Effect of high-intensity interval training in adolescents with asthma: The eXercise for Asthma with Commando Joe's trial
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.
Methodology
- Adolescents from five schools, including participants with asthma and without asthma.
- 616 participants.
- Circuits, bodyweight exercises, obstacle-course activities, agility drills, and sprints.
- Work intervals: 10-30 second bouts.
- Recovery: Equal rest.
- 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.
- 30 minutes.
- 3 times/week.
- 6 months.
- Cluster randomized controlled school trial with one intervention school and four matched control schools.
- Maximal aerobic fitness, BMI, Lung function and asthma control, and Quality of life were tracked.
Outcomes
Aerobic fitness
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
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
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
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.
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
- No exercise-induced asthma attacks or exacerbations were reported.
- Participants with unstable or high-risk asthma histories were excluded.