Relative Energy Deficiency in Sport (RED-S)

Introduction

Relative Energy Deficiency in Sport (RED-S) (the updated model of the female athlete triad) was defined by the International Olympic Committee in 2014 as: ‘impaired physiological functioning caused by relative energy deficiency, and includes but is not limited to impairments of metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health’ (1) This term has replaced the female athlete triad as we are now aware that this syndrome impacts both female and male individuals experiencing low energy availability.

Definitions

- Amenorrhea - An abnormal absence of menstruation (Oxford Dictionary, 2016)

- Dysmenorrhea - Painful menstruation, typically involving abdominal cramps (Oxford Dictionary, 2016)

- The Female Athlete Triad – The interrelationship of menstrual cycle dysfunction, reduced energy availability and reduced bone mineral density (Nazem and Ackerman, 2012)

- Hypomenorrhea – Abnormally light menstrual bleeding (Yaffe et al., 1978)

- Menarche – ‘The occurrence of the first menstrual period in the female adolescent’ (Lacroix et al., 2020)

- Menorrhagia – Heavy menstrual blood loss (National Institute for Health and Care Excellence, 2018)

- Menstrual cycle - The process of ovulation and menstruation (Oxford Dictionary, 2016)

- Menstruation - The process of discharging blood and other material from the lining of the uterus at intervals of about one lunar month from puberty to the menopause, except during pregnancy (Oxford Dictionary, 2016)

- Oligomenorrhea - Menstrual cycle length of greater than 45 days (Ibáñez et al., 2000)

- Osteopenia - A medical condition in which the protein and mineral content of bone is reduced, but less severely than in osteoporosis (Oxford Dictionary, 2016)

- Relative Energy Deficiency in Sport (RED-S) - This is impaired physiological function including, but not limited to impairment of: metabolic rate; menstrual function; bone health; immunity; protein synthesis; and cardiovascular health, caused by energy deficiency (Mountjoy et al., 2014)

Prevalence

The prevalence of RED-S is not well documented as there are inherent methodological difficulties in diagnosing true low energy availability.

The understanding of RED-S and its symptoms are poorly known by athletes and coaches, and therefore it is not commonly recognised (Logne et al., 2020). Fewer than 50% of physicians, coaches, physiotherapists and athletic trainers could identify the triad components (Low energy availability +/- disordered eating, menstrual dysfunction, low bone mineral density (IOC update RED-S0.

Prevalence varies between sports and ranges in the literature between 22-58% (Lague et al, 2020).

Screening tools

RED-S CAT - Relative Energy Deficiency in Sport (RED-S) Clinical Assessment Tool (CAT) https://bjsm.bmj.com/content/bjsports/49/7/421.full.pdf – (Mountjoy et al, 2014) - Can assess males and females - Assesses risk and return to play - Is a more functional model using a traffic light system

LEAF-Q – Low Energy Availability in Females Questionnaire http://www.diva-portal.org/smash/get/diva2:1303041/FULLTEXT02.pdf – (Melin, 2013) - High Sensitivity (78%) and specificity (90%) - For female athletes only

Management

Must be a multidisciplinary approach given the multi-modal causative factors and the large variety of health and performance implications. It is evident that there is regularly disordered eating associated with LEA and RED-S and therefore it is often imperative to involve a nutritionist or dietician. Alongside these are often anxity and depression

IOC Update:

Non-pharmacologic – nutritional information to optimise energy availability. Bone building nutrients eg vitamin D. CBT

Pharmacologic – oral contraceptive is not recommended as it creates false menstruation or a ‘pseudo-period’. They are currently reviewing the use of recombinant parathyroid hormones and its role in improving bone mineral density.

References

1. Mountjoy, M., Sundgot-Borgen, J., Burke, L. M., Carter, S., Constantini, N., Lebrun, C., ... Ljungqvist, A. (2014). The IOC consensus statement: beyond the female athlete triad--relative energy deficiency in sport (red-s). British Journal of Sports Medicine, 48(7), 491–497. https://doi.org/10.1136/bjsports-2014-093502 2. Muia, E. N., Wright, H. H., Onywera, V. O., & Kuria, E. N. (2016). Adolescent elite kenyan runners are at risk for energy deficiency, menstrual dysfunction and disordered eating. Journal of Sports Sciences, 34(7), 598–606. https:// doi.org/10.1080/02640414.2015.1065340