When it comes to interpreting DEXA scans in athletes, a result that falls within the “normal” range doesn’t always tell the whole story.
Picture this… an athlete has a history of stress fractures, so their provider orders a DEXA scan to evaluate bone density.
The results come back and their bone mineral density falls within the expected range.
Sounds like great news, right?! Not so fast.
Just because a DEXA scan is considered “normal” doesn’t necessarily mean an athlete’s bone health is optimal. This is where interpreting bone density in athletes gets a little more complicated.
Athletes, particularly those participating in high-impact and weight-bearing sports, often develop greater bone mineral density as an adaptation to training.
So what happens when an athlete who should have relatively strong bones has a bone density measurement that’s technically within the expected range for the general population?
Is that reassuring? Or could it be telling us something about how their body is responding to training, fueling, and recovery?
The number isn’t the only thing that matters when evaluating athletes for Relative Energy Deficiency in Sport (REDs)… context does, too.
What Does a DEXA Scan Actually Measure?
A DEXA scan, also called DXA or dual-energy X-ray absorptiometry, is considered the gold standard for assessing bone mineral density (BMD).
It uses low-dose X-rays to estimate the amount of mineral present in bone at specific skeletal sites, commonly including the lumbar spine and hip.
Bone mineral density helps us understand one component of bone strength, but bone strength isn’t the same thing as total bone health.
Bone is metabolically active tissue that’s constantly being broken down and rebuilt through a process called bone remodeling.
Old or damaged bone is removed through bone resorption, while new bone tissue is formed through osteogenesis.
In a healthy, adequately fueled athlete, those processes work together to help the skeleton adapt to the mechanical demands of training.
But when an athlete experiences low energy availability (LEA), hormonal disruption, or inadequate recovery, that balance can shift.
Bone breakdown may begin to outpace bone formation, and over time, that can compromise bone health.
A DEXA scan can help us identify concerns with bone mineral density, but it doesn’t tell us everything about bone microarchitecture, remodeling activity, or why an athlete may be experiencing recurrent bone stress injuries.
That’s why interpreting a DEXA scan should never stop at one number.
What’s the Difference Between a T-Score vs. Z-Score?
When you look at a DEXA report, you’ll typically see bone mineral density measurements along with a T-score and/or Z-score.
These numbers compare the athlete’s bone density with a reference population, but they’re not interchangeable.
What Is a T-Score?
A T-score compares an individual’s bone mineral density with that of a healthy young adult reference population.
T-scores are primarily used when evaluating osteoporosis in postmenopausal women and older men.
They’re useful in the appropriate population, but they aren’t generally the preferred way to interpret bone density in younger athletes.
What Is a Z-Score?
A Z-score compares an individual’s bone mineral density with what’s expected for people of a similar age and sex, using the relevant reference population.
For children, adolescents, premenopausal women, and men younger than 50, Z-scores are generally more appropriate than T-scores.
That’s particularly relevant when we’re working with adolescent, collegiate, and younger adult athletes.
The Z-score helps us understand how an athlete’s bone density compares with others in their reference population.
But here’s where we need to dig deeper.
That reference population isn’t necessarily made up of athletes with similar training histories, mechanical loading, or sport-specific adaptations, and that matters.
Why “Normal” Bone Density May Not Be Normal for an Athlete
Let’s think about what happens when someone participates in years of running, jumping, lifting, or other weight-bearing activities.
Those activities place mechanical stress on bone, and under the right conditions, that stress stimulates bone adaptation.
Athletes participating in high-impact sports often develop greater bone mineral density than their non-athletic peers.
In other words, we may expect their bones to be stronger because of the demands their sport places on them.
Now, imagine a collegiate athlete who has spent years participating in a high-impact sport.
They’ve experienced multiple bone stress injuries.
Maybe they’ve also had menstrual irregularities, a history of restrictive eating, or periods of inadequate fueling.
Their DEXA scan comes back with a Z-score of -0.8.
Technically, that score doesn’t fall below the commonly used -1.0 threshold that raises concern in certain athletic bone-health assessments.
But should we automatically assume everything is fine? Not necessarily.
