# High-Intensity Interval Training in Female Adolescents with Moderate or Severe Obesity

PMID: 37761456
Journal: Children (Basel, Switzerland)
Published: 2023 Sep 1
Authors: Racil G, Russo L, Migliaccio GM, Signorelli P, Larion A, Padulo J, Jlid MC

## Question

Do 12 weeks of high-intensity versus moderate-intensity interval cycling produce different anthropometric and biological effects in adolescent girls with moderate or severe obesity?

## Summary

This randomized stratified trial compared moderate- and high-intensity interval cycling in 57 adolescent girls with moderate or severe obesity. All groups improved body-composition measures and insulin resistance, while the high-intensity groups showed larger insulin and HOMA-IR reductions and increased lean body mass. The moderate-obesity HIIT group had the strongest body-fat, growth hormone, and glucose responses.

## Population

- Adolescent girls with moderate or severe obesity, BMI >=97th percentile and body fat >=30%.
- Sample size: 57
- Age: 16.4 +/- 0.8 years.
- Sex: All female.
- Fitness level: No systematic exercise beyond two hours of school PE in the prior three months.
- Health status: Moderate or severe obesity without reported lower-body injury, medical, cardiovascular, or orthopedic dysfunction.

## Methodology

- Randomized stratified 2 x 2 intervention trial by obesity class and training intensity.
- 12 weeks with pre- and post-intervention testing.
- School/pediatric recruitment with supervised laboratory cycle-ergometer training.
- Randomized and controlled study design.

## Protocol

- HIIT cycling for adolescent girls with obesity.
- Modality: Cycle ergometer.
- Work intervals: 1 minute.
- Recovery: 2 minutes active recovery at 50% HR reserve; 4 minutes free pedaling between sets.
- Sets or repetitions: 2 x 4 intervals in weeks 1-4; 2 x 5 intervals in weeks 5-12.
- Intensity: 85% HR reserve in weeks 1-4, 90% in weeks 5-8, 95% in weeks 9-12.
- Session duration: About 35-41 minutes including warm-up, intervals, between-set recovery, and cooldown.
- Frequency: 3 sessions/week.
- Program length: 12 weeks.
- Progression: Intensity increased by 5% HR reserve after each 4-week block and interval count increased after week 4.
- MIIT cycling.
- Modality: Cycle ergometer.
- Work intervals: 1 minute.
- Recovery: 2 minutes active recovery at 50% HR reserve; 4 minutes free pedaling between sets.
- Sets or repetitions: 2 x 4 intervals in weeks 1-4; 2 x 5 intervals in weeks 5-12.
- Intensity: 65% HR reserve in weeks 1-4, 70% in weeks 5-8, 75% in weeks 9-12.
- Session duration: About 35-41 minutes including warm-up, intervals, between-set recovery, and cooldown.
- Frequency: 3 sessions/week.
- Program length: 12 weeks.
- Progression: Intensity increased by 5% HR reserve after each 4-week block and interval count increased after week 4.

## Outcomes

### Anthropometry
Status: improved
All four groups reduced body mass, BMI, body fat percentage, and waist circumference; moderate-obesity HIIT had the largest percentage changes.

Post-intervention reductions p<0.05, most pronounced in MOG HI with p<0.01 and body fat change -7.52%.

### Lean body mass
Status: improved
Only the HIIT groups significantly increased lean body mass.

MOG HI and SOG HI p<0.05.

### Insulin and HOMA-IR
Status: improved
All groups improved insulin and HOMA-IR, with the largest reductions in HIIT groups.

Insulin changes: MOG HI -25.49%, SOG HI -25.34%; HOMA-IR: MOG HI -31.42%, SOG HI -28.88%; HIIT reductions p<0.01.

### Growth hormone and glucose
Status: mixed
Only the moderate-obesity HIIT group significantly improved growth hormone and blood glucose.

MOG HI GH and glucose p<0.05; GH correlated with body fat r=-0.76 and waist circumference r=-0.77; glucose correlated with body fat r=-0.72 and waist r=-0.82.

### Blood lactate
Status: improved
Both HIIT groups significantly decreased blood lactate values.

MOG HI ES=0.56 and SOG HI ES=0.61; both p<0.05.

## Practical Insights

- For adolescent obesity, HIIT intensity progression may matter for insulin-resistance outcomes.
- Moderate and severe obesity groups may respond differently; severe obesity may need extra tolerance planning.
- HR reserve prescription and screening are central to this protocol.

## Limitations

- Female-only sample.
- No non-exercise control group.
- Diet was not monitored daily during the intervention.
- Growth hormone was not measured at multiple times throughout the day.
- No detailed adverse-event reporting.

## Safety And Adherence

- Five initial candidates were excluded after safety/familiarization testing.
- Lower-body injury and cardiovascular/orthopedic dysfunction were exclusion criteria.
- No training adverse events were reported.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/37761456/) (pubmed)
- [DOI](https://doi.org/10.3390/children10091495) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10528164/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.