# Inflammatory cytokines and metabolic responses to high-intensity intermittent training: effect of the exercise intensity

PMID: 35309531
Journal: Biology of sport
Published: 2022 Mar
Authors: Rhibi F, Zouhal H, Lira FS, Ouerghi N, Prioux J, Besbes S, Tijani JM, Hackney AC, Ben Abderrahman A

## Question

Do 8-week HIIT programs at 100% versus 110% maximal aerobic velocity produce different metabolic, hormonal, and inflammatory adaptations in young men?

## Summary

In young active men, 8 weeks of outdoor running HIIT using 30-second work and 30-second active recovery improved maximal aerobic velocity and reduced several inflammatory and metabolic responses to an intermittent exercise test. Training at 110% of maximal aerobic velocity generally produced larger improvements than 100% MAV, and no test or training injuries were reported.

## Population

- Young active male physical education students
- Sample size: 37
- Age: Group means about 21.3-22.1 years
- Sex: Male only
- Fitness level: Active students with MAV about 16 km/h
- Health status: Healthy after medical examination

## Methodology

- Randomized controlled training study with two HIIT groups and two control test groups
- 8 weeks
- Outdoor 400 m track with laboratory blood analysis
- Randomized and controlled study design.

## Protocol

- HIIT 100%/110% MAV.
- Modality: Track running.
- Work intervals: 30 s at 100% or 110% MAV.
- Recovery: 30 s active recovery at 50% MAV.
- Sets or repetitions: 2 sets of 8-12 repetitions.
- Intensity: 100% MAV or 110% MAV.
- Session duration: Variable, with warm-up and cooldown.
- Frequency: 3 sessions/week.
- Program length: 8 weeks.
- Progression: Repetition count progressed across weeks with planned volume reductions.
- Control.
- Modality: Testing only.
- Intensity: No physical training program.
- Program length: 8 weeks.
- Progression: No training.

## Outcomes

### MAV
Status: improved
Both HIIT protocols increased maximal aerobic velocity, with greater increase at 110% MAV.

EG100 +5.4%, p<0.001; EG110 +8.5%, p<0.001; EG110 vs EG100 p=0.017.

### Glucose
Status: improved
Glucose response at end HIIE decreased after HIIT, especially at 110% MAV.

EG100 Glu_end -14.7%, p=0.009; EG110 Glu_end -18.8%, p<0.001; EG110 lower than EG100 p=0.012.

### IL-6
Status: improved
IL-6 decreased at rest, end exercise, and 15-min recovery after both protocols.

EG100 IL-6rest -34.4%, IL-6end -33.7%; EG110 IL-6rest -40.8%, IL-6end -22.8%; all p<0.001.

### Safety
Status: no clear change
No training- or test-related injuries occurred and adherence was complete.

100% adherence and compliance reported.

## Practical Insights

- A progressive 30/30 running format can be advanced by adding repetitions within two sets.
- Supramaximal 110% MAV intervals may provide stronger performance and biomarker adaptations in already active young men.

## Limitations

- Small groups
- Male-only
- Active young adults only
- Biomarker surrogate outcomes
- MAV testing required

## Safety And Adherence

- No test or training-related injuries occurred.
- All subjects had 100% adherence and compliance.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/35309531/) (pubmed)
- [DOI](https://doi.org/10.5114/biolsport.2022.104914) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8919870/) (full text)

## Agent Guidance

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