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Don't Run on Empty: Understanding Low Energy Availability (LEA) and Relative Energy Deficiency Syndrome (RED-S)

Two runners running in a field

As a Physical Therapist with a passion for working with female athletes, and a former collegiate runner, I am well aware of the impact that fueling can have on one's recovery. For many athletes, dedication and training are second nature. But pushing for peak performance can sometimes lead down a dangerous path, one paved with inadequate energy intake and compromised health. In this post I will discuss what was previously widely described as the "Female Athlete Triad," now more accurately as Low Energy Availability (LEA) leading to Relative Energy Deficiency Syndrome (RED-S). LEA means the body simply doesn't have enough fuel to function optimally. Chronically being in this state can lead to the more serious RED-S.

LEA Explained: The Cause of RED-S

Think of the body as an energy bank account. When you burn more calories through exercise than you consume through food, your account goes into deficit. This is Low Energy Availability, and chronically being under-fueled leads to hallmark physiological disruptions of RED-S. Both LEA and RED-S impacts everything from your performance to your overall health.

Why did they call it the "triad"?

There are three major issues associated with what was previously more widely known as the Female Athlete Triad. It is now referred to as the Female and Male Athlete Triad or Relative Energy Deficiency Syndrome - as the issues associated with LEA can happen to anyone regardless of sex.

The three key factors: 1. reproductive suppression (absence of period or low testosterone), 2. bone health changes, 3. low energy availability, with or without disordered eating.

There are other symptoms and issues that can result, thus the switch to use of RED-S nomenclature.

Risk Factors

Athletes in weight-sensitive sports like gymnastics, dance, swimming, wrestling, and distance running are particularly susceptible. However, anyone prioritizing intense training over balanced nutrition can be at risk, regardless of the sport or level.

Warning Signs of RED-S:

-Decreased performance


-Frequently sick (impaired immune function)

-Disrupted menstrual cycle (inconsistent, or little to no period)

-Increased incidence or persistence of injuries

-Stress Fractures

-Decreased bone mineral density

-Exercising to "burn off what I ate"

-Exercising while injured despite medically prescribed rest

-Excessive training beyond prescribed training plan

What does physical therapy have to do with this?

A PT's main concern is that their patients are getting better. Without sufficient fuel, you can't repair and recover. What was a simple strain could take an excessive amount of time to heal, and your risk for injury is much higher. PT can help you adjust your programming, determine what to focus on, and how to safely build back up once you are recovered from your injury.

Fueling Your Passion

The good news? RED-S is preventable and treatable. Here are some key steps:

-Fuel for performance: Consult a sports dietitian to create a personalized fueling plan based on your training needs and goals.

-Balance is key: Prioritize nutrient-dense whole foods like fruits, vegetables, whole grains, and protein. Do not avoid carbs!

-Rest and recovery: Don't underestimate the power of rest days and sleep to allow your body to refuel and rebuild.

-Seek professional support: Talk to coaches, trainers, or healthcare professionals if you suspect LEA or have concerns about your nutrition and training. Physical therapists are able to help with programming and movement suggestions to ensure you can get back to your sport safely.

Remember: You are not alone. By understanding LEA and RED-S, you can take proactive steps and ensure you are ready to enjoy your sports.

Additional Resources and Further Reading

The Female and Male Athlete Triad Coalition:

National Eating Disorders Association (NEDA):

Academy of Nutrition and Dietetics:

Relative Energy Deficiency in Sport (RED-S): Scientific, Clinical, and Practical Implications for the Female Athlete.

Low Energy Availability and Relative Energy Deficiency in Sport: What Coaches Should Know.

Disclaimer: This blog post is for informational purposes only and does not substitute for professional medical advice. Please consult with a qualified healthcare professional for personalized guidance.

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