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Donald Dengel and patient.

In his obesity study, U researcher Donald Dengel monitors a child's blood vessel lining for signs of dysfunction, which are precursors of cardiovascular diseases.

Saving young hearts

U professor looks for early interventions to restore cardiac health in overweight children

Nov. 10, 2006

It's no secret that the United States is in the midst of a childhood obesity epidemic. According to the 1999-2002 National Health and Nutrition Examination Survey, 16 percent of American children ages 6 to 19 are overweight--triple the proportion of 1980. If you add to that number the additional 15 percent of American kids who are at risk for becoming overweight, an astounding one-third of our children face a dismal medical future due to obesity-related illnesses.

While a solution to halt the childhood overweight epidemic remains elusive, Donald Dengel of the College of Education and Human Development studies cardiovascular health in overweight children--looking for promising early interventions that might give America's more than nine million overweight kids a healthy future.

Perhaps what's most startling about the incidence of childhood obesity is its momentum. After holding steady at 5 to 7 percent from the 1960s through the late 1980s, the current numbers represent a 45 percent increase in overweight children from just a decade ago.

"If we think about schools as just a place where intellectual learning happens, we will continue to add to the problem of childhood overweight and obesity," explains Dengel.

The terms "overweight" and "at-risk for overweight" are used to help children avoid the stigma attached to "obese," but they carry the same health risks--including formerly adult-only diseases like hypertension, elevated cholesterol, Type 2 diabetes, heart disease and stroke.

What the research shows

Dengel, associate professor of kinesiology and co-director of the General Clinic Research Center's Body Composition Human Performance Laboratory, focuses much of his research on studying the endothelium--or lining of the blood vessel--looking for signs of dysfunction that are the precursors of cardiovascular disease, and working on ways to improve the endothelia of overweight children.

How's your body weight?

The terms "overweight" and "obese" are linked to a person's body mass index or BMI. Using a BMI calculator, you can see where you or your child are in relation to a healthy weight.

Dengel's recent research followed a group of overweight children with known endothelial dysfunction as they participated in four-times-weekly exercise sessions on a stationary bike. Their peers in the control group did not change their exercise habits. The findings at the end of the eight-week study revealed some eye-opening results, both in the exercise and control groups.

After just eight weeks, the exercise group demonstrated dramatic systemic improvement in vascular health, with endothelial functions returning to normal. This is not the case in adults, who can improve endothelial function with exercise, but not totally reverse the damage. In addition, the kids improved their physical fitness and increased their HDL cholesterol (the good cholesterol).

Perhaps surprisingly, the study participants who exercised didn't lose weight nor reduce their body fat, but from a vascular health standpoint, Dengel says weight loss appears to be less important than exercise. "This study shows that if we get kids to exercise early enough--regardless of being overweight--they can have a chance at a healthy future."

An unexpected thing happened in the control group that shed further light on the acceleration of overweight among kids. During the eight weeks, the non-exercising control group's endothelial dysfunction worsened, fitness decreased, and the children gained weight--an average of 1.8 pounds each of body weight--on track for an annual weight gain of at least 10 pounds. Researchers determined that the unstructured nature of summer--when the research took place--led to unrestricted access to food and less activity than during the school year.

Why this research matters

Children are ill equipped to deal with complex medical problems and interventions because, after all, they are kids. Dengel's exercise study identifies a simple, non-pharmacological intervention that truly improves heart health in young individuals.

Dengel hopes his research can lead to societal changes to promote health among all children, starting with improvements in the nutritional value of school lunches, and increased physical education and recess time. While there is no mystery that exercise is good for kids, P.E. and recess have been reduced to a bare minimum, taking away the only source of physical activity for many kids.

"If we think about schools as just a place where intellectual learning happens, we will continue to add to the problem of childhood overweight and obesity," explains Dengel. "If we are going be a society with a strong future, we have to be concerned about academic, social and physical health. We need to treat the whole child, not just the academic aspect."

Dengel thinks the economic impact of obesity will bring changes. Currently, according to the Department of Health and Human Services, obesity, poor nutrition, and physical inactivity result in total health-related costs of $117 billion annually. "Using current projections, when today's kids reach age 44, approximately 87-90 percent will be overweight," says Dengel. "Will that cause a drain on the healthcare system? Quite simply, caring for this generation will ruin our economy."