Physical activity surveillance in the 21st century

PURPOSE: The 1996 Surgeon Generalʹs Report on Physical Activity and Health emphasized the health-related benefits of moderate-intensity physical activities, especially everyday activities. Unfortunately most surveillance systems in the U.S. primarily measure sports-related activities, particularly vigorous intensity sports. This report describes a new physical activity surveillance instrument designed to go beyond our current measures and include moderate-intensity everyday activities. METHODS: Data were collected from a nationally representative sample of adults (n = 5010). Questions were asked about occupational activity (mostly sitting; mostly walking; mostly heavy labor); walking (for exercise, transportation, or any other reason); moderate-intensity activities (brisk walking, yard work, vacuuming); vigorous-intensity activities (running, aerobics, heavy yard work); and strengthening activities (lifting weights, pull-ups, sit-ups). Questions included frequency and duration of activities. Respondents were defined as recommended if they participated in either moderate-intensity activities greater-or-equal, slanted30 min/day for greater-or-equal, slanted5 days/wk OR vigorous-intensity activities greater-or-equal, slanted20 min/day for greater-or-equal, slanted3 days/wk. Insufficient was defined as not meeting recommended levels while inactive was defined as no leisure-time activity. RESULTS: Overall 40% of adults were in the recommended group, 44% were in the insufficient group and 16% were inactive. Among working adults 37% had jobs that involved mostly walking or heavy labor and about 50% of those also were in the recommended group. Among the 63% of working adults who report mostly sitting at work, 39% were in the recommended group. CONCLUSIONS: These results suggest that measuring only leisure-time physical activity may under represent the physical activity experience of many U.S. adults. Broadening the concept of physical activity beyond traditional sports-related vigorous “exercise” may provide a more accurate picture of the prevalence of health-related physical activity.