# Similar Health Benefits of Endurance and High-Intensity Interval Training in Obese Children PMID: 22880097 Journal: PLOS ONE Published: 2012-08-06 Authors: Corte de Araujo AC, Roschel H, Picanço AR, do Prado DM, Villares SM, de Sá Pinto AL, Gualano B ## Question Do endurance training and high-intensity interval training produce different health-related effects in physically inactive obese children aged 8-12 years? ## Summary This randomized 12 week trial compared treadmill endurance training with high-intensity interval training in obese children aged 8-12 years. Both groups improved aerobic fitness, exercise test performance, insulin, HOMA-IR, and BMI. The HIT group trained for much less time and also showed within-group reductions in body weight and systolic blood pressure. No adverse events were detected by weekly medical examination. ## Population - Physically inactive obese outpatient children aged 8-12 years recruited from a university hospital obesity clinic in Sao Paulo, Brazil. - Sample size: 30 - Age: ET 10.4 (0.9) years; HIT 10.7 (0.7) years. - Sex: ET 11 female and 4 male; HIT 10 female and 5 male. - Fitness level: Physically inactive except school physical education twice weekly; baseline maximal treadmill testing used for training prescription. - Health status: Obese, BMI at or above 95th percentile; no metabolic, hormonal, orthopedic, or cardiovascular disease at commencement. ## Methodology - Randomized two-arm exercise training trial comparing continuous endurance training with treadmill high-intensity interval training. - 12 weeks. - Exercise training on treadmills in a clinical/research setting associated with the University of Sao Paulo obesity clinic. - Randomized and controlled study design. ## Protocol - Treadmill HIT. - Modality: Walking/running on treadmill. - Work intervals: 60 seconds at 100% of peak velocity. - Recovery: 3 minutes active recovery at 50% of exercise velocity. - Sets or repetitions: 3 to 6 efforts. - Intensity: 100% of peak velocity from maximal graded cardiorespiratory test. - Session duration: Approximately 9 to 21 minutes including active recoveries, depending on 3 to 6 bouts; about 70% less time than ET. - Frequency: 2 sessions per week on alternate days. - Program length: 12 weeks. - Progression: Added one bout every three weeks; maximal graded test repeated after 6 weeks to adjust intensity. - Continuous endurance training. - Modality: Walking/running on treadmill. - Work intervals: Continuous exercise. - Sets or repetitions: One continuous bout. - Intensity: 80% of peak heart rate. - Session duration: 30 minutes initially, increasing by 10 minutes every three weeks to 60 minutes during weeks 10-12. - Frequency: 2 sessions per week on alternate days. - Program length: 12 weeks. - Progression: Duration increased by 10 minutes every three weeks. ## Outcomes ### Aerobic fitness Status: improved Absolute and relative VO2peak increased significantly in both ET and HIT, with similar response patterns. Absolute VO2peak: ET +26.0%, HIT +19.0%; relative VO2peak: ET +13.1%, HIT +14.6%; within-group p<0.05 in figures/table ranking. ### Exercise test performance Status: improved Total exercise time and peak velocity improved across interventions. Total exercise time: ET +19.5%, HIT +16.4%; peak velocity: ET +16.9%, HIT +13.4%. ### Insulin resistance markers Status: improved Insulinemia and HOMA-index were significantly lower after both ET and HIT. Insulinemia: ET -29.4%, p=0.008; HIT -30.5%, p=0.010. HOMA-index: ET -42.8%, p=0.006; HIT -37.0%, p=0.002. ### Body mass and BMI Status: mixed BMI decreased significantly in both groups; body mass decreased significantly only in the HIT group; fat mass measures did not significantly change. BMI: ET p=0.003, HIT p=0.0001. Body mass: HIT p=0.030; ET p=0.600. Fat mass percentage non-significant in both groups. ### Blood pressure Status: mixed Systolic blood pressure decreased significantly within the HIT group but not ET; DBP did not significantly change in either group. HIT SBP 115 (10) to 106 (10), p=0.020, ES=-0.896; ET SBP p=0.400. DBP ET p=0.140; HIT p=0.330. ### Safety Status: no clear change No clinical evidence of excessive exhaustion, pain, osteoarticular injury, muscle soreness, or other adverse event was noticed. ## Practical Insights - For obese children under supervision, treadmill HIT can produce similar short-term aerobic and insulin-sensitivity benefits to longer endurance training. - A 1 minute hard / 3 minute active recovery format can be progressed by adding bouts every three weeks. - Time efficiency does not mean lower monitoring needs; this study used clinical screening, supervised treadmills, HR monitoring, and weekly medical checks. ## Limitations - No non-exercise control group. - Small analyzed sample of 15 per group. - Short-term 12 week intervention with no long-term safety or efficacy follow-up. - No dietetic prescription or psychological therapy, limiting conclusions about multidisciplinary obesity treatment. - Treadmill and maximal testing requirements limit direct translation to app-based bodyweight HIIT. ## Safety And Adherence - Weekly medical examination found no clinical evidence of excessive exhaustion, pain, osteoarticular injury, muscle soreness, or any other adverse event. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/22880097/) (pubmed) - [DOI](https://doi.org/10.1371/journal.pone.0042747) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3412799/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.