Overweight Kids Think Better After Exercise

Regular exercise improves the ability of overweight, previously inactive children to think, plan and even do math, Georgia Health Sciences University researchers report.  They hope the findings in 171 overweight 7- to 11-year-olds -- all sedentary when the study started -- gives educators the evidence they need to ensure that regular, vigorous physical activity is a part of every school day, said Dr. Catherine Davis, clinical health psychologist at GHSU's Georgia Prevention Institute and corresponding author on the study in Health Psychology.

"I hope these findings will help reestablish physical activity's important place in the schools in helping kids stay physically well and mentally sharp," Davis said. "For children to reach their potential, they need to be active."

To measure cognition, researchers used the Cognitive Assessment System and Woodcock-Johnson Tests of Achievement III that measure abilities such as planning and academic skills such as math and reading. A subset of the children received functional magnetic resonance imaging highlighting increased or decreased areas of brain activity.

MRIs showed those who exercised experienced increased brain activity in the prefrontal cortex -- an area associated with complex thinking, decision making and correct social behavior -- and decreased activity in an area of the brain that sits behind it. The shift forward appears consistent with more rapidly developing cognitive skills, Davis said.

And the more they exercised, the better the result. Intelligence scores increased an average 3.8 points in those exercising 40 minutes per day after school for three months with a smaller benefit in those exercising 20 minutes daily.

Activity in the part of their brain responsible for so-called executive function also increased in children who exercised. "In kids you just don't know what impact you are going to have when you improve their ability to control their attention, to behave better in school, to make better choices," Davis notes. "Maybe they will be more likely to stay in school and out of trouble."

Similar improvements were seen in math skills; interestingly, no improvements were found in reading skill. Researchers note that improved math achievement was "remarkable" since no math lessons were given and suggests longer intervention could produce even better results.

Children in the exercise program played hard, with running games, hula hoops and jump ropes, raising their heart rates to 79 percent of maximum, which is considered vigorous.

Cognitive improvements likely resulted from the brain stimulation that came from movement rather than resulting cardiovascular improvements, such as increased blood and oxygen supplies, Davis said. "You cannot move your body without your brain."

The researchers hypothesize that such vigorous physical activity promotes development of brain systems that underlie cognition and behavior. Animal studies have shown that aerobic activity increases growth factors so the brain gets more blood vessels, more neurons and more connections between neurons. Studies in older adults have shown exercise benefits the brain and Davis's study extends the science to children and their ability to learn in school.

About one-third of U.S. children are overweight. Davis suspects exercise would have a similar impact on their leaner counterparts.

Source: Medical College of Georgia and By Davis, Catherine L.; Tomporowski, Phillip D.; McDowell, Jennifer E.; Austin, Benjamin P.; Miller, Patricia H.; Yanasak, Nathan E.; Allison, Jerry D.; Naglieri, Jack A. Exercise improves executive function and achievement and alters brain activation in overweight children: A randomized, controlled trial.. Health Psychology, Vol 30(1), Jan 2011, 91-98

See also: Surprising Study Says Inactivity Not The Cause Of Childhood Obesity and Fit Kids Get Better Grades

Exercise Grows Kids' Brains, Literally

Researchers have found an association between physical fitness and the brain in 9- and 10-year-old children: Those who are more fit tend to have a bigger hippocampus and perform better on a test of memory than their less-fit peers.  The new study, which used magnetic resonance imaging to measure the relative size of specific structures in the brains of 49 child subjects, appears in the journal Brain Research.

"This is the first study I know of that has used MRI measures to look at differences in brain between kids who are fit and kids who aren't fit," said University of Illinois psychology professor and Beckman Institute director Art Kramer, who led the study with doctoral student Laura Chaddock and kinesiology and community health professor Charles Hillman. "Beyond that, it relates those measures of brain structure to cognition."

The study focused on the hippocampus, a structure tucked deep in the brain, because it is known to be important in learning and memory. Previous studies in older adults and in animals have shown that exercise can increase the size of the hippocampus. A bigger hippocampus is associated with better performance on spatial reasoning and other cognitive tasks.

"In animal studies, exercise has been shown to specifically affect the hippocampus, significantly increasing the growth of new neurons and cell survival, enhancing memory and learning, and increasing molecules that are involved in the plasticity of the brain," Chaddock said.

Rather than relying on second-hand reports of children's physical activity level, the researchers measured how efficiently the subjects used oxygen while running on a treadmill.

"This is the gold standard measure of fitness," Chaddock said.

The physically fit children were "much more efficient than the less-fit children at utilizing oxygen," Kramer said.  When they analyzed the MRI data, the researchers found that the physically fit children tended to have bigger hippocampal volume -- about 12 percent bigger relative to total brain size -- than their out-of-shape peers.

