Overview
Definition:
The concept of Relative Energy Deficiency in Sport (RED-S) encompasses the physiological and psychological consequences of chronic low energy availability in athletes, both male and female
In female athletes, this often manifests as menstrual irregularities, including amenorrhea (absence of menstruation) and oligomenorrhea (infrequent menstruation), which are core components of the historical Female Athlete Triad
RED-S is a broader syndrome that includes not just menstrual dysfunction but also impaired bone health, impaired immune function, psychological disturbances, and altered metabolic rate.
Epidemiology:
Menstrual irregularities are common in female athletes, with prevalence rates varying significantly based on sport type, intensity, and training volume
Oligomenorrhea and amenorrhea can affect 2-5% and up to 15% of elite female athletes, respectively, compared to less than 1-2% in the general population
RED-S affects a substantial proportion of athletes engaging in sports requiring lean physique or endurance.
Clinical Significance:
Menstrual irregularities in athletes are not merely an inconvenience
they are a critical indicator of underlying RED-S and can lead to serious long-term health consequences
These include increased risk of osteoporosis and fractures, impaired reproductive function, cardiovascular issues, psychological distress, and reduced athletic performance
Early recognition and management are crucial for preserving the athlete's health and career.
Clinical Presentation
Symptoms:
Primary complaint of absent or irregular menstrual periods
Delayed menarche in adolescent athletes
Associated symptoms may include fatigue, frequent illness, poor concentration, mood changes, disordered eating patterns (restrictive eating, purging), and performance decline
Athletes may also report stress fractures or persistent musculoskeletal pain.
Signs:
Physical examination may reveal low body weight and BMI, low percentage of body fat, and signs of delayed puberty in adolescents
Vital signs may show bradycardia or hypotension
Signs of disordered eating or psychological distress may be apparent
Examination should include assessment of bone tenderness and joint stability.
Diagnostic Criteria:
The diagnosis of RED-S and its component, the Female Athlete Triad, is based on clinical assessment
Diagnostic criteria for the Female Athlete Triad include: 1
Low Energy Availability (with or without disordered eating)
2
Menstrual Dysfunction (oligomenorrhea or amenorrhea)
3
Low Bone Mineral Density (osteopenia or osteoporosis)
RED-S is diagnosed when any of these health consequences are present in the context of low energy availability, regardless of menstrual status.
Diagnostic Approach
History Taking:
A detailed history is paramount, focusing on menstrual cycle history (age of menarche, regularity, duration, flow), dietary habits (energy intake, macronutrient balance, disordered eating behaviors), training history (volume, intensity, duration, recent changes), psychological state (stress, mood, body image), medical history (past illnesses, injuries, medications), and family history of bone disease or eating disorders
Inquire about symptoms of fatigue, illness, and bone pain.
Physical Examination:
Perform a thorough physical examination, including anthropometric measurements (height, weight, BMI, body fat percentage), assessment of pubertal development, cardiovascular assessment (heart rate, blood pressure), musculoskeletal assessment (evaluating for injuries, bone tenderness), and dermatological examination for signs of malnutrition
Assess for signs of disordered eating behavior.
Investigations:
Initial investigations may include a complete blood count (CBC) to rule out anemia, thyroid-stimulating hormone (TSH) to assess thyroid function, and serum electrolytes
If significant menstrual dysfunction is present, consider assessing for pregnancy, prolactin, and follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol levels to assess the hypothalamic-pituitary-gonadal axis
Bone mineral density (BMD) assessment via dual-energy X-ray absorptiometry (DXA) is crucial to evaluate for osteopenia or osteoporosis
Vitamin D and calcium levels should be checked
If gastrointestinal symptoms are present, consider celiac screening.
Differential Diagnosis:
Differential diagnoses for menstrual irregularities in athletes include pregnancy, polycystic ovary syndrome (PCOS), thyroid disorders, hyperprolactinemia, premature ovarian insufficiency, and adrenal disorders
It is crucial to rule out these organic causes before attributing menstrual dysfunction solely to RED-S
Disordered eating needs to be differentiated from true eating disorders.
