# Long- and Short-Term High-Intensity Interval Training on Lipid Profile and Cardiovascular Disorders in Obese Male Adolescents

PMID: 37508677
Journal: Children (Basel, Switzerland)
Published: 2023 Jul 7
Authors: Racil G, Chelly MS, Coquart J, Padulo J, Teodor DF, Russo L

## Question

How do 8 and 16 weeks of cycling HIIT affect body composition, cardiovascular variables, lipids, insulin/glucose markers, lactate, walking performance, and perceived exertion in moderately and severely obese adolescent boys?

## Summary

This study followed moderately and severely obese adolescent boys through 16 weeks of supervised cycling HIIT. Both groups improved body composition, 6-minute walk distance, blood pressure, lipids, insulin, HOMA-IR, lactate, and perceived exertion. However, there was no non-exercising control group, five participants dropped out for personal reasons, and the authors cautioned that long, intense sessions may be hard for severely obese boys.

## Population

- Obese adolescent boys with BMI >=97th percentile and body fat >34%, classified as moderate or severe obesity.
- Sample size: 35
- Age: 16.2 +/- 0.7 years.
- Sex: All male.
- Fitness level: No systematic exercise training in prior 3 months; only school PE.
- Health status: Moderate or severe obesity without chronic disease or obesity drug/therapy use.

## Methodology

- Two-group longitudinal pre-post intervention comparing moderate and severe obesity groups; no non-exercising control group.
- 16 weeks with measurements at baseline, 8 weeks, and 16 weeks.
- School-linked recruitment and supervised cycle-ergometer training/testing.

## Protocol

- 16-week cycling HIIT for obese adolescent boys.
- Modality: Cycle ergometer.
- Work intervals: 30 seconds at 100% peak power output at ventilatory threshold.
- Recovery: 30 seconds at 50% peak power output; 5 minutes passive recovery between blocks.
- Sets or repetitions: Two blocks of 10 bouts.
- Intensity: 100% PPO at ventilatory threshold; recovery 50% PPO.
- Session duration: 35-55 minutes depending on phase, including warm-up, interval blocks, between-block rest, and cool-down.
- Frequency: 3 sessions/week.
- Program length: 16 weeks.
- Progression: Session duration increased from 35 to 45 to 55 minutes; power could increase by 5% when HR at VT decreased by 5 bpm.

## Outcomes

### Body composition and 6-minute walk
Status: improved
Both groups improved body-composition measures and 6-minute walking distance by 16 weeks.

Body mass/BMI p<0.01; body fat, LBM, RPE, and 6-min walk p<0.001; 6-min walk SOG 582 to 636 m, MOG 594 to 646 m.

### Blood pressure and lipids
Status: improved
Both groups improved blood pressure and lipid profile, with severe obesity showing larger percentage changes in several variables.

DBP and HDL-C p<0.01; SOG SBP, resting lactate, and total cholesterol p<0.001 versus MOG p<0.05; TG/LDL-C SOG p<0.001 versus MOG p<0.01.

### Glucose and insulin resistance
Status: improved
Insulin and HOMA-IR decreased in both groups; MOG had lower HOMA-IR post-intervention and greater glucose improvement.

Insulin and HOMA-IR p<0.001; MOG post HOMA-IR lower than SOG p<0.05.

### Lactate and RPE
Status: mixed
Lactate and RPE improved overall, but severe obesity RPE rose from week 8 to 16 as sessions lengthened.

BL5min decreased p<0.01; RPE SOG 8.8 to 7.2 to 7.3, MOG 8.5 to 6.8 to 6.7.

## Practical Insights

- Longer HIIT can improve cardiometabolic markers in obese boys but may increase perceived difficulty in severe obesity.
- Shorter sessions or gradual duration increases may be more appropriate for severe obesity.
- RPE should be tracked alongside objective measures.

## Limitations

- Boys only.
- No non-training control group.
- Small sample with five dropouts.
- Lower baseline fitness may contribute to rapid improvements.
- No detailed adverse-event reporting.

## Safety And Adherence

- Five adolescents dropped out for personal reasons.
- No adverse events or injuries were reported.
- Authors caution about overexertion, joint stress, and the need for warm-up/cool-down and tailored progression.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/37508677/) (pubmed)
- [DOI](https://doi.org/10.3390/children10071180) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10378083/) (full text)

## Agent Guidance

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