The children who were in better physical condition also did better on tests of relational memory -- the ability to remember and integrate various types of information -- than their less-fit peers.

"Higher fit children had higher performance on the relational memory task, higher fit children had larger hippocampal volumes, and in general, children with larger hippocampal volumes had better relational memory," Chaddock said.

Further analyses indicated that a bigger hippocampus boosted performance on the relational memory task.

"If you remove hippocampal volume from the equation," Chaddock said, "the relationship between fitness and memory decreases."

The new findings suggest that interventions to increase childhood physical activity could have an important effect on brain development.  "We knew that experience and environmental factors and socioeconomic status all impact brain development," Kramer said. "If you get some lousy genes from your parents, you can't really fix that, and it's not easy to do something about your economic status. But here's something that we can do something about."

Source: University of Illinois at Urbana-Champaign and A neuroimaging investigation of the association between aerobic fitness, hippocampal volume and memory performance in preadolescent children. Brain Research, 2010; DOI: 10.1016/j.brainres.2010.08.049

See also: Fit Kids Get Better Grades and For Kids' Health, Just Let Them Play

Surprising Study Says Inactivity Not The Cause Of Childhood Obesity

A new report from the EarlyBird Diabetes Study suggests that physical activity has little if any role to play in the obesity epidemic among children. Obesity is the key factor behind diabetes, heart disease and some cancers.  EarlyBird is based at the Peninsula Medical School in Plymouth, UK, and has been observing in detail a cohort of city school children for the past 11 years.

A review published in 2009 of all trials using physical activity to reduce childhood obesity showed weight loss amounting to just 90g (3oz) over three years, and the EarlyBird study wanted to know why the trials were so ineffective. So they challenged some popular paradigms.

It is well known that less active children are fatter, but that does not mean -- as most people assume it does -- that inactivity leads to fatness. It could equally well be the other way round: that obesity leads to inactivity.

And this is the question EarlyBird was uniquely placed to answer. With data collected annually over several years from a large cohort of children, it could ask the question -- which comes first? Does the physical activity of the child precede changes in fatness over time, or does the fatness of the child precede changes in physical activity over time?

And the answer, published recently in Archives of Disease in Childhood, was clear. Physical activity had no impact on weight change, but weight clearly led to less activity.

The implications are profound for public health policy, because the physical activity of children (crucial to their fitness and well-being) may never improve unless the burgeoning levels of childhood obesity are first checked. If this cannot be achieved through physical activity, the focus has to be on what -- and how much -- children consume.

EarlyBird has already shown how the trajectory leading to obesity is established very early in life, long before children go to school, and how most childhood obesity is associated with obesity in the same-sex parent.

While portion size, calorie-dense snacks and sugary drinks are all important contributors, early feeding errors seem crucial -- and physical activity is not the answer.

Source: Peninsula College of Medicine and Dentistry and Fatness leads to inactivity, but inactivity does not lead to fatness: a longitudinal study in children (EarlyBird 45). Archives of Disease in Childhood, 2010

See also: Fit Kids Get Better Grades and For Kids' Health, Just Let Them Play

Fit Kids Get Better Grades

Physical fitness is associated with academic performance in young people, according to a report presented at the American Heart Association's 2010 Conference on Nutrition, Physical Activity and Metabolism.

"As children's health continues to be a concern -- especially when it comes to obesity -- some have suggested that children's physical fitness is associated with their academic performance," said Lesley A. Cottrell, Ph.D., study presenting author and associate professor of pediatrics at West Virginia University in Morgantown, W.Va. "The research, however, had not developed enough to define the nature of that relationship."

To study the association between children's physical fitness and academic performance, Cottrell and colleagues analyzed the body mass index percentiles, fitness levels and standardized academic test scores of 725 fifth grade students in Wood County, W.Va. The researchers focused more on the children's fitness level than their weight. They then compared that data to students' fitness and academic performance two years later, in the seventh grade...

They separated the participants into four groups of students who were:

* in high physical fitness levels in fifth grade and remained so in seventh grade;
* fit in fifth grade but had lost their fitness by seventh grade;
* not fit in fifth grade but were physically fit by seventh grade;
* not physically fit at the beginning of the study, in fifth grade, nor at the end of the study, in seventh grade.

Children who had the best average scores in standardized tests in reading, math, science and social studies were fit at the start and end of the study, researchers found. The next best group, academically, in all four subjects, was made up of children who were not fit in fifth grade but had become fit by seventh grade. The children who had lost their fitness levels between fifth and seventh grades were third in academic performance. Children who were not physically fit in either the fifth or seventh grades had the lowest academic performance.

