Prevalence of Relative Energy Deficiency in Sport (RED-S)
The prevalence of RED-S indicators among athletes is alarmingly high, affecting approximately 23-79.5% of female athletes and 15-70% of male athletes, with significant variation across different sports and assessment methodologies 1.
Current Prevalence Data
According to the most authoritative 2023 IOC Consensus Statement, the wide range in reported prevalence reflects several critical factors 1:
- Lack of singular definitive diagnosis for RED-S
- Methodological inconsistencies in research (inaccurate energy availability measurements)
- Confusion between LEA and RED-S as interchangeable terms when they are not
- Variation in physiological demands among different sports
- Participant volunteering biases in studies
Recent Meta-Analysis Findings
A 2024 systematic review and meta-analysis provides more specific numbers 2:
- 44.7% of all athletes (2,737 of 6,118) demonstrated low energy availability (LEA)
- 44.2% of female athletes had LEA
- 49.4% of male athletes had LEA
- 63.0% of athletes (460 of 730) were determined to be at risk of RED-S across eight studies
Sport-Specific Prevalence
The prevalence varies dramatically by sport type 1, 3:
Highest risk sports:
- Dancers: up to 69% prevalence of menstrual disorders
- Collegiate long-distance runners: up to 69%
- Cheerleading, diving, and gymnastics: 22% primary amenorrhea
- Weight-sensitive sports (endurance, aesthetic, weight-class sports)
General athletic populations:
- Disordered eating: ~20% in adult female elite athletes, 13% in adolescent females
- Males: 8% in adult elite athletes, 3% in adolescents 3
Real-World Application Data
A 2024 study applying the IOC RED-S Clinical Assessment Tool Version 2 (CAT2) across 213 elite athletes revealed 4:
- 55% green light (no RED-S)
- 36% yellow light (mild RED-S)
- 5% orange light (moderate RED-S)
- 4% red light (severe RED-S)
This means 45% of elite athletes showed some degree of RED-S severity.
Sport-Specific Recent Studies
Professional female football players (2024) 5:
- 22% at risk for RED-S overall
- 17% mild risk, 3% moderate-high risk, 2% very high/extreme risk
- 30% of non-contraceptive users reported secondary amenorrhea
Malaysian national athletes (2023) 6:
- 67.2% classified as medium/high RED-S risk
- Female athletes: 41.2% highest prevalence
- Weight-class sports: 23.9%
- Intermittent sports: 20.3%
Female adolescent artistic athletes (2026) 7:
- 45.9% (34 of 74) demonstrated ≥1 primary RED-S indicator
- Included artistic swimmers, dancers, and figure skaters aged 9-19 years
Critical Clinical Implications
Why These Numbers Matter for Morbidity and Mortality
The high prevalence translates directly to serious health consequences 1, 2:
Bone health impacts:
- Increased risk of bone stress injuries
- Decreased bone mineral density
- Potentially irreversible bone loss during critical growth periods
Performance and injury:
- Decreased run performance, endurance, coordination, explosive power, and agility
- Increased likelihood of absence from training due to illness
- Higher risk of bone stress injuries specifically
Systemic effects:
- Cardiovascular complications
- Gastrointestinal dysfunction
- Endocrine disruption
- Reproductive system impairment
- Immune suppression
- Reduced protein synthesis
- Psychological stress and depression
Important Caveats
The wide prevalence ranges exist because:
- No gold standard diagnostic test exists for RED-S—it remains a clinical syndrome diagnosis
- LEA is difficult to measure accurately in free-living athletes
- Different studies use different screening tools (LEAF-Q, BEDA-Q, CAT2) with varying sensitivity and specificity
- Self-reporting bias affects questionnaire-based studies
- Sport-specific demands create vastly different risk profiles
Common pitfall: Assuming all athletes with LEA have RED-S. LEA exists on a continuum from "adaptable LEA" (benign, reversible changes) to "problematic LEA" (which causes RED-S). Not all LEA progresses to the syndrome 1.
Bottom Line for Clinical Practice
Given that approximately 45-67% of athletes show indicators of RED-S risk depending on the population and assessment method used, universal screening should be implemented for all athletes, particularly those in high-risk sports (endurance, aesthetic, weight-class sports). The 2023 IOC guidelines emphasize that both male and female athletes are affected, though females show slightly higher rates in most studies 1.