Obese children less physically fit


American Heart Association meeting report

SAN FRANCISCO, March 4 Weight gain is associated with decreased physical fitness, researchers report today at the American Heart Association's 44th annual Conference on Cardiovascular Disease, Epidemiology and Prevention.

The researchers referred to excessive weight gain during childhood as a "vicious cycle" where children who lack physical activity are more likely to gain weight, but the weight gain impairs a child's ability to be active.

Weight gain that lead to obesity increases the risk of type 2 diabetes in adolescence, a disease previously observed in middle age adults. Obesity also increases the risk of early development of joint problems and atherosclerosis.

"Obesity in children has dramatically increased in recent years. At the same time, physical fitness in children and adolescents has been declining," said Maria Serratto, M.D., lead investigator and an attending cardiologist at both the University of Illinois at Chicago Medical Center and JHS Hospital of Cook County. "We are also seeing the accelerated occurrence of type 2 diabetes in youth that once only occurred in adults."

The study of 525 children (303 boys and 222 girls), aged 4 to 18 years, evaluated for overweight or obesity to determine how it affects physical fitness in healthy children. About 12 percent of the children had body mass indexes (BMI) above the 95th percentile for their age and gender and were considered obese. Most of these children were 30 to 40 pounds over weight.

Endurance was tested by the Bruce treadmill protocol where they walked on a treadmill at varying speeds and inclines. When the child grew too tired, they stopped and left the treadmill. The researcher compared BMI and treadmill times among boys and girls separately.

The impact of obesity on endurance was significant for boys and girls at any age. Boys who were obese had two minutes less treadmill time than non-obese boys. Obese girls had 1.5 minutes less treadmill time than non-obese girls. However, maximum heart rates at peak exercise were similar among the obese children and normal weight children.

"Our results indicate that obese children can be motivated to perform at the same maximum heart rate of non-obese children," Serratto said.

"However, obese children reach maximum heart rate sooner, because they are less fit and this translates into less endurance. "Most of the obese children in our study did not take gym nor did they participate in physical activities. Once they become overweight, they are much less likely to exercise," she said.

Serratto said children could be motivated through school or community center programs to become more physically active.

"If you expose them to such programs they can raise to the occasion," she said. "The results of weight loss and physical activity could be maintained through adulthood with resulting decrease in cardiovascular risk factors."

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