What is REDs?
Relative Energy Deficiency (REDs) is a syndrome of impaired physiological and/or psychological functioning experienced by female and male athletes that is caused by exposure to problematic (prolonged and/or severe) low energy availability (LEA) (IOC, 2023). Problematic LEA is where an individual’s dietary energy intake is insufficient to support the energy expenditure required for health, function, and daily living once the cost of exercise and sporting activities is taken into account (IOC, 2023). So, REDs is essentially the bad outcomes that occur from chronic inadequate energy intake.
How can REDs affect you?
REDs can have detrimental impacts on an athletes health and performance. Associated detrimental outcomes include but are not limited to decreases in metabolic function, reproductive function, as well as compromised musculoskeletal, cardiovascular and haematological health, which can individually and synergistically lead to impaired well-being, increased injury risk, and decreased sports performance (Mountjoy et al., 2023). The International Olympic Committee (IOC) REDs Clinical Assessment Tool Version 2 (CAT2), published in 2023, conceptualised the negative consequences of REDs on athlete health and performance.
The REDs health conceptual model highlights the following as potential health consequences of REDs (IOC, 2023):
- Impaired reproductive function
- Impaired bone health
- Impaired gastrointestinal function
- Impaired energy metabolism/regulation
- Impaired haematological function
- Urinary incontinence
- Impaired glucose & lipid metabolism
- Mental health issues (can be the result of and/or the cause of REDs)
- Sleep disturbances
- Impaired cardiovascular function
- Reduced skeletal muscle function
- Impaired growth & development
- Reduced immunity
The REDs performance conceptual model highlights the following as potential performance consequences of REDs (IOC, 2023):
- Decreased athlete availability
- Decreased training response
- Decreased recovery
- Decreased cognitive performance/skill
- Decreased motivation
- Decreased muscle strength
- Decreased endurance performance
- Decreased power performance
Whilst these are the identified adverse REDs outcomes, it is unlikely that athletes in a state of REDs will experience all of these health and performance issues simultaneously. Further, the signs and symptoms associated with REDs could be attributed to other health issues. Therefore, screening and diagnosis of REDs is difficult.
Is REDs the same as an eating disorder?
Whilst the negative health and performance outcomes of REDs are very similar to those that would be experienced by an athlete clinically diagnosed with an eating disorder (ED), they are not the same. The IOC REDs CAT2 screening tool divides symptoms into severe primary indicators, primary indicators, secondary indicators, and potential indicators. A clinical diagnosis of an ED or an elevated score for the Eating Disorder Examination Questionnaire is a primary indicator of REDs, therefore it is a significant symptom, however diagnosis of an ED in itself does not confirm a REDs diagnosis. Similarly, diagnosis of REDs does not confirm diagnosis of an ED.
However, there is discussion around whether REDs can occur without disordered eating. Disordered eating refers to abnormal eating patterns that do not meet the criteria for clinical diagnosis of an ED. Jeukedrup et al. (2024) argue that whilst it is possible to inadvertently be in a state of LEA for a short period of time, it is unlikely that this energy deficit could become chronic by accident. Therefore, these authors are not convinced that REDs can occur without the presence disordered eating.
Is REDs a prevalent issue?
The 2023 IOC consensus statement on REDs reported a prevalence range of 23-79.5% in females and 15-70% in males (Mountjoy et al., 2023). However, not all sporting cohorts have been researched in the same depth. Most studies investigating REDs have focused on female athletes in aesthetic, endurance, or weight-restricted sports as these cohorts are deemed at greater risk of REDs due to the attention placed on body image and/or weight in these sports. Despite this, research indicates that REDs may also be a prevalent issue in the male and/or team ball sport population. Therefore, as my first PhD study, we completed a systematic review to investigate the prevalence of REDs among elite adult team ball sport athletes. This review of 14 studies analysed REDs and LEA prevalence in elite adult team ball sport athletes and identified a prevalence range of 0-80% among participants. Whilst this indicates that REDs and LEA may be prevalent issues among team ball sport athletes, the varied use of methods to assess REDs across and within studies weakens the reliability of results. The IOC REDs CAT2 does not name a single criterion method to identify REDs, in fact there are 13 separate questionnaires recommended to initially screen for the syndrome. Therefore, whilst we currently believe that REDs prevalence may be significantly high among athlete populations, the sensitivity and validity of methods of assessment can be bought into question.
My PhD investigates REDs in Rugby. Following the systematic review on REDs in team ball sport athletes, we are examining the knowledge and reporting of REDs in Rugby players, coaches, and medical support staff internationally. This will be a key component for improving the recognition and reporting of REDs signs and symptoms.
References
Jeukendrup, A. E., Areta, J. L., Van Genechten, L., Langan-Evans, C., Pedlar, C. R., Rodas, G., Sale, C., & Walsh, N. P. (2024). Does Relative Energy Deficiency in Sport (REDs) Syndrome Exist? Sports Medicine, 54(11), 2793–2816. https://doi.org/10.1007/s40279-024-02108-y
Medicine, B. P. G. L. and B. A. of S. and E. (2023). International olympic committee relative energy deficiency in sport clinical assessment tool 2 (IOC REDs CAT2). British Journal of Sports Medicine, 57(17), 1068–1069. https://doi.org/10.1136/bjsports-2023-107549
Mountjoy, M., Ackerman, K. E., Bailey, D. M., Burke, L. M., Constantini, N., Hackney, A. C., Heikura, I. A., Melin, A., Pensgaard, A. M., Stellingwerff, T., Sundgot-Borgen, J. K., Torstveit, M. K., Jacobsen, A. U., Verhagen, E., Budgett, R., Engebretsen, L., & Erdener, U. (2023). 2023 International Olympic Committee’s (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine, 57(17), 1073–1098. https://doi.org/10.1136/bjsports-2023-106994
Tabby Billingham is a PhD researcher working in the Irish Rugby Injury Surveillance (IRIS) Group in the Department of Physical Education and Sport Sciences at the University of Limerick. Her research focuses on Relative Energy Deficiency in Sport (REDs) in Rugby. Tabby is supervised by Professor Ian Kenny, Professor Tom Comyns, Dr Catherine Norton, and Professor Giles Warrington.
Contact: Email billingham.tabitha@ul.ie Follow on X: @tabbybillingham ORCID ResearchGate LinkedIn
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