IOWA CITY, Iowa — Parents intent on getting their kindergartners to sit still might want to reconsider.
A University of Iowa study shows that being active at age 5 helps kids stay lean as they age, even if they are not as active later in childhood.
But that doesn't mean parents should be complacent once their children are past age 5. Lead author Kathleen Janz said the health benefits of remaining active are well known.
"You get something from activity whenever you do it," said Janz, UI professor of health and sport studies.
The study, published this month in the American Journal of Preventive Medicine, indicates that kids who are active at age 5 end up with less fat at ages 8 and 11, even when controlling for accumulated activity levels.
Researchers call the effect "banking" because kids benefit later in life.
"The implication is that even 5-year-olds should be encouraged to be as active as possible because it pays off as they grow older," Janz said. UI researchers measured the bone, body fat, muscle tissue and activity level of 333 Iowa children at ages 5, 8 and 11.
The children wore accelerometers, a type of high-tech pedometer that measures acceleration.
Janz said participants reflected Iowa: mostly white kids from middle-income families in both rural and urban areas.
The average 5-year-old participant got 30 minutes of moderate to vigorous exercise daily. For every 10 minutes beyond that, the kids had one-third of a pound less fat tissue at ages 8 and 11. Boys were more likely to show sustained benefits than girls.
Further study is needed to see if the active 5-year-olds didn't develop as many fat cells, improved their insulin response, or had something happen metabolically to provide later benefits.
Janz doesn't want the study to spawn preschool exercise classes or other mandates.
Rather, parents should allow their children unstructured outdoor play time and avoid long periods — more than an hour — of being sedentary.