Less than half of U.S. adolescents are living heart-healthy lives, and lack of exercise and poor diets could be creating a new generation of heart-disease patients.
It’s no surprise that American adolescents aren’t the healthiest eaters, and that they aren’t as physically active as they should be. But the latest survey confirms the fear that the current generation of teens could be at greater risk of heart disease than their parents if they don’t change their behaviors.
Christina Shay, an epidemiologist at the University of Oklahoma Health Sciences Center, led a study of 4,673 teens ages 12 years old to 19 years old who participated in the National Health and Nutrition Examination Surveys between 2005 and ’10. The volunteers answered questions about their eating and exercise habits by phone once every two years and also provided occasional blood samples and were examined in person at mobile centers to record their blood pressure, weight and height. The sample is demographically representative of the 33.2 million adolescents in the U.S.
As in previous studies, Shay and her colleagues found that these teens were a sedentary group that ate unhealthy foods. More than 80% ate what the researchers rated as a poor diet — high in fast foods and processed foods as well as sugar-sweetened drinks, and low in fruits and vegetables and whole-grain products. The scientists ranked the children’s heart-disease risk behaviors according to how well they complied with the seven factors that the American Heart Association (AHA) recently defined as critical for optimal heart health: maintaining a healthy body weight; eating a healthy diet; being physically active; keeping blood pressure, cholesterol and blood glucose within normal ranges; and not smoking. If the teens met the recommended requirements, their behavior was rated as ideal; if they fell short, their compliance was considered poor; and if they fell in between, the researchers ranked them as intermediate.
Only 45% of boys and 50% of girls in the study met five or more of these criteria, and less than 1% of the teens were eating an ideal healthy diet.
As for physical activity, 44% of the girls and 67% of boys exercised an hour or more per day, with 13% of boys and 23% of girls not physically active at all.
The combination of poor diet and lack of exercise took a predictable toll: 20% of boys and 17% of girls have a poor body mass index (BMI) that placed them in the 95th percentile or greater by height and weight.
The data, published in the journal Circulation, should be a wake-up call, says Shay, to the worsening health of today’s teens, which could put them at greater risk of chronic illnesses like heart disease and diabetes as adults. “It wasn’t surprising that adolescents have terrible levels of physical activity and a poor diet,” she says. “But even at this age, we are already seeing unfavorable levels of elevated cholesterol, higher levels of impaired glucose tolerance and Type 2 diabetes.” Blood-pressure levels were also affected.
That’s particularly worrisome in youngsters for several reasons. First, heart-disease risk factors remain stubbornly unchanged throughout life, so the kids’ health profiles now will probably be the same when they’re adults — with all the cardiac danger that implies. Blood pressure can be especially difficult to lower, for example, without drastic changes in behavior.
There’s also the toll that unhealthy actions have over time. A 40-year-old who develops high blood pressure, for example, may have to weather the negative effects of that risk for three or four decades, but a teen who develops hypertension has to endure another six or seven decades of wear and tear on the blood vessels and other organs.
“If you take this to the logical conclusion, from the path these kids are on if they continue with these trends, then they are likely to have dramatically higher rates of cardiovascular disease than the current adult generation,” says Shay.
Fortunately for them, advances in heart-disease care are making it possible for more heart patients to survive, albeit with weaker and more vulnerable tickers. So the current cohort of teens may live as long as their parents, but they may not be as healthy.
The results highlight the disconnect between the greater awareness of what contributes to heart disease and better knowledge about how to intervene to prevent health problems, and the growing number of young people who might be at risk. That’s why the AHA recently shifted the focus of their public-health messages away from telling people what not to do to avoid a heart attack — don’t eat high-fat foods, don’t sit on the couch — to defining what it means to live a heart-healthy life. And that includes eating more fish, fruits and vegetables, and exercising at least an hour a day. By 2020, the AHA is hoping to see a 20% improvement in the percentage of Americans who meet five or more of the seven heart-healthy behaviors.
For adolescents, the good news is that studies show it doesn’t take expensive or complicated treatments to reverse the unhealthy trends revealed in the current study. Lifestyle changes, such as eating a healthy diet and becoming more active every day, can lead to improvements in many of the clinical factors that contribute to heart disease, like cholesterol levels, glucose levels and blood pressure. To accomplish that, Shay says doctors and health-care providers need to take a more active role in advocating for healthy lifestyle behaviors and in encouraging children to eat healthy foods and to exercise more. In addition, legislators and industry leaders need to address the social and cultural environment that promotes unhealthy habits and start to make changes that help, rather than hinder attempts by youngsters and their families to live a heart-healthy lifestyle. “Especially with kids, if you instill positive behavior changes, they’ll see improvements their whole lives, and that’s a much more long-term effect than any pill for blood pressure can have,” says Shay.