PMID 36046991

Research
All papers

Effects of low and high intensity interval training exercises on VO(2max) and components of neuromuscular and vascular system in male volunteers

Eken Ö, Kafkas ME

Question

How do low- and high-intensity bodyweight interval training affect VO2max, Yo-Yo IR-1 performance, and serum BDNF, TrkB, VEGF, PGC-1alpha, and irisin in inactive male volunteers?

Summary

In physically inactive young men, 4 weeks of bodyweight interval training at either low or high heart-rate intensity improved reported VO2max and several blood biomarkers, with high intensity generally showing larger effects. Several results relied on surrogate biomarkers and some interaction tests were not significant.

Methodology

  • Male volunteers without regular exercise habits.
  • 36 participants.
  • bodyweight circuit.
  • Work intervals: 20 s.
  • Recovery: 20 s rest; 3 min between cycles.
  • Intensity: 85-90% maximum heart-rate intensity.
  • 25 min main session.
  • 2 sessions/week on non-consecutive days.
  • 4 weeks.
  • three parallel-group randomized controlled trial
  • VO2max, Yo-Yo IR-1, and Neuromuscular and vascular biomarkers were tracked.

Outcomes

VO2max

Groups differed, but the measurement interaction was not significant.

between-groups p=0.004; interaction p=0.523; measurement effect p reported as >0.05

Mixed

Biomarkers

The authors reported higher BDNF, TrkB, PGC-1alpha, VEGF, and irisin values after interval training, especially HIIT.

significant interactions for PGC-1alpha p=0.031, TrkB p=0.003, and VEGF p=0.001; no significant interaction for BDNF p=0.270 or irisin p=0.308

Improved

HIIT vs LIIT

Authors concluded HIIT had greater effects than LIIT, but not every outcome showed a significant group-by-time interaction.

Yo-Yo IR-1 and VO2max group differences significant; interactions not significant

Mixed

Insights

  • The protocol is directly recognizable as a 20 s work/20 s rest bodyweight circuit.
  • Heart-rate monitoring and coaching were used to keep participants in target intensity zones.
  • Claims about brain, vascular, and metabolic benefits should be qualified because many outcomes were serum biomarkers.

Limitations

  • Small sample size.
  • Healthy male participants only.
  • Short 4-week intervention.
  • Several endpoints are surrogate biomarkers.
  • Some interaction tests were not significant despite broad positive conclusions.

Safety

  • No adverse events were reported; participants had no recent upper/lower extremity injury and HR was monitored during exercise.