# Effects of High-Intensity Interval Training vs. Sprint Interval Training on Anthropometric Measures and Cardiorespiratory Fitness in Healthy Young Women

PMID: 30568598
Journal: Frontiers in Physiology
Published: 2018-12-05
Authors: Naves JPA, Viana RB, Rebelo ACS, de Lira CAB, Pimentel GD, Lobo PCB, de Oliveira JC, Ramirez-Campillo R, Gentil P

## Question

How do 8 weeks of cycling HIIT and sprint interval training compare for anthropometric measures and cardiorespiratory fitness in healthy young women?

## Summary

In 49 healthy active young women, both 8-week cycling HIIT and all-out sprint interval training improved VO2peak, waist circumference, and skinfold measures without reported dietary changes. SIT produced greater reductions in total skinfolds and was shorter per session, but the study lacked a no-exercise control group and was closely supervised one-to-one.

## Population

- Healthy physically active premenopausal women.
- Sample size: 49
- Age: 30.4 +/- 6.1 years
- Sex: Female only
- Fitness level: Physically active at least 150 minutes/week
- Health status: Healthy, BMI 18.5-29.9 kg/m2

## Methodology

- Randomized clinical trial comparing two interval-training protocols
- 8 weeks
- Standard fitness facility/laboratory cycle ergometer setting in Brazil
- Randomized and controlled study design.

## Protocol

- Cycling HIIT.
- Modality: Cycle ergometer.
- Work intervals: 4 minutes.
- Recovery: 3 minutes active recovery.
- Sets or repetitions: 4 bouts.
- Intensity: 90-95% HRpeak; recovery 50-60% HRpeak.
- Session duration: 33 minutes.
- Frequency: 3 sessions/week.
- Program length: 8 weeks.
- Progression: Load adjusted when HR deviated from target zone.
- Sprint interval training.
- Modality: Cycle ergometer.
- Work intervals: 30 seconds all-out.
- Recovery: 4 minutes passive or unloaded light cycling.
- Sets or repetitions: 4 bouts.
- Intensity: All-out; load adjusted to maintain cadence at least 60 rpm.
- Session duration: 23 minutes.
- Frequency: 3 sessions/week.
- Program length: 8 weeks.
- Progression: Load adjusted as needed for cadence.

## Outcomes

### VO2peak
Status: improved
Both HIIT and SIT improved VO2peak, with no significant between-group difference.

HIIT +14.5 +/- 22.9%, SIT +16.9 +/- 23.4%, both p<.001; between-group p=.097.

### Skinfolds
Status: improved
Both groups reduced skinfolds; SIT reduced the sum of skinfolds more than HIIT.

Sum skinfolds change favored SIT; between-group p=.045.

### Waist
Status: improved
Waist circumference decreased similarly in both groups.

HIIT -3.1 +/- 1.1%; SIT -3.3 +/- 1.8%; both p<.001; no between-group difference.

### Diet
Status: no clear change
Dietary intake did not significantly change in either group.

No significant between-group or pre-post dietary intake differences, p>.05.

## Practical Insights

- Both 4 x 4-minute HIIT and 4 x 30-second SIT are time-efficient cycling options for active young women.
- SIT may reduce skinfold measures more but uses all-out intensity and should be screened carefully.
- VO2peak gains were similar despite different session durations.

## Limitations

- No no-exercise control group.
- One-to-one supervision limits translation to unsupervised use.
- No VO2peak responder analysis.
- Skinfolds are less accurate than imaging or DXA.
- Healthy active female sample only.

## Safety And Adherence

- Researchers monitored for dizziness, nausea, and muscle soreness.
- No specific adverse-event counts were reported in the extracted results.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/30568598/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2018.01738) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6290642/) (full text)

## Agent Guidance

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