PMID 37761456

Research
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High-Intensity Interval Training in Female Adolescents with Moderate or Severe Obesity

Racil G, Russo L, Migliaccio GM, Signorelli P, Larion A, Padulo J, Jlid MC

Question

Do 12 weeks of high-intensity versus moderate-intensity interval cycling produce different anthropometric and biological effects in adolescent girls with moderate or severe obesity?

Summary

This randomized stratified trial compared moderate- and high-intensity interval cycling in 57 adolescent girls with moderate or severe obesity. All groups improved body-composition measures and insulin resistance, while the high-intensity groups showed larger insulin and HOMA-IR reductions and increased lean body mass. The moderate-obesity HIIT group had the strongest body-fat, growth hormone, and glucose responses.

Methodology

  • Adolescent girls with moderate or severe obesity, BMI >=97th percentile and body fat >=30%.
  • 57 participants.
  • Cycle ergometer.
  • Work intervals: 1 minute.
  • Recovery: 2 minutes active recovery at 50% HR reserve; 4 minutes free pedaling between sets.
  • Intensity: 85% HR reserve in weeks 1-4, 90% in weeks 5-8, 95% in weeks 9-12.
  • About 35-41 minutes including warm-up, intervals, between-set recovery, and cooldown.
  • 3 sessions/week.
  • 12 weeks.
  • Randomized stratified 2 x 2 intervention trial by obesity class and training intensity.
  • Body composition, Growth hormone and glucose, Insulin resistance, and Blood lactate were tracked.

Outcomes

Anthropometry

All four groups reduced body mass, BMI, body fat percentage, and waist circumference; moderate-obesity HIIT had the largest percentage changes.

Post-intervention reductions p<0.05, most pronounced in MOG HI with p<0.01 and body fat change -7.52%.

Improved

Lean body mass

Only the HIIT groups significantly increased lean body mass.

MOG HI and SOG HI p<0.05.

Improved

Insulin and HOMA-IR

All groups improved insulin and HOMA-IR, with the largest reductions in HIIT groups.

Insulin changes: MOG HI -25.49%, SOG HI -25.34%; HOMA-IR: MOG HI -31.42%, SOG HI -28.88%; HIIT reductions p<0.01.

Improved

Growth hormone and glucose

Only the moderate-obesity HIIT group significantly improved growth hormone and blood glucose.

MOG HI GH and glucose p<0.05; GH correlated with body fat r=-0.76 and waist circumference r=-0.77; glucose correlated with body fat r=-0.72 and waist r=-0.82.

Mixed

Blood lactate

Both HIIT groups significantly decreased blood lactate values.

MOG HI ES=0.56 and SOG HI ES=0.61; both p<0.05.

Improved

Insights

  • For adolescent obesity, HIIT intensity progression may matter for insulin-resistance outcomes.
  • Moderate and severe obesity groups may respond differently; severe obesity may need extra tolerance planning.
  • HR reserve prescription and screening are central to this protocol.

Limitations

  • Female-only sample.
  • No non-exercise control group.
  • Diet was not monitored daily during the intervention.
  • Growth hormone was not measured at multiple times throughout the day.
  • No detailed adverse-event reporting.

Safety

  • Five initial candidates were excluded after safety/familiarization testing.
  • Lower-body injury and cardiovascular/orthopedic dysfunction were exclusion criteria.
  • No training adverse events were reported.