Relative Energy Deficiency in Sport (RED-S): Understanding and Managing Its Impact on Athletes

Relative Energy Deficiency in Sport (RED-S) is a condition that significantly impacts athletes’ health and performance. It results from prolonged low energy availability (LEA), where the body does not receive enough energy to support both the demands of training and normal physiological functions. This blog post explores the causes, signs, symptoms, pathophysiology, and implications of RED-S, emphasising the importance of a multidisciplinary approach to management.

What is Low Energy Availability (LEA)?

Low Energy Availability (LEA) occurs when an athlete’s energy intake does not sufficiently cover the energy expended during exercise and the energy required for bodily functions. Essentially, the body lacks the necessary fuel to perform optimally and maintain health. LEA can result from inadequate nutritional intake, excessive energy expenditure, or a combination of both.

How LEA Contributes to RED-S

When the body operates under conditions of LEA for an extended period, it enters a state of energy deficiency that affects multiple physiological systems, including the cardiovascular, endocrine, and skeletal systems. This state, known as RED-S, can lead to severe health consequences, such as impaired metabolic rate, menstrual function, bone health, immunity, and cardiovascular health.

Signs and Symptoms of RED-S

Recognising the signs and symptoms of RED-S is crucial for early intervention. Common indicators include:

• Physical Signs: Decline in performance, recurrent injuries, fatigue, frequent illnesses, weight fluctuations, and irregular menstrual cycles (especially hard to detect if on birth control).
• Psychological Signs: Mood disturbances, disordered eating habits, overtraining, and spikes in training volume.

Pathophysiology of RED-S

RED-S occurs when the body’s energy expenditure exceeds its intake, forcing it into a conservation mode. To prioritise essential functions, the body reduces energy expenditure on non-essential processes, such as reproduction, bone growth, and immune function. This imbalance disrupts hormonal levels, leading to:

• Hormonal Imbalances: Decreased levels of oestrogen in women and testosterone in men, which negatively affect bone density and reproductive health.
• Bone Health: Reduced bone formation and increased bone resorption lead to decreased bone density and a higher risk of stress fractures.
• Metabolic Rate: A lowered metabolic rate conserves energy, impacting overall performance and recovery.

Impact on Performance and Body Systems

RED-S can severely impact athletic performance and overall health. The most notable effects include:

• Bone Stress Injuries and Stress Fractures: Reduced bone density increases the risk of stress fractures and other bone injuries.
• Tendon and Ligament Issues: Weakened connective tissues due to insufficient energy for repair and maintenance.
• Decreased Muscle Strength and Endurance: LEA impairs muscle protein synthesis, reducing muscle mass and strength.
• Impaired Recovery: Slower recovery times due to insufficient energy and nutrient availability.
• Compromised Immune Function: Increased susceptibility to illnesses.
• Menstrual Dysfunction: Irregular or absent menstrual cycles.
• Early Onset Osteoporosis: Increased risk of osteoporosis due to compromised bone health.

Preventing RED-S

Preventing RED-S involves a comprehensive approach that includes proper nutrition, balanced training, and professional guidance:

• Fueling: Ensure you are eating three meals a day plus snacks, including pre-exercise fueling and post-exercise recovery nutrition. During heavy training, you may need to eat beyond your level of hunger. Focus on energy-dense foods and balance your plate with adequate carbohydrates, proteins, and fats.
• Avoid Prolonged Fasting: Avoid long periods without eating to maintain energy availability.
• Rest: Ensure adequate rest between training sessions to allow for recovery.
• Gradual Increases: Avoid increasing multiple training variables simultaneously. For example, if increasing running volume, do not also increase speed within the same week.
• Listen to Your Body: Pay attention to signs of overtraining and avoid prolonged high-intensity, high-volume training without sufficient recovery.
• Monitor Training Load: Keep track of your training and increase volume gradually. Use a training diary or apps like Garmin, Apple Watch, or Whoop to monitor your progress.

Role of a Multidisciplinary Team

Managing RED-S requires a comprehensive approach involving a multidisciplinary team:

• Sports Dietitian: Ensures adequate energy intake and balanced nutrition to meet the demands of training and recovery.
• Physiotherapist: Monitors physical health, manages injuries, and develops safe training programs.
• Sports Doctor: Oversees medical aspects, including hormonal balance and overall health assessment.

Takeaway for Physiotherapists

1. Screen for RED-S: Assess your patients’ training loads, injury history, eating behaviors, rest days, and menstrual cycles for females.
2. Use Tools: The RED-S Clinical Assessment Tool (CAT) can help evaluate athletes suspected of having LEA and guide return-to-sport decisions.
3. Collaborate: Work with other health professionals for additional support in preventing and treating RED-S.

By understanding LEA and its consequences, athletes can take proactive steps to maintain their health and optimise their performance. Working with a team of professionals ensures a holistic approach to addressing and overcoming RED-S.

Eliza Whitford, Physiotherapist
Melbourne CBD Physiotherapy and Sports Medicine Clinic

Eliza, a skilled physiotherapist with a passion for running and a background in dance, brings a wealth of experience to managing RED-S. At Melbourne CBD Physiotherapy and Sports Medicine Clinic, she combines her expertise in running and overuse injuries with a focus on women’s health. Eliza is dedicated to helping athletes navigate the challenges of RED-S, providing comprehensive care and support for a safe and effective return to activity. Her collaborative approach with her team ensures that patients receive tailored strategies to address their unique needs and achieve optimal performance and recovery.