RED-S stands for relative energy deficiency in sport, and refers to “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.” (Mountjoy et al., 2014).
RED-S is more common in females, but is certainly not exclusively seen in this population. It tends to affect endurance athletes, physique athletes, weight category athletes (e.g. boxing) and athletes in other sports where leanness (e.g. gymnastics) or lightness (e.g. figure skating) is advantageous. RED-S has also been associated with the development of eating disorders.
The basis of this condition is that the energy demands of the individual are not met by their nutrition, either due to a purposeful decrease in consumption to encourage weight loss, or inadvertently as athletes increase their training without realising the increased energy demands.
This may also occur with non–athletic populations, who make sudden changes to their eating and exercise habits and in doing so create a large energy deficiency.
Primary signs of RED-S may include decreased performance, fatigue, and menstrual irregularities. Sustained energy deficiency may lead to hormonal irregularities, low bone density, gastrointestinal & immunological disorders, iron deficiency, mental health issues,
Further examination may show decreased bone density, as well as decrease white blood cell count, hormonal imbalances, and impaired thyroid function.
Management of RED-S revolves around achieving adequate energy availability for the individual, and this is best achieved under the supervision of a dietician. Calcium/vitamin D intake in particular should be optimised to restore bone health. If there are underlying mental issues, psychological intervention may also be required. In some cases hormonal therapy may be required, particularly if menstruation issues persist.
If you have changed your exercise or nutrition habits and are noticing these types of symptoms, it is important to have this investigated as soon as possible to maximise your chances of recovery.