But a team of researchers led by Anne-Maree Parrish from the University of Wollongong's Early Start Research Institute is determined to find a way to make students more active during the day.

The study will investigate how much time young people spend sitting and how this harms them physically and mentally.

"You find that in the age group going from primary to high school, students tend to be sitting more," said Dr Parrish.

"We've got data on girls, and assume it's similar for boys, that as they age the amount of time spent sitting increases. For girls in year 7, by the time they are in year 10 it increases to 70 per cent of their school day."

Dr Parrish and the team will look at whether the time spent sitting also affects students' concentration and cognitive abilities.

If this proves to be so, small changes to the classroom such as standing desks or having students stand during lessons in science labs could help address the problem, she said.

During the study, students will visit the university and mimic a normal school day in the facility's whole-room calorimeter to measure how much energy they expend.

The study requires 15 participants between 12 and 15 years old who have a body mass index above the healthy range for their age and gender.

Concurrent studies are also being conducted at the University of Queensland and Deakin University.

For more information visit ieri.uow.edu.au/standupforhealth/index.html.