RED-S (Relative Energy Deficiency in Sport is a serious thing and something all endurance athletes should have a little bit of awareness of, as well as anyone who is active and looking to shed some body fat and change their body composition.

Low Energy Availability (LEA) discussed in a previous post (find it here: https://differentbreed.io/low-energy-availability-lea/)and RED-S are closely related concepts in sports nutrition and exercise physiology.

Studies suggest that 20-60% of endurance athletes may experience LEA which can then lead to RED-S. Female endurance athletes are at higher risk, but male athletes are also affected. Ironman triathletes and ultramarathon runners are particularly susceptible due to extremely high energy demands.

Definition:

RED-S refers to impaired physiological functioning caused by relative energy deficiency and includes, but is not limited to, impairments of metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health.

Evolution of the concept:

• Originated from the Female Athlete Triad (disordered eating, amenorrhea, osteoporosis).
  *The Female Athlete Triad is a syndrome of the three interrelated conditions that was first recognised in the 1990s. It’s an important concept in sports medicine and women’s health
• Expanded to include all athletes, regardless of gender.
• Recognises a wider range of health and performance consequences.

Health consequences:

• Menstrual function: Irregular or absent periods in females
• Bone health: Decreased bone mineral density, increased fracture risk
• Endocrine system: Hormonal imbalances (e.g., thyroid, growth hormone, cortisol)
• Metabolic rate: Decreased BMR to conserve energy
• Cardiovascular health: Reduced heart rate, blood pressure changes
• Gastrointestinal function: Delayed gastric emptying, constipation
• Immunological function: Increased susceptibility to infections
• Hematological: Anaemia
• Growth and development: Potential stunting in adolescents
• Psychological: Depression, anxiety, disordered eating

Performance consequences:

• Decreased endurance capacity
• Reduced muscle strength
• Increased injury risk
• Decreased training response
• Impaired judgment
• Decreased coordination and concentration
• Irritability and depression
• Increased risk of fatigue and exhaustion

Risk factors

RED-S is more prevalent in endurance athletes due to the potentially high training volumes, which is one of the key risk factors.
It can also be seen in sports where leanness is seen as the ideal, and also sports utilising weight categories as these can lead to rapid weight loss practices.
Other common risk factors are disordered eating, a lack of nutrition knowledge leading to excessive calorie deficits and also perfectionist personality traits.

Diagnosis and assessment:

There is no single diagnostic test, instead the usual routes to diagnosis involve:
– Comprehensive assessment including building a detailed history of medical records, nutrition, psychological mapping, training history etc.
– Physical examination
– Laboratory tests ( hormones, bloods, bone density etc)

Challenges specific to endurance sports

As touched on above endurance athletes are an at risk group due to training volumes.
The key to be aware of and manage to avoid LEA and RED-S is consuming enough calories during long training sessions and also proper management of pre and post fuelling.

Where some athletes struggle is:
– Suffering gastrointestinal issues during prolonged exercise.
– Having a suppressed appetite after intense endurance exercise.
– Dealing with the pressure to maintain low body weight for perceived performance benefits.

Prevention strategies for endurance athletes:

• Regular monitoring of energy intake, body composition, and performance
• Emphasizing fueling for performance rather than weight loss
• Incorporating strength training to maintain muscle mass and bone density
• Periodizing nutrition to match training cycles
• Education on nutrition and the importance of adequate fuelling during long training sessions and races

Final Thoughts

As we navigate the complex landscape of athletic performance and health, it’s crucial to remember that our bodies are not mere machines, but intricate systems requiring balance and care.
RED-S serves as a stark reminder that the pursuit of athletic excellence should never come at the cost of long-term well-being.
I hope that by fostering a culture of open communication, prioritising education, and embracing a holistic approach to training and nutrition, I can help create an environment where athletes thrive both on and off the field.
The journey towards peak performance is a marathon, not a sprint, and maintaining energy balance is the fuel that will carry athletes through their careers and beyond.
I want to champion a future where athletic achievement and vibrant health go hand in hand, creating a legacy of sustainable excellence in sports.