# IL-6, Antioxidant Capacity and Muscle Damage Markers Following High-Intensity Interval Training Protocols

PMID: 28469752
Journal: Journal of human kinetics
Published: 2017 Feb
Authors: Cipryan L

## Question

How do 15/15, 30/30, and 60/60 treadmill HIIT protocols with matched work differ in acute inflammatory, antioxidant, and muscle-damage markers?

## Summary

In twelve moderately trained young men, three short treadmill HIIT formats with the same work-rest ratio all increased IL-6, antioxidant capacity, and muscle-damage markers after exercise. The 30-second format produced smaller IL-6 and myoglobin responses than the 15-second and 60-second formats.

## Population

- Twelve healthy moderately trained young men.
- Sample size: 12
- Age: 22.8 +/- 1.7 years
- Sex: Male
- Fitness level: Moderately trained; VO2max 57.2 +/- 6.3 ml/kg/min
- Health status: Healthy

## Methodology

- Randomized-order acute crossover trial
- Three acute HIIT trials separated by 1-2 weeks
- Exercise physiology laboratory
- Randomized and controlled study design.

## Protocol

- Treadmill HIIT interval-duration protocols.
- Modality: Treadmill running.
- Work intervals: 15, 30, or 60 seconds.
- Recovery: Equal-duration active recovery.
- Sets or repetitions: 12-minute interval block; 6 minutes total work.
- Intensity: 100% vVO2max work; 60% vVO2max recovery.
- Session duration: 23 minutes.
- Frequency: Single acute session per protocol.
- Program length: Three acute trials separated by 1-2 weeks.
- Progression: None.
- Alternative HIIT timing formats.
- Modality: Treadmill running.
- Work intervals: 15, 30, or 60 seconds depending on comparator.
- Recovery: Equal-duration active recovery.
- Sets or repetitions: Matched 12-minute interval block.
- Intensity: 100% vVO2max work; 60% vVO2max recovery.
- Session duration: 23 minutes.
- Frequency: Single acute session per protocol.
- Program length: Three randomized trials.
- Progression: None.

## Outcomes

### IL-6
Status: mixed
All protocols increased IL-6; 15/15 and 60/60 produced larger effects than 30/30.

Effect sizes: 15/15 1.51, 30/30 0.84, 60/60 1.80.

### TAC
Status: improved
Total antioxidant capacity increased immediately after all protocols without major between-protocol differences.

Large immediate increases reported for all protocols.

### Muscle markers
Status: worse/safety concern
CK, myoglobin, and LDH rose after HIIT; myoglobin was lowest after 30/30.

Myoglobin effect sizes: 15/15 1.11, 30/30 0.45, 60/60 1.09.

## Practical Insights

- Equal work/rest HIIT formats are not equivalent for acute muscle and inflammatory markers.
- The 30/30 format may be a lower acute muscle-stress option than 15/15 or 60/60 in trained runners.

## Limitations

- Small all-male trained sample.
- Acute-only outcomes.
- Biomarkers are surrogate outcomes.
- Glycogen and direct RONS were not measured.

## Safety And Adherence

- No explicit adverse events, injuries, or symptoms were reported.
- Safety-relevant findings were biochemical: muscle-damage markers rose after all HIIT formats; testing involved screening, lab supervision, medical blood draws, and post-exercise rest.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/28469752/) (pubmed)
- [DOI](https://doi.org/10.1515/hukin-2017-0031) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5384061/) (full text)

## Agent Guidance

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