0259 The Role of Sleep Within the 24-Hour Activity Cycle in Executive Functioning Across Childhood and Young Adulthood ADHD

Abstract Introduction Attention-Deficit/Hyperactivity Disorder (ADHD), marked by executive dysfunction, is often diagnosed in childhood and persists into adulthood. Components of the 24-hour activity cycle (24-HAC), including sleep, sedentary behavior (SB), and physical activity (PA), are modifiable factors that may improve executive function. However, little research has examined how these behaviors interact and which combinations benefit individuals with ADHD, despite this developmental stage being pivotal for healthy habit formation. This study examines associations between the 24-HAC and executive dysfunction in children and young adults with ADHD. Methods 46 children (10.65±2.79 years) and 51 young adults (22.04±2.95 years) with ADHD participated in a cross-sectional design. Assessments included demographics (age, sex, parent income) and body mass index (BMI). Awake behaviors were obtained via 7-day wrist-worn accelerometry and averaged for school-days and weekends (light PA LPA, moderate-to-vigorous PA MVPA, and SB). Sleep duration was self-reported using logs and the Pittsburgh Sleep Quality Index. Executive dysfunction was measured via the Behavior Rating Inventory of Executive Function, with parent-report for children (BRIEF-2) and self-report for young adults (BRIEF-A). Compositional Data Analysis predicted changes in executive dysfunction based on 60-minute reallocations between 24-HAC behaviors, using isometric log-ratio transformation and adjusting for age, sex, BMI, and parent income with 95% confidence intervals. Results In children, reallocating a total of 60 minutes from sleep to LPA and MVPA in proportion to relative balance during school-days reflected less dysfunction for emotional control (β=-0.43, p=0.04). Additionally, decreasing 60 minutes of weekend sleep predicted less dysfunction in emotional control among children (β=-0.65, p=0.03). In young adults, reallocating LPA and MVPA to sleep and SB during school-days was associated with less dysfunction of shifting regulation (β=-0.43, p=0.01). Conclusion Reallocating time from sleep toward PA on both school-days and weekends may support emotional regulation for children with ADHD, while increasing sleep on school-days may benefit cognitive flexibility in young adults with ADHD. The present study reflects a shift toward restorative behaviors rather than SB time alone, highlighting the dynamic role of sleep and PA for supporting executive functioning across developmental stages in ADHD-related difficulties. Support (if any) Rhode Island Foundation Medical Research Grant