Dr Nicky Keay

Relative energy deficiency in sport (RED-S)[1] is a clinical syndrome encompassing adverse health and performance (figure 1) consequences of low energy availability (LEA)[2] in male[3] and female exercisers of all ages and all levels from recreational to elite.

LEA is a situation where energy intake is insufficient to cover the combined energy demands of training and baseline physiological processes to maintain health. LEA can arise unintentionally or intentionally (figure 2). Unintentional LEA results from increased training load, which is not matched by an increased energy intake. Intentional LEA is more likely to arise in sports where low body weight confers a performance or aesthetic advantage, for example, gravitational sports including cycling, ski-jumping, climbing; weight-category sports including boxing and judged artistic sports including gymnastics, aquatic disciplines. RED-S is also a risk in dancers of all genres, but in particular ballet[4]. Intentional LEA can be due to spectrum of disordered eating to eating disorders. The body responds to LEA by downregulating fundamental physiological processes. This ‘energy saving mode’ is of particular clinical significance in the endocrine network system (figure 3).

For women, LEA can manifest itself as menstrual disruption, in men this corresponds to low testosterone. The net effects of dysfunctional endocrine feedback loops are adverse effects on health and dampened response to training stimuli. For example, endocrine dysfunction manifests as suboptimal bone health with increased risk of bone stress injuries. Increased duration of LEA accrues cumulative effects on endocrine networks and hence health and performance (figure 2). Although the exerciser may initially improve athletic performance with short-term LEA, long-term LEA will lead to deterioration in health and performance.

Therefore, early identification of those at risk of LEA is essential in preventing the clinical consequences of RED-S. This is the purpose of the BASEM website Health4Performance[5] to raise awareness of RED-S among athletes/dancers, coaches, parents, friends and healthcare professionals to encourage a multidisciplinary team approach to identifying and supporting those at risk of RED-S.

Authors:

Dr Nicola Keay, Department of Sport and Exercise Sciences, Durham University, UK.

Dr Alan Rankin Department of Sports Medicine, Sport Ireland Institute, Dublin, Ireland

Br J Sports Med 2019;0:1–3. doi:10.1136/bjsports-2018-100354

References
1 Mountjoy M, Sundgot-Borgen J, Burke L, et al. The IOC consensus statement: beyond the Female Athlete Triad–Relative Energy Deficiency in Sport (RED-S). Br J Sports Med 2014;48:491–7.
2 Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med 2018;52:687–97.
3 Keay N, Francis G, Hind K. Low energy availability assessed by a sport-specific questionnaire and clinical interview indicative of bone health, endocrine profile and cycling performance in competitive male cyclists. BMJ Open Sport Exerc Med 2018;4:e000424.
4 Keay N. Raising Awareness of RED-S in Male and Female Athletes and Dancers. Br J Sport Med blog 2018. https://blogs.bmj.com/bjsm/2018/10/30/raisingawareness-of-red-s-in-male-and-female-athletes-anddancers/ (accessed 19 Jan 2019).

5 Health4Performance. Educational BASEM website raising awareness of RED-S Working group on RED-S. BMJ Open Sport Exerc Med 2018. http:// health4performance.co.uk (accessed 19 Jan 2019).

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ. To cite Keay N, Rankin A. Br J Sports Med Epub ahead of print: [please include Day Month Year]. doi:10.1136/ bjsports-2018-100354