# Protein Composition of Circulating Extracellular Vesicles Immediately Changed by Particular Short Time of High-Intensity Interval Training Exercise

PMID: 34276412
Journal: Frontiers in Physiology
Published: 2021
Authors: Kobayashi Y, Eguchi A, Tamai Y, Fukuda S, Tempaku M, Izuoka K, Iwasa M, Takei Y, Togashi K

## Question

How does a single 4-minute cycling HIIT exercise session change circulating extracellular vesicle number and protein composition in young men?

## Summary

In 17 physically active young male baseball players, one 4-minute Tabata-style cycling HIIT session acutely raised pulse rate and systolic blood pressure and changed circulating extracellular vesicle number and protein composition, but it was a mechanistic acute study rather than a training trial.

## Population

- Physically active young male university baseball players.
- Sample size: 17
- Age: Median 20 years
- Sex: Male
- Fitness level: Physically active athletes
- Health status: Young active men; detailed health exclusions not reported

## Methodology

- Prospective single-arm acute exercise study
- Single acute HIIT session with blood sampling through 120 min post-exercise
- University laboratory cycling exercise

## Protocol

- 4-minute cycling HIIT-Ex.
- Modality: Cycle ergometer.
- Work intervals: 20 s at 140% VO2max workload.
- Recovery: 10 s rest.
- Sets or repetitions: 8.
- Intensity: 140% VO2max workload.
- Session duration: 4 min HIIT plus 10 min warm-up and 5 min rest.
- Frequency: Single acute session.
- Program length: Single session.
- Progression: None.
- Pre-HIIT baseline.

## Outcomes

### Pulse/BP
Status: mixed
Pulse and systolic blood pressure rose immediately; diastolic blood pressure did not rise immediately and was lower at 30 min.

Pulse p<0.001; systolic BP p<0.05; diastolic BP at T30 p<0.05.

### EV number
Status: mixed
EV number was reduced at 30 and 120 min, while 11 of 17 participants showed immediate increases.

T30 vs pre p<0.01; T120 vs pre p<0.05.

### EV proteins
Status: mixed
Twenty EV proteins changed, including proteins related to coagulation, antioxidant response, and acid-base balance.

Selected proteins changed with p values from <0.05 to <0.0001.

## Practical Insights

- A 4-minute Tabata-style session is enough to cause measurable acute biological changes.
- Acute EV and proteomic findings should not be converted into claims about fitness or health outcomes.
- Short supramaximal intervals need screening and monitoring.

## Limitations

- Acute-only study
- No control group
- Small young male athletic sample
- Proteomics subset included only three selected responders
- Surrogate mechanistic outcomes

## Safety And Adherence

- No adverse events or injuries were reported.
- Pulse rate and systolic/diastolic blood pressure were measured before and after HIIT; pulse and systolic blood pressure increased immediately post-exercise.
- The study was limited to active young men, so safety cannot be generalized to sedentary or higher-risk users.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/34276412/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2021.693007) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8280769/) (full text)

## Agent Guidance

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