For an athlete whose sport typically promotes higher bone mineral density, a Z-score near the lower end of the expected range may deserve additional investigation, particularly when other REDs risk factors are present.
This doesn’t mean every athlete should have an unusually high Z-score.
Different sports create different mechanical demands, and not all athletes develop the same skeletal adaptations.
But it does mean we shouldn’t interpret bone density without considering what we would reasonably expect for that athlete.
What Does a Bone Density Z-Score Below -1.0 Mean?
One of the most important distinctions providers need to understand is that Z-score interpretation depends on the population and clinical context.
A Z-score below -1.0 may warrant concern in an athlete, particularly when accompanied by low energy availability, recurrent bone stress injuries, menstrual dysfunction, or other REDs indicators.
However, a Z-score below -1.0 does not automatically diagnose osteoporosis or REDs.
Likewise, a Z-score above -1.0 doesn’t rule out compromised bone health.
Here’s a simplified way to think about the results.
What Your Athlete’s Z-Score Might Be Telling You
| Z-score | What it may mean | What providers should consider |
| Above -1.0 | Generally reassuring, but not automatically optimal for every athlete | Consider sport type, injury history, fueling, hormonal function, and other REDs risk factors |
| -1.0 to -2.0 | May raise concern in athletes, particularly when additional risk factors are present | Investigate LEA, recurrent bone stress injuries, menstrual or reproductive changes, and other contributors |
| -2.0 or lower | Below the expected range for age under standard Z-score interpretation | Comprehensive clinical evaluation, including nutritional, hormonal, skeletal, and other potential causes |
These ranges are a simplified clinical guide, not standalone diagnostic criteria. Interpretation should account for age, sex, skeletal site, applicable athlete-specific guidance, and the athlete’s overall clinical picture.
The takeaway here is, a Z-score isn’t a diagnosis. It’s another piece of information we can use to understand what’s happening with the athlete.
Sometimes, the most important information isn’t whether the number crossed a cutoff.
It’s what that number means alongside everything else we’re seeing.
Why Bone Density Shouldn’t Be Interpreted in Isolation
This is something I talk about frequently when it comes to REDs.
As providers, we love numbers… screening scores, lab values, body weight, heart rate, and bone mineral density. Don’t get me wrong, numbers absolutely have value. But problems arise when we use a single number to decide whether an athlete is healthy.
Think about an athlete whose DEXA Z-score falls within the expected range.
Now add a few more pieces of information.
They’ve had two bone stress injuries in the past year.
Their menstrual cycle has become irregular.
They’ve increased training volume without increasing food intake.
They’re intentionally trying to maintain a lower body weight.
Their recovery has been getting worse.
Would you feel comfortable saying their bone health is fine simply because their DEXA result doesn’t cross a particular threshold?
I wouldn’t.
A normal result doesn’t erase the clinical history.
When we assess athletes for REDs, we need to understand how their physiological systems are functioning together.
Bone density is one part of that assessment, not the entire assessment.
What Else Should Providers Evaluate Alongside a DEXA Scan?
When an athlete has low bone mineral density, recurrent bone stress injuries, or other concerns about bone health, there are several areas I want providers to investigate.
1. Bone Stress Injury History
Has the athlete experienced previous stress reactions or stress fractures?
How many?
Where were they located?
How long did they take to heal?
Did another injury develop shortly after returning to sport?
The number, location, severity, and timing of bone stress injuries can provide important clues.
In particular, injuries involving trabecular-rich skeletal sites, such as the pelvis, spine, and femoral neck, may raise additional concern when evaluating low energy availability and REDs.
2. Menstrual and Reproductive Function
Estrogen plays an important role in maintaining bone mineral density by helping regulate bone resorption.
When low energy availability disrupts reproductive hormones, bone health can be affected.
That’s why menstrual dysfunction in an athlete with a history of bone stress injuries should never be brushed off as simply a normal consequence of training.
And this isn’t only a concern for female athletes.
Male athletes experiencing low energy availability may also develop hormonal changes, including reduced testosterone, that can affect skeletal health.
Questions about menstrual function, libido, and other reproductive changes can provide important information.
3. Energy Availability
Is the athlete consuming enough energy to support both their training and their other physiological needs?
This may be one of the most important questions we ask, because bone remodeling requires energy.
