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Yearly screenings to measure aerobic fitness in children and teens can help identify who needs help in protecting their overall health into the future, a new report says.
Research shows nearly 60% of 12- to 15-year-olds in the U.S. do not have healthy cardiorespiratory fitness, a measure of the body's ability to supply oxygen to the muscles during physical activity. It is a key marker of overall health.
While weight, blood pressure, cholesterol, and blood sugar can track individual risk factors, measuring cardiorespiratory fitness gives an overall health picture of the heart, lungs, and blood circulation, said Dr. Geetha Raghuveer, writing committee chair for the new scientific statement from the American Heart Association. It was published Monday in the journal Circulation.
"Every child would benefit from (cardiorespiratory fitness) testing as part of a yearly physical and doing so may identify children who would benefit from lifestyle interventions that can help improve health," said Raghuveer, a cardiologist at Children's Mercy Hospital and professor of pediatrics at the University of Missouri, both in Kansas City.
Children with low or unhealthy aerobic fitness are at higher risk for developing premature heart disease, Type 2 diabetes, and high blood pressure at younger ages, and they are at increased risk for premature death from heart disease and stroke as adults.
The new scientific statement reviewed studies that have linked better aerobic fitness in children with improved academic achievement, clearer thinking, better mental health, and a higher sense of self-worth and life satisfaction. The level of cardiorespiratory fitness among kids has been declining in the U.S. and internationally over the past six decades, the report said.
"We've got to get kids moving and engaged in regular physical activity, such as in any sports they enjoy," Raghuveer said. "The best activity is the activity a child or teen likes and that is sustained for a longer period. The habits they learn when they're young will directly benefit their health as they become adults."
Studies conducted prior to the COVID-19 pandemic show children are spending more time using electronic devices, not only for education needs but for recreation and entertainment. However, the relationship between sedentary time and aerobic fitness in youth is unclear. A recent analysis that combined the results of multiple studies found that higher inactivity was associated with lower levels of cardiorespiratory fitness in children, but not teens.
The scientific statement said the "gold standard" for measuring cardiorespiratory fitness involves special tracking of breathing during regular intervals while the participant is exercising to exhaustion on a treadmill or on an adapted stationary bike called an ergometer.
But most pediatric health care offices don't have the facilities or personnel to routinely do that. So, the report's authors said schools could provide a solution.
Schools widely administer fitness tests such as the shuttle run, an effective measure of cardiorespiratory fitness. Students are measured by how many 20-meter laps they finish before timed beeps that get shorter as the test progresses, forcing them to run faster. Many schools also measure body mass index, weight, abdominal strength, upper-body strength, and flexibility through a group of tests called FitnessGram, which is administered in all 50 states.
Currently, those important pieces of information regarding a child's health "are not easy to access because they are in a silo," Raghuveer said. Instead, schools could share their aerobic fitness testing results with health care providers – in just the way those same providers routinely share immunizations records with schools.
The report also looked at several social, economic, and environmental disparities that affect cardiorespiratory fitness in youth.
The statement cited studies that have found lower-income families tend to have children with lower or unhealthy cardiorespiratory fitness, possibly because they do not have access to safe places to exercise, play sports and be physically active. In many communities, physical education is not provided in schools, and outdoor recess opportunities have been reduced or eliminated.
In addition, many lower-income families live in food deserts, making it difficult to find or afford healthy foods, factors that contribute to obesity in young people and adults.
Raghuveer hopes the new report inspires research to find "valid, lower-cost alternative options for traditional cardiopulmonary exercise testing to assess … all children, and improved (cardiorespiratory fitness) tests that can be done in an office with limited space and without the need for formally trained exercise physiology personnel.
"In the meantime," she said, "requiring physical activity for every grade level through high school would be a step in the right direction."