# Effects of high-intensity interval training on vascular function and maximum oxygen uptake in young sedentary females

PMID: 31983915
Journal: International journal of health sciences
Published: 2020 Jan-Feb
Authors: Chidnok W, Wadthaisong M, Iamsongkham P, Mheonprayoon W, Wirajalarbha W, Thitiwuthikiat P, Siriwittayawan D, Vachirasrisirikul S, Nuamchit T

## Question

Does 6 weeks of supervised cycling HIIT improve vascular function and cardiorespiratory fitness in sedentary young adults?

## Summary

In sedentary young women, 6 weeks of supervised cycling HIIT improved flow-mediated dilation and VO2max within the HIIT group, and FMD was higher than control after training. The protocol was 25 minutes per session, three times weekly, with five 1-minute cycling bouts at at least 80% maximum heart rate separated by 2-minute recoveries.

## Population

- Sedentary healthy young women
- Sample size: 22
- Age: 21 +/- 0.7 years
- Sex: Women completers
- Fitness level: Sedentary
- Health status: Lean with no underlying diseases

## Methodology

- Randomized controlled pilot intervention
- 6 weeks
- Supervised laboratory cycling sessions
- Randomized and controlled study design.

## Protocol

- Cycling HIIT.
- Modality: Cycle ergometer.
- Work intervals: 1 minute.
- Recovery: 2 minutes.
- Sets or repetitions: 5 bouts.
- Intensity: At least 80% MHR.
- Session duration: 25 minutes.
- Frequency: 3 sessions per week.
- Program length: 6 weeks.
- Progression: No progression reported.
- No-exercise control.
- Modality: No structured exercise.
- Program length: 6 weeks.

## Outcomes

### FMD
Status: improved
HIIT improved FMD from baseline and had higher post-training FMD than control.

HIIT 9.26 +/- 6.5% to 14.01 +/- 4.3%, p<0.05; post HIIT vs control 14.01 +/- 4.3% vs 9.15 +/- 4.16%, p<0.05.

### VO2max
Status: improved
VO2max increased significantly within the HIIT group.

20.10 +/- 4.31 to 24.34 +/- 5.71 ml/kg/min, p<0.05.

### CAVI
Status: improved
CAVI improved within the HIIT group, while values remained in normal range.

5.91 +/- 0.58 after vs 6.22 +/- 0.86 before, p<0.05; abstract reports 6.39 +/- 0.76 vs 5.91 +/- 0.58.

### Weight
Status: no clear change
Weight and BMI did not significantly change.

## Practical Insights

- A 5x1-minute cycling HIIT session can be time efficient and tolerable in screened sedentary young women.
- Do not use this paper for weight-loss claims.

## Limitations

- Male participants dropped out
- Small sample
- No dietary control
- Outside physical activity not reported

## Safety And Adherence

- No injuries occurred.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/31983915/) (pubmed)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6968882/) (full text)

## Agent Guidance

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