RED-S: When 'More' Isn’t Better

Let’s be honest—our lives these days are packed. Between work, family, maintaining a household, nurturing relationships, and trying to stay active, many of us are constantly juggling competing priorities. In the midst of all this, we’re encouraged to do more, be more productive, and push harder.

But in our efforts to keep up with it all—especially when we’re adding workouts or fitness goals to the mix—we may unintentionally neglect a critical part of the equation: proper rest and fueling. And that’s where the risk of RED-S comes in.

What Is RED-S?

RED-S stands for Relative Energy Deficiency in Sport. It occurs when the energy we expend throughout daily activities and exercise exceeds the energy we take in through food.

In other words, we’re burning more than we’re fueling.

When the body doesn’t get enough fuel to meet its daily demands, it starts to conserve energy—leading to changes across multiple systems. This is not just about fatigue. RED-S can impact hormonal function, bone health, the immune system, cardiovascular health, and cognitive function. It’s similar to running a car without enough gas: eventually, performance suffers, and parts begin to break down.

Common Signs and Symptoms

RED-S can present differently depending on the person, but here are some of the more common signs:

• Persistent fatigue

• Frequent injuries or stress fractures

• Irregular or absent menstrual cycles (in women)

• Fewer morning erections or slower facial hair growth (in men)

• Decreased libido

• Frequent illness or slow recovery

• Difficulty sleeping or changes in mood

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Why RED-S Matters

While the term may sound like it applies only to competitive athletes, RED-S is something I often see in the clinic among people living highly active or high-demand lives. It affects individuals who are doing their best to stay fit and healthy, but who may be unintentionally under-fueling.

It might look like:

• A new mom returning to her workouts, skipping meals while caring for her children

• A professional training for a marathon while skipping lunch due to back-to-back meetings

• Someone pushing through daily high-intensity workouts while eating less to meet weight goals

RED-S often develops without someone realizing it. Over time, the effects compound and begin to impact quality of life, recovery, and performance.

Health Consequences of RED-S

When energy availability is low over time, several physiological consequences can occur:

Physiological impacts:

1. Decreased bone density

2. Menstrual dysfunction or loss of cycles (in women)

3. Reduced muscle mass

4. Decreased strength

Performance and injury-related consequences:

1. Increased risk of urinary incontinence

2. Potential fertility issues

3. Bone stress injuries

4. Higher likelihood of muscular injuries

5. Mood disturbances

6. Reduced strength, endurance, and capacity for physical performance

Are You at Risk?

Some common factors that can contribute to RED-S include:

• Attempting to lose weight or preoccupation with weight/body image

• High-intensity or high-volume training routines without adequate rest

• Busy lifestyles that limit opportunities for consistent meals and recovery

Questions to Reflect On

General:

• Are you currently trying to lose weight or concerned about your body image?

• Do you have a history of stress fractures or bone-related injuries?

• Have you noticed changes in your libido or energy levels?

For women:

• Are your menstrual cycles regular?

For men:

• Do you experience regular morning erections?

• Have you noticed a decrease in facial hair growth?

How Physical Therapy Can Help

As physical therapists, we’re trained to look beyond just the injury in front of us. We consider the bigger picture of how the body is functioning, recovering, and adapting to stress. Here are a few ways we support individuals at risk of or recovering from RED-S:

Movement assessment

We assess how you’re moving and training to ensure your body is functioning efficiently and safely—helping you avoid overuse injuries or compensatory patterns.

Injury prevention

We provide education and customized exercises that support strength, mobility, and body awareness to reduce your risk of injury, especially when recovery is compromised.

Recovery strategies

We can help you build structured recovery plans that include mobility work, rest strategies, and modifications to your training load to better support your overall health.

Our bodies are resilient, but they’re not invincible. In a culture that celebrates pushing harder, it's important to remember that rest and fuel are not optional—they’re essential. RED-S is a powerful reminder that more is not always better.

By staying mindful of your energy balance and recognizing early signs of dysfunction, you can protect your long-term health while still pursuing your fitness goals.

Balance, not burnout, is the goal.

Resources:

Blagrove RC, Brooke-Wavell K, Plateau CR, Nahman C, Hassan A, Stellingwerff T. The Role of Musculoskeletal Training During Return to Performance Following Relative Energy Deficiency in Sport. Int J Sports Physiol Perform. 2024;19(7):623-628. Published 2024 Jun 4. doi:10.1123/ijspp.2023-0532

Cabre HE, Moore SR, Smith-Ryan AE, Hackney AC. Relative Energy Deficiency in Sport (RED-S): Scientific, Clinical, and Practical Implications for the Female Athlete. Dtsch Z Sportmed. 2022;73(7):225-234. doi:10.5960/dzsm.2022.546

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