Vigorous and Moderate Physical Activity among U.S. Adults-A Reaction to Seo and Torabi

Physical inactivity is a major public health issue in this country. The majority of adults do not engage in recommended amounts of physical activity, obesity is on the rise, and health care costs for diseases associated with a sedentary lifestyle continue to skyrocket. Given the numerous health benefits that can be obtained by engaging in regular physical activity, many health education and promotion professionals are planning, refining, and implementing physical activity interventions for individuals and communities. Understanding the various correlates of physical activity is a necessary prerequisite for developing physical activity interventions. In a study discussed in this issue of the journal, Seo and Torabi examined several demographic correlates of moderate and vigorous physical activity in adults. Specifically, they analyzed correlates of moderate and vigorous physical activity separately, which makes a valuable contribution to the physical activity correlates literature. Previously, the majority of correlate studies used physical activity or exercise during leisure time as the dependent variable and did not address activity intensity. (1) In their study, Seo and Torabi found that age, gender, race, income, and education were independent predictors of vigorous physical activity. These demographic correlates of vigorous physical activity are similar to those reported by Trost and colleagues (1) in their comprehensive review of adult physical activity correlate studies. When discussing the results of their study, Seo and Torabi state, "it has not been clearly shown that increased moderate PA (i.e., meeting the moderate guideline on 5 days or more) leads to reduced body weight" (p127). Health education and promotion professionals should consider the desired outcome of a physical activity intervention when deciding which recommendation to endorse. If general health benefits are desired, the moderate physical activity recommendation (2) of at least 30 minutes per day on most ([greater than or equal to] 5) days of the week would be appropriate because it was developed as a public health recommendation that, if followed, would reduce morbidity and mortality from chronic diseases, particularly among sedentary adults. (3) If, however, the desired outcome of the intervention is weight loss or the prevention of weight gain, then health professionals should promote the Institute of Medicine recommendation of 60 minutes of daily moderate-intensity physical activity (4) or the Dietary Guidelines for Americans recommendation of at least 60 minutes of moderate-to-vigorous physical activity most days of the week. (5) Further more, dietary modification to control caloric intake is also advised if weight loss is the goal of the intervention. (5) Seo and Torabi encourage health education and promotion professionals to "put more emphasis on vigorous PA than moderate, especially to help halt the increasing trend of obesity" (p127). They also state that "added emphasis on vigorous activity seems justifiable, as an equal amount of energy expenditure can be attained faster through vigorous-intensity activity than moderate-intensity activity (although it should be noted that vigorous activity is associated with higher risks for injuries, especially among the elderly)" (p127). While I agree with the authors that increased intensity leads to additional caloric expenditure, I strongly encourage health education and promotion professionals to carefully consider all components of physical activity (frequency, intensity, duration, and mode), the desired outcome of the intervention, the target population, and participants' baseline activity levels when deciding the appropriate intensity to promote. A unique finding of Seo and Torabi's study was that Hispanics were more likely than Whites to meet the moderate physical activity recommendation of at least 30 minutes per day on most ([greater than or equal to] 5) days of the week. …