Similar Health Benefits of Endurance and High-Intensity Interval Training in Obese Children
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.
Methodology
- Physically inactive obese outpatient children aged 8-12 years recruited from a university hospital obesity clinic in Sao Paulo, Brazil.
- 30 participants.
- Walking/running on treadmill.
- Work intervals: 60 seconds at 100% of peak velocity.
- Recovery: 3 minutes active recovery at 50% of exercise velocity.
- Intensity: 100% of peak velocity from maximal graded cardiorespiratory test.
- Approximately 9 to 21 minutes including active recoveries, depending on 3 to 6 bouts; about 70% less time than ET.
- 2 sessions per week on alternate days.
- 12 weeks.
- Randomized two-arm exercise training trial comparing continuous endurance training with treadmill high-intensity interval training.
- VO2peak, Time-to-exhaustion and peak velocity, Insulinemia and HOMA-index, and Body composition and BMI were tracked.
Outcomes
Aerobic fitness
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
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
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
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
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
No clinical evidence of excessive exhaustion, pain, osteoarticular injury, muscle soreness, or other adverse event was noticed.
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
- Weekly medical examination found no clinical evidence of excessive exhaustion, pain, osteoarticular injury, muscle soreness, or any other adverse event.