Relative energy deficiency (RED-S): recognition & management


The term “female athlete triad” has been used for several decades to describe an association between disordered eating, an irregular menstrual cycle and impaired bone health. While disordered eating and low energy availability clearly have an effect on a woman’s menstrual cycle and bone health, almost every system in the body can also be involved. It can affect metabolic rate, immunity and protein synthesis as well as cardiovascular and psychological health.

Most importantly for the athlete, it can negatively impact on performance. It is also now recognised that low energy availability can also occur in male athletes. As a result, the diagnosis of “female athlete triad” is now no longer widely used. It has therefore been renamed Relative Energy Deficiency in Sport or RED-S. 

RED-S has been most commonly described in aesthetic sports like gymnastics or ballet but can be present in any code. Pressure to reduce weight is a common explanation for the frequent disordered eating among athletes. Further factors include starting sport-specific training at a young age, personality factors, frequent weight-cycling to “make weight” in weight category sports and certain coaching behaviours. Elite athletes and those who train particularly hard are at the highest risk.

The underlying pathology in RED-S is reduced energy availability for physiological processes where:

Energy available (EA) = Energy intake (EI) - Exercise Energy Expenditure (EEE) relative to fat-free mass (FFM)

While some athletes have an associated eating disorder, inadvertent energy deficits can also occur. Athletes who increase their training loads, for example when they enter an elite training program, may not appreciate that they need to increase their energy intake. Most athletes with relative energy deficiency, however, consciously either reduce dietary energy intake or increase energy expenditure on exercise.

It is important to appreciate that prolonged energy deficit can cause considerable morbidity.

Objectives of this course:

  • Identify features of the RED-S and recognise athletes who may be at risk of this.
  • Understand the pathophysiological mechanisms that underpin RED-S.
  • Institute appropriate initial management of athletes presenting with features of RED-S.


Once you have completed this short course and quiz, please click 'submit' where you will be taken to the results page. From here you can print your certificate for 1 Continuing Professional Development (CPD) hour.


This content was created by Dr Helen Joyce Fulcher MBChB, DipPaed, PGCertHSc (Sports Med), in June 2016.

The material is presented by the Goodfellow Unit (GFU), an accredited continuing medical education/ continuing professional development (CME/CPD) provider for the Royal New Zealand College of General Practitioners and functions under a tripartite agreement between the Goodfellow Foundation, the College and the University of Auckland. The Unit is located within the Department of General Practice and Primary Health Care, and within the School of Population Health.


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