# Effectiveness of high intensity and sprint interval training on metabolic biomarkers, body composition, and physical fitness in adolescents: randomized controlled trial

PMID: 39157534
Journal: Frontiers in public health
Published: 2024
Authors: González-Gálvez N, López-Gil JF, Espeso-Garcia A, Abenza-Cano L, Mateo-Orcajada A, Vaquero-Cristóbal R

## Question

What are the effects of school-based HIIT and SIT on adolescent body composition, blood pressure, lipids, glucose, cardiorespiratory fitness, and strength, and do the two protocols differ?

## Summary

In a Spanish secondary-school randomized trial, adolescents completed either SIT, HIIT, or regular physical education for 8 weeks. Both interval programs improved body composition and strength markers, but the 3 x 2 min HIIT protocol produced broader benefits than the 6 x 1 min SIT protocol, including improvements in blood pressure, heart rate, and estimated VO2max. The study was school-relevant but had attrition and a final analyzed sample smaller than randomized.

## Population

- Healthy adolescents recruited from a high school in Murcia, Spain.
- Sample size: 60
- Age: Mean analyzed age 12.51 +/- 0.75 years
- Sex: Both sexes
- Fitness level: Physically active in PE sessions.
- Health status: No pathology preventing required physical activity.

## Methodology

- Randomized controlled trial with SIT, HIIT, and regular physical education control groups.
- 8 weeks
- Secondary school physical education classes in Murcia, Spain.
- Randomized and controlled study design.

## Protocol

- School HIIT.
- Modality: Running.
- Work intervals: 3 x 2 min.
- Recovery: 2 min rest at 50-55%.
- Sets or repetitions: 3.
- Intensity: 80-85% during work.
- Session duration: 12 min intervention block.
- Frequency: 2 sessions/week.
- Program length: 8 weeks.
- Progression: No progression reported.
- SIT and regular PE control.
- Modality: Running for SIT; regular PE for control.
- Work intervals: SIT 6 x 60 s.
- Recovery: SIT 60 s at 50-55%.
- Sets or repetitions: 6 SIT sets.
- Intensity: SIT 90-95%.
- Session duration: 12 min SIT block.
- Frequency: 2 sessions/week.
- Program length: 8 weeks.

## Outcomes

### Body composition and strength
Status: improved
Both HIIT and SIT reduced fat mass and trunk fat mass and increased lean mass, handgrip, and long jump after sex adjustment.

Fat and trunk fat p<0.01; lean mass p=0.01/<0.01; handgrip p<0.01; long jump p=0.05-0.04.

### Cardiovascular fitness and BP
Status: improved
HIIT, but not SIT, significantly improved blood pressure, diastolic blood pressure, heart rate, and VO2max.

HIIT p<0.05 for BP/DBP/HR/VO2max.

### LDL
Status: mixed
HIIT showed only a tendency toward LDL reduction.

p value described as tendency, not significant.

### Protocol comparison
Status: mixed
The 3 x 2-min HIIT protocol produced more benefits than the shorter, more intense SIT protocol.

## Practical Insights

- A 12-min 3 x 2-min running HIIT block is a plausible school-friendly structure.
- For adolescents, slightly longer intervals at lower intensity may be more beneficial than harder 1-min SIT.
- Report and monitor attrition when using school HIIT evidence.

## Limitations

- Small sample
- Single secondary school
- Final analyzed sample smaller than randomized
- No long-term follow-up
- Adverse events not clearly reported

## Safety And Adherence

- Adverse events were not specifically reported.
- Exercise-limiting pathology was excluded.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/39157534/) (pubmed)
- [DOI](https://doi.org/10.3389/fpubh.2024.1425191) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11328537/) (full text)

## Agent Guidance

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