Children who exercise for at least one hour a day, get nine to 11 hours of sleep at night and spend two hours or less in front of screens return 'significantly higher' mental test scores.

The findings come from a study by Canada’s Healthy Active Living & Obesity Research Group, which charted a number of abilities – from children's memory and language skills to the ability to plan.

Published in the medical journal The Lancet, the cross-sectional observational study used data from Adolescent Brain Cognitive Development, a 10-year longitudinal, observational study on 4,524 US children aged 8–11 years.

It investigated the relationship between adherence to the Canadian 24-Hour Movement Guidelines for Children and Youth, which recommends at least 60 min physical activity per day, two hours or less recreational screen time per day, and 9–11 hours of sleep per night for children aged 8–11 years.

Overall, 51 per cent of participants met the sleep recommendation, 37 per cent met screen time, and 18 per cent met the physical activity recommendation. 71 per cent of participants met at least one recommendation, whereas 5 per cent of participants met all three recommendations.

Global cognition was positively associated with each additional recommendation met. In other words, the more recommendations the children met, the better their cognitive results.

The results follow on from a separate study by University of Bristol, which found that physical activity outside of school is vital for child health. The study suggests that efforts to increase exercise during the school day will not be enough for children to meet the recommended one hour of physical activity a day, set by the chief medical officer.

To download and read the full research article in The Lancet, click here