New Zealand schools should devote more time to physical education to tackle the shortage of exercise experienced by many children, according to new research.
The recommendation comes from a University of Otago research paper, which found more than a third of primary and secondary school-aged kids do not clock up seven hours of exercise per week - the level deemed "sufficient" by international guidelines.
The paper said the situation has become "urgent".
Lead researcher Dr Anja Mizdrak told Morning Report that recommended seven hours of exercise was "any kind of activity".
"We have got almost one in five kids who are minimally active, so they are doing less than half that amount of activity that is recommended.
"This is problematic because we know that it's really important for kids - both for their mental and physical health... that they be doing enough physical activity."
She said at present, there was no specific requirement in the curriculum for a minimum level of physical activity.
"Some schools are doing a great job and some kids are reporting doing plenty of school physical activity, but then when it comes to other kids they are reporting less than an hour of physical activity during school time across the week."
Part of the problem was a lack of facilities, but elsewhere, a time requirement had been shown to be effective in schools getting kids active, Mizdrak said.
Asked about whether kids were getting their activity in outside school hours, Mizdrak said: "The reason we looked at the school setting is it has the ability to really reach the kids who need it most, the kids in the least active category, and also to reach kids in more deprived areas who do not have access to the other physical activity opportunities".
Thirty minutes of physical activity at school per day was the level the researchers advised.
"It's important that's quality time where kids have a positive experience. So it could be an activity or it could be incorporated in terms of other lessons."