Habitual Activity and Executive Function in Adolescents: Longitudinal Wearable Study

Across one academic year in secondary-school students, investigators reported that higher physical activity (steps/day) was associated with better performance on some executive-function measures, while sleep duration showed no significant main effects.

Using a consumer wearable (Fitbit Charge 6) to monitor habitual behaviors from September 2024 to June 2025, the authors described a pattern in which adolescents with higher usual step counts tended to perform better on select reaction-time and vigilance outcomes, whereas mean sleep time showed little alignment with task performance in adjusted analyses. Executive-function outcomes included inhibitory control, sustained attention, and working memory.

The study followed 168 Spanish adolescents aged 13–16 years and assessed them at baseline and again about 9 months later. Each wave included a 7-day wearable monitoring period and a standardized cognitive test session. The executive-function battery comprised the Stroop task, the Brief Psychomotor Vigilance Task (PVT-B), and the Paced Auditory Serial Addition Test (PASAT). Exposures were defined as average daily steps and average sleep duration over each 7-day window, and participants were assigned to High versus Low groups using sample-derived medians; these median-split step and sleep group definitions were held constant across both timepoints. Analyses related these habitual step and sleep averages to task performance across time.

For physical activity, the authors reported that linear mixed models showed a main effect of High versus Low activity for Stroop reaction time (p=0.007) and PVT-B lapses (p=0.014). In separate regression analyses treating steps as a continuous measure, higher daily steps were also reported to correlate with faster inhibitory-control reaction time on the Stroop task (r=−0.173, p=0.002). The paper summarized Cohen’s d values in an approximately 0.24–0.37 range to describe the magnitude of these between-group differences. Overall, these results were presented as modest, task-specific associations between habitual step volume and aspects of inhibitory-control speed and vigilance (reported linear mixed models and regression results).

For sleep duration, adjusted models did not show significant main effects of High versus Low sleep grouping across the executive-function outcomes (all p>0.05), as described by the authors. The report also described sensitivity analyses using clinically informed thresholds (≥10,000 steps/day and ≥8 h/night) and alternative models using continuous predictors, with findings characterized as convergent with the primary approach. In discussing interpretation limits, the authors noted that the observational design does not support causal inference and that the protocol did not include acute post-exercise neurophysiology measures or biomarker data such as circulating neurotrophic factors; they also highlighted an unexpected within–Low_PA subgroup pattern for inhibitory control.

Overall, the data were framed as reflecting habitual behavior patterns over months rather than cognition measured immediately after a workout.

Key Takeaways:

• Compared with the Low_PA group, the High_PA group was reported to have faster inhibitory-control reaction times (Stroop) and fewer sustained-attention lapses (PVT-B).
• Average sleep duration, when grouped and modeled as described, was reported not to show a significant main effect on executive-function outcomes in adjusted analyses.
• The study paired 7-day consumer-wearable monitoring with repeated executive-function testing, while explicitly noting that results are observational and do not address acute-exercise neurophysiology or biomarker responses.