"The take-home message from this study is that we want our kids to be fit as long as possible and it will show in their academic performance," Cottrell said. "But if we can intervene on those children who are not necessarily fit and get them to physically fit levels, we may also see their academic performance increase."

Youth who are regularly active also have a better chance of a healthy adulthood. The American Heart Association recommends that children and adolescents should do 60 minutes or more of physical activity daily and they participate in physical activities that are appropriate for their age and enjoyable.

The study suggests that focusing more on physical fitness and physical education in school would result in healthier, happier and smarter children, Cottrell said.

Source: American Heart Association.

See also: For Kids' Health, Just Let Them Play and Kids Who Exercise Can Get Better Grades

For Exercise, Kids Do As Parents Say Not As They Do

According to a new study, there is no direct link between parents' own level of physical activity, and how much their child may exercise. In fact, parents' perceptions of their children's athleticism are what have a direct impact on the children's activity.

The study by Oregon State University researchers Stewart Trost and Paul Loprinzi, published in the journal Preventive Medicine, studied 268 children ages 2 to 5 in early childhood education centers in Queensland, Australia. Of these children, 156 parents or caregivers were surveyed on their parental practices, behaviors related to physical activity and demographic information.

What they found is that parents' level of physical activity is not directly associated with their children, but instead that the direct link was between parental support and a child's level of physical activity.

"Active parents may be more likely to have active children because they encourage that behavior through the use of support systems and opportunities for physical activity, but there is no statistical evidence that a child is active simply because they see that their parents exercise," Trost said.

Trost, who is director of the Obesity Prevention Research Core at the new Hallie Ford Center for Healthy Children and Families at OSU, is an international expert on the issue of childhood obesity.

His study found that parents who think their children have some sort of athletic ability were much more likely than other parents to provide instrumental and emotional support for young children to be physically active.

"I think this underscores the need for parents to provide emotional support, as well as opportunities for activity," Trost said. "Regardless of whether a child is athletic or is perceived to be physically gifted, all children need opportunities and encouragement of physical activity."

However, Trost said parental support of physical activity did not translate to a child's behavior once they were not in the home and were in a childcare setting. He said this adds to the body of research showing that both parents as well as childcare providers must provide support for physical activity.

Sources:  Oregon State University and Parental influences on physical activity behavior in preschool children, Preventive Medicine

For Kids' Health, Just Let Them Play

As usual, your Mom was right. When she told you to get outside and play, she instinctively knew that would be good for you.

Health science researchers at the University of Exeter have found that kids' natural short bursts of play energy contribute just as much to a healthy lifestyle as longer bouts of organized exercise, such as gym class.
As of 2008, 32 percent of U.S. children were overweight or obese, as measured by their body mass index. While many organized programs have studied this epidemic, the prescription remains the same: less food, more exercise.

In fact, a previous health science study of 133 children found that the physical activity of the obese children over a three-week period was 35 prcent less during school days and 65 percent less on weekends compared to the children who were within accepted healthy weight norms.

In the new study, Michelle Stone and Roger Eston of Exeter's School of Sport and Health Sciences measured the activity level of 47 boys aged between 8 and 10 over seven days using an accelerometer strapped to each boy's hip (similar to the one inside your iPhone or Wii controller that senses motion).
The key was to find a model that would record the shortest bursts of energy, sometimes less than 2 seconds. As any boy's parents know, those spurts can happen all afternoon, whether it be chasing the dog, throwing rocks in the lake or climbing a tree.

The researchers also measured waist circumference, aerobic fitness and blood pressure of each boy. They found that even though their activity levels came in many short chunks, their health indicators were all in the normal range.

Stone explains their conclusion, "Our study suggests that physical activity is associated with health, irrespective of whether it is accumulated in short bursts or long bouts. Previous research has shown that children are more naturally inclined to engage in short bursts of running, jumping and playing with a ball, and do not tend to sustain bouts of exercise lasting five or more minutes. This is especially true for activities that are more vigorous in nature.

Their findings are in the April edition of the International Journal of Pediatric Obesity.

The researchers admit that more research is needed to measure long-term effects on health.  Establishing activity guidelines for parents and schools will help the kids plan time to move each day.

The National Football League has even started a program called NFL Play 60 that encourages kids to move for at least 60 minutes each day.  "Our players know the importance of staying healthy and it’s important that young fans also understand the value of exercise," said NFL Commissioner Roger Goodell. "Play 60 is an important tool in ensuring children get their necessary daily physical activity as recommended by health and fitness experts."

So, more recess and less physical education in our schools? Maybe, according to Stone, "If future research backs up our findings, we would do better to encourage young children to do what they do naturally, rather than trying to enforce long exercise sessions on them. This could be a useful way of improving enjoyment and sustainability of healthy physical activity levels in childhood."

