The female athlete triad is recognized as a disorder involving the interrelationship between menstrual dysfunction, low bone mineral density (BMD), and low energy availability (EA). The underlying cause of the triad is an imbalance in an athlete’s energy intake and energy expenditure.

It’s also important to note that while the triad is referred to as the “female athlete triad”, it can also affect men. In fact, the term relative energy deficiency in sport (RED-S) is an extension of the triad that explains both the physiological and psychological implications of under-fueling for all genders.

When an athlete consistently burns more energy than they are consuming, over time the body begins to have difficulty carrying out basic physiological functions. This causes complications of multiple systems in the body:

• Cardiovascular – increased risk of abnormal heart rhythm, low heart rate (bradycardia), orthostasis (change in heart rate and/or blood pressure with positional changes), congestive heart failure
• Gastrointestinal – increased incidence of leaky gut and irritable bowel conditions
• Endocrine – hormonal imbalance and metabolic regulation
• Growth and development – poor recovery (low glycogen stores) and training response (decreased muscular strength and endurance) leading to high injury risk
• Immunological – increased risk of illness and fatigue  
• Skeletal – decreased bone mineral density
• Renal – high risk for dehydration and poor regulation of fluid and electrolyte balance 
• Menstrual dysfunction – missed periods, amenorrhea
• Hematological – biomarkers in suboptimal ranges and deficiency
• Psychological –  decreased coordination and concentration, impaired judgment depression, anxiety, irritability

Who is at risk?

Various factors can contribute to an imbalance in energy intake and energy expenditure. For example, it could be due to a lack of knowledge about how to meet energy requirements and/or misguided attempts to lose body and fat mass. However, disordered eating is often the major cause of this imbalance.

Any athlete who is not consuming enough calories to support the amount of energy they’re burning is at risk of relative energy deficiency, or under-fueling. Specific individuals at risk include competitive athletes, athletes who play sports where they are required to track and maintain their weight, athletes who participate in sports where thinness is highly emphasized, athletes with eating disorders (ED) or disordered eating (DE) or a history of ED/DE, and athletes who struggle with anxiety and/or depression.

Warning signs indicating energy deficiency?

Some signs to watch for that can indicate an athlete may have RED-S :

• Menstrual irregularity and/or loss of period (amenorrhea)
• Dehydration
• Gastrointestinal issues
• Hypothermia (cold intolerance)
• Decreased performance — endurance, strength, speed, power, lactate threshold
• Increased risk of stress fractures and overuse injury
• Significant weight loss 
• Muscle cramps, weakness, fatigue 
• Poor muscle recovery 
• Insomnia and/or difficulty sleeping 
• Dental and gum problems
• Mood changes – irritability, anxiety, depression
• Preoccupation with weight, eating, and/or food
• Difficulty concentrating 
• Avoidance of eating and eating situations
• Use of diet pills, laxatives, etc.

Preventing Relative Energy Deficiency

Prevention is key here. Once an athlete shows physiological signs of RED-S, it can be very difficult to treat. Some things an athlete can do to prevent the triad are: 

• Eat a nutrient-dense, balanced diet that accommodates both daily basal energy needs and activity needs
• Properly fueling the body before, during, and after exercise 
• Allow for adaptability with exercise/ training regimen
• De-emphasize weight as a factor in performance. Thin DOES NOT equal fast.
• Appreciate your health FIRST. Understand the importance of nutrition as nourishment for your muscles, bones, brain, etc.
• Think of fuel as the number one performance enhancer work with a sports dietitian to understand the best way to fuel your body for your specific sport and exercise routine 

It is always best for an athlete who has RED-S or the triad to work with an interdisciplinary healthcare team including a dietitian, physician, psychologists, coaching staff, and/or athletic administration can be extremely helpful. Working with an interdisciplinary healthcare team is especially important when it comes to athletes who struggle with disordered eating or eating disorders to best support their mental and physical health.

If you are unsure of whether you have RED-S, the triad, or are at risk of energy deficiency it is always a good idea to consult with a health professional to understand how to best support yourself and your body.

We stress the importance of fueling to perform in BOTH life and sport. Food is fuel, friends. It provides nourishment to your body so you can support it in doing all that you love to do every single day.

-Dana Eshelman, MS, RDN, CSSD, METS I

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