Management
Initial Management:
The cornerstone of RED-S management is restoring energy balance
This involves increasing energy intake to meet expenditure, which may necessitate reducing training load temporarily
A multidisciplinary approach involving physicians, registered dietitians, sports psychologists, and potentially orthopedic specialists is essential.
Medical Management:
Nutritional rehabilitation is key, focusing on adequate caloric intake and balanced macronutrient distribution
Calcium and Vitamin D supplementation are vital for bone health, with specific dosages determined by serum levels and age
Hormonal therapy (e.g., oral contraceptives or hormone replacement therapy) may be considered to manage menstrual dysfunction and bone loss, but it does not address the underlying energy deficiency
The decision to use hormonal therapy should be individualized and discussed with the athlete and her guardians.
Surgical Management:
Surgical management is generally not indicated for RED-S itself
However, surgical intervention might be required for complications such as severe stress fractures requiring fixation
Nutritional support should be optimized pre- and post-operatively.
Supportive Care:
Psychological support is crucial to address disordered eating, body image concerns, and the psychological stress associated with RED-S
Behavioral interventions and counseling can help athletes develop healthier relationships with food and their bodies
Education for athletes, coaches, and parents about RED-S and the Female Athlete Triad is vital for prevention and early intervention.
Complications
Early Complications:
Early complications include frequent illness due to impaired immune function, mood disturbances, decreased athletic performance, and bone stress injuries
Psychological distress, including anxiety and depression, can also manifest early.
Late Complications:
Long-term complications are significant and include osteoporosis, with an increased risk of debilitating fractures
Impaired fertility and potential long-term reproductive health issues can arise
Cardiovascular consequences, such as arrhythmias and impaired cardiac function, have also been reported
Gastrointestinal disturbances can persist.
Prevention Strategies:
Prevention of RED-S focuses on promoting adequate energy availability, balanced nutrition, and appropriate training loads
Education of athletes, coaches, and parents about the risks of low energy availability and the signs of RED-S is critical
Regular health screenings, including assessment of menstrual history and bone health, are recommended for athletes at risk
Coaches should be trained to recognize signs of overtraining and disordered eating.
Prognosis
Factors Affecting Prognosis:
Prognosis is generally good with early recognition and comprehensive management
Factors influencing prognosis include the severity of RED-S, the presence of comorbidities (e.g., eating disorders), the athlete's adherence to treatment, and the support system available
Bone health recovery can be slow and may not always be complete.
Outcomes:
Successful management can lead to the restoration of normal menstrual cycles, improvement in bone mineral density, enhanced athletic performance, and improved psychological well-being
However, some residual effects on bone health may persist.
Follow Up:
Long-term follow-up is essential to monitor menstrual regularity, bone health (repeat DXA scans as indicated), nutritional status, and psychological well-being
Regular contact with the multidisciplinary team is recommended throughout the athlete's career, especially during periods of increased training or competition.
Key Points
Exam Focus:
RED-S is a continuum of health consequences of low energy availability in athletes
Menstrual irregularities (oligo/amenorrhea) are a key indicator but not the sole criterion
Bone health (osteopenia/osteoporosis) and impaired immune/endocrine function are other critical components
Management prioritizes restoring energy balance and addressing psychological factors.
Clinical Pearls:
Always consider RED-S in female athletes presenting with menstrual dysfunction, even if they do not outwardly appear "thin" or exhibit overt disordered eating
A high index of suspicion is warranted
DXA scan is essential for assessing bone density
Emphasize education for athletes, coaches, and parents as a primary prevention strategy.
Common Mistakes:
Mistakenly attributing menstrual irregularities solely to stress or overtraining without investigating underlying energy deficiency
Delaying or neglecting bone density assessments
Using hormonal therapy without addressing the fundamental issue of energy imbalance
Underestimating the psychological component of RED-S and disordered eating.