Walking more in adolescence linked to better mental health and brain development

A new study indicates that increasing daily steps through routine activities like walking to school and playing outdoors may boost teenage mental health and brain development, with no apparent plateau at higher activity levels.

A large new study suggests that something as ordinary as walking to school, playing in the park or running errands on foot may be linked to better mental health in the teenage years. Researchers working between King’s College London and the University of Massachusetts Amherst followed 5,515 adolescents in the US Adolescent Brain Cognitive Development Study and found that those who took more daily steps tended to have fewer mental health problems a year later.

The teenagers wore Fitbit devices for three weeks when they were about 11 or 12 years old. A year on, researchers assessed their mental health with the Child Behavior Checklist, a standard questionnaire completed by young people and parents that looks for signs of anxiety, low mood and behavioural difficulties. The pattern was clear: adolescents taking fewer than 5,000 steps a day had the most symptoms, those averaging around 8,000 had fewer, and those reaching 12,000 or more had the lowest levels overall. The study also found that young people with the highest step counts had slightly thicker brain tissue in two areas involved in movement and emotional regulation, which appeared to explain part of the association.

Qingyang Li, the study’s lead author, said the findings offer some of the strongest evidence yet that a simple, low-cost form of physical activity is tied to adolescent brain and mental health development. Divyangana Rakesh, senior author and a senior lecturer at King’s College London, said the benefit did not appear to level off within the range measured, even among the most active teenagers. Amanda Paluch, an associate professor of kinesiology at the University of Massachusetts Amherst, said the message was not that young people need to become elite athletes, but that small increases in daily movement can matter, particularly when they are built into normal routines such as walking to school or active play.

The findings fit into a wider body of King’s College London research on adolescent brain development and mental health, including work on early adversity, psychosis-related brain activity and brain connectivity in young people. But the new study remains observational, which means it cannot prove that walking more directly improves mental health. The researchers did take account of earlier mental health problems, yet they said it is still possible that teenagers with fewer difficulties were simply more active to begin with. The brain differences were modest, and relatively few participants recorded extremely high step counts, so it is not yet clear whether the pattern continues beyond the range measured in this study.