Current international guidelines which state that children should be active for a minimum of 60 minutes per day may be too low, according to new evidence.
The findings of a recent study suggest that schoolchildren should engage in physical activity for up to 150 minutes each day in order to maintain a normal body weight.
The results of the study were presented as part of an address by Juliette Hussey, head of physiotherapy in Trinity College Dublin at the Irish Society of Chartered Physiotherapists' annual conference, held in Croke Park last weekend.
The study found that about 120 minutes of physical activity per day for girls and 150 minutes of activity per day for boys are necessary for normal body weight.
This represents a significant increase on current minimum guidelines, which recommend that "school-aged youth should participate in 60 minutes or more of moderate to vigorous physical activity that is developmentally appropriate, enjoyable, and involves a variety of activities".
These guidelines were developed by an expert consensus group in the United States and have been adopted internationally, according to Ms Hussey.
However, the recent study, carried out by Catrine Tudor-Locke of Arizona State University, looked at levels of exercise necessary for healthy body composition, whereas previous guidelines took into account other factors such as healthy bones and good cardiovascular profile, explained Ms Hussey.
By profiling a large group of children aged six to 12-years-old, researchers were able to determine how much physical activity those of a healthy body weight engaged in.
Another recent European study came to a similar conclusion, said Ms Hussey.
"That study found that almost two hours of physical activity per day was needed in order to prevent cardiovascular risk," she said.
There is growing concern about the epidemic of childhood obesity and its associated health consequences. Contributing factors to this epidemic are reduced levels of physical activity and higher levels of physical inactivity, according to Ms Hussey.
"There is far more choice nowadays of sedentary activities and people have far more motorised transport," she said.
"Within a society that is increasingly more sedentary, we need to put more focus on the amount of exercise that children need to do each day. Forty years ago we didn't have to think about it."
Physical activity needs to be incorporated into the school day in order for children to achieve these levels, said Ms Hussey. "Children are in school for five hours every day and if they don't have the opportunity to do much physical activity, then it will be hard for them to achieve the recommended amount," she said.
"They can achieve a certain amount by walking or cycling to school, or playing games at break time," she said.
Daily physical education classes would also be of enormous benefit, said Ms Hussey.
"With regular PE, they would be getting almost half of that daily recommendation," she said.