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Exercise
Is Key To Reversing Obesity-Related Heart Risk in Children
The arteries of overweight children act like those of middle-aged
smokers, increasing their risk of an early heart attack
or stroke. But the damage can be reversed through diet and
regular exercise, according to a report in an issue of Circulation:
Journal of the American Heart Association.
We were surprised that the children had developed vascular
abnormalities at such a young age and by how readily these
could be reversed with simple lifestyle measures, says Kam
S. Woo, M.D., chair and professor of medicine and therapeutics
and a consultant cardiologist at The Chinese University
of Hong Kong.
The researchers studied 54 boys and 28 girls, average age
9.9 years. Based on body
mass index (BMI),
28 were deemed overweight and 54 were obese.
The study did not include children with a family history
of early heart disease, but the youngsters already showed
signs of early atherosclerosis. Using ultrasound, the researchers
measured the ability of the brachial artery in the arm to
expand in response to increased blood flow. This response
is called endothelium-dependent dilation, and is a measure
of an artery's reactivity.
A less-reactive artery is a sign of vascular damage and
an early feature of atherosclerosis, the disease process
that underlies heart disease and stroke. The researchers
also used ultrasound to measure the thickness of inner layers
in the wall of the carotid arteries, which are in the neck
and supply blood to the brain. This measure is a well-established,
noninvasive way to assess plaque build-up in the arteries
and monitor its progression.
The children hadn't entered puberty, but their vascular
test results “matched those of a 45-year-old adult
who had been smoking for more than 10 years, Woo said. “Compared
to normal-weight children, by adulthood they are three to
five times more likely to suffer a heart attack or stroke
before age 65.
To assess whether these risk factors could be improved,
the researchers divided the children into two groups –
diet-only or diet-plus-exercise.
For the first six weeks, all the children met with a dietitian
twice a week and followed a 900–1,200 calorie diet
that was low in fat and high in complex carbohydrates. Children
in the diet-plus-exercise group met with an exercise trainer
weekly and were led through a 75-minute program twice a
week that included aerobics, resistance training and agility
exercises.
After six weeks, overweight and obese children in both
groups had significantly reduced their waist-hip ratio,
lowered their total cholesterol and increased their endothelium-dependent
dilation. Diet and exercise were associated with a significantly
greater improvement in endothelial function than diet alone.
Endothelial function in children in the diet-plus-exercise
group improved from 6.8 to 8 percent; it improved from 6.9
to 7.5 percent for the diet-only group.
During the next year, the children met the dietitian twice
a month and were 80 percent successful in following the
prescribed balanced diet. Twenty-two children in the diet-and-exercise
group continued training once a week; 19 stopped. At the
end of the year, the children who continued exercising had
significantly less thickening of the carotid wall and more
improvements in body fat content and lipid measures. By
the end of the year, the endothelium-dependent dilation
increased significantly in the initial exercise group (to
7.4 percent) and to 8.6 percent in those who kept exercising.
“This highlights the importance of regular exercise
in preventing obesity-related vascular dysfunction in children,
Woo said.
According to government surveys, 15.3 percent of children
ages 6–11 in the United States are overweight or obese.
Almost half of young people get no regular exercise, Woo
said.
“Adopting a healthy lifestyle in childhood is the
most cost-effective and practical way to prevent heart disease
in adults, Woo said.
Co-authors are Ping Chook, M.D.; Chung W. Yu, Ph.D.; Rita
Y.T. Sung, M.D.; Mu Qiao, M.S.; Sophie S.F. Leung, M.D.;
Christopher W.K. Lam, Ph.D.; Con Metreweli, M.D.; and David
S. Celermajer, Ph.D.
More
Information on Child Obesity Prevention in Schools
Article Source: Circulation: Journal of the American Heart
Association
Article Author: N/A
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