Even with a more complex measure of physical activity than used previously, the majority of US adults are not physically active at levels that can promote health.

The annual report, issued by the Centers for Disease Control and Prevention (CDC) and published in Morbidity and Mortality Weekly Report on August 15, 2003, details the prevalence of physical activity, including lifestyle activities, of Americans in 2001. Even after expanding the list of activities counted as "moderate" exercise compared with previous surveys by, for instance, including ballroom dancing, playing with children, shoveling snow, or household chores such as vacuuming or gardening, still less than half the population met physical-activity recommendations of exercising at moderate intensity (>30 minutes per day, >5 days per week) or at vigorous intensity (>20 minutes per day, >3 days per week).

In the 2000 survey, which focused on intense exercise, 74% missed the recommendations and 27.4% did not report any kind of relevant activity. Due to the changes in the survey design, the difference to the 2001 survey "might not reflect an actual increase in physical activity," Dr Caroline Macera (San Diego State University, CA) and colleagues from the CDC report. "The findings indicate that even with a more complex measure of physical activity than used previously, the majority of US adults are not physically active at levels that can promote health." The rate of people exercising enough was highest in Wyoming (55.8%), followed by Washington (55.5%) and Vermont (55%), whereas less than 29% fulfilled the requirements in Kentucky.

"It's surprising," coauthor Dr Harold Kohl (CDC) told the Associated Press. "From an overall health standpoint...we've really got to move the needle substantially from where it is right now." Lack of physical activity is an established risk factor for cardiovascular disease (CVD) and many of its contributors, such as hypertension, obesity, and diabetes. The CDC's recommendations in terms of sufficient frequency and duration of exercise are just minimum numbers to prevent these conditions.

As part of the Behavioral Risk Factor Surveillance System, respondents in all 50 states, the District of Columbia, Guam, Puerto Rico, and the US Virgin Islands were asked to report overall frequency and duration of household, transportation-related, and leisure activities in a normal week. Intensity was classified as "moderate" or "vigorous," depending on small or large changes in breathing and heart rate.