Training in the Fasted State, Glucose Metabolism and Energy Balance
Research type
Research Study
Full title
Can exercise in the fasted state unlock metabolic health benefits for overweight and obese individuals?
IRAS ID
209109
Contact name
Javier Gonzalez
Contact email
Sponsor organisation
University of Bath
Clinicaltrials.gov Identifier
Duration of Study in the UK
1 years, 3 months, 1 days
Research summary
Research Summary
Insufficient physical activity can contribute to skeletal muscle insulin resistance, the first detectable defect in individuals at high risk of type 2 diabetes. An acute bout of exercise enhances skeletal muscle insulin sensitivity for up to 72 hours after completion. Regular training also increases the content of proteins in muscle involved in insulin signalling pathways, improving insulin sensitivity and in the long-term, whole-body tolerance to glucose. However, exercise interventions in a ‘real world’ setting do not always report expected results in this respect. One explanation is that these studies do not control for the feeding status in which exercise is performed and this might hold the key to improving their effectiveness.\n\nExercise in a fasted state may result in improved whole-body glucose tolerance and augmented muscle-specific adaptations, compared to exercise after a meal (Van Proeyen et al., 2010; 2011). However, this research is limited to athletic populations and not with those at risk of metabolic diseases.\n\nThe objective of this project is to investigate the effects of a six-week exercise intervention, performed either fasted or in the fed state, on whole body glucose tolerance, changes in cardio-respiratory fitness (VO2max) body mass index and the waist-to-hip ratio. We also want to investigate changes in the characteristics of skeletal muscle myotubes (muscle cells) ex vivo, and the content of proteins involved in insulin signalling and glucose transport within skeletal muscle. We will also measure subsequent energy intake and expenditure to investigate how the training may influence energy balance. \n\nParticipants who will be overweight (BMI > 25 kg/m2) and unaccustomed to structured exercise, will be randomised to either a 1) fasted exercise, 2) fed exercise or 3) control group. Training will be cycling exercise (increasing from 30 to 50 mins and 50 to 70% maximal power output), three times weekly, for six weeks.
Summary of Results
The aim of this study was to assess if blood sugar control is improved to a greater extent when exercise training is performed after an overnight fast (before breakfast), when compared with exercise performed after breakfast. We found that exercise training performed before breakfast improved blood sugar control to a greater extent than when exercise was performed after breakfast. In addition, a number of adaptations within the muscles of these people were greater after exercise performed before breakfast, which might (in part) explain why blood sugar control was improved.
REC name
South West - Central Bristol Research Ethics Committee
REC reference
16/SW/0260
Date of REC Opinion
25 Oct 2016
REC opinion
Further Information Favourable Opinion