“Mass child neglect.”

That’s the stark phrase that Dr Richard Weiler, one of the UK’s leading consultant physicians in sport and exercise medicine, uses to describe the government’s approach to children’s health and wellbeing.

Weiler - who has worked with Olympic and Paralympic athletes, Premier League footballers, NHS trusts, universities and the Department of Health - says that the need to simply help children to get fitter keeps being overlooked in favour of a focus on measuring body mass index and childhood obesity.

“Every week, you read about some child who’s come home in tears because they’ve been stigmatised, because they’re being told, basically, that they’re fat,” he says. “In fact, fitness is independent of your weight: it is possible to be fit and fat. But we’re in a society that is obsessed with measuring weight.”

The result of this obsession? Children are not getting fitter. In fact, it’s the very opposite. Weiler says that paediatric clinics are now seeing children as young as 7 presenting with diseases that were previously thought of as exclusively adulthood disorders: coronary artery disease, clogged arteries and Type 2 diabetes.

In fact, children are now so unhealthy that research studies in the US have predicted that this is the first generation in a number of years that will not outlive the life expectancy of their parents.

With the amount of time that children spend at school, one argument goes that teachers have a big part to play in reversing this trend. Weiler agrees, and thinks that one major area to tackle is the sedentary nature of much of the school day.

“Children are in state care for most of the year,” he says, “and we force them to sit.”

He adds that children end up sitting down for seven or eight hours a day - time that cannot be mitigated by a mere two hours a week of physical education lessons, which is the amount of time that, in a report of 2013, Ofsted found “most schools” provided for students.

The quality of that physical activity - and its quantity - needs to be increased, says Weiler. Government initiatives are, he believes, too focused on “sport and how wonderful this country is at sport”.

“That’s great, but there are an enormous number of people who aren’t interested in sport,” he says. “And actually, a focus on sport isn’t going to improve public health in the future. Children who are sporty will play sports and be active; it’s far more important that we empower those who aren’t interested in sport and who are less fit to be able to have a more active day.”

In particular, he would like to see the Department for Education and Ofsted take more interest in the quality of physical activities in schools. He says that it is “an absolute disgrace” that the inspectorate does not use this as a metric when visiting schools. “The fact that physical literacy is viewed as second fiddle to academic subjects that are looked at - that’s a humdinger of a mistake,” he argues.

Nor does the DfE issue any statutory guidance on what constitutes a PE lesson. This means, Weiler says, that although schools may be giving students those two hours per week, the time spent changing and walking to playing fields - “if they’ve not been sold off, that is” - could mean that only 40 minutes or less is spent being active.

Weiler also wants schools to focus on weaving physical activity throughout the day and the curriculum. This, he claims, is possible without distracting from other subjects. “It’s not a big deal - it’s not hard,” he insists. “It is possible to make small changes; we’re not talking about massive changes.”

But while lessons such as science and drama can complement PE in offering periods of standing and moving, it can be difficult to see how a less sedentary approach could work in other subjects, such as maths or history.

To work out a solution to that problem, Weiler conducted a pilot study, funded by biopharmaceutical company AbbVie, at Sandringham School in St Albans, Hertfordshire. Central to the research was the idea that the students themselves would take ownership of how they could change their behaviours.

“We didn’t go in and say, ‘This is our idea and research, this is what you will do’,” he explains. “We said: ‘This is why it’s important - you’re the experts in yourselves and your school: what’s going to work for you?’”

After workshops and assemblies to teach children about the importance of an active lifestyle, students in Years 7-9 were asked to come up with ideas for how they could change their school day. The concepts - “some amusing, some brilliant”, according to Weiler - were put to the staff, who worked with the students to work out what could be put into practice.

This included lessons spent standing, as well as giving every child a pedometer and encouraging them to walk more by putting on treasure hunts and house competitions. The pedometer data was even collected by maths teachers, who used them in their lessons.

The students involved “generally enjoyed” their experience, says Weiler: “It worked well in some respects; in others, it was more challenging, as people changing their behaviours usually is.”

Weiler says he’d like to see this approach developed and trialled in more schools, to prove its efficacy. But, he adds, it is “absolutely shameful” that the encouragement of children’s fitness is something that is only taking off at a grassroots, bottom-up level.

Improved wellbeing

The government taking more of an interest in child fitness - and even measuring it in schools - is not something that is completely untested. Over two-thirds of school districts in the US require or recommend that schools measure their students’ fitness levels, according to a 2014 report from the Presidential Youth Fitness Program.

In 13 states, fitness data is collected and used to “inform the development or improvement of policies, standards, or instruction for physical education”. And four of those states - California, Delaware, Texas and West Virginia - went one step further, investigating the link between children’s fitness and academic achievement.

“Regardless of age or socioeconomic status, children who are fitter get better grades,” Weiler says. “And children who are fitter have better social relationships, their behaviour is better and they have fewer detentions. It’s not just about grades. Their emotional wellbeing is also enhanced.”

While reaping these benefits may appear to require the onerous task of ripping up the current timetable, Weiler stresses that he is not asking for a complete rethink, just a better structuring of the day to get kids fitter.

“I’m not saying do away with chairs,” he says. “What I am saying is we want everyone to take a look at their school day and make it a bit more active and a bit less sedentary.”

Weiler says that everyone would benefit from such a move and the long-term impact would be substantial.

“If people are more physically active, everyone that moves a little more stands to gain from that, if they can sustain it. What better opportunity than to start looking at this at schools when children are forming behaviours that will influence their health and wellbeing for the rest of their lives?”

Sarah Cunnane is deputy head of editorial content curation at Tes. She tweets @Sarah_Cunnane