美国国家公共电台 NPR New Federal Exercise Guidelines Emphasize Moving More Through（在线收听）

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Move more. Sit less. We've all heard this, but these are the new physical activity recommendations out today from the federal government. As NPR's Allison Aubrey reports, the updated guidelines aim to help people offset the damage of sitting around too much.

ALLISON AUBREY, BYLINE: You've likely heard the idea that sitting is the new smoking. And as a nation, we sit a lot. The lack of physical activity is linked to $117 billion in the annual health care costs. But the good news is you can counteract the damages. Loretta DiPietro is a professor of exercise science at George Washington University.

LORETTA DIPIETRO: People would think, oh, I can't go to the gym for an hour. Well, there's evidence that you don't need to go to the gym.

AUBREY: In order to maintain good health, the guidelines recommend you do need to aim for at least 150 minutes of moderate-intensity aerobic activity each week. That works out to about 20 or 25 minutes a day. And the new guidelines emphasize that you don't have to get it all at once. So if you walk or bike to the bus stop, then you take the stairs instead of the elevator, all this counts towards your daily target. Here's DiPietro again. She served on the advisory committee that reviewed all of the new evidence on exercise.

DIPIETRO: It's really an accumulation over the course of 24 hours that's important. And so moderate-intensity activity, no matter how you accomplish it and in as many bouts as you can do, are what matters.

AUBREY: Now, this applies to all age groups from preschool-aged kids to older adults. For the first time, the updated physical activity guidelines make recommendations for 3-to-5-year-olds, prescribing active play throughout the day. Maybe this will nudge parents and caregivers to take electronic devices out of little hands.

DIPIETRO: The increasing amount of screen time - that is a factor driving these recommendations.

AUBREY: Increasing physical activity in childhood does more than just fend off weight problems. Exercise can also have some immediate benefits. It can help boost our moods, tamp down anxiety. And in children, it can help them do better in school. Here's Chuck Hillman of Northeastern University who was also on the advisory committee.

CHUCK HILLMAN: This is a really exciting area - the study of a single bout of exercise having a benefit to cognition and brain function.

AUBREY: Hillman explains what he's found is that a single workout - say, 20 minutes on a treadmill - can lead to improved attention span and an enhanced ability to fend off distractions.

HILLMAN: So we see using standardized achievement tests that following a single bout of exercise, we find benefits to reading comprehension and arithmetic.

AUBREY: The effects fade quickly, which suggests that daily exercise or daily movement is key.

KATHLEEN JANZ: The secret to physical activity's success is for it to become habitual. So if we do it every day, we're going to get that benefit every day.

AUBREY: That's Kathleen Janz of the University of Iowa. She was also on the Physical Activity Advisory Committee. She says if you start healthy habits in childhood, they're likely to carry over. And over the long term, people who have physically active lifestyles cut their risk of all sorts of diseases, not just heart disease and many types of cancer but also a decreased risk of dementia. Another benefit - perhaps you'll have a sunnier outlook on life.

JANZ: Every time you're active, you think better. You sleep better, and you feel better.

AUBREY: She says focusing on these immediate benefits can help motivate us to move. Allison Aubrey, NPR News.