0009 Feasibility of the Iheartrhythm Intervention: A Circadian Health Intervention for the Prevention of Accelerated Summer Weight Gain

Abstract Introduction Around 20% of children began a trajectory toward overweight or obesity during early elementary school (ages 5-8). The transition from structured school routines to the less consistent summer period commonly disrupts children’s daily routines, impairing metabolic regulation and contributing to weight gain. Yet, no evidence-based interventions address behavioral rhythms to prevent summer BMI increases in children. Further, engaging families during summer is challenging, making mHealth a promising solution. This study examined the feasibility of i♥rhythm, an mHealth intervention designed to reduce BMI gains in children. Methods In this randomized controlled trial, parents and their 5-8-year-old children with BMI > 50th percentile were recruited. A sample of 46 children (63% female, 52% White, 50% Hispanic) was randomly allocated to the intervention group (n=23) or the control group (n=23). The 5-week i♥rhythm intervention topics include consistent bedtimes, optimal light exposure, physical activity, timing of the last meal of the day, and maintenance planning. Data was collected at four time points over one year: baseline (B0, Spring), post-intervention (P1, Summer), nine months post-intervention (P2, Spring), and 12 months post-intervention (P3, Summer). Descriptive statistics of recruitment goals, intervention fidelity, intervention adherence (no. of intervention sessions completed), and retention were computed. Results Overall, we recruited 46 participants (recruitment criteria: n=40). Across the intervention group, 78% of the diaries were completed, and 82% had a diary completion level greater than 60% (criteria: 60%). Eighty-nine percent of the intervention sessions were watched in their entirety, with an average of 4.8 out of 5 intervention sessions (criteria 80%). Participant retention was 98% (45/46) at P1, 89% (41/46) at P2 and P3 (criteria: P1: 80% and P3: 60%). While salivary dim light melatonin sample were obtained on all participants that were retained at each time point, DLMO could be calculated for 93.48% (43/46) at B0, 85.4% (35/41) at P1, 75.6% (31/41) at P2, 82.9% (34/41) at P3, respectively. Conclusion The mHealth i♥rhythm intervention trial was found to be feasible for parents and children aged 5-8 years. Future studies may consider enhancing biofeedback with wearable data and providing personalized real-time feedback. Sample sizes should account for potential missing DLMO data. Support (if any) R00HD091396