# Effects of low and high intensity interval training exercises on VO(2max) and components of neuromuscular and vascular system in male volunteers

PMID: 36046991
Journal: Journal of musculoskeletal & neuronal interactions
Published: 2022 Sep 1
Authors: Eken Ö, Kafkas ME

## Question

How do low- and high-intensity bodyweight interval training affect VO2max, Yo-Yo IR-1 performance, and serum BDNF, TrkB, VEGF, PGC-1alpha, and irisin in inactive male volunteers?

## Summary

In physically inactive young men, 4 weeks of bodyweight interval training at either low or high heart-rate intensity improved reported VO2max and several blood biomarkers, with high intensity generally showing larger effects. Several results relied on surrogate biomarkers and some interaction tests were not significant.

## Population

- Male volunteers without regular exercise habits.
- Sample size: 36
- Age: CNT 22.00 +/- 1.65; HIIT 20.83 +/- 2.32; LIIT 22.66 +/- 2.74 years
- Sex: male only
- Fitness level: physically inactive/no regular exercise habits
- Health status: no health problems limiting testing or exercise; no upper/lower extremity injury in previous 6 months

## Methodology

- three parallel-group randomized controlled trial
- 4 weeks
- exercise sessions with heart-rate monitors; Yo-Yo test on a 20 m indoor running track
- Randomized and controlled study design.

## Protocol

- Bodyweight HIIT.
- Modality: bodyweight circuit.
- Work intervals: 20 s.
- Recovery: 20 s rest; 3 min between cycles.
- Sets or repetitions: 8 movements x 3 cycles.
- Intensity: 85-90% maximum heart-rate intensity.
- Session duration: 25 min main session.
- Frequency: 2 sessions/week on non-consecutive days.
- Program length: 4 weeks.
- Progression: same structure across first 4 weeks.
- Bodyweight LIIT and non-exercise control.
- Modality: bodyweight circuit.
- Work intervals: 20 s.
- Recovery: 20 s rest; 3 min between cycles.
- Sets or repetitions: 8 movements x 3 cycles.
- Intensity: LIIT 57-64% maximum heart-rate intensity; control did not exercise.
- Session duration: 25 min for LIIT.
- Frequency: 2 sessions/week for LIIT.
- Program length: 4 weeks.
- Progression: same as first 4 weeks.

## Outcomes

### VO2max
Status: mixed
Groups differed, but the measurement interaction was not significant.

between-groups p=0.004; interaction p=0.523; measurement effect p reported as >0.05

### Biomarkers
Status: improved
The authors reported higher BDNF, TrkB, PGC-1alpha, VEGF, and irisin values after interval training, especially HIIT.

significant interactions for PGC-1alpha p=0.031, TrkB p=0.003, and VEGF p=0.001; no significant interaction for BDNF p=0.270 or irisin p=0.308

### HIIT vs LIIT
Status: mixed
Authors concluded HIIT had greater effects than LIIT, but not every outcome showed a significant group-by-time interaction.

Yo-Yo IR-1 and VO2max group differences significant; interactions not significant

## Practical Insights

- The protocol is directly recognizable as a 20 s work/20 s rest bodyweight circuit.
- Heart-rate monitoring and coaching were used to keep participants in target intensity zones.
- Claims about brain, vascular, and metabolic benefits should be qualified because many outcomes were serum biomarkers.

## Limitations

- Small sample size.
- Healthy male participants only.
- Short 4-week intervention.
- Several endpoints are surrogate biomarkers.
- Some interaction tests were not significant despite broad positive conclusions.

## Safety And Adherence

- No adverse events were reported; participants had no recent upper/lower extremity injury and HR was monitored during exercise.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/36046991/) (pubmed)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9438513/) (full text)

## Agent Guidance

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