Schoolchildren across Europe sit about 65% of their school hours.

In a study just published in the Journal of Science and Medicine in Sport, with Dr. Maartje van Stralen as first author, we investigated how much time children spent on sedentary and physical activities at school in five European countries. We also looked at differences between countries and differences between girls and boys, children from native and foreign ethnicity, normal and overweight children, and from lower or higher educated parents.
We used data from the ENERGY cross-European cross-sectional survey. Primary schoolchildren (n=1025) aged 10-12 years in Belgium, Greece, Hungary, the Netherlands, and Switzerland wore accelerometers -a device to objectively measure (lack of) activity- for at least six consecutive days. Only weekdays were used for this study to calculate the percentages of school-time spent in sedentary activities and moderate to vigorous intensity physical activities. Children were also measured for their height and weight.
We found that across the five countries, the children spent on average 65% of their time at school in sedentary activities and 5% on moderate to vigorous intensity activities. The differences between countries were small. Girls spent somewhat more time sitting than boys (67 vs. 63% of their school hours) and a little less time on moderate to vigorous intensity activities (4 vs. 5%). Children who were overweight were substantially  less active than normal weight children, but we found no differences according to parental education or ethnicity.