New Federal Exercise Recommendations

The New York Times

Very Brief Workouts Count Toward 150-Minute Goal, New Guidelines Say

New federal exercise recommendations include the first-ever federal activity parameters for 3-year-olds, as well as a few surprising omissions.

CreditJeenah Moon for The New York Times

As of Monday, the United States has new federal physical-activity guidelines. The new guidelines, which represent a scientific consensus about how much and what types of physical activities we should complete for good health, bear a strong resemblance to the existing, 10-year-old governmental recommendations. But they also feature some important updates and expansions, including the first-ever federal activity parameters for 3-year-olds, as well as a few surprising omissions.

And they offer a subtle, admonitory reminder that a substantial majority of us are not moving nearly as much as we should.

The idea that the government might suggest how much we need to exercise is relatively new. The first federal exercise recommendations were released in 2008, after several years of scientific background study.

 

During that time, an advisory board of researchers, most of them from academia, scoured the available scientific literature for clues about the relationships between physical activity and health and how much and what types of exercise seemed best able to lengthen people’s life spans and reduce their risks for disease.

Using that information, they assembled and presented a scientific report to the Department of Health and Human Services, which used it as the basis for the original 2008 guidelines.

Most of us probably know what those guidelines suggested.

In essence, they called for adults who are not disabled to complete at least 150 minutes a week of moderate-intensity exercise, such as brisk walking or other activities that raise people’s heart rates and breathing to the point that they can talk to a companion but cannot, should they be so inclined, sing.

The guidelines also noted that 75 minutes of vigorous exercise, such as jogging, would be equally effective but that the exercise, whatever its intensity, should take place in nonstop bouts of at least 10 minutes at a time and preferably every day.

Adults were urged, too, to do some type of strength training twice a week, while children older than 6 and teenagers were told to exercise moderately for at least 60 minutes a day.

 

That was 10 years ago. Since then, exercise scientists have published a mountain’s worth of new research about the health effects of physical activity — and of sitting — and of how much time we really need to spend in motion.

So two years ago, the Department of Health and Human Services convened a new panel of scientific advisers to sift through this research and provide updated exercise recommendations.

Earlier this year, that group delivered a 779-page scientific report to H.H.S., from which the new recommendations were devised.

To the surprise of some scientists and other observers, these guidelines, which were published on Monday in JAMA, are broadly the same as the previous set.

Again, they call for adults to complete at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous activity every week, along with strength training twice a week.

They also suggest balance training for older people and, for the first time, urge kids between the ages of 3 and 5 to be active for at least three hours a day, an acknowledgment that even small children run the risk of being too sedentary these days.

 

The most substantive change in the new recommendations involves how long each bout of exercise should be. The new guidelines say they do not need to last for 10 minutes.

Any physical activity, no matter how brief, including walking up stairs or from the car to the office, provides health benefits, according to the new guidelines, and counts toward exercise goals.

Using these parameters, “it will be much easier” for people to accumulate the desired 150 weekly minutes of moderate activity, says Adm. Brett Giroir, the assistant secretary for health at H.H.S., who oversaw the development of the formal guidelines.

This idea is captured in a new H.H.S. website cheerfully titled “Move Your Way” that summarizes the latest guidelines.

But despite this expansiveness, the 2018 recommendations do not cover some types or aspects of exercise, including high-intensity interval training. Although these brief, intense workouts are popular and widely studied, the guidelines’ writers felt that more research was needed about their safety and effects.

For the same reason, the guidelines do not set a target for how much — or little — time people should spend sitting or how many steps they should take each day, instead reiterating that the best goal is 150 minutes a week of activity.

Helpfully, the new guidelines do include some practical proposals for increasing exercise, including having health care workers ask people about their exercise habits during every appointment and employers promote physical activity at work.

But such efforts are voluntary, of course, and may be unable to overcome the greatest challenge facing the implementation of the new guidelines, which is us.

Despite 10 years of hearing that we should be moving more, few of us are.

Only about 20 percent of American adults meet the existing recommendations, and a third never work out at all, statistics show.

But Admiral Giroir says he believes that the new guidelines can and should inspire large numbers of people to get moving.

“They are so simple,” he says. “You can walk, dance, mow your lawn, park your car a little farther away. It all counts and could really make an impact on people’s health.”

