Move more, sit less: a first-line, public health preventive strategy?

Despite the widely cited Centers for Disease Control and Prevention (CDC) ⁄American College of Sports Medicine (ACSM) exercise guidelines, the much-heralded surgeon general’s report, and the recently published ACSM ⁄American Heart Association exercise statement and federal physical activity guidelines (Table I), the conventional model for getting people to be more physically active (ie, structured exercise program) has been only marginally effective. Traditional exercise programs have typically reported dropout rates of 50% or more at 1 year, highlighting the compliance problem among those who voluntarily initiate exercise, regardless of health status. Other enrollees, who do not technically meet the criteria for ‘‘exercise dropout,’’ may continue exercising at a subthreshold intensity, frequency, or duration. According to the CDC, only 31% of American adults meet contemporary physical activity recommendations (ie, moderate-intensity activity for 30 min ⁄d, 5 or more d ⁄wk, or vigorous activity for 20 min ⁄d, 3 or more d ⁄wk), and 24% of the adult population reportedly engage in no leisure time physical activity. Men are more likely to meet the recommendation than women, and black and Hispanic or Latino persons demonstrate the lowest prevalence of regular leisure time physical activity: 25% and 23%, respectively. Morbidly obese individuals in particular are often completely sedentary. According to a recent report, morbidly obese adults (mean SD body mass index, 53.6 11.7 kg ⁄m) were asked to wear an activity sensor that monitored their caloric expenditure, minute-by-minute physical activity, and number of steps per day. The participants spent an average of 23 hours and 52 min ⁄d sleeping, sitting, lying down, or performing sedentary activities (<3 metabolic equivalents [METs; 1 MET=3.5 mL O2 ⁄kg ⁄min]). Collectively, these data suggest that structured exercise is not unlike other health-related behaviors in that only a fraction of those who initiate the behavior will continue, regardless of their age, sex, race, ethnicity, education level, or health status. To understand why people sometimes lack the motivation for a structured exercise commitment, one must first acknowledge a simple yet important fact: exercise is voluntary and time-consuming. Therefore, planned exercise may extend the day or compete with other valued interests and responsibilities of daily life. In addition, considerable time may be spent in transit, driving to and from a health club or recreation facility. In one study, coronary patients undergoing medically supervised gymnasium-based exercise training spent more time in their cars going to and from the programs than patients in a home training comparison group spent on their cycle ergometers. Other investigators have reported that structured rehabilitation exercise training is associated with a low caloric expenditure and has little impact on body weight and selected coronary risk factors.