greater benefits ("Effects of the Amount of Exercise on Body Weight, Body Composition, and Measures of Central

TABLE 6.2 Examples of moderate amounts of physical activity^a "Appendix H. Examples of Moderate Amounts of Physical Activity," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, October 2000, http://www.nhlbi.nih.gov/guidelines/obesity/practgde.htm (accessed January 12, 2006)

TABLE 6.2
Examples of moderate amounts of physical activitya
Common chores	Sporting activities
aA moderate amount of physical activity is roughly equivalent to physical activity that uses approximately 150 calories of energy per day, or 1,000 calories per week.
bSome activities can be performed at various intensities; the suggested durations correspond to expected intensity of effort.
SOURCE: "Appendix H. Examples of Moderate Amounts of Physical Activity," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, October 2000, http://www.nhlbi.nih.gov/guidelines/obesity/practgde.htm (accessed January 12, 2006)
Washing and waxing a car for 45-60 minutes	Playing volleyball for 45-60 minutes
Washing windows or floors for 45-60 minutes	Playing touch football for 45 minutes
Gardening for 30-45 minutes	Walking 1 3/4 miles in 35 minutes (20 min/mile)
Wheeling self in wheelchair for 30-40 minutes	Basketball (shooting baskets) for 30 minutes
Pushing a stroller 1 1/2 miles in 30 minutes	Bicycling 5 miles in 30 minutes
Raking leaves for 30 minutes	Dancing fast (social) for 30 minutes
Walking 2 miles in 30 minutes (15 min/mile)	Water aerobics for 30 minutes
Shoveling snow for 15 minutes	Swimming laps for 20 minutes
Stairwalking for 15 minutes	Basketball (playing a game) for 15-20 minutes
	Jumping rope for 15 minutes
	Running 1 1/2 miles in 15 minutes (15 min/mile)

Weight change was 3.5% loss in the high-dose/vigorous-intensity group, about 1% loss in the two low-dose exercise groups, compared with a 1.1% gain in the control group. Increases in lean body mass were 1.4% in the two vigorous intensity groups and 0.7% in the low-intensity group. Body fat mass increased by 0.5% in the control group and decreased by 2.0% in the low-dose/moderate-intensity group, by 2.6% in the low-dose/vigorous-intensity group, and by 4.9% in the high-dose/vigorous-intensity group. Waist circumference increased by 0.8% in the control group and decreased by 1.6% in the low-dose/moderate-intensity group, by 1.4% in the low-dose/vigorous-intensity group, and by 3.4% in the high-dose/vigorous-intensity group. The three exercise groups also had significantly decreased waist and hip circumference measurements compared with controls.

Discussing their results, the researchers offered that "From the perspective of prevention, it appears that the thirty minutes per day will keep most people from gaining the additional weight associated with inactivity. Given the increase in obesity in the U.S., it would seem likely that many in our society may have fallen below this minimal level of physical activity required to maintain body weight."