Relative Energy Deficiency in Sport (REDS) and the Female Athlete Triad
- Alexa Nikolai
- May 28, 2025
- 3 min read
Updated: Jul 10, 2025
Overview
Proper nutrition and fueling is essential for athletes of all levels. Your body already needs enough fuel to complete basic processes (such as temperature regulation and digestion), and activity and training just add to your nutritional requirement.
The consequences of not fueling your body sufficiently can be serious. Relative Energy Deficiency in Sport (REDS) describes the collection of symptoms that can develop when the energy demands of the body are consistently undermet. Although symptoms vary from individual to individual, REDS typically leads to increased risk of injury, greater susceptibility to illness, declining athletic performance, and other health issues.
Causes
Since your body uses energy during exercise, it is normal to experience low energy availability after a fitness session. However, resting and eating helps to replenish your energy in time for your next session. If an athlete fails to rebuild their energy store sufficiently before they deplete it again, their energy deficit will increase. Over time, this energy deficit can have health consequences.
Symptoms
Common symptoms of REDS include:
Tiredness and trouble focusing
More injuries and slower healing
Worsening bone health, leading to more stress fractures or early onset osteoporosis
Missed or abnormal periods and delayed puberty in females and decreased libido in males
Decreased immunity, leading to more illnesses and infections
Slower metabolism, making replenishing energy even more difficult
Lower heart rate and lower blood pressure, which can cause dizziness
Mood changes, such as moodiness, depression, or anxiety
Problems sleeping
Over time, REDS also leads to decreased athleticism, such as:
Decreased muscle strength
Decreased endurance
Decreased training response
Impaired judgement
Decreased coordination
Decreased concentration
The Female Athlete Triad
The Female Athlete Triad is a subset of REDS, which describes three interrelated conditions: low energy availability, irregular menstruation, and bone loss. These conditions are especially prevalent among female athletes, but do not describe the full scope of REDS.
Diagnosis
Anybody can be affected by REDS. However, the syndrome is particularly common amongst athletes who participate in sports that encourage smaller body types or frequent weigh-ins, such as gymnastics, figure skating, or lightweight rowing. Although cutting back on calories may result in short-term gains in these types of sports, in the long run, too much caloric deficiency will only decrease performance.
REDS can be difficult to diagnose, because the effects are spread across all body systems, and the causes are not always obvious. Athletes should always listen to their bodies and take note if they experience increasing levels of fatigue or moodiness, more illness than usual, or irregular menstrual cycles.
Treatment
Any athlete who suspects they may be experiencing REDS should speak to their doctor to make a treatment plan. The first step will be to work on replenishing energy levels, so a nutritionist may also be involved. Depending on the severity of the condition, athletes may need to cut back on their activity levels until their energy deficiency is addressed.
Prevention
As is often the case, prevention is typically a better strategy for REDS than treatment. Always make sure you are effectively fueling your body and speak to a doctor or nutritionist if you need help doing so. Also, set aside time to rest and recover from activity.
Unfortunately, REDS is not only a physical issue, but also a social issue. Pushing back against toxic practices in training that prioritize low body weight or a particular body shape over athlete health is essential in fighting the prevalence of REDS, especially among young athletes. Raising awareness about the need for proper nutrition and fueling can also help.
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