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

PMID: 29099031
Journal: Medical Sciences
Published: 2017-07-19
Authors: 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.

## Population

- Ten healthy sedentary young men.
- Sample size: 10
- Age: 20.00 +/- 1.33 years; 18-24 years.
- Sex: Male
- Fitness level: Sedentary.
- Health status: Healthy, non-smoking, no medication or antioxidant supplements.

## Methodology

- Single-group acute repeated-measures laboratory study.
- One acute HIIT session with blood sampling before, immediately after, 3 hours after, and 6 hours after exercise.
- Exercise physiology laboratory.

## Protocol

- Acute Wingate HIIT.
- Modality: Cycle ergometer sprints.
- Work intervals: 30 s all-out Wingate.
- Recovery: 4 min rest between bouts.
- Sets or repetitions: 4 bouts.
- Intensity: 75 g/kg body mass resistance; all-out effort.
- Session duration: At least 14 min excluding any unreported warm-up/cooldown.
- Frequency: Single acute session.
- Program length: Single session.
- Progression: None.

## Outcomes

### Red cell markers
Status: improved
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.

### Platelets
Status: improved
Platelet count increased immediately after exercise and decreased at 3 and 6 hours compared with post-exercise.

Immediate increase p=0.001.

### White blood cells
Status: mixed
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).

### Mean cell hemoglobin
Status: no clear change
Mean cell hemoglobin did not significantly change across timepoints.

p=0.980.

## Practical 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 And Adherence

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

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/29099031/) (pubmed)
- [DOI](https://doi.org/10.3390/medsci5030015) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5635806/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.