PMID 32848854

Research
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Circulating and Adipose Tissue miRNAs in Women With Polycystic Ovary Syndrome and Responses to High-Intensity Interval Training

Lionett S, Kiel IA, Camera DM, Vanky E, Parr EB, Lydersen S, Hawley JA, Moholdt T

Question

How do selected circulating and adipose-tissue miRNAs differ in women with PCOS and how do they respond to 16 weeks of low- or high-volume HIT?

Summary

This randomized trial in women with PCOS compared 16 weeks of low-volume HIT, high-volume HIT, and non-exercise control. High-volume HIT improved VO2peak, low-volume HIT reduced circulating miR-27b, and neither protocol changed body composition or adipose-tissue miRNA expression.

Methodology

  • Women aged 18-45 years with PCOS; separate matched non-PCOS comparison group for baseline profiles
  • 54 participants.
  • Aerobic HIT.
  • Work intervals: LV-HIT 1 minute; HV-HIT 4 minutes.
  • Recovery: LV-HIT 1 minute passive or low-intensity walking; HV-HIT 3 minutes active recovery at about 70% HRmax.
  • Intensity: Maximal sustainable intensity or 90-95% HRmax.
  • LV-HIT about 33 minutes including warm-up/cool-down; HV-HIT about 41 minutes if each bout was followed by active recovery.
  • 3 sessions/week.
  • 16 weeks.
  • Two-center randomized controlled exercise trial with matched non-PCOS comparison for baseline miRNA profiles
  • miRNA expression, VO2peak, and Body composition were tracked.

Outcomes

c-miR-27b

Women with PCOS had higher basal circulating miR-27b; LV-HIT reduced it, but HV-HIT did not.

PCOS vs non-PCOS p=0.006; LV-HIT 0.5-fold decrease p=0.007.

Mixed

VO2peak

Only HV-HIT significantly increased VO2peak.

VO2peak L/min +9%, p=0.008.

Improved

Body composition

No body composition changes were detected.

No clear change

AT miRNAs

Gluteal and abdominal adipose-tissue miRNAs were not altered by either HIT protocol.

No clear change

Insights

  • Four-by-four-minute HIT is more clearly tied to VO2peak improvement in this PCOS sample than the 10 x 1-minute protocol.
  • Mechanistic biomarker changes should not be equated with user-facing health outcomes.

Limitations

  • Small groups
  • Targeted miRNA panel
  • Mechanistic endpoints
  • PCOS-specific population

Safety

  • Article did not report adverse events, injuries, dropout counts, or actual attendance/adherence rates.
  • Participants were screened out for cardiovascular disease, other endocrine disorders, pregnancy/breastfeeding within 24 weeks, exercise-limiting ailments or injuries, and relevant medication use without washout.
  • At least one weekly session was supervised and Polar M400 heart-rate monitors were worn during all sessions to ensure protocol compliance.