# Small non-coding RNAs are altered by short-term sprint interval training in men

PMID: 29611322
Journal: Physiological Reports
Published: 2018
Authors: Denham J, Gray AJ, Scott-Hamilton J, Hagstrom AD, Murphy AJ

## Question

Does short-term sprint interval training alter circulating small non-coding RNAs in whole blood, and are chronically changed miRNAs also changed after one acute SIT session?

## Summary

Ten healthy untrained men completed six weeks of cycle sprint interval training and improved VO2max, maximal power, and functional threshold power while many circulating small non-coding RNAs changed.

## Population

- Apparently healthy recreationally active but aerobically untrained men in the training cohort.
- Sample size: 10
- Age: 33.3 +/- 10.9 years
- Sex: Male
- Fitness level: Recreationally active, not structured aerobic training
- Health status: Apparently healthy after ESSA and medical questionnaire screening

## Methodology

- Single-group pre-post training study plus separate acute SIT trial
- 6 weeks for training cohort; one session for acute cohort
- Cycle ergometer training/testing with blood sampling

## Protocol

- Cycle sprint interval training.
- Modality: Cycle ergometer.
- Work intervals: Maximal efforts; acute trial explicitly four 30 s sprints.
- Recovery: 4 min between sets.
- Sets or repetitions: 4-6.
- Intensity: Maximal.
- Session duration: Not fully reported.
- Frequency: 3 sessions/week.
- Program length: 6 weeks.
- Progression: Not fully reported.

## Outcomes

### VO2max
Status: improved
Relative VO2max increased after six weeks.

42.8 +/- 6.2 to 46.2 +/- 6.0 mL/kg/min; p=0.006.

### Cycling power
Status: improved
Pmax and FTP improved; Wingate mean/peak power did not significantly change.

Pmax/kg p=0.001; FTP/kg p<0.001; Wingate mean/peak p>0.05.

### Small RNAs
Status: mixed
Many circulating small ncRNAs changed after chronic SIT; acute SIT did not consistently change selected miRNAs.

1266 small ncRNAs q<0.05; 13 miRNAs q<0.05; acute all p>0.05.

## Practical Insights

- Short-term SIT can improve VO2max and cycling threshold power in healthy men.
- Small RNA findings are mechanistic and should not be turned into consumer claims yet.

## Limitations

- No control group
- Small male cohort
- Diet, sleep, stress, and anxiety not monitored
- Biological function of ncRNA changes not established
- Training protocol details partly deferred to prior publications

## Safety And Adherence

- No adverse events were reported.
- Participants were apparently healthy by ESSA prescreening and medical questionnaires, gave written informed consent, and the study had ethics approval.
- Ten men completed the six-week SIT cohort; recruitment dropouts and detailed session attendance were not reported in this article.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/29611322/) (pubmed)
- [DOI](https://doi.org/10.14814/phy2.13653) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5880879/) (full text)

## Agent Guidance

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