COLUMBIA, S.C. (AP) — Children as young as 3-5 years old may be on their way to obesity because of a lack of exercise, a new study shows. The University of South Carolina’s Arnold School of Public Health tracked the activity levels preschool kids found that many were not getting even half the required two hours of moderate to vigorous activity they need.

The study is one of a few to focus on the physical activity of 3- to 5-year-olds and is reported in the November issue of the journal Pediatrics, released Monday.

“Obesity rates are skyrocketing in Americans in general and kids included,” said Russ Pate, the professor and researcher who led the study. “If we’re going to learn how to prevent this problem, we’ll need to include actions that can be taken with young kids.”

The level of activity varied widely among preschools, Pate said.

Parents should ask about activity hours when considering a preschool.

“They’re going to be there for a lot of hours,” he said. “It’s enough time to matter.”

One thing to look for is a safe and attractive outdoor play area, which appears to promote more activity during the preschool day.

For the study, 281 children from nine Columbia-area preschools were fitted with activity-monitoring devices called Actigraph accelerometers. Information was recorded for an average of 4.4 hours a day for 6.6 days.

On average, children engaged in 7.7 minutes of moderate-to-vigorous physical activity for each hour they were in preschool — that is equal to about an hour during an eight-hour day.

The National Association for Sport and Physical Education recommends a two-hour physical activity requirement during a six-hour preschool day.

The study also found that boys are more active than girls — something other studies have found.

Researchers said the findings suggest that girls should be encouraged as early as possible to be more active.

More than half of those in the age group studied are in preschool. More than 10% of 4- and 5-year-old children were overweight in 1994, compared with 5.8% in 1974.

Pate, 57 and a father of two, said he had pictured preschoolers as little bundles of energy always on the move. But like other Americans, kids live in an environment in which people do less walking and more electronic gaming and TV-watching than previous generations. He said it was unclear whether preschools had changed their focus on physical activity.

“But we do have to remember that young children learn by moving … by interacting with other kids and their environment,” Pate said.

Eastminster Day School on Trenholm Road takes that philosphy to heart and most kids there get close to two hours of activity a day, director Mele Baize said.

The children at the school also sign up for programs, such as gymnastics, dance and karate. The school is next door to a church and has access to the gym.

Pate said the size, resources and equipment at preschools play a role in whether they promote healthy levels of activity.

“I really think that if directors of preschools and people who work in preschools are sensitized to this issue, we can readily influence this,” he said.