Summary:
A large longitudinal study of more than 5,500 American adolescents found that higher daily step counts were linked to fewer mental health problems one year later. Conducted by teams at King’s College London and the University of Massachusetts Amherst using data from the Adolescent Brain Cognitive Development (ABCD) Study, the research shows a steady, dose-dependent benefit: teens who averaged 12,000 or more steps per day reported the fewest emotional and behavioral symptoms. Structural MRI analyses also showed that those with the highest step counts had modestly greater cortical thickness in brain regions involved in movement and emotion regulation.
Key Facts:
- Dose-dependent protection with no plateau: Mental health benefits increased progressively across the observed step range. Adolescents taking fewer than 5,000 steps per day had the highest rates of anxiety, depression, and behavioral problems, while those taking 12,000 or more steps daily had the lowest.
- Cortical thickness in emotional circuits: Higher daily step counts were associated with slightly thicker gray matter in networks related to motor control and frontolimbic emotional regulation.
- No elite fitness required: Small, realistic increases—1,000 to 2,000 extra steps per day—were linked to measurable improvements in brain structure and emotional resilience, independent of school performance.
Source: King’s College London
Adolescence is a sensitive neurodevelopmental stage when substantial synaptic pruning and structural remodeling take place. This period also coincides with an increased vulnerability to psychiatric disorders such as major depressive disorder, generalized anxiety, and behavioral dysregulation. While the mental benefits of exercise in adults are well known, objectively measuring how everyday physical activity affects the developing adolescent brain has been limited by reliance on self-report. This study uses wearable data to overcome that limitation.
Led by the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London with collaborators at the University of Massachusetts Amherst, the research used wearable accelerometer data and neuroimaging to assess whether habitual walking behavior predicts later mental health and brain structure in early adolescents.
Wearable tracking reveals a linear benefit
To avoid recall bias, researchers analyzed data from 5,515 adolescents across 21 U.S. research sites. Participants wore research-grade Fitbit accelerometers continuously for three weeks at baseline around ages 11–12 to record average daily steps. One year later, mental health outcomes were assessed using the standardized Child Behavior Checklist (CBCL), completed by adolescents and their parents to screen for internalizing symptoms (such as anxiety and depression) and externalizing behaviors.
Results showed a clear inverse dose-response relationship:
- Sedentary baseline (<5,000 steps/day): Adolescents with under 5,000 daily steps had the highest burden of psychological and behavioral symptoms at follow-up.
- Moderate activity (~8,000 steps/day): Those averaging around 8,000 steps daily experienced notable reductions in anxiety and mood symptoms.
- High activity (≥12,000 steps/day): Teens who reached 12,000 or more steps per day showed the lowest levels of mental health complaints and greatest emotional resilience.
Importantly, the association did not show a plateau within the observed range: each incremental increase in steps was associated with better mental health scores. The study found no link between step count and academic performance, suggesting the benefits were specific to emotional and behavioral health rather than school-related cognitive outcomes.
Neurobiological correlates: rewiring the developing brain
To explore possible mechanisms, the team examined structural MRI scans from the ABCD cohort. Adolescents with higher daily step counts had modestly greater cortical thickness in two networks: the paracentral region involved in motor control and the rostral anterior cingulate region linked to emotional regulation. Mediation analyses indicated that increased paracentral thickness partially explained the association between higher step counts and fewer depressive and anxiety symptoms one year later.
“These neuroimaging findings are preliminary but help identify brain regions that may play a role in how everyday physical activity supports mental health during adolescence,” said lead author Qingyang Li.
An accessible public-health approach
Because the ABCD Study is observational, causation cannot be definitively established. The associations remained robust after adjusting for baseline mental health, but it is still possible that adolescents with better initial psychological health are more active. Nevertheless, the results highlight the potential of simple, low-cost movement—like walking—to support mental health in young people.
“Adolescence is a crucial window for brain and mental health development,” said co-author Amanda Paluch. “You don’t need to be an elite athlete to benefit—small, sustainable increases in daily steps, such as walking to school or active play, were linked to better brain structure and mental health.”
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The full journal paper was reviewed.
- Additional context was added by staff.
About this neurodevelopment and mental health research:
- Media Contact: Francesca Greenstreet
- Source: King’s College London
- Image Credit: Image credited to Neuroscience News
- Original Research (Open Access): JAMA Network Open (Oct 1, 2026). Article title: “Physical Activity and Adolescent Brain Structure, Mental Health, and Academic Performance.” Authors: Qingyang Li, MSc; Amanda Paluch, PhD; Divyangana Rakesh, PhD.
- DOI: 10.1001/jamanetworkopen.2026.36973
Abstract
Physical Activity and Adolescent Brain Structure, Mental Health, and Academic Performance
Importance
Urbanization and increased screen time have contributed to declines in physical activity among adolescents. Daily step count is a widely accessible measure of movement, but its relationship with adolescent mental health, academic achievement, and brain structure has been unclear.
Objective
To examine whether average daily step count predicts future mental health and academic performance in adolescents, and to test whether differences in brain structure mediate those relationships.
Design, Setting, and Participants
This cohort study used release 5.1 of the Adolescent Brain Cognitive Development (ABCD) Study, a large longitudinal investigation of psychological and neurobiological development across 21 U.S. sites. Participants included adolescents with valid 3-week pedometer data and usable MRI scans collected between November 2018 and November 2020. Data were analyzed from May 2025 to August 2026.
Exposure
Average daily step count measured by research-grade pedometers over a three-week baseline period.
Main Outcomes and Measures
Linear mixed models assessed associations of daily steps with mental health, academic performance, and brain morphology, including dose-response patterns and mediation by brain structure using structural equation modeling.
Results
The study included 5,515 adolescents (47.9% female; mean age 11.93 years). Higher step counts were associated with fewer total mental health problems and greater cortical thickness in paracentral and rostral anterior cingulate regions. A dose-response pattern showed progressively lower mental health problems with higher step categories compared with the under-5,000-step group, and mediation analysis indicated that paracentral thickness partially mediated the link between steps and mental health one year later.
Conclusions and Relevance
In this cohort, higher daily step counts were associated with small but meaningful structural brain differences that related to better mental health outcomes prospectively. Benefits appeared to accumulate across the observed range without a clear threshold, underscoring the potential value of promoting daily steps as a practical public-health strategy for adolescents.