The US government unveiled a exercise guide for Americans on Tuesday, recommending two and half hours of physical activity a week for adults as a means of avoiding a range of health problems.
The guide, presented by the Department of Health and Human Services, suggested activity that could be easily incorporated into daily routines such as bike-riding or vigorous walking.
"The evidence is clear, regular physical activity over months and years produces long-term health benefits and reduces the risk of many diseases," US Health and Human Services Secretary Mike Leavitt said in a statement.
Obesity continued to creep up in the United States last year and now affects more than one in four US adults, a US government report showed in July.
In 2005, 23.9 percent of adults in the United States were obese, or had a body mass index greater than 30, while in 2007, the percentage had grown to 25.6 percent, data issued by the Centers for Disease Control showed.
The new "Physical Activity Guidelines for Americans" are the most comprehensive of their kind and are based on the first thorough review of scientific research about physical activity and health in more than a decade, the statement said.