Learn about Relative Energy Deficiency in Sport (RED-S), a condition affecting athletes who don't meet their nutritional needs. Discover the causes, health and performance consequences, and how to detect and prevent RED-S.
The Core Problem: Low Energy Availability (LEA)
RED-S is fundamentally caused by a lack of sufficient energy remaining after exercise to support normal bodily functions.
The Energy Balance Equation
Energy intake must cover two critical needs:
Energy Expenditure (EE): Calories burned during exercise and daily activities.
Energy Available (EA): Calories left over to fuel essential life processes (breathing, heart function, bone health, immune function, etc.).
When an athlete is in a state of Low Energy Availability (LEA), the body must conserve resources by shutting down non-essential biological processes. This is the root cause of the widespread symptoms of RED-S.
Primary Causes of RED-S
Intentional Restriction: Dietary practices aimed at reducing body weight or altering body composition (e.g., in weight-class sports).
Unintentional Deficiency: Failure to meet the massive caloric demands of high-volume training due to poor nutrition planning, lack of knowledge, or time constraints.
Increased Training Load: A rapid, significant increase in training intensity or duration without a corresponding increase in caloric intake.
Health Consequences: The Cost of Chronic Energy Deficiency
The effects of RED-S are systemic, impacting nearly every biological system in the body.
Endocrine and Reproductive Dysfunction
One of the most noticeable effects, especially in female athletes (formerly known as the "Female Athlete Triad"), is the disruption of hormone production.
Menstrual Changes (Female Athletes): Leads to functional hypothalamic amenorrhea (loss of periods), which signals severe energy conservation.
Hormonal Decline (Male Athletes): Results in decreased testosterone levels, which compromises recovery, mood, and bone health.
Bone Health and Injury Risk
Low energy availability dramatically impairs bone remodeling, leading to severe bone fragility.
Increased Risk of Stress Fractures: Chronic energy deficiency reduces the activity of bone-forming cells, making bones weaker and increasing the risk of painful, recurring stress fractures.
Long-Term Consequences: Low bone mineral density (osteoporosis) that may be irreversible.
Psychological and Immune Effects
Mental Health: Often presents as irritability, depression, lack of concentration, and heightened stress.
Immune Suppression: Compromises the body's ability to fight off infection, leading to frequent illnesses, especially upper respiratory infections.
Performance Consequences: Hitting the Brakes
RED-S directly undermines the qualities athletes train hard to build, leading to impaired performance in training and competition.
Decline in Physical Output
Reduced Endurance and Strength: Muscle repair is compromised, leading to chronic muscle fatigue, decreased maximal strength, and a noticeable drop in endurance capacity.
Impaired Glycogen Storage: The body is less efficient at storing carbohydrates, resulting in persistent low energy and inability to maintain high intensity.
Slower Recovery and Increased Injury
Prolonged Muscle Soreness: Slower tissue repair means muscle soreness (DOMS) lasts longer.
Poor Coordination: Fatigue and neurological disruption can lead to decreased coordination and poor decision-making during competition.
Detection and Prevention: Taking Action Against RED-S
Early intervention is vital to reversing the health and performance damage caused by RED-S.
Key Warning Signs for Athletes and Coaches
Health Markers: Recurring injuries (especially stress fractures), persistent fatigue that doesn't resolve with rest, frequent illness, and irregular or absent menstrual cycles.
Performance Markers: Sudden decrease in performance, difficulty maintaining pace or volume, poor motivation, and increased irritability.
Practical Prevention Strategies
Prioritize Energy Intake: Always fuel before and after every workout, ensuring you cover your caloric deficit. Never skip meals.
Focus on Nutrient Density: Emphasize high-quality carbohydrates (rice, oats, potatoes) and lean protein at all meals.
Regular Monitoring: Female athletes should track menstrual cycles. All athletes should monitor body weight and energy levels. Seek medical attention if any warning signs persist.
RED-S is a treatable condition, but it requires a change in mindset from "train harder" to "fuel smarter." Prioritizing long-term health and adequate energy availability is the only way to sustain peak athletic performance.