Please visit my other sports science articles at Livescience.com

Kids Who Exercise Can Get Better Grades

The end of 2008 brings some discouraging news about our kids' brains and brawn. Recent results from an international math and science test show United States students are performing near the middle of the pack compared to other countries, while their levels of obesity continue to climb.

Historically, these two trends were studied independently with plans of action developed for each. However, several researchers and a new book have been making the case for linking these two problems by showing the effects of aerobic exercise not only on a student's fitness level but also on their test scores.

Last month, the latest (2007) TIMSS (Trends in International Mathematics and Science Study) scores were released. They compare fourth grade students from 36 countries and eighth grade students from 48 countries. They were tested on subjects that were common to all of the countries, including algebra, geometry, chemistry and physics. Overall, 425,000 students participated in the test, which is administered every four years.

In math, American fourth graders came in at 11th place of the 36 countries while eighth graders scored ninth out of 48. Hong Kong and Taiwan ranked first for fourth grade and eighth grade, respectively.  In science, Singapore topped the list for both fourth grade and eighth grade, with U.S. science students taking eighth place and 11th place.

While the American math scores have improved slightly, the science scores have dropped. In 2003, U.S. fourth graders were in sixth place in the world and eighth graders were in ninth place.

Only 6 percent of U.S. eighth-grade students reached the TIMSS "advanced" level in math, compared to 45 percent of students in Chinese Taipei, 40 percent in Korea, 40 percent in Singapore, 31 percent in Hong Kong, 26 percent in Japan and 10 percent in Hungary.

Regarding student fitness, the most recent figures from the Centers for Disease Control and Prevention report that the percentage of overweight or obese 6- to 11-year-olds has tripled since 1980, with more than 125 million children at unhealthy levels.

Leaping backward

Ironically, one of the solutions proposed for raising test scores, No Child Left Behind, encourages schools to focus more of the school day on the core academic subjects while reducing class time in peripheral subjects, like art, music, and physical education.  In fact, only 6 percent of American high schools offer a daily gym class. Yet a 2002 Virginia Tech study showed no relationship between reduced class time in those subjects and higher overall standardized tests.

In his latest book, "Spark: The Revolutionary New Science of Exercise and the Brain" (2008, Little, Brown), John Ratey, a Harvard clinical associate professor of psychiatry, argues for more physical fitness for students as a cure for not only their obesity but also their academic performance.

"I cannot underestimate how important regular exercise is in improving the function and performance of the brain." Ratey writes. "Exercise stimulates our gray matter to produce Miracle-Gro for the brain." That "Miracle-Gro" is a brain chemical called brain-derived neurotropic factor, or BDNF. When we exercise, our working muscles send chemicals into our bloodstream, including a protein known as IGF-1.

Once in the brain, IGF-1 orders the production of more BDNF. The additional BDNF helps new neurons and their connections grow. In addition, levels of other neurotransmitters are increased after a strenuous exercise session.

"Dopamine, serotonin, norepinephrine — all of these are elevated after exercise," says Ratey. "So having a workout will help focus, calming down, and impulsivity — it’s like taking a little bit of Prozac and a little bit of Ritalin."

Evidence mounts

Research showing a link between fitness and academics is growing. The California Department of Education (CDE) looked for a correlation between fitness scores and test scores. They found that kids who were deemed fit (by a standard test of aerobic capacity, BMI, abdominal strength, trunk strength, upper body strength and overall flexibility) scored twice as well on academic tests as those that were unfit.  In the second year of the study, socio-economic status was taken into account, to possibly eliminate that variable as an explanation. As expected, those in the upper-income brackets scored better overall on the academic tests, but within the lower-income set of students, the same results were observed — kids who were more fit performed better academically.

Charles Hillman, associate professor of kinesiology at the University of Illinois, was able to duplicate these findings with 259 third and fifth-grade Illinois students. His team also noticed that two of the tests, BMI and aerobic capacity, were significantly more influential to higher academic scores than the other four fitness factors. Digging deeper, he isolated two groups of 20 students, one fit and the other unfit. They were given cognitive tests of attention, working memory and processing speed while their brain's electrical activity was being measured by an electroencephalogram (EEG) test.

The fit kids’ brains showed more activity in the prefrontal cortex, known for its executive function and control over other brain processes.

So, just send the kids on a fast jog and they will ace all of their tests?  Not quite.

“The exercise itself doesn’t make you smarter, but it puts the brain of the learners in the optimal position for them to learn,” Ratey said. “There’s no way to say for sure that improves learning capacity for kids, but it certainly seems to correlate to that."

Please visit my other articles on Livescience.com

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