# Feasibility and efficacy of adding high-intensity interval training to a multidisciplinary lifestyle intervention in children with obesity-a randomized controlled trial PMID: 39390066 Journal: International journal of obesity (2005) Published: 2025 Feb Authors: Eggertsen CN, Larsen RG, Duch K, Simonsen MB, Christensen CB, Warner TC, Frøkjær JB, Handberg A, Stjernholm T, Vestergaard ET, Hagstrøm S ## Question Does adding a 12-week supervised HIIT program to a 12-month multidisciplinary lifestyle intervention improve BMI z-score, waist circumference, blood pressure, and health-related quality of life in children and adolescents with obesity, and is the program feasible? ## Summary This two-arm randomized controlled trial tested whether adding a 12-week community-based HIIT program to a 12-month multidisciplinary family lifestyle intervention improved outcomes in children and adolescents with obesity. HIIT did not add benefit for BMI z-score, waist circumference, or blood pressure versus lifestyle intervention alone, though the pooled cohort improved BMI z-score. HIIT improved child-reported quality of life at 3 months, was associated with lower dropout from the lifestyle intervention, and achieved 68% average attendance, but child-reported physical quality of life was lower in the HIIT group at 12 months after the exercise program ended. ## Population - Children and adolescents aged 9-16 years with obesity enrolled in Danish obesity treatment clinics. - Sample size: 173 - Age: Mean 12.3 +/- 1.7 years. - Sex: 101 boys and 72 girls; 58.4% male. - Health status: BMI above 90th percentile for age and sex; mean BMI z-score 2.5 +/- 0.6. ## Methodology - Two-arm randomized controlled trial comparing 12 months of TCOCT lifestyle intervention with or without a supplementary 12-week HIIT program. - 12 months total, with 12 weeks of HIIT in the intervention group and follow-up at 3 and 12 months. - Municipal obesity clinics, outpatient childhood obesity clinic, and local school facilities in Northern Denmark; HIIT was mostly indoor, with some outdoor sessions during COVID-19 restrictions. - Randomized and controlled study design. ## Protocol - TCOCT plus HIIT. - Modality: Playful group activities including strength-based exercise, ball games, and running games. - Work intervals: 4 minutes. - Recovery: 3 minutes active recovery. - Sets or repetitions: 4 bouts. - Intensity: Greater than 85% estimated HRmax target; actual average high-intensity time 8.7 +/- 4.8 minutes/session. - Session duration: 45-50 minutes prescribed; 47.5 +/- 10.5 minutes average. - Frequency: 3 sessions/week. - Program length: 12 weeks HIIT plus 12 months TCOCT. - Progression: Activities were regularly changed or adjusted to maintain interest and intensity. - TCOCT lifestyle intervention. - Modality: Family-based multidisciplinary lifestyle treatment. - Intensity: Physical activity recommendations included in lifestyle plan, but no structured exercise program. - Session duration: Follow-up visits every 6 to 12 weeks. - Frequency: Clinic follow-up every 6 to 12 weeks. - Program length: 12 months. - Progression: Individual treatment plan of 15-20 items adjusted to child and family needs. ## Outcomes ### BMI z-score Status: no clear change Adding HIIT did not further reduce BMI z-score compared with TCOCT alone, although BMI z-score improved across the pooled cohort. Between-group MD 0.01 at 3 months, 95% CI -0.09 to 0.12, p=0.82; MD 0.06 at 12 months, 95% CI -0.07 to 0.19, p=0.34. Pooled cohort change -0.11 at 3 months and -0.20 at 12 months, both p<0.01. ### Waist circumference Status: no clear change No significant between-group waist circumference benefit from HIIT. MD 1.34 cm at 3 months, 95% CI -1.58 to 4.26, p=0.37; MD 2.81 cm at 12 months, 95% CI -0.51 to 6.12, p=0.09. ### Blood pressure Status: no clear change No clinically relevant or significant between-group blood pressure effects were found. Systolic BP MD 0.05 mmHg at 3 months, p=0.97; -0.33 mmHg at 12 months, p=0.83. Diastolic BP MD -0.72 mmHg at 3 months, p=0.47; -0.51 mmHg at 12 months, p=0.66. ### Health-related quality of life at 3 months Status: improved HIIT improved child-reported PedsQL total and psychosocial scores more than control at 3 months. PedsQL child total MD 2.73, 95% CI 0.01 to 5.44, p=0.05; psychosocial MD 3.85, 95% CI 0.96 to 6.74, p=0.01. ### Health-related quality of life at 12 months Status: worse/safety concern At 12 months, child-reported physical score and parent-proxy physical score were lower in HIIT than control. PedsQL child physical MD -6.89, 95% CI -10.97 to -2.83, p<0.01; parent physical MD -5.04, 95% CI -9.53 to -0.56, p=0.03. ### Feasibility and adherence Status: improved HIIT attendance averaged 68%, 61.1% completed at least 70% of sessions, and dropout was lower than control at both 3 and 12 months. Attendance 68.0 +/- 23.2%; dropout HIIT vs control 7.8% vs 20.5% at 3 months and 25.5% vs 48.2% at 12 months. ## Practical Insights - For children with obesity, HIIT may be more useful as an engagement and quality-of-life support than as an add-on weight-loss lever. - Playful, non-competitive, varied movement formats are important pediatric HIIT design features. - A short supervised HIIT program needs a continuation plan; participants may struggle after the structured program ends. - App translation should keep pediatric HIIT claims bounded to supervised, family-supported contexts. ## Limitations - Sample size was below the planned 202 participants. - COVID-19 disrupted recruitment and intervention timing and may have decreased the intervention signal. - Some teams had delayed HIIT sessions and outdoor sessions because of restrictions. - The flexible activity approach may have reduced the intensity achieved during sessions. - No adverse-event details were reported in the main text. - No structured exercise comparator was included. ## Safety And Adherence - No adverse-event results were reported in the main text. - Children with physical limitations or mental illness that would complicate participation were excluded. - The HIIT intervention used trained in-person supervisors and continuous HR monitoring. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/39390066/) (pubmed) - [DOI](https://doi.org/10.1038/s41366-024-01645-w) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11805701/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.