When energy availability is low, the body has to make physiological trade-offs.
Maintaining essential functions takes priority over building stronger bones, and when that pattern continues over time, bone health may suffer.
4. Dietary Restriction
Is the athlete avoiding entire food groups?
Restricting carbohydrates?
Intentionally pursuing weight loss?
Following rigid food rules?
Or eating what appears to be a balanced diet, but simply not consuming enough total food?
An athlete can have adequate calcium and vitamin D intake and still be chronically underfueled.
You can’t supplement your way out of chronic underfueling.
We need to understand both the quality AND quantity of their nutritional intake.
5. Training History and Sport Type
Different sports create different demands on the skeleton.
High-impact and weight-bearing activities often stimulate bone development, but sports with less mechanical loading may not produce the same adaptations.
We also need to consider training volume, intensity, recent changes, recovery opportunities, and the athlete’s history of participation.
This helps us interpret whether the bone density result is consistent with what we might expect.
6. Other Signs of REDs
Bone health concerns rarely exist alone.
We may also see:
- Poor recovery
- Persistent fatigue
- Recurrent illness or injury
- GI symptoms
- Hormonal disruption
- Changes in mood
- Declining performance
- Restrictive eating behaviors
- Changes in sleep or energy
Individually, these symptoms may seem unrelated.
But together, they can reveal a much bigger picture.
Don’t look at one number. Look for the pattern.
What If an Athlete Has Recurrent Stress Fractures but a Normal DEXA?
This is where I want providers to be especially careful.
A normal DEXA scan doesn’t mean an athlete can’t experience bone stress injuries. Bone strength involves more than mineral density alone.
Bone microarchitecture, mechanical loading, hormonal status, nutritional availability, and recovery all contribute to how bone responds to stress.
An athlete may have a DEXA result within the expected range while still experiencing impaired bone remodeling or other factors that increase injury risk.
So if an athlete keeps developing stress fractures, we shouldn’t automatically dismiss concerns about REDs just because their bone density doesn’t appear low.
Instead, ask:
Why isn’t this athlete’s bone keeping up with the demands being placed on it?
Are they adequately fueled?
Are there hormonal changes?
Are they returning to training before healing is complete?
Have we addressed the factors that contributed to the first injury?
Because treating the current stress fracture without addressing the underlying physiological environment may leave the athlete vulnerable to another one.
When Should Providers Consider Repeat DEXA Assessment?
A DEXA scan can provide a useful baseline when evaluating an athlete with concerns about bone health, and in some cases, repeat testing can help providers monitor changes over time.
For example, follow-up assessment may be useful when an athlete has:
- Previously identified low bone mineral density
- A history of recurrent bone stress injuries
- Ongoing or previously prolonged low energy availability
- Menstrual or other hormonal dysfunction
- A treatment plan intended to improve skeletal health
But repeat DEXA scans shouldn’t be ordered simply because we want to see a better number.
Bone density changes gradually.
The timing of repeat testing should be individualized based on clinical circumstances, the athlete’s age, expected rate of change, and whether the results would meaningfully influence care.
Whenever possible, follow-up scans should use consistent measurement sites and comparable equipment and techniques.
Even if bone mineral density improves, we still need to evaluate the athlete’s broader recovery.
Are they fueling adequately?
Has hormonal function improved?
Are they tolerating training?
Have bone stress injuries stopped recurring?
Improving a number is not the same thing as resolving the underlying problem.
The Bigger Question Isn’t Just Whether Bone Density Is Normal
When we order a DEXA scan, we’re often looking for an answer.
Is bone density low?
Is this athlete at risk?
Should we be concerned?
While a DEXA can provide valuable information, it shouldn’t be treated as the final word on an athlete’s skeletal health, because an athlete can have a Z-score within the expected range and still have important risk factors that deserve attention.
They can have a technically reassuring result while experiencing recurrent bone stress injuries.
They can have adequate calcium intake but insufficient total energy.
They can have years of mechanical loading without the physiological resources needed to adapt appropriately.
That’s why I want providers to move beyond simply asking:
“Is this DEXA normal?”
And start asking:
“Is this bone density result appropriate for this athlete, given their sport, training