# Effects of High Intensity Interval Training and Strength Training on Metabolic, Cardiovascular and Hormonal Outcomes in Women with Polycystic Ovary Syndrome: A Pilot Study

PMID: 26406234
Journal: PLOS ONE
Published: 2015
Authors: Almenning I, Rieber-Mohn A, Lundgren KM, Shetelig Løvvik T, Garnæs KK, Moholdt T

## Question

Do HIIT and strength training improve metabolic, cardiovascular, and hormonal outcomes in women with PCOS compared with usual-care control?

## Summary

In women with PCOS, 10 weeks of supervised HIIT improved insulin resistance and HDL cholesterol compared with control, while strength training improved some body-composition and hormonal outcomes. The study was small and exploratory.

## Population

- Women diagnosed with PCOS by Rotterdam criteria
- Sample size: 31
- Age: 27.2 +/- 5.5 years
- Sex: Female
- Fitness level: Excluded women already doing regular high-intensity endurance or strength training
- Health status: PCOS, mean BMI 26.7 +/- 6.0 kg/m2; medication restrictions applied

## Methodology

- Pilot three-arm randomized controlled trial
- 10 weeks
- Norwegian university/hospital exercise intervention
- Randomized and controlled study design.

## Protocol

- HIIT.
- Modality: Self-selected treadmill, outdoor walking/running, or cycling.
- Work intervals: Two weekly sessions of 4 x 4 minutes at 90-95% HRmax; one weekly session of 10 x 1 minute maximal/all-out efforts.
- Recovery: 3 minutes at about 70% HRmax for 4 x 4 sessions; 1 minute rest or very low activity for 10 x 1 sessions.
- Sets or repetitions: 2 sessions/week of 4 intervals and 1 session/week of 10 intervals.
- Intensity: 90-95% HRmax or maximal/all-out depending on session.
- Session duration: Not fully specified; structured interval sessions performed 3 times weekly.
- Frequency: 3 sessions per week.
- Program length: 10 weeks.
- Progression: Intensity and compliance monitored weekly through HR files and diary feedback.
- Strength training and control.
- Modality: Dynamic resistance training or usual-care activity recommendation.
- Work intervals: Strength: 8 exercises, 10 repetitions x 3 sets at 75% 1RM.
- Recovery: Strength: 1 minute rest between sets.
- Sets or repetitions: Strength 3 sessions/week; control recommended >=150 minutes/week moderate exercise without follow-up.
- Intensity: Strength 75% 1RM; control moderate activity advice.
- Session duration: Strength session duration not clearly specified.
- Frequency: 3 sessions per week for strength; no monitored frequency for control.
- Program length: 10 weeks.
- Progression: Strength load increased progressively.

## Outcomes

### HOMA-IR
Status: improved
Insulin resistance improved after HIIT compared with control.

HIT change -0.83, 95% CI -1.45 to -0.20; between-group p=0.014; HIT vs control p=0.013.

### HDL
Status: improved
HDL cholesterol increased after HIIT.

HIT change +0.2 mmol/L, 95% CI 0.02 to 0.5; between-group p=0.04.

### Body fat
Status: improved
Fat percentage decreased after both HIIT and strength training, while body weight and waist circumference did not clearly change.

Fat percentage decreased by -0.9 after HIT and -1.6 after strength training; weight and waist were unchanged.

### FMD
Status: mixed
Flow-mediated dilation increased after HIIT, but the between-group test was not conventionally significant.

HIT change +2.0 percentage points, 95% CI 0.1 to 4.0; between-group p=0.08.

## Practical Insights

- A mixed HIIT week combining 4 x 4 minute intervals and 1-minute maximal intervals was feasible for many women with PCOS.
- Heart-rate monitoring and weekly diary review supported intensity fidelity.
- Clinical PCOS programming should account for dropout and medication/diet confounding.

## Limitations

- Pilot sample with many outcomes and no multiple-testing adjustment.
- Participants using oral contraceptives were included if stable.
- Diet was not controlled.
- HOMA-IR was used rather than clamp methods.
- The HIIT arm combined two different interval protocols.

## Safety And Adherence

- The authors reported no adverse events. Six of 31 women dropped out during the study.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/26406234/) (pubmed)
- [DOI](https://doi.org/10.1371/journal.pone.0138793) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4583183/) (full text)

## Agent Guidance

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