# Moving for optimal immunity: the effect of acute high-intensity interval training on phenotype, virus specificity and chemokine receptor expression in human CD8+ T cells

PMID: 41675500
Journal: Frontiers in Immunology
Published: 2026 Jan 19
Authors: Leuchte K, Luu TV, Fresnillo Saló S, Madsen K, Heide-Ottosen L, Skadborg SK, Kemming JS, Holmström MO, Chen H, Olsen LR, Vinther A, Andersen MH, Hadrup SR, Thor Straten P, Holmen Olofsson G

## Question

How does acute high-intensity interval exercise affect CD8+ T-cell phenotype, virus specificity, chemokine receptor expression, and related soluble factors in healthy adults?

## Summary

In 23 healthy HLA-A2-positive adults, one physiotherapist-supervised high-intensity interval session rapidly mobilized CD8+ T cells, especially differentiated and virus-reactive subsets, into blood immediately after exercise, followed by egress below or toward baseline by 60 minutes. No adverse events occurred.

## Population

- Healthy HLA-A2-positive adults from the INHALE study.
- Sample size: 23
- Age: Mean 37.3 years, range 25-65
- Sex: 13 male, 10 female
- Fitness level: Varied healthy fitness assessed by CPET
- Health status: Healthy, without unstable or exercise-limiting conditions

## Methodology

- Acute mechanistic exercise immunology study
- Single acute session with blood sampling immediately and 60 minutes post-exercise
- Physiotherapist-supervised group-based exercise after CPET

## Protocol

- Acute mixed-mode HIIT.
- Modality: Cycling plus circuit warmup.
- Work intervals: 20 seconds all-out within 3-minute blocks.
- Recovery: 20 seconds easy pedaling within blocks and 3-minute steady-state sequences between blocks.
- Sets or repetitions: 3 x 3-minute high-intensity blocks.
- Intensity: All-out segments aimed at 100% CPET maximal power.
- Session duration: About 34 minutes of exercise work described.
- Frequency: Single session.
- Program length: One session.
- Progression: None.

## Outcomes

### CD8 cells
Status: improved
CD8+ T cells mobilized strongly immediately after HIIT.

+2.6-fold, p<0.0001

### Virus cells
Status: improved
Virus-reactive T cells increased immediately after exercise.

EBV, SARS-CoV-2, CMV and other peptide-reactive cells increased in matching participants

### Safety
Status: no clear change
No adverse events occurred.

## Practical Insights

- Acute HIIT can transiently mobilize immune cells, but this is not the same as proven clinical immune benefit.
- Individualized intensity testing and supervision were part of the protocol context.
- Mechanistic immune claims should be scoped to healthy adults and acute time windows.

## Limitations

- Healthy HLA-A2-positive sample limits generalizability.
- CMV serostatus was unavailable.
- Recent vaccination history was unavailable.
- Only acute immune redistribution was measured.

## Safety And Adherence

- The full text states no adverse events occurred.
- Participants were healthy and screened; CPET was used before the session.
- The protocol was supervised by an experienced physiotherapist and individualized by CPET-derived power.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/41675500/) (pubmed)
- [DOI](https://doi.org/10.3389/fimmu.2025.1739657) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12888222/) (full text)

## Agent Guidance

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