The intervention focused on moderate to vigorous aerobic activities designed to engage the children. They started physical education (PE) classes with warm-up exercises, such as jumping rope, and spent the majority of time on vigorous non-competitive games that the children enjoyed. The school intervention involved 24 exercise lessons over eight weeks, with three sessions of 20 minutes each per week, at low or no cost to the schools.
"This modest, eight-week school intervention changed and heightened the intensity levels of the existing physical exercise program in the schools and benefited children by encouraging more vigorous physical activities and less sedentary activities at home," said lead author Tom H. Cook, Ph.D., R.N., assistant professor at Vanderbilt University School of Nursing in Nashville, Tenn.
Cook said African-American children, particularly girls, experienced the greatest increase in physical activity levels following the exercise intervention.
CVD is the No. 1 killer and a leading cause of disability in the United States. The behavioral risk factors of overweight/obesity such as a sedentary lifestyle begin during childhood and form the backdrop for CVD in adulthood.
Funded by the National Institutes of Health, the intervention study (which added a nutrition and family component) uses a public health model of intervention to prevent cardiovascular disease in children. It replicates and extends the Cardiovascular Health in Children (CHIC) study.
The study involved third-grade children in three metropolitan Nashville public schools in differing socio-economic communities. African-American children (55 total) were the largest group, followed by Caucasians (44), and children representing other groups, including Hispanics and Asians (14). The 45 boys and 68 girls were 8- and 9-years old.
"Before the intervention, African-American children had the lowest level of high intensity physical activities, particularly African-American girls, who are most at risk for cardiovascular disease," Cook said.
Before researchers began the study, children provided a self-report on their three most frequent leisure activities. About 24 percent reported sedentary behaviors such as watching television, reading and playing video games. After the eight-week PE intervention, this dropped to 16 percent. More than 13 percent of the students who initially reported moderate physical activity such as bicycling increased their activities to more vigorous activities such as swimming and running.
The exercise activities were assigned metabolic equivalent scores, which ranged from 0 to 8. Caucasian children showed the smallest increase in activity after the intervention, from 6.3 to 6.4. African-American children and students in the "other race" category (including Hispanics and Asians) increased their activity by one met score increasing from 5.5 to 6.5.
"After the study, there was a significant increase in vigorous activities and a decrease in more sedentary activities," Cook said. "Playing soccer and going swimming became the most frequent leisure activities and, at the same time, there was a significant decrease in sedentary activities, such as watching television."
Cook received positive responses from school officials and parents. "The kids loved it," he said. Barbara B. Frey, Ph.D., was co-author.
Statements and conclusions of study authors that are published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.