People seeking to stay healthy can get their exercise in small increments(n.增量) of just a few minutes at a time, according to new guidelines issued by the American government that again encourage a largely sedentary(adj.久坐的) nation to start moving.
The guidance from a committee appointed by the Department of Health and Human Services of America does away with the official government position that physical activity should occur in sessions of at least 10 minutes.
"Current evidence shows that the total volume of moderate-to-vigorous(adj.有力的) physical activity is related to many health benefits; bouts of a prescribed duration are not essential," the committee of health experts wrote.
"Sit less, move more. Whatever you do, it really all counts," Brett P. Giroir, assistant secretary for health at HHS, said in an interview.
健康与人类服务部的助理健康书记官Brett P. Giroir说：“少坐一点，多动一点。不管你怎么动，真的都有用。”
Thomas Allison, director of sports and exercise cardiology(n.心脏病学) at the Mayo Clinic in Rochester, Minnesota, said short bouts of exercise are valuable to break up long stretches of sitting.
But research shows that multiple short sessions should involve similar energy expenditure to have the same impact as one longer session, or additional time moving will be needed, he said.
For adults to stay healthy, the new guidelines call for 150 to 300 minutes of moderate-intensity exercise or 75 to 150 minutes of vigorous-intensity physical activity each week, along with at least two days a week of muscle-strengthening exercises.
The guidelines cite walking briskly at 3.9 to 6.4 kilometres per hour, playing volleyball or raking leaves as moderate-intensity activity.
Vigorous-intensity exercise includes jogging or running, carrying heavy groceries or taking a strenuous fitness class, the panel said.
Some workouts, such as swimming and cycling, can fall into either category, depending on the effort expended.