Is sitting too long harming children?

Deb Anderson

February 28, 2012

Professor Jo Salmon

THE modern office workday can feel like one great sit-in – and it can be deadly for adult health. A recent American study shows the longer you sit, the shorter your lifespan. But the modern school day can be cause for concern too, according to Jo Salmon, Heart Foundation fellow and associate head (research) of the school of exercise and nutrition sciences at Deakin University. Her research team is taking action in 20 Victorian schools.

Why focus on sitting time?

Wow! So unfair.

Yes! And this emerging research is a really hot area in our field. My message is, please, adults do your 30 minutes a day and if you’ve got children make sure they’re doing an hour a day – and please don’t spend the rest of your time sitting. It’s good to be up and down. A colleague in the US identified people as either ”squatters or scurriers”. It’s probably better, health-wise, to be a scurrier than a squatter.

But children are squatters now?

Children today have increasing opportunities to be sedentary throughout the day – that has changed over the past 20 to 30 years. We also, of course, have seen increases in children’s weight and other health concerns with one study suggesting a 300 per cent increase in type 2 diabetes in adolescents.

Tell us about your research.

We’ve got funding from the National Health and Medical Research Council for a three-year intervention, looking at how effective active curriculum is on children’s overall health outcomes, with strategies to reduce sitting time and promote physical activity during and after school.

All in Victoria?

Yes, about 600 children. When we started the study in 2010, they were eight years old, in year 3, and they’re going into year 5 this year. To recruit participants, using the Australian Bureau of Statistics’ Socioeconomic Index for Areas, we went to high, mid and low SEIFA areas around Melbourne. Interestingly, we only got one school from a higher SEIFA area; many schools that agreed to participate are disadvantaged.

For how long are children sitting at school?

About six hours a day, our research is showing. Also, nowadays extended teaching blocks in the school curriculum is much greater. Academic outcomes and student attention are shown to be better if children have interruptions to sitting time, and more active curriculum.

What is the longest time you should be sitting?

We don’t have good health evidence on that at the moment. But research groups around the world are examining the metabolic effects of sitting. It’s a field called ”inactivity physiology”, a term coined by American Professor Marc Hamilton.

What do you promote?

We’re discouraging more than 30 minutes of sitting at a time, at which point we’re asking the teacher to get the children up – we have timer teddies in the classroom to help! We’re also asking them to deliver a 30-minute standing lesson, and have given them easels to stand at.

Have the schools embraced it?

They really have. We’ve also provided schools with playground line markings. They’re very novel – it’s not just little hopscotch markings! We’re finding teachers are using those for the active lessons as well. So if the government were to do anything, putting in playground line markings is a very doable, cost-effective way to promote activity and active lessons in primary schools.

And the children?

It looks like the interventions are really working in the schools and the children seem to be more active, particularly boys. But we’re going to have to work a little harder this year to encourage the child to still be active and sit less when they get home.