chapter 19 Exercise and Obesity Dixie L. Thompson

Obesity Overview Obesity classification Class I: BMI is 30 to 34.9 kg · m–2 Class II: BMI is 35 to 39.9 kg · m–2 Class III: BMI ≥40 kg · m–2 Lifestyle and genetic factors contribute to obesity. U.S. obesity prevalence rose from 13.4% in the early 1960s to 30.9% in 2000. Nearly two thirds of American adults are either overweight or obese.

Trends for BMI and Waist Circumference in U.S. Adults

Effects of Obesity Comorbidities include CHD, CHF, stroke, type 2 diabetes, hypertension, dyslipidemia, gallbladder disease, osteoarthritis, some cancers, sleep apnea, and menstrual irregularities. Some estimate that more than 300,000 deaths occurring in the United States each year can be attributed to the complications of obesity. (continued)

Effects of Obesity (continued) The total economic cost of obesity was approximately $117 billion in 2000. This health problem is so important that it led the U.S. Surgeon General to issue The Surgeon General’s Call to Action to Prevent and Decrease Overweight and Obesity in 2001.

Prevention of Obesity Through Physical Activity A number of cross-sectional studies indicate that individuals who are inactive are more likely to be overweight or obese. Individuals who maintain an active lifestyle accumulate less excess fat than their inactive counterparts accumulate. (continued)

Prevention of Obesity Through Physical Activity (continued) Once excess weight has been gained, exercise alone can result in modest weight loss. Caloric restriction combined with aerobic exercise seems to be most useful in weight loss and weight maintenance.

Screening and Testing Obese Clients It is important to screen for comorbid conditions (e.g., hypertension). It is critical to screen for medications on the medical history. Include screening for prescription medications used for treating obesity (e.g., Xenical and Meridia). Standard exercise testing protocols can be used, but the choice of protocol must take into consideration the potential for severe deconditioning.

Exercise Prescription Frequency: 5 to 7 day · wk–1 (optimally) Intensity: moderate (40%-60% HRR) progressing to higher intensity (50%-75% HRR) Duration: start low and progress to 45 to 60 min · day–1 ACSM suggests minimum of 150 min · wk–1 of aerobic activity but recommends 200 to 300 min · wk–1 for more effective long-term weight control.

Other Considerations for Exercise Prescription Choose exercise that limits potential for orthopedic problems. Use care to maintain hydration and avoid overheating. Resistance exercise can be used to help sustain lean tissue. Couple exercise with modest caloric restriction. Focus on long-term lifestyle change.

Combining Caloric Restriction With Exercise Appropriate weight loss goals are typically 0.5 to 1 kg · wk–1. Avoid diets that consist of fewer than 1,200 kcal · day–1. Choose a varied diet with attention to adequacy of vitamin and mineral intake. Choose a diet low in fat, particularly saturated fat. See ACSM position and stand on weight loss and weight maintenance (2001).