PMID 41423624

Research
All papers

Acute hematological, metabolic, and inflammatory responses to simulated-6000 ft masked versus unmasked high-intensity interval training in youth soccer players: a randomized crossover pilot study

Akol T, Yapici A, Ergin GF, Atabaş EG

Question

Does adding a simulated-6000 ft respiratory-restricting mask change the acute metabolic, hematological, hormonal, inflammatory, and cardiorespiratory response to supramaximal Eurofit HIIT in amateur soccer players?

Summary

In 12 male amateur soccer players, the same shuttle-run HIIT session caused more lactate and hemoconcentration when performed with a simulated-altitude breathing mask than without the mask. Heart rate and oxygen saturation responses were not significantly different, and the article reported no adverse events, discomfort, or respiratory distress.

Methodology

  • Healthy male amateur soccer players
  • 12 participants.
  • Running shuttle.
  • Work intervals: 15 s out, 15 s rest, 15 s return cycle.
  • Recovery: 15 s intra-cycle rest and 3 min passive recovery between sets.
  • Intensity: 120% MAS with mask at simulated 6000 ft.
  • Planned about 22 min.
  • Acute single masked session.
  • Single session crossover.
  • Randomized single-blind two-period crossover pilot study
  • Blood lactate, Hemoconcentration markers, Heart rate and SpO2, and Metabolic and hormonal markers were tracked.

Outcomes

lactate

Masked HIIT produced higher post-exercise lactate than unmasked HIIT.

5.11 +/- 1.59 vs 4.34 +/- 1.32 mmol/L; p=0.015

Safety concern

hemoconcentration

Hemoglobin, hematocrit, and platelet increases were larger after masked HIIT, indicating greater acute fluid-shift stress.

Hb p=0.006; Hct p=0.013; PLT p=0.015

Mixed

heart rate and SpO2

Both sessions raised HR and lowered SpO2, with no significant between-condition difference.

HR p=0.253; SpO2 p=0.206

No clear change

safety

No adverse events, discomfort, or respiratory distress were observed.

No clear change

Insights

  • A mask-like respiratory load can turn a familiar interval session into a higher-stress session without obvious extra cardiovascular benefit.
  • For app programming, use the shuttle interval structure and recovery gates, not the mask as a default recommendation.
  • Hydration and symptom monitoring matter when HIIT is designed to increase acute metabolic strain.

Limitations

  • Small pilot sample
  • Male amateur soccer players only
  • Acute crossover design
  • No direct arterial blood gas or EPO measures
  • Pulse oximetry after intense exercise may be imprecise

Safety

  • No adverse events, discomfort, or respiratory distress were observed.
  • Authors advise monitoring HR, SpO2, RPE, hydration, and avoiding use in respiratory or thrombotic contraindications.