Understanding Kids’ Fitness From in Utero to the Soccer Field

Call it the ultimate workout — a baby’s ninth month in utero.

Near the conclusion of a full-term pregnancy, an infant often pushes vigorously against the uterine walls, and as strange as this may sound, these movements may lay a foundation for fitness in later years.

“It’s like a gym. It’s exercise,” explained Dr. Dan Cooper, pediatrician and director of the Pediatric Exercise Research Center (PERC) at UC Irvine.

The center is researching how premature babies — who don’t get the gym effect, are often frail at first and are not encouraged to expend energy — might later be more prone to obesity and other chronic illnesses. Preterm birth, which occurs more often among low-income mothers, is just one of the conditions that the UCI center is linking to pediatric exercise through its research in and around Orange County.

In an interview with Voice of OC, Cooper explains some of the center’s research findings, including how an Irvine PE teacher (now a principal) came to influence groundbreaking research into pediatric fitness.

Q: What new information is the center bringing to public health issues beyond what we know to be obvious about the value of exercise?

A: It’s intuitive that exercise is good for children, but translating that into drugs, devices, approaches and prescriptions that influence health has been enormously difficult for a couple reasons.

One reason is that it may be surprising but the fundamental question of how much activity children do naturally is one of the most fundamentally difficult to measure in all of physiology. When you try to determine how much exercise is good, it’s been difficult.

Two, we’re increasingly seeing children survive conditions that used to be fatal, such as premature birth. Many more children are surviving but with disabilities and chronic conditions. You have leukemia and cystic fibrosis, heart disease. In these children you can’t just say, “Go out and play.” They’re constrained by underlying disease or disability. So how much is the right exercise for a child who has congenital heart disease? We don’t know any of the answers to these questions.

Q: Why don’t we know how much exercise is the right amount?

A: Humans evolved in an environment that no longer exists. Children played freely in rougher environments and didn’t always eat. That environment in which we evolved doesn’t exist anymore. So how do we determine now what’s the right amount of physical activity? Is it the young kid in South OC whose parents hope he’ll be a star pitcher but who may be overworking and overtraining his arm? Is it club soccer? Because we have so altered the environment, it’s now up to us to figure out the optimal level of physical activity.

Q: But we know kids, and particularly low-income kids, need more opportunities to exercise.

A: Yes, we were part of the HEALTHY Study, the largest study its kind ever undertaken. We did studies in and around Orange County, drawing on physical fitness tests in fifth, seventh and ninth grade. You might say it’s obvious, but it needed to be proven that with the right kind of PE teachers and emphasis on healthy lifestyles, you can influence body mass index (BMI) and physical activity levels in children. That’s the good news. The bad news is why isn’t it done? That’s an issue of training our PE teachers and not just relegating PE as an afterthought to the math and English teachers.

Since PE is not part of No Child Left Behind, there’s not a lot impetus for schools to support outstanding programs. For example, California has mandates as to what you’re supposed to teach, like shooting a basket. You will see frequently in poorly run programs, 60 kids line up. One kid shoots, then the next. How much vigorous activity is occurring there? Very little. But you can get parents involved and teachers and cafeterias involved, to serve lower fat and calorie foods the kids like. You have to have the will, the mandate and the funds to make these changes.

Q: How do you make PE work well for all kids?

A: We brought together the very best middle school PE teachers for the study. One was Scott Bowman (now principal at Rancho San Joaquin Middle School). Here’s how I discovered Scott. When the HEALTHY Study came out 12 years ago, I literally walked around neighborhoods talking to kids to find out which kids enjoyed PE. Most hated it except kids at Rancho. I said, “Why do you love it?” and they said “Mr. Bowman.”

He used Fitness Lab on Wheels, FLOW, which are circuit-training activities you can set up in minutes to get kids active in seconds. Every kid loved these activities because they were fun. Scott became part of this National Institutes of Health (NIH) project, and we used FLOW nationally as part of that study.

Q: What are you learning about illnesses that are more highly concentrated in low-income areas, such as asthma?

A: The relationship between physical activity and asthma is triggers. One of the things that causes children to wheeze is exercise. You want kids to be physically active, but if the activity causes them to wheeze and end up in hospital, you have a problem. Can exercise be good for them, and if so, what is the right dose?

There’s no question there’s an epidemiologically proven link between obesity and asthma. Obese children have more asthma. We have a theory at PERC. To put it simply, obesity causes inflammation, and inflammation causes asthma.

It’s a vicious cycle. The otherwise healthy obese child also has a harder time finding places to play. In lower socioeconomic status [SES] neighborhoods, parents are afraid of letting kids play. The advantage of kids in better socioeconomic circumstances is that parents can pay for sports that mitigate the effects of obesity.

Q: Can you say more about research on school lunches?

A: In lower SES areas, kids are part of national school lunch program. Those programs were developed at a time when the nation felt the nutritional concern was lack of calories. There’s probably too many calories in the program. The food people will put a piece of cake on a kid’s tray; they are mandated by law to provide calories. When we wanted to redo the cafeterias, we ran into the problems that these calorie numbers are state-mandated so you can’t arbitrarily lower them. Food vendors don’t want to hear the schools need less.

Q: But you often hear kids will refuse to eat more healthful alternatives.

A: You can do taste tests, introduce new foods with celebrations. If you’re clever and creative you can introduce kids to new foods. What’s a fruit salad in school cafeterias? A wilted fruit you or I wouldn’t eat. When packaged the right way, they eat it.

Q: Can you talk about some of PERC’s studies in Orange County?

A: We’re studying premature, low birth weight babies. If you have a premature baby, you’re sitting there in the NICU, and nurses are saying, “Don’t touch the baby.” Now the baby gets discharged, and there’s a real tendency to minimize physical activity, because you’re so worried. So how do we make that switch, and what’s the role of activity early in life?

Q: Does low birth weight lead to being heavier later?

A: There’s a high incidence of obesity among very low and very high birth weight babies. The high makes sense but low birth weight is interesting. Perhaps the baby didn’t have an optimal uterine environment — it wasn’t getting the nutrition it needed. The baby is born, and food is more accessible. You’ve programmed the baby to do catch-up growth, combined with less exercise.

Q: Do you also look for connections between premature births and later obesity?

During the last trimester, a pregnant woman is feeling the baby move more and more. The baby is moving increasingly in a confined environment [pushing against uterine walls], and it’s like a gym. That’s exercise.

So in fact, in conditions where the baby has restricted physical activity, atrophy can occur. In a normal, full-term baby they’re able to push and it contributes to bone growth. In a prematurely born baby, we wrap them up and do everything we can to minimize energy expenditure at the expense of maximizing energy.


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