How Exercise Can Boost Young Brains

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Researchers studied participants in an after-school exercise program.
Researchers studied participants in an after-school exercise program.Credit L. Brian Stauffer

 

Encourage young boys and girls to run, jump, squeal, hop and chase after each other or after erratically kicked balls, and you substantially improve their ability to think, according to the most ambitious study ever conducted of physical activity and cognitive performance in children. The results underscore, yet again, the importance of physical activity for children’s brain health and development, especially in terms of the particular thinking skills that most affect academic performance.

The news that children think better if they move is hardly new. Recent studies have shown that children’s scores on math and reading tests rise if they go for a walk beforehand, even if the children are overweight and unfit. Other studies have found correlations between children’s aerobic fitness and their brain structure, with areas of the brain devoted to thinking and learning being generally larger among youngsters who are more fit.

But these studies were short-term or associational, meaning that they could not tease out whether fitness had actually changed the children’s’ brains or if children with well-developed brains just liked exercise.

So for the new study, which was published in September in Pediatrics, researchers at the University of Illinois at Urbana-Champaign approached school administrators at public elementary schools in the surrounding communities and asked if they could recruit the school’s 8- and 9-year-old students for an after-school exercise program.

This group was of particular interest to the researchers because previous studies had determined that at that age, children typically experience a leap in their brain’s so-called executive functioning, which is the ability to impose order on your thinking. Executive functions help to control mental multitasking, maintain concentration, and inhibit inappropriate responses to mental stimuli.

Children whose executive functions are stunted tend to have academic problems in school, while children with well-developed executive functions usually do well.

The researchers wondered whether regular exercise would improve children’s executive-function skills, providing a boost to their normal mental development.

They received commitments from 220 local youngsters and brought all of them to the university for a series of tests to measure their aerobic fitness and current executive functioning.

The researchers then divided the group in half, with 110 of the children joining a wait list for the after-school program, meaning that they would continue with their normal lives and serve as a control group.

The other 110 boys and girls began being bused every afternoon to the university campus, where they participated in organized, structured bouts of what amounted to wild, childish fun.

“We wanted them to play,” said Charles Hillman, a professor of kinesiology and community health at the University of Illinois who led the study.

Wearing heart rate monitors and pedometers for monitoring purposes, the children were guided through exercise that doubled as romping. The activities, which changed frequently, consisted of games like tag, as well as instruction in technique skills, such as how to dribble a soccer ball. The exercise curriculum was designed to improve both aerobic endurance and basic motor skills, Dr. Hillman said.

Each two-hour session also included downtime, since children naturally career about and then collapse, before repeating the process. In total, the boys and girls generally moved at a moderate or vigorous intensity for about 70 minutes and covered more than two miles per session, according to their pedometers.

The program lasted for a full school year, with sessions available every day after school for nine months, although not every child attended every session.

At the end of the program, both groups returned to the university to repeat the physical and cognitive tests.

As would have been expected, the children in the exercise group were now more physically fit than they had been before, while children in the control group were not. The active children also had lost body fat, although changes in weight and body composition were not the focus of this study.

More important, the children in the exercise group also displayed substantial improvements in their scores on each of the computer-based tests of executive function. They were better at “attentional inhibition,” which is the ability to block out irrelevant information and concentrate on the task at hand, than they had been at the start of the program, and had heightened abilities to toggle between cognitive tasks.

Tellingly, the children who had attended the most exercise sessions showed the greatest improvements in their cognitive scores.

Meanwhile, the children in the control group also raised their test scores, but to a much smaller extent. In effect, both groups’ brains were developing, but the process was more rapid and expansive in the children who ran and played.

“The message is, get kids to be physically active” for the sake of their brains, as well as their health, Dr. Hillman said. After-school programs like the one he and his colleagues developed require little additional equipment or expense for most schools, he said, although a qualified physical education instructor should be involved, he added.

Extended physical education classes during school hours could also ensure that children engage in sufficient physical activity for brain health, of course. But school districts nationwide are shortening or eliminating P.E. programs for budgetary and other reasons, a practice that is likely “shortsighted,” Dr. Hillman said. If you want young students to do well in reading and math, make sure that they also move.