PMID 38918508

Research
All papers

Cardiovascular and cardiorespiratory effects of high-intensity interval training in body fat responders and non-responders

Domaradzki J, Koźlenia D

Question

Do adolescents who reduce body-fat percentage after school-based HIIT differ from non-responders in cardiovascular and cardiorespiratory adaptations?

Summary

In 73 adolescents assigned to a 10-week school Tabata HIIT program, body-fat responders gained more cardiorespiratory fitness than body-fat non-responders, but systolic blood pressure improved in both groups. The analysis was based on responder subgroups from the HIIT arm and did not include a parallel control comparison.

Methodology

  • Adolescents from the experimental arm of a school-based HIIT intervention.
  • 73 participants.
  • Bodyweight exercises.
  • Work intervals: 20 seconds.
  • Recovery: 10 seconds active recovery.
  • Intensity: 75-80% HRmax; first-session mean HR 155.8 +/- 18.2 bpm.
  • 45-minute PE lesson with 14-minute HIIT block.
  • 1 session per week.
  • 10 weeks.
  • Responder/non-responder subgroup analysis within the experimental arm of a school HIIT intervention.
  • Body-fat response, Fitness index, and Resting blood pressure were tracked.

Outcomes

Body fat

Responder classification separated participants with decreased body fat from those with increased body fat.

Responder change -2.30 +/- 3.51 percentage points; non-responder change +1.51 +/- 1.54; delta p<0.001.

Mixed

Fitness index

Fitness index improved in body-fat responders but not non-responders.

Interaction F(1,71)=14.12, p<0.001; responders p<0.001, d=0.82; non-responders p=0.576, d=0.13.

Mixed

Blood pressure

Systolic blood pressure decreased over time in both responder categories.

SBP time effect F=38.68, p<0.001; no responder x time interaction.

Improved

DBP

DBP reporting was internally inconsistent, but the model showed a significant time effect and no responder interaction.

DBP time effect F=11.40, p=0.001; text and discussion differed on whether both groups improved.

Mixed

Insights

  • Do not treat body-fat non-response as overall non-response.
  • Fitness and blood-pressure outcomes should be tracked separately.
  • Short bodyweight HIIT can fit into a school PE lesson.

Limitations

  • Responder subgroup analysis without a concurrent control in this paper.
  • Small subgroups after responder/non-responder classification.
  • Responder threshold based on typical error.
  • Harvard Step Test instead of VO2max.
  • BIA instead of DEXA.
  • Sexes were agglomerated in key analyses.

Safety

  • No adverse events or injuries were reported in the the paper.
  • Heart-rate monitoring was used during supervised PE.