Abstract
Background: Problematic low energy availability (LEA), the underlying aetiology of Relative Energy Deficiency in Sport (REDs), can have catastrophic consequences on an athlete’s health and career. The condition is challenging to diagnose and treat due to the available assessment tools being costly, time-consuming, and requiring specialised equipment and expertise. Moreover, the evidence base for developing effective treatment plans to improve energy availability (EA), which is essential for REDs recovery, remains insufficient. Further, there is a scarcity of evidence derived from those with a clinical diagnosis of REDs.
Methods: Study 1 (Chapter 3) is a cross-sectional retrospective study whereby 55 females (mean age 25.6 ± 6.3 years) clinically diagnosed with REDs completed an online questionnaire to capture their experience of a sports dietitian consultation and implementing a personalised energy intake (EI) plan. Study 2 (Chapter 4) is a cross-sectional feasibility intervention study of 19 females, nine with a clinical diagnosis of REDs (mean age 28.5 ± 6.9 years) and 10 healthy matched controls (mean age 30.4 ± 7.5 years). Four days of dietary intake and eight days of exercise and interstitial glucose data (via continuous glucose monitoring (CGM)) were collected. Study 3 (Chapter 5) is a qualitative study with eight female REDs participants (mean age 26.75 ±6.44 years) completing individual, semi-structured interviews exploring the acceptability of using CGM during the recovery of REDs. Data was analysed using inductive thematic analysis, and relevant data was mapped using the capability, opportunity, and motivation behaviour model.
Results: Study 1: Participants reported they significantly underestimated their estimated energy expenditure and required EI (87% and 93%, respectively). Intake pre-exercise was implemented most frequently (69%, n=38) and least likely to elicit feelings of stress and anxiety (69%, n=38). Weight gain/shape change was the most frequently reported barrier to implementation (62%, n=34). Study 2: The groups had no significant differences in mean interstitial glucose or glycaemic variability. A significant negative correlation between nocturnal mean interstitial glucose and carbohydrate intake was evident in the REDs group (r=-0.698, p=0.04) and a converse moderate positive correlation in the controls (r=0.415, p=0.23). A similar opposing correlation was observed for carbohydrate intake and nocturnal mean amplitude of glycaemic excursion (REDs r=-0.592, p=0.09, control r=0.716, p=0.02). Study 3: Two themes emerged. The first, “Tolerated technology”, captured the participants’ experience using CGM while recovering from REDs. The second theme, “Engagement with the data”, identified how the physical opportunity of CGM provided the reflective motivation to change eating behaviour before exercise.
Conclusion: Study 1: In the recovery of REDs, providing the athlete with education on their current and required EA, alongside a personalised EI plan structured around exercise, may provide the “lightbulb” moment needed to overcome the associated anxiety with increasing EI.
Studies 2 and 3: Opposing perturbations of glycaemic control to low carbohydrate availability in the REDs and control group were unexpected but may be explained by the REDs group undergoing adaptive homeostasis to maintain blood glucose availability. Due to the conflicting evidence, CGM is not currently an applicable diagnostic or monitoring tool for athletes with problematic LEA. However, CGM may have the potential to create behavioural changes in nutrition around exercise.