The findings of the study that involved over 500 four-year-olds are contrary to the popular assumption that in this age which is dominated by television and computer games, children could shed weight if they climbed more trees.
The study was led by John Reilly, a professor in pediatric energy metabolism at Glasgow University. Its findings have been published in the British Medical Journal this week. The study was aimed at establishing whether greater physical activity would prevent children from becoming overweight. 545 children in their last year at 36 nursery schools were recruited for the study.
The schools were made to institute three extra half-hour sessions of physical play and activity every week, while parents were given information packs that encouraged them to give their children more activity and less television. The other half had no extra activity or information.
Weights, measurements and body mass index were regularly measured and calculated, and no difference was found between the groups.
The researchers wrote, "Despite rigorous implementation, we found no significant effect of the intervention on physical activity, sedentary behavior or body mass index."
Besides, tendency of these children to sit about was not particularly less nor was there any greater inclination to run around. However one positive observation made was that the more active children had better motor and movement skills, which would probably increase their confidence about doing physical activity in the future.
Still as the researchers point out the problem is serious. In Scotland in 2001 at least 10% of children aged four to five and 20% of children aged 11 to 12 were obese. They wrote, "Children in Scotland establish a physically inactive lifestyle before school entry."
The study was aimed at finding some way to increase activity and prevent the progression to obesity before children start mainstream school. The program was designed to be inexpensive, costing £200 and involving the training of just two members of staff at each nursery, to make it feasible if adopted at all schools.
The researchers wrote, "Successful interventions to prevent obesity in early childhood may require changes not just at nursery, school and home but in the wider environment. Changes in other behaviors, including diet, may also be necessary."
According to the British Heart Foundation, which partly-funded the study, accepted the research was solid, but said it did not mean it was not necessary to encourage children to run about and play.
Mike Knapton, its director of prevention and care said, "It's absolutely vital for young children to be active. Although this study suggests that the benefits of a small amount of extra exercise for nursery children are not visible immediately, we know it's crucial to encourage good exercise habits from an early age.
"Children get less active as they get older so it's vital that youngsters get regular physical activity to lay the foundations for good health as they grow up."