Using 13C MRS to monitor the effects of gonadal steroids throughout the menstrual cycle on substrate utilisation

Motivation: The menstrual cycle has been shown to effect substrate utilisation in response to exercise, but the impact during varying stages within the follicular and luteal phase is less known and can provide useful insight into metabolic processes and athletic performance. Goal(s): To monitor the effects of the menstrual cycle on substrate utilisation. Approach: 13C MRS and blood sampling was used to measure exercise induced changes in muscle glycogen, liver glycogen, blood glucose and fatty acid concentration in the early- and late- follicular and luteal phases. Results: Muscle glycogen utilisation was reduced in the early follicular phase, with a potential shift to lipid oxidation. Impact: This study provides novel in-vivo data of exercise induced changes in substrate utilisation which can be used to inform future research and interventions in energy metabolism. Data provides useful knowledge in sports science and medicine.