How many steps should a child do a day? The NHS does not set a step target, but it advises children and young people aged 5–18 to average at least 60 minutes of moderate or vigorous activity a day. In this new study, more steps went with fewer mental health problems, with no clear upper limit.
About four in five adolescents worldwide fall short of recommended activity levels. New research suggests that ordinary walking, counted step by step, is tied to how young teenagers feel a year later.
In a study led by King’s College London with the University of Massachusetts Amherst, researchers analysed data from 5,515 young people in the US Adolescent Brain Cognitive Development Study. The findings appear in JAMA Network Open. Participants, aged about 12 on average, wore Fitbit trackers for three weeks to measure their usual daily steps.
Dr Divyangana Rakesh, senior lecturer at King’s College London, said: “We wanted to provide evidence that could inform practical physical activity advice for children and families. Much of the existing research focuses on moderate-to-vigorous physical activity, so we explored daily steps (a simple, accessible measure of movement) and their relationship with mental health and brain structure”.
A year later, the young people completed a short questionnaire on worry, low mood, behaviour, and attention. Brain scans taken around the time of step tracking measured the thickness and size of different brain regions. The analysis allowed for family income, parental education, neighbourhood deprivation, green space, and body weight.
Teenagers who took more steps reported fewer mental health problems a year later, even after allowing for their earlier mental health. Compared with those taking under 5,000 steps a day, every higher band did better, and those taking 12,000 or more had the fewest problems. There was no point at which extra steps stopped making a difference.
More active teenagers also had slightly thicker tissue in two areas of the brain’s outer layer: the paracentral region, which helps control the legs, and the rostral anterior cingulate, which helps handle conflicting information. Put simply, their brains looked a little different, and the paracentral difference accounted for a small part of the link with mental health.
Step counts were not linked to school grades a year later. The researchers suggest that grades may depend more on harder exercise, teaching, and many other factors than on everyday walking.
The study has clear limits. It was observational, so it cannot prove that walking causes better mental health, and teenagers who already felt better may simply have moved more. The brain differences were small, mental health was self-reported, the young people were all from the US, and those included came from somewhat better-off families. Step counters also miss much of what happens in organised sport and free play.
Looking ahead, Rakesh said: “If we were to conduct follow-up research, we would consider longitudinal studies that would help us establish causal relationships as well as explore whether daily steps are associated with brain development over time”.
For parents, the practical message is modest and encouraging. Walking to school, taking the dog out, or a kickabout in the park all add steps without the cost of a sports club. Because the link grew steadily, small increases may be easier to aim for than one big target.
On what it means for families, Rakesh added: “Being active does not only have to mean going to the gym or doing intense exercise. The key takeaway is to move more and stay active in daily life”.
The work adds a UK-led voice to research on exercise and social anxiety in teenagers and on how everyday habits relate to teenage mental health around the world.
Young teenagers who took more daily steps reported fewer mental health problems a year later, with no clear upper limit.
