Imagine there is an intervention that has the potential to raise the attainment of every child in your school. This approach costs relatively little, but has the power to instantly enhance pupils’ focus, memory and problem-solving skills.

As an added bonus, it will boost their emotional regulation and may relieve feelings of anxiety and depression in those suffering from poor mental health. Oh, and it will also help children to live longer.

This sounds like a fantasy, but such an intervention already exists: exercise.

Research has shown that increasing young people’s physical activity has broad benefits for their physical and mental health, as well as their academic performance, yet its potential is often neglected.

As Tes recently reported, the time dedicated to PE has seen a steady decline over the past decade. In 2011-12, the total number of hours of PE and sports taught in state secondary schools was 326,277. By 2024-25, that figure had dropped to 281,291, perhaps due to an increased focus on “core” subjects. School breaktimes - an important opportunity for playful exercise - have been subjected to a similar erosion to allow more teaching time.

It’s a shift that the charity Youth Sport Trust draws attention to in their annual report, which was published last week. Commenting on the decline of PE in secondary schools, the charity’s chief executive Ali Oliver said that society risks “failing a generation” if these “damaging trends” are not reversed.

In the wake of these trends, many researchers argue that it’s time to seriously rethink our approach to fitness in schools, with new interventions to increase physical activity being introduced throughout the school day.

But what would that shift look like in practice? And what would the implications of it be, within an already squeezed curriculum?

A global perspective

Physical inactivity in children and adolescents is a global problem, although its magnitude depends on which recommendations you follow. According to the World Health Organization’s 2010 guidelines, five- to 17-year-olds should accumulate at least 60 minutes of moderate-to-vigorous exercise every day. This includes any pursuit that raises their heart rate, breathing and body temperature - such as brisk walking, cycling, swimming or dancing.

According to these criteria, the vast majority of young people across the world - around 80 per cent - fail to make the grade.

“The UK falls in line with that estimate,” says Esther van Sluijs, an epidemiologist at the University of Cambridge’s School of Medicine, who published a review of the evidence in The Lancet in 2021. The WHO has recently softened its guidelines, however, so the recommended physical activity is now an average of 60 minutes a day, rather than 60 minutes each day, every day.

“This means it’s OK to be a ‘weekend warrior’, with three hours on the Saturday and four hours on the Sunday,” says Regina Guthold, a scientist at the WHO’s Department for Maternal, Newborn, Child and Adolescent Health and Ageing. The result is a slightly more optimistic picture. “But it would still be between 50 and 60 per cent [of children or adolescents] who do not meet the easier recommendations,” she estimates.

(If these recommendations are making you - as an adult - feel lazy, it’s worth noting that the guidelines for people aged 18-65 years are less stringent. We should be aiming for around 2.5 hours a week - which can itself be hard to fit into a busy schedule.)

‘Exercise is - quite literally - helping the child or adolescent to build a better brain’

As for the consequences of young people not meeting their daily exercise requirements, the most obvious relate to their bodily health. Frequent movement burns calories and therefore reduces the risk of obesity. It also encourages the development of strong bones and muscles, and improves blood circulation throughout the body - potentially meaning lower blood pressure and cholesterol.

As you might expect, someone who is in much better condition at the start of adulthood will be less likely to experience problems like diabetes or cardiovascular disease later in life than someone who was already developing the early markers of illness before they’d finished education.

Just as importantly, however, exercise in adolescence predicts physical activity in later life.

“There’s very good evidence that physical activity tracks from adolescence into adulthood,” says van Sluijs. “That doesn’t necessarily mean that you maintain the same level of activity, but you maintain your position within the group. So if, as an adolescent, you are among the more active ones, you are far more likely to be among the more active adults 10 to 15 years later.”

Healthy body, healthy mind?

Exercise’s effects on mental health are slightly more complicated.

“The evidence is quite clear that physical activity is beneficial for adolescents who already have depression or anxiety,” van Sluijs says. It may not, however, be enough to prevent those disorders from developing in the first place.

Norway’s School in Motion project helps to demonstrate this. A few years ago, Andreas Åvitsland, an associate professor in education and sports science at the University of Stavanger, recruited around 2,000 participants from 29 secondary schools. Around a third continued their education as normal, while the rest were given more opportunity to engage in physical activities throughout their school timetable - amounting to an hour or so extra each week.

The intervention tended to bring the greatest benefits for those who were already suffering from poor mental health, and did little to improve the emotional wellbeing of the average pupil.

What appears to be more universal, though, is the power of exercise to enhance cognitive performance: exercising the body brings great benefits for the constellation of mental abilities, such as memory, focus and problem solving, that together constitute “intelligence”.

Various experiments over the past few years have tested whether physical activity can enhance young people’s IQs - with most revealing a positive effect. Analysing 14 randomised controlled trials covering more than 3,000 children and adolescents, Javier Morales at the University of Cádiz and colleagues found that increased exercise could boost IQ scores by around four points - a small but significant improvement.

Further studies have demonstrated enhanced “executive function”, which includes mental focus; working memory (someone’s capacity to juggle information in the short term); and cognitive flexibility, which is the ability to adjust thinking and behaviour in the face of new demands.

‘Physical activity can be a tool for attentional reset’

Multiple biological pathways may lie behind the exercise-driven brain boost. One is enhanced blood flow. The brain is one of our hungriest organs, and any improvements to its circulation ensures that it receives enough oxygen and glucose to function well.

Such effects can be seen in the short term, since a single bout of exercise will lead the heart to pump more blood to the brain, resulting in sharper thinking over the following hour. In the long term, regular exercise can trigger the growth of new capillaries - a process called angiogenesis - in the brain that will ensure more efficient delivery of its fuel throughout the day and night.

