They may be among the world's hardest workers but a new study shows most Americans don't break enough of a sweat when it comes to exercise.
Most U.S. adults failed to exercise at the minimum recommended level in 2003, according to a federal government study released on Thursday that suggested America's "couch potatoes" are still in recline.
Only 45.9 percent of those aged 18 and over met the U.S. government's recommendation of at least 30 minutes of brisk walking or other moderate exercise five days a week or at least 20 minutes of vigorous exercise three days a week, the Centers for Disease Control and Prevention said in the report.
Running, aerobics and heavy yard work are examples of vigorous activity.
Almost one-fifth of those who responded to the CDC telephone survey were classified as inactive — they had not exercised at a moderate or vigorous level for at least 10 minutes per week.
The levels of activity were little changed from those reported in 2001, said the Atlanta-based CDC, which hopes to raise the proportion of adults who engage in regular exercise to at least 50 percent by 2010.
Some health experts worry an indifferent attitude toward physical activity is helping fuel a rise in obesity and related health problems in the United States. About one half of U.S. adults are considered overweight and about one-fifth obese.
Americans work hundreds of hours more each year than Austrians, Belgians, Danes, Germans, Italians and Norwegians, according to the Organization for Economic Cooperation and Development.
Dr. Sanjeeb Sapkota, a CDC epidemiologist and one of the study's authors, said the data highlighted a lack of knowledge about the importance of physical activity and breaking out of a sedentary lifestyle.
He added that it was important for people to understand the links between physical inactivity and increased risks of heart disease, diabetes and some types of cancer.