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

PMID: 30057778
Journal: BMJ open sport & exercise medicine
Published: 2018
Authors: 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.

## Population

- Overweight or obese women accepted for assisted fertilisation.
- Sample size: 18
- Age: HIT 33.1 +/- 5.9 years; control 31.7 +/- 4.3 years
- Sex: Female only
- Fitness level: Not regular high-intensity exercisers
- Health status: BMI >25 kg/m2 and seeking assisted fertilisation

## Methodology

- Pilot randomized controlled trial
- 10-week intervention before assisted fertilisation
- Norwegian University of Science and Technology, St. Olavs Hospital, and local gym setting in Trondheim, Norway
- Randomized and controlled study design.

## Protocol

- HIT before assisted fertilisation.
- Modality: Aerobic gym-based intervals.
- Work intervals: 4 minutes or 1 minute.
- Sets or repetitions: Two sessions/week of 4 x 4 minutes; one session/week of 10 x 1 minute.
- Intensity: 85-95% HRmax for 4 x 4; maximum intensity for 10 x 1.
- Frequency: 3 sessions/week.
- Program length: 10 weeks.
- Progression: No explicit progression reported.
- Usual care.
- Modality: Physical-activity advice.
- Program length: 10 weeks before fertility treatment for the original protocol.

## Outcomes

### Pregnancy
Status: no clear change
Pregnancy occurred in 4/8 HIT participants and 4/9 control participants.

Between-group p=0.6.

### Insulin sensitivity
Status: improved
M-value improved by 23% in HIT and did not improve in control.

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

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

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

### Abdominal fat
Status: mixed
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.

## Practical 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 And Adherence

- No adverse events were reported during the intervention period.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/30057778/) (pubmed)
- [DOI](https://doi.org/10.1136/bmjsem-2018-000387) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6059324/) (full text)

## Agent Guidance

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