# Effects of two forms of school-based high-intensity interval training on body fat, blood pressure, and cardiorespiratory fitness in adolescents: randomized control trial with eight-week follow-up-the PEER-HEART study

PMID: 40265155
Journal: Frontiers in Physiology
Published: 2025
Authors: Domaradzki J, Popowczak M, Kochan-Jacheć K, Szkudlarek P, Murawska-Ciałowicz E, Koźlenia D

## Question

Do two school-based HIIT formats improve body fat, blood pressure, and cardiorespiratory fitness in adolescents, and are effects maintained after 8 weeks?

## Summary

This school randomized trial compared two 8-week PE-class HIIT variants in adolescents: bodyweight resistance-style HIIT and plyometric HIIT. Both variants used short Tabata-style rounds and were associated with favorable changes in body fat, blood pressure, and VO2max that were maintained 8 weeks later, though many between-group post-test contrasts were small or not significant.

## Population

- Healthy first-year high-school adolescents
- Sample size: 307
- Age: Approximately 15 years old
- Sex: Boys and girls
- Fitness level: General school population after excluding regular sports participation and contraindications
- Health status: Healthy adolescents without contraindications to exercise

## Methodology

- School-based randomized controlled trial
- 8-week intervention with 8-week follow-up
- High-school PE classes
- Randomized and controlled study design.

## Protocol

- School Tabata HIIT/HIPT.
- Modality: Bodyweight resistance or plyometric exercises.
- Work intervals: 20 seconds.
- Recovery: 10 seconds.
- Sets or repetitions: 4 rounds weeks 1-2, 6 rounds weeks 3-4, 8 rounds weeks 5-8.
- Intensity: All-out, target >=75% HRmax.
- Session duration: 10-minute warm-up plus Tabata rounds.
- Frequency: 2 sessions/week.
- Program length: 8 weeks.
- Progression: Increase rounds from 4 to 8.
- Standard PE.
- Modality: Usual physical education curriculum.
- Frequency: Regular PE classes.
- Program length: 8 weeks.

## Outcomes

### Health markers
Status: improved
Body fat, systolic and diastolic blood pressure, and VO2max changed favorably across the intervention period.

Significant time x variant x group interactions with small effects.

### Follow-up
Status: no clear change
Improvements were generally maintained at the 8-week follow-up.

No significant post-intervention to follow-up deterioration was reported (p>0.05).

### Safety
Status: no clear change
No adverse effects were observed.

Descriptive safety reporting.

## Practical Insights

- A 20:10 Tabata format with round-count progression is highly translatable to bodyweight app programming.
- Heart-rate targets can be used to verify that short sessions are actually vigorous.
- Low-impact alternatives are needed for users who should avoid plyometrics.

## Limitations

- Adolescent school sample.
- Supervised PE context.
- Small effects and some non-significant post hoc contrasts.
- Low-attendance participants were excluded from final analysis.

## Safety And Adherence

- No adverse effects were observed.
- Students with contraindications to exercise were excluded.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/40265155/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2025.1530195) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12011756/) (full text)

## Agent Guidance

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