RED-S 1.0: What I’m Learning About Energy, Injury, and Running

Lately, I’ve been learning more about something that feels like a missing puzzle piece in the world of running injuries and performance: RED-S, or Relative Energy Deficiency in Sport. It’s when your body doesn’t get enough fuel to support what you’re asking it to do—not just in training, but in recovery, in sleep, in hormone function, even in basic day-to-day living.

Put simply: not enough energy in, too much energy out = trouble.

For runners, that can mean lingering fatigue, recurrent injuries, missed PRs, or a body that just doesn’t feel like it’s working right—even if training looks “smart” on paper. And for the therapists, coaches, and clinicians working with these athletes, it’s something that can fly under the radar if we’re only zooming in on biomechanics or strength programs.

I’ve been especially influenced by the work of Jay Dicharry and Nathan Carlson, who both talk about the importance of zooming out and looking at the whole athlete—what’s going on outside of the strength and gait labs. And Rebecca McConville’s work has been super eye-opening too—especially her framing of RED-S as a performance and health issue, not just a food issue.

This post isn’t me pretending to be an expert. It’s more like a RED-S 1.0: me starting to connect the dots and wanting to share the learning as I go.

What RED-S Can Look Like (Even If You’re “Doing Everything Right”)

One of the trickiest things about RED-S is that it doesn’t always scream for attention. Sometimes, it whispers. And for runners who pride themselves on pushing through discomfort—or clinicians who are trained to look for movement faults or training errors—it’s easy to miss those whispers.

As a Runner, RED-S Might Look Like:

Injuries that don’t make sense, even with “good” training
Fatigue that lingers no matter how much you rest
Mood swings or lack of motivation to train
Disrupted sleep, especially waking up in the middle of the night
Performance plateaus despite solid workouts
Missed or irregular menstrual cycles (for women)
For males…think male hormones, sex drive and morning erections will be impacted.

As a Clinician or Coach, RED-S Might Look Like:

The “frequent flyer” athlete with recurring injuries
Solid mechanics and rehab compliance, but stalled progress
Fatigue and burnout out of proportion to training load
Low RPE (rating of perceived exertion) tolerance in sessions
Noticeable loss of lean body mass or overly lean appearance.
Be sure you zoom out as clinicians and coaches to ask about these other important things in the runner’s life.

Why RED-S Often Gets Missed: A Culture Issue

Part of what makes RED-S so slippery is that some of its early warning signs can actually look like discipline. In endurance sports, we often glorify behaviors that may actually be harming athletes:

Training through fatigue = “mental toughness”
Skipping rest = “commitment”
Staying lean = “faster”

But what we call “grit” is sometimes a red flag in disguise.

Jay Dicharry reminds us that athletes are more than their movement patterns. A perfect gait doesn’t matter if the body behind it is under-fueled. And Nathan Carlson emphasizes the importance of seeing the whole human, not just the injury or performance data.

Rebecca McConville’s perspective is especially helpful here—she frames RED-S not as a disordered eating issue, but a performance limiter. Her book, Finding Your Sweet Spot, offers practical, compassionate tools for finding that balance between fueling, training, and performance. I ordered this book and sent it to our collegiate running daughter.

What To Do When RED-S Might Be in the Picture

If you’re wondering whether RED-S could be playing a role—in your own training or in an athlete you’re working with—here are a few ways to start investigating:

For Runners:

Pay attention to energy in as much as energy out
Track how you feel after workouts, not just mileage or paces
Seek out a RED-S-aware sports dietitian
Shift your mindset: fueling and recovery are part of training

For Therapists & Coaches:

Ask bigger questions: sleep, stress, nutrition, menstrual history
Collaborate with RDs, MDs, and mental health pros
Educate without shaming—many RED-S cases are unintentional
Stay curious when progress stalls despite “perfect” rehab plans

Why This Matters to Me

This topic isn’t just academic—it’s personal. Over the last five years, I’ve seen an alarming increase in bone stress injuries in our local running community, especially among young athletes. These aren’t kids who are ignoring advice. They’re diligent, driven, and doing what they think is right. And yet, they’re breaking down.

It hit even closer to home when my own daughter experienced two bone stress injuries at the college level. As both a parent and a professional, it was a wake-up call. Something bigger is going on.

One thing Nathan Carlson said really stuck with me:

“A bone stress injury is considered a fueling issue until proven otherwise.”

That simple statement shifted my entire lens. Instead of starting with the usual suspects—volume, mechanics, shoes—we need to ask the energy question first.

And that brings me back to Rebecca McConville’s advice:

“Runners should aim for at least 100 nutrient-dense calories per 10 miles run each week.”

It’s not a perfect metric for everyone, but it’s a practical, compassionate place to start.

This issue is too important to ignore. Whether you’re a runner, therapist, coach, or parent—it’s time we treat energy availability as a vital sign of performance and health.

I’m still learning, but I hope this post sparks some curiosity or starts a few conversations. There’s a lot more to uncover—and a lot of athletes who need us to look deeper.