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Relative energy deficiency in sports (RED-S)

Once known as the Female Athlete Triad, RED-S includes the previous concepts of the Triad (disordered eating, menstrual dysfunction and reduced bone density) but acknowledges the extensive impacts energy deficiency has on the entire body as well as including male athletes.

Low energy availability =

dietary energy intake (energy for basic body functions + energy expended for exercise).

RED-S can be intentional or unintentional. Unintentional is relatively easy to resolve and often due to someone struggling to meet the high energy demands of their sport, or suddenly ramping up their training load for the first time, in addition to an active lifestyle/job. However, when an energy deficit is intentional, it becomes more complicated as this starts to cross over into disordered eating territory. This requires much more intensive treatment and an entirely different approach from both the dietitian and wider multidisciplinary team.

RED-S can occur to any athlete of any gender and is not limited to the elite. In fact, weekend warriors or recreational runners are at greater risk because they may not have as much of a support network around them (e.g. coaches, dietitians, physiotherapists, sorts doctors etc.) and also lack the sporting experience and knowledge an elite athlete may have. However, RED-S is typically more common in sports where power to weight ratio is key, where body aesthetics are a focus, or body weight classes are a requirement for competing. Some examples include jockeys, long-distance running, weight lifting, combat sports, rowers, dancers, gymnasts, and cyclists.

What are the signs and symptoms of RED-S?

  • Frequent sickness

  • Reoccurring injuries or injuries not healing

  • Menstrual dysfunction (amenorrhea - in females)

  • Reduced testosterone and libido (males)

  • Low mood/irritability

  • Fatigue and lethargy

  • Always feeling cold

  • Disordered eating behaviours and preoccupation with food

  • Low bone density and increased risk stress fractures

  • Digestive issues, particularly constipation

What are the impacts of RED-S on performance?

  • Reduced strength

  • Reduced endurance

  • Increased risk of injury e.g. stress fractures.

  • Reduced adaptation to training load

  • Reduced motivation to train

  • Reduced coordination and concentration

  • Frequent injuries and niggles

  • Increased risk of nutritional deficiencies e.g. iron

  • Increased risk of osteoporosis due to reduced bone density

Diagnosis of RED-S requires a multidisciplinary team approach and medical intervention is vital. If left untreated, sickness or injury will force the athlete to take a long period of time off training to let their body recover appropriately. Worst-case scenario the individual may suffer long-term health consequences, e.g. impacts on fertility and bone health (osteoporosis).


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