PMID 35822439

Research
All papers

Influence of high-intensity interval training to exhaustion on the directional sensitivity of the cerebral pressure-flow relationship in young endurance-trained men

Abbariki F, Roy MA, Labrecque L, Drapeau A, Imhoff S, Smirl JD, Brassard P

Question

Does six weeks of high-intensity interval training to exhaustion alter directional sensitivity of the cerebral pressure-flow relationship in young endurance-trained men?

Summary

In young endurance-trained men, six weeks of cycling HIIT to exhaustion improved VO2max and lowered resting heart rate. Cerebrovascular pressure-flow responses changed in a frequency- and direction-specific way, but these are mechanistic surrogate outcomes rather than direct app-user performance outcomes.

Methodology

  • Young endurance-trained men
  • 18 participants.
  • Cycle ergometer.
  • Work intervals: 1-7 minutes at 85% maximal aerobic power or 30-60 seconds at 115%.
  • Recovery: Active recovery at 50% maximal aerobic power or 150 W if maximal power was under 300 W.
  • Intensity: 85% or 115% maximal aerobic power.
  • Varied.
  • 3 sessions per week.
  • 6 weeks.
  • Secondary analysis of a randomized training study with pooled HIIT groups
  • Cerebral pressure-flow sensitivity, VO2max, and Resting heart rate were tracked.

Outcomes

VO2max

VO2max increased after six weeks of HIIT.

55.5 +/- 4.7 to 58.7 +/- 4.1 ml/kg/min; +5.8%; p=0.008.

Improved

Resting HR

Resting heart rate decreased after training.

54 +/- 8 to 51 +/- 7 bpm; p=0.002.

Improved

Pressure-flow sensitivity

Directional sensitivity changed differently by squat-stand frequency.

At 0.05 Hz post-training, MAP increases exceeded decreases, p=0.002; at 0.10 Hz, pre-training directional sensitivity disappeared post-training, p=0.359.

Mixed

Resting cerebrovascular state

Resting MAP, MCAv, and PETCO2 did not significantly change.

Reported as non-significant.

No clear change

Insights

  • Exhaustion-based cycling HIIT can still improve VO2max in endurance-trained men.
  • Cerebrovascular findings should be treated as mechanistic, not user-facing performance claims.
  • Hard HIIT sessions in trained athletes were separated by 48-72 hours.

Limitations

  • Small sample.
  • Male endurance-trained athletes only.
  • No non-HIIT or non-training control group.
  • Secondary analysis.
  • Transcranial Doppler velocity is a surrogate that assumes stable vessel diameter.
  • PETCO2 data were incomplete because of technical issues.

Safety

  • No adverse events were reported.
  • One participant was excluded because post-training tests were incomplete.