The second and third pathways are neurogenesis and synaptogenesis - which refer to the growth of new brain cells and the junctions between them. Exercise is - quite literally - helping the child or adolescent to build a better brain. These changes appear to come from the release of a chemical called brain-derived neurotropic factor (BDNF). If the brain were a garden, then BDNF is the fertiliser that helps its neural connections to branch and bloom.

Consider a small trial by Yong Kyun Jeon at Dankook University in South Korea and Chang Ho Ha at Texas A&M University in the US. The researchers recruited 40 male students from a middle school in Yongin City, who were randomly assigned to different exercise regimes of varying intensity for 12 weeks. At the start and end of this period, the scientists drew small samples of the participants’ blood and asked them to take an assessment of working memory that involved recalling a string of digits.

The students engaging in regular moderate-to-high-intensity workouts each week showed elevated levels of BDNF in their blood, and this was accompanied by an improvement in their working memory. Jeon and Ha conclude that “a strong case is developing” for introducing new exercise regimes for adolescents, “as this is a significant period in which physical development, learning and cognitive ability can likely be enhanced”.

If nothing else, exercise during the day can break someone out of lethargy and has the potential to calm problematic behaviour in the classroom. “Physical activity can be a tool for attentional reset,” says Anna Chalkley, a senior research fellow at the University of Bradford.

The combined effects of these cognitive enhancements are evident in overall academic performance. Around a decade ago, researchers from Harvard University and the New York City Department of Health and Mental Hygiene examined data from 83,111 middle school students between the 2006-07 and 2011-12 academic years.

The students were all part of the “NYC FITNESSGRAM” project, which included annual measures of aerobic capacity during a run, as well as muscle strength and endurance in push-ups and curl-ups.

As the children and adolescents marched through their education, the researchers observed a clear correlation between changes in their fitness and their grades in English and mathematics. The effects went both ways: an increase in physical fitness was associated with better performance, while a decrease in physical fitness came with poorer marks.

The academic benefits of greater fitness were most pronounced in the students from poorer backgrounds. This may be because the richer families had greater material resources to support their children’s education, which had the power to uncouple the link between physical activity, cognitive ability and academic performance. Impaired concentration may be less important, for instance, if your parents can pay for a private tutor to repeat all the lessons that you missed. Those from less advantaged families, in contrast, would be unable to rely on external help.

Barriers to exercise

Such findings are particularly concerning, given that children with a low household income are even less likely to meet the weekly recommendations for exercise than their richer peers. “People from poorer socioeconomic backgrounds have more barriers to being physically active,” says Chalkley. “And that gap has been growing over the past decade.”

The cause of this inequality is multifactorial. Many families simply cannot afford to pay for extracurricular activities, such as judo or dance classes, that encourage exercise. The exercise gap between rich and poor may also be linked to the home environment and the local neighbourhood: whether the family has a garden, and if the local streets and parks are safe for outdoor play.

Walking or cycling to school can be an excellent way to increase a child’s physical activity - but that may not be practical if they will have to cross a series of busy roads each morning and evening.

For these reasons, van Sluijs believes we need a “system-wide approach” that attempts to address the many barriers to exercise - though she stresses that schools can be one part of the solution. So, what might that look like?

Movement mastery

In her review for The Lancet, van Sluijs found that certain educational approaches to enhancing physical activity are considerably more effective than others. For instance, children and adolescents are more likely to develop good habits if PE lessons focus on “mastery”.

“It’s about developing skills and competence, as opposed to competition,” van Sluijs says. There’s nothing wrong with a little competitive spirit in after-school clubs, of course - but these initiatives tend to be more effective if they include matches and tournaments within each school, rather than between them, since that allows more students to take part rather than limiting involvement to a small group of elite athletes.

Movement should not be limited to PE lessons and after-school clubs, however; researchers stress that it can be incorporated across the curriculum through “physically active learning”. In mathematics, for example, the class might go out into the playground and enact calculations involving physical distances - or, during a quiz, they might jump up or sit down to signal whether a fact is true or false.

“Physically active learning helps to connect the body and the mind,” says Chalkley.

Incorporating activities like those mentioned above wouldn’t require teachers to make extra space in already packed timetables, or completely overhaul their lesson plans; it would simply require a change in mindset and a lack of opposition from senior leadership teams.

A cultural shift

The benefits of physically active learning are not to be underestimated, though. Indeed, the evidence is stark. Emma Norris, a lecturer in public health at Brunel University, and colleagues recently analysed the results of 42 studies trialling this approach in primary and secondary education across the world. As you would hope, it improved the students’ physical activity, but also resulted in better memory and understanding of the lessons’ concepts.

In an ideal world, of course, it wouldn’t be just one or two teachers leading the charge on making learning more active. What many researchers would like to see is a more widespread cultural shift in schools.

“We see really positive changes when these interventions align with school values,” says van Sluijs.

As part of that, members of school staff can be encouraged to model the right attitude by becoming more physically active themselves - for their own good as well as that of their students.

That doesn’t mean lecturing teachers or mandating that they participate in movement-based “enforced fun”, but that leaders should perhaps consider whether they are doing enough to enable staff to prioritise their own physical wellbeing.

As headteacher Emma Jones previously told Tes, something as simple as encouraging teachers to “get off site at lunchtime and take a 10-minute walk” - and, crucially, ensuring that they are free to do this - could make all the difference.

David Robson is an award-winning science writer. His latest book, The Laws of Connection: 13 Social Strategies that Will Transform Your Life (Canongate), is out now

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