Summary:
A longitudinal study tracking more than 5,500 American adolescents reveals that higher daily step counts directly correlate with fewer mental health issues one year later. Led by researchers at King’s College London and the University of Massachusetts Amherst, the investigation found no biological “ceiling” to these mental health gains: teens taking 12,000 or more steps daily displayed the fewest behavioral and emotional symptoms. Neuroimaging confirmed that adolescents with the highest step counts exhibited thicker cortical tissue in brain regions that govern movement and emotion regulation.
Key Facts:
- Dose-Dependent Protection Without a Plateau: Daily physical activity provided linear mental health benefits across the observed range. Adolescents taking fewer than 5,000 steps daily reported the highest rates of anxiety, depression, and behavioral issues, while those averaging 12,000 steps or more had the lowest.
- Cortical Thickness in Emotional Circuits: Adolescents with higher step counts displayed structural neuroplastic benefits, characterized by slightly thicker brain tissue within brain areas governing motor control and emotional regulation.
- No Elite Fitness Required: Incremental increases of just 1,000 to 2,000 steps daily from any baseline were associated with measurable improvements in brain structure and emotional resilience, independent of academic performance.
Source: King’s College London
Adolescence represents one of the most critical neurodevelopmental windows in the human lifespan. During this formative transition, the brain undergoes extensive synaptic pruning and structural remodeling, coinciding with an increased vulnerability to psychiatric conditions, including major depressive disorder, generalized anxiety, and behavioral dysregulation.
While physical fitness is widely recognized as a pillar of adult mental health, quantifying the direct developmental impact of habitual, everyday physical activity during the vulnerable early-teen window has historically relied on imprecise, self-reported questionnaires.
Now, a collaborative study led by the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London alongside the University of Massachusetts Amherst provides objective, longitudinal evidence that habitual daily walking actively shields developing minds.
Published using data from the expansive Adolescent Brain Cognitive Development (ABCD) Study, the research demonstrates that daily step count is directly tied to lower rates of anxiety, low mood, and behavioral difficulties in teenagers, while concurrently altering the structural thickness of key emotional centers in the brain.
“This study gives us some of the clearest evidence yet that even an everyday, low-cost, accessible measures of physical activity like daily step count is tied to how adolescent brains and mental health develop,” said senior author Divyangana Rakesh, Ph.D., Senior Lecturer in Neuroscience and Psychology at King’s College London. “What’s striking is that we don’t see this benefit levelling off in the observed range, even among the most active young people in our sample.”
Wearable Tracking Uncovers a Linear Benefit
To eliminate the recall bias common in youth physical activity research, the researchers evaluated 5,515 adolescents across 21 research sites in the United States. Participants wore research-grade Fitbit accelerometers for three continuous weeks around the ages of 11 to 12 to record baseline movement patterns.
One full year later, the team assessed participants’ psychological well-being using the validated Child Behavior Checklist (CBCL), a comprehensive diagnostic questionnaire completed by both the adolescents and their parents to screen for internalizing symptoms (such as social withdrawal, depression, and anxiety) and externalizing behavioral problems.
The behavioral results demonstrated a clear, inverse dose-response relationship:
- Sedentary Baseline (<5,000 steps/day): Youths averaging fewer than 5,000 daily steps exhibited the highest burden of psychological and behavioral symptoms at the one-year follow-up.
- Moderate Activity (~8,000 steps/day): Teenagers maintaining around 8,000 steps per day showed marked reductions in anxiety and mood symptoms.
- High Activity (≥12,000 steps/day): Adolescents hitting 12,000 steps or more demonstrated the best emotional resilience and fewest mental health complaints.
Crucially, the statistical association did not plateau, showing that every incremental step contributed to improved mental health scores. In contrast, physical activity levels showed no association with academic performance, demonstrating that the benefits were specific to emotional and behavioral health rather than cognitive schooling metrics.
Rewiring the Developing Brain
To determine the neurobiological mechanisms underlying these psychological gains, the investigators analyzed structural magnetic resonance imaging (MRI) brain scans from the ABCD cohort.
Adolescents who maintained the highest daily step counts showed measurably thicker cortical gray matter in two specific neural networks: brain regions dedicated to motor coordination and frontolimbic circuits responsible for top-down emotional regulation. Statistical mediation analysis indicated that these structural differences partially accounted for the link between walking and reduced depressive and anxious symptoms.
“We’re starting to understand parts of the brain that might be involved in the link between daily steps and young people’s mental health,” said lead author Qingyang Li of King’s College London. “It’s preliminary, but it gives us a clearer idea of where to look next.”
An Accessible, Non-Clinical Public Health Strategy
Because the ABCD Study is observational, the researchers acknowledge that the study cannot definitively prove direct causation. While the protective relationship remained robust after adjusting for pre-existing baseline mental health scores, the possibility remains that youth with better baseline psychological health are naturally inclined to move more.
Nevertheless, the findings underscore the therapeutic potential of accessible, everyday physical movement as a preventative mental health intervention.
“Adolescence is a key period for brain development and mental health, so it’s encouraging to see that physical activity’s benefits extend to both,” noted co-author Amanda Paluch, Ph.D., Associate Professor of Kinesiology at the University of Massachusetts Amherst.
“It is not an all-or-nothing situation. Adolescents don’t need to be elite athletes to benefit. 1,000 to 2,000 higher daily step increments, from any starting point, was associated with better brain structure and mental health outcomes, and that beneficial association keeps building from there,” added Dr. Paluch. “The goal is finding realistic, sustainable ways to move more, through everyday opportunities like walking to school, active play, and activities kids actually enjoy, so these benefits are accessible wherever an adolescent is starting from.”
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our 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 is Open Access: JAMA Network Open (Oct 1, 2026). “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 digitalization are contributing to reductions in the physical activity of adolescent individuals. Daily step count is an increasingly accessible and widely used metric for quantifying physical activity, yet little is known about how it is associated with mental health, academic performance, and brain health in adolescents.
Objective
To investigate the association of daily step count and future mental health and academic performance in adolescents, and whether differences in brain structure mediate these associations.
Design, Setting, and Participants
This cohort study used data from participants in the Adolescent Brain Cognitive Development (ABCD) Study (release 5.1), a large-scale, longitudinal investigation designed to comprehensively characterize psychological and neurobiological development from late childhood to adolescence. The ABCD Study was conducted across 21 sites across the US, providing a diverse and geographically distributed sample. Participants were adolescent individuals with valid daily step count data and usable neuroimaging data collected between November 2018 to November 2020. Data were analyzed from May 2025 to August 2026.
Exposure
Pedometer-based measurements of average daily step count over the previous 3 weeks.
Main Outcomes and Measures
Linear mixed models examined associations of daily step count with mental health, academic performance, and brain structure, and assessed how these associations varied between different step count categories. Using structural equation modeling, step-count–associated brain morphology was examined to determine whether it statistically mediated the association between physical activity and mental health, and/or academic outcomes 1 year later. Dose-response associations were also examined.
Results
This study included 5515 adolescent participants (2640 [47.9%] female; mean [SD] age 11.93 [0.65] years) using step counters. Higher step count was associated with lower total mental health problems (B [SE], −0.080 [0.015]; t = −5.497; P < .001) and greater cortical thickness in the paracentral (B [SE], 0.057 [0.016]; t = 3.621; P < .001) and rostral anterior cingulate (B[SE], 0.052 [0.016]; t = 3.319; P = .001) regions. Further analyses showed a significant dose-response association, with progressively lower mental health problems across higher step categories compared with the under 5000-step group. Mediation analyses revealed that greater paracentral thickness statistically mediated the association between higher daily step count and fewer mental health problems 1 year later.
Conclusions and Relevance
In this cohort study, higher daily step counts were associated with structural differences in the brains of adolescents, which were in turn associated with better mental outcomes prospectively. Beneficial associations for mental health appeared to accrue continuously across the observed range, with no evidence of a threshold or plateau, highlighting that every step counts and the potential value of promoting daily steps in adolescents.
