By DAVID WILLIAMSON
UNC-CH News Services
CHAPEL HILL -- Vigorous exercise and health education classes can cut adolescents' cholesterol levels and reduce their risk of developing heart disease later in life, according to a new study.
The study, conducted by University of North Carolina at Chapel Hill researchers, showed adolescents who participated in a health and physical education program designed by the scientists lowered total fat in their blood by an average of 7 percent. Subjects' LDL, or so-called "bad" cholesterol, dropped by 10 percent during the program.
Children who participated in either the exercise or the classroom instruction arms of the program also showed drops in cholesterol, but not as much, said Dr. Joanne S. Harrell, professor of nursing and principal investigator. HDL, or "good" cholesterol, increased slightly among the children.
"I don't think most parents realize how little actual physical activity their children get at school nowadays," Harrell said. "Most middle-aged and older people in this country were far more active when they were children than kids are now. Our study was to see if we could make a difference in one of the major risk factors for heart disease."
The professor reported her team's results at a news conference today (March 19) at an American Heart Association meeting in Santa Fe, N.M.
Other investigators, including schools of medicine, nursing and public health faculty, were Dr. Robert G. McMurray, professor of physical education; Dr. Shrikant Bangdiwala, research associate professor of biostatistics; Dr. Amy Levine, assistant professor of pediatrics; Shibing Deng, a biostatistician in nursing; and project director Chyrise B. Bradley, research assistant professor of nursing.
The study is part of the larger continuing Cardiovascular Health in Children study, a unique effort in North Carolina to learn about improving children's -- and later adults' -- heart and lung health. Six hundred middle-school students, ages 11 to 14, from five rural N.C. schools in three counties participated in the evaluation announced today.
Subjects were divided into four groups. During the 1995-96 school year they received both physical activity and classroom training, either one or the other "intervention" or neither.
Physical activity was vigorous and sustained three times a week but did not require special sports skills. Classroom teaching focused on nutrition, fitness, not smoking, blood pressure and other topics.
Researchers measured fat levels in the blood of children before and after completing the program. Among middle-schoolers in the combined group, total cholesterol dropped an average of 10.6 milligrams per deciliter and LDL dropped 8.7 milligrams per deciliter.
"We conclude that the combination of both a knowledge and attitude program and a physical activity program was highly effective in improving lipid (fat in the blood) profiles in this group of adolescents," Harrell said. "Our work is important because the few studies that have been done before on this looked at younger children, and none has tested older children the way we did."
"We strongly believe that if such programs were adopted statewide, in the future we would see a reduction of heart disease in North Carolina."
The UNC-CH study showed a larger drop in blood fats than previous work, she said, possibly because physical activity among middle-schoolers tested was more sustained and vigorous.
Participating schools were located in Brunswick, Harnett and Warren counties. Researchers chose those counties because rural children tend to be at greater risk of heart disease later in life than urban or suburban children. A third of those studied were overweight.
"There is a lot of pressure on school systems to have their children perform well on tests, but the old adage about healthy minds and healthy bodies going together still applies," Harrell said.
Note: Harrell can be reached through the meeting press room at (505) 982-6615 or 982-8816 in Santa Fe today and at her office, (919) 966-4284, after the meeting.
Bradley can be reached at (919) 966-3610.
School of Nursing Contact: Renee Kinzie, (919) 966-1412.
News Services Contact: David Williamson, (919) 962-8596.