# Chemokine Receptor Profile of Circulating Leukocyte Subsets in Response to Acute High-Intensity Interval Training

PMID: 41750333
Journal: Biomolecules
Published: 2026 Feb 7
Authors: Leuchte K, Fresnillo Saló S, Rahbech A, Byrdal M, Vinther A, Holmen Olofsson G

## Question

How does one bout of HIIT affect chemokine receptor expression and mobilization of leukocyte subsets in healthy adults?

## Summary

Sixteen healthy adults completed one supervised mixed warm-up plus cycling HIIT session. Blood tests showed rapid immune-cell redistribution immediately after exercise and partial reversal one hour later, but the study measured immune phenotypes rather than fitness or health outcomes.

## Population

- Healthy adults from the INHALE cohort.
- Sample size: 16
- Age: Mean 31.7 years, range 25-65
- Sex: 11 male, 5 female
- Fitness level: Generally healthy, varying fitness; VO2peak mean 39.7 mL/min/kg
- Health status: Healthy; exercise-limiting conditions and relevant medications excluded

## Methodology

- Acute interventional laboratory study
- Single exercise session with blood sampling through 60 min postexercise
- Physiotherapist-supervised exercise facility and laboratory

## Protocol

- Acute INHALE HIIT session.
- Modality: Mixed warm-up plus cycling.
- Work intervals: 20 s all-out at about 100% CPET maximal power.
- Recovery: 20 s easy pedaling at about 50%; 3 min steady-state between 3 min blocks.
- Sets or repetitions: 3 x 3 min interval blocks after warm-up.
- Intensity: All-out/prescribed power with HR monitoring.
- Session duration: About 32 min plus transitions.
- Frequency: Single session.
- Program length: Acute study.
- Progression: No progression; acute study.

## Outcomes

### NK cells
Status: mixed
NK cells strongly mobilized immediately and fell below baseline after 60 min.

6.6-fold increase at Ex02 and 2.7-fold below baseline at Ex60; p<0.0001.

### CD4 T cells
Status: mixed
CD4+ T cells increased immediately and returned toward baseline by 60 min.

1.5-fold increase and 1.8-fold decrease at Ex60; p<0.0001.

### Gamma-delta T cells
Status: mixed
Gamma-delta T cells mobilized immediately and returned to baseline after recovery.

4.2-fold increase at Ex02; p<0.01.

## Practical Insights

- Short all-out intervals can produce rapid systemic physiological effects in healthy adults.
- Immune-marker findings are mechanistic and should not be converted into consumer claims about immunity without functional outcome evidence.

## Limitations

- Small sample.
- Single acute bout only.
- Healthy participants only.
- Functional immune consequences were not measured.
- Limited chemokine receptor panel.

## Safety And Adherence

- No adverse events were reported.
- Participants were screened as healthy, excluded for exercise-limiting conditions and relevant medications, and exercised under experienced physiotherapist supervision.
- The study used all-out intervals, so safety should not be generalized to unscreened or clinical users.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/41750333/) (pubmed)
- [DOI](https://doi.org/10.3390/biom16020263) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12937720/) (full text)

## Agent Guidance

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