Schools should "redefine" physical activity, focusing on low-level effort rather than strenuous exercise, says a leading sports medicine consultant.
Dr Mike Loosemore argues cramming "heavy exercise" into a crowded school curriculum does not work.
He says getting children to stand up and move around more could have an extraordinary impact on their health.
Public Health England says activity must become the default choice rather than an effort.
There is growing concern over the public health impact of inactivity, particularly for the well-being of children.
Read more: www.bbc.co.uk/news/health-30294607