# Effect of high-intensity interval training in adolescents with asthma: The eXercise for Asthma with Commando Joe's trial

PMID: 34304826
Journal: Journal of sport and health science
Published: 2021 Jul
Authors: Winn CON, Mackintosh KA, Eddolls WTB, Stratton G, Wilson AM, McNarry MA, Davies GA

## Question

Is a 6-month field-based school HIIT program effective and tolerable for improving fitness, BMI, lung function, asthma control, and quality of life in adolescents with asthma compared with adolescents without asthma?

## Summary

This cluster randomized school trial tested a 6-month, game- and circuit-based HIIT program in adolescents with and without asthma. The intervention improved maximal aerobic fitness and helped maintain BMI, while lung function, asthma control, and quality of life did not improve. Adolescents with mild asthma tolerated the program similarly to peers without asthma, with no exercise-induced asthma attacks reported.

## Population

- Adolescents from five schools, including participants with asthma and without asthma.
- Sample size: 616
- Age: 13.0 +/- 1.1 years.
- Sex: 334 boys overall; 155 participants had asthma, including 78 boys.
- Fitness level: School adolescents; asthma subgroup had similar aerobic fitness to peers at baseline but greater BMI.
- Health status: Mostly mild persistent asthma among those with asthma; excluded unstable asthma, recent severe asthma events, exercise-induced severe attack, or intensive-care asthma history.

## Methodology

- Cluster randomized controlled school trial with one intervention school and four matched control schools.
- 6-month intervention with baseline, mid-intervention, post-intervention, and 3-month follow-up assessments.
- Five schools in South Wales; intervention sessions before or after school delivered by a Commando Joe's personal trainer.
- Randomized and controlled study design.

## Protocol

- X4ACJ school HIIT.
- Modality: Circuits, bodyweight exercises, obstacle-course activities, agility drills, and sprints.
- Work intervals: 10-30 second bouts.
- Recovery: Equal rest.
- Sets or repetitions: Session-specific repeated activities; exact bout count not reported.
- Intensity: Designed to elicit >90% age-predicted HRmax; actual mean HR during sessions was 78% HRmax and mean peak HR was 95% HRmax; HR exceeded >90% HRmax for 24% of main-session time.
- Session duration: 30 minutes.
- Frequency: 3 times/week.
- Program length: 6 months.
- Progression: Varied session content with individual encouragement if HR target was not achieved.
- Usual day-to-day activity control schools.
- Modality: Usual activity.
- Program length: 6 months.

## Outcomes

### Aerobic fitness
Status: improved
HIIT improved maximal aerobic fitness similarly in adolescents with and without asthma.

Scaled peak VO2 showed significant time and group-by-time effects; both asthma and non-asthma intervention groups increased peak VO2 while controls did not.

### BMI
Status: mixed
Intervention participants maintained BMI during the intervention, while BMI increased in control participants; all groups had higher BMI than baseline by 3-month follow-up.

Time effect F(2.23,782)=15.4, p<0.05; group effect F(3,351)=5.29, p<0.05; no time-by-group interaction.

### Lung function, asthma control, and quality of life
Status: no clear change
HIIT did not significantly improve lung function, asthma control, asthma-related quality of life, or general quality of life.

Authors report no significant changes in lung function and no intervention effect on asthma control or asthma-related quality of life.

### Safety
Status: improved
No exercise-induced asthma attacks were reported, supporting tolerability in screened adolescents with mostly mild stable asthma.

Authors state there were no exacerbations throughout the study.

## Practical Insights

- Varied short-bout HIIT can be feasible in school adolescents with stable mild asthma when monitored and supervised.
- Fitness gains should not be translated into claims of improved asthma control or lung function.
- Screening and asthma stability boundaries are central to safe interpretation.

## Limitations

- Only one intervention school was used.
- Volunteer/self-selection bias was possible.
- Attendance was uneven, with some participants minimally attending.
- Most asthma participants had mild asthma, limiting generalization to more severe asthma.
- The intervention did not isolate which specific activities drove the effect.

## Safety And Adherence

- No exercise-induced asthma attacks or exacerbations were reported.
- Participants with unstable or high-risk asthma histories were excluded.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/34304826/) (pubmed)
- [DOI](https://doi.org/10.1016/j.jshs.2019.05.009) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8343006/) (full text)

## Agent Guidance

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