PMID 30057778

Research
All papers

Women undergoing assisted fertilisation and high-intensity interval training: a pilot randomised controlled trial

Kiel IA, Lundgren KM, Mørkved S, Kjøtrød SB, Salvesen Ø, Romundstad LB, Moholdt T

Question

Does HIT before assisted fertilisation improve pregnancy rates and metabolic factors in overweight or obese women?

Summary

In a small pilot RCT of overweight or obese women waiting for assisted fertilisation, 10 weeks of supervised and diary-recorded HIT improved insulin sensitivity, fasting glucose, waist circumference, visceral fat, and VO2peak, but pregnancy rates were similar to usual care. The trial was stopped early because recruitment was much slower than planned.

Methodology

  • Overweight or obese women accepted for assisted fertilisation.
  • 18 participants.
  • Aerobic gym-based intervals.
  • Work intervals: 4 minutes or 1 minute.
  • Intensity: 85-95% HRmax for 4 x 4; maximum intensity for 10 x 1.
  • 3 sessions/week.
  • 10 weeks.
  • Pilot randomized controlled trial
  • Ongoing pregnancy, Insulin sensitivity, VO2peak, and Abdominal fat were tracked.

Outcomes

Pregnancy

Pregnancy occurred in 4/8 HIT participants and 4/9 control participants.

Between-group p=0.6.

No clear change

Insulin sensitivity

M-value improved by 23% in HIT and did not improve in control.

Between-group p=0.04; HIT within-group p=0.02.

Improved

VO2peak

VO2peak increased within HIT, but the between-group difference was not statistically significant.

HIT +2.6 mL/kg/min; between-group p=0.10.

Mixed

Abdominal fat

Visceral fat and waist circumference decreased within HIT, with trends but no significant between-group differences.

Fat mass p=0.06 and visceral fat p=0.08 between groups.

Mixed

Insights

  • Heart-rate-guided HIT can be feasible in a motivated, screened clinical group.
  • Metabolic improvements can occur even without significant body weight loss.
  • Do not use this pilot as evidence that HIT improves assisted fertilisation success.

Limitations

  • Severely underpowered because recruitment stopped at 18 participants.
  • Only 13 participants had post-intervention data.
  • Participants self-selected into a demanding exercise trial.
  • Control-group timing changed during the trial.
  • Several outcome assessors were not blinded.

Safety

  • No adverse events were reported during the intervention period.