# Effects of a High Intensity Interval Training (HIIT) Program on Anthropomorphic and Cardiometabolic Variables in School Children with Overweight and Obesity

PMID: 36832446
Journal: Children
Published: 2023-02-07
Authors: Espinoza Silva JM, Latorre Román PÁ, Cabrera Linares JC, Párraga Montilla JA, Martínez Salazar C

## Question

Does a 28-week school-based HIIT program improve anthropometric and cardiometabolic variables in first- and second-grade children with overweight and obesity?

## Summary

A long school-based HIIT program using games and motor activities was associated with improved BMI, body fat, and skinfold measures in young children with overweight/obesity, but the comparison group was normal-weight children in usual physical education, making causal interpretation limited.

## Population

- First- and second-grade schoolchildren; intervention group had overweight or obesity and control group was normal weight.
- Sample size: 443
- Age: Mean 6.37 +/- 0.65 years.
- Sex: Schoolchildren of both sexes; sex distribution not central in the extracted summary.
- Fitness level: General schoolchildren participating in physical education.
- Health status: Children without physical or intellectual disabilities and with medical certificate permitting exercise; intervention group had overweight/obesity.

## Methodology

- School-based controlled intervention comparing overweight/obese children assigned to HIIT with normal-weight children attending usual physical education.
- 28 weeks
- Six schools in Temuco, Chile, during physical education classes.
- Controlled study design.

## Protocol

- School-based ludic HIIT.
- Modality: Games, outdoor chase/race activities, jumping, and basic motor-skill exercises.
- Work intervals: High-intensity activities lasting 30 seconds to 1 minute in one block; lower-intensity activities lasting about 4 minutes in another block.
- Recovery: 1-2 minutes rest/recovery between bouts or sets.
- Sets or repetitions: Two main blocks of 15-20 minutes; second block included 3-4 sets.
- Intensity: Children's modified Borg 10-point scale; high intensity targeted above 8.
- Session duration: 40-50 minutes including 5-minute warm-up and 5-minute calm-down.
- Frequency: 2 sessions per week.
- Program length: 28 weeks; 56 sessions.
- Progression: Protocol used varied child-selected games and activities; specific progressive overload was not clearly quantified.
- Usual physical education in normal-weight children.
- Modality: Habitual school PE classes based on national curriculum.
- Intensity: Described by authors as usually low intensity with little incentive to effort.
- Frequency: Usual school PE schedule.
- Program length: 28 weeks.
- Progression: Usual curriculum.

## Outcomes

### BMI and body fat
Status: improved
The overweight/obese HIIT group improved BMI, body fat percentage, and sum of four skinfolds.

EG BMI 20.29 to 19.62 kg/m2, p < 0.001; body fat 22.02% to 20.61%, p < 0.001; sum of four skinfolds 49.05 to 44.98, p < 0.001.

### Waist circumference and WHtR
Status: mixed
Waist and waist-to-height findings were less consistent; control waist circumference increased.

EG waist 62.08 to 61.78 cm, p = 0.413; CG waist 54.29 to 55.56 cm, p = 0.018.

### Blood pressure and resting HR
Status: no clear change
No meaningful changes were reported for blood pressure or resting heart rate.

Authors reported no significant changes for BP and RHR.

### Six-minute walk test
Status: mixed
Both groups improved six-minute walk performance without a between-group difference.

Improvement occurred in both groups; no between-group difference reported.

## Practical Insights

- Game-based intervals may be a practical school format for young children.
- A long two-session-per-week program can be embedded inside PE time.
- Because the comparator was normal-weight usual-PE children, this should not be used as strong proof of efficacy versus usual PE for children with overweight/obesity.

## Limitations

- Non-randomized design.
- Comparator group differed by weight status and received usual PE, creating confounding.
- Intensity was estimated by child Borg scale rather than objective HR monitoring.
- Diet and extracurricular physical activity were not controlled.
- Adherence and adverse-event reporting were unclear.

## Safety And Adherence

- Children required medical certificate permitting physical exercise.
- Sessions were delivered by a volunteer professional physical education teacher.
- The article did not report adverse events, attendance, or dropout in the extracted text.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/36832446/) (pubmed)
- [DOI](https://doi.org/10.3390/children10020317) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9955470/) (full text)

## Agent Guidance

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