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Isolated and combined effects of high-intensity interval training and time-restricted eating on glycaemic control in reproductive-aged women with overweight or obesity: study protocol for a four-armed randomised controlled trial
  1. Trine Moholdt1,2,
  2. Catalina P Silva1,
  3. Stian Lydersen3,
  4. John A Hawley4
  1. 1 Department of Circulation and Medical Imaging, Norwegian University of Science and Technology Faculty of Medicine and Health Sciences, Trondheim, Sør-Trøndelag, Norway
  2. 2 Department of Obstetrics and Gynaecology, St Olavs Hospital University Hospital in Trondheim, Trondheim, Norway
  3. 3 Regional Centre for Child and Youth Mental Health and Child Welfare, Department of Mental Health, Norwegian University of Science and Technology Faculty of Medicine and Health Sciences, Trondheim, Sør-Trøndelag, Norway
  4. 4 Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, Australia
  1. Correspondence to Dr Trine Moholdt; trine.moholdt{at}


Introduction Overweight and obesity in reproductive-aged women is a global problem due to the increased risk of subfertility, pregnancy complications and cardiometabolic diseases. High-intensity interval training and time-restricted eating are two primary lifestyle interventions that, independently, have positive effects on a range of health outcomes. Whether these two strategies have synergistic effects is currently unknown. Our primary aim is to determine the isolated and combined effect of high-intensity interval training and time-restricted eating on glycaemic control in reproductive-aged women with overweight/obesity.

Methods and analysis The study is a randomised controlled trial with four parallel groups. Women (N=120) aged 18–45 years with body mass index ≥27 kg/m2 will be randomly allocated (1:1:1:1) to either: (1) high-intensity interval training, (2) time-restricted eating, (3) a combination of high-intensity interval training and of time-restricted eating, or (4) a control group. The duration of each intervention will be 7 weeks. The primary outcome measure will be glycaemic control, determined by the total area under the plasma glucose curve over 2 hours after a 75-gram oral glucose tolerance test. Secondary outcome measurements will include markers of cardiovascular and metabolic health (peak oxygen uptake, blood pressure, blood lipids, body composition, insulin sensitivity), sleep quality, physical activity, diet and adherence rates to the intervention.

Ethics and dissemination The Regional Committee Medical Research Ethics, Norway has approved the trial protocol. This study will provide important new knowledge to both the scientific community and the general population about the isolated and combined effects of two novel diet–exercise strategies on cardiovascular and metabolic health among women with overweight/obesity.

Trial registration number NCT04019860.

  • preventive medicine
  • sports medicine
  • public health
  • nutrition & dietetics

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  • Contributors TM drafted the manuscript. TM, JAH, CPS and SL conceived and contributed to the design of the study and to the plan for analyses. TM and CPS will coordinate the study, perform measurements on test days, monitor participants and supervise the exercise training. All authors provided feedback and approved the final manuscript.

  • Funding TM is supported by the EFSD/Novo Nordisk Foundation Future Leaders Awards Programme (NNF19SA058975). This work is supported by the Norwegian University of Science and Technology, by The Central Norway Regional Health Authority (2020/39645), and by a Novo Nordisk Foundation Challenge Grant (NNF14OC0011493) to JAH. The Unit for Applied Clinical Research, NTNU, provided the internet-based randomisation. The equipment and lab facilities for the training sessions and exercise testing will be provided by NeXt Move, Norwegian University of Science and Technology. NeXt Move is funded by the Faculty of Medicine and Health Sciences, NTNU and Central Norway Regional Health Authority.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.