PMID 29099031

Research
All papers

The Effects of Acute High-Intensity Interval Training on Hematological Parameters in Sedentary Subjects

Belviranli M, Okudan N, Kabak B

Question

How does one acute Wingate-style HIIT session affect hematological parameters in sedentary young men over the following 6 hours?

Summary

Ten sedentary young men completed four all-out 30-second Wingate cycling bouts with 4-minute rests. Many blood-cell and hematology measures rose immediately after the session and generally returned toward baseline within 3 to 6 hours. The study measured acute blood responses only, not fitness gains or user experience.

Methodology

  • Ten healthy sedentary young men.
  • 10 participants.
  • Cycle ergometer sprints.
  • Work intervals: 30 s all-out Wingate.
  • Recovery: 4 min rest between bouts.
  • Intensity: 75 g/kg body mass resistance; all-out effort.
  • At least 14 min excluding any unreported warm-up/cooldown.
  • Single acute session.
  • Single session.
  • Single-group acute repeated-measures laboratory study.
  • Hematological parameters, and White blood cells were tracked.

Outcomes

Red cell markers

Hematocrit, hemoglobin, red cell count, and mean cell volume increased immediately after HIIT and then declined toward baseline.

Hematocrit p=0.002; hemoglobin p<0.001; red cell count p=0.009; MCV p=0.001.

Improved

Platelets

Platelet count increased immediately after exercise and decreased at 3 and 6 hours compared with post-exercise.

Immediate increase p=0.001.

Improved

White blood cells

WBC increased immediately and at 3 hours, with differential changes over 6 hours.

WBC p<0.001; neutrophil count and percentage increased at 3 and 6 h (p=0.007 and p=0.003).

Mixed

Mean cell hemoglobin

Mean cell hemoglobin did not significantly change across timepoints.

p=0.980.

No clear change

Insights

  • All-out Wingate intervals create acute blood-marker changes in sedentary young men.
  • This paper is more useful for safety/mechanistic context than for workout recommendation.
  • General-user HIIT should not infer safety or benefit from this acute surrogate-outcome study.

Limitations

  • Small sample of 10 men.
  • No control condition.
  • Acute-only design.
  • Surrogate outcomes rather than fitness, adherence, or clinical endpoints.
  • Specialized Wingate protocol.

Safety

  • No actual adverse events were reported.
  • The authors cautioned that acute HIIT may challenge hemorheological state in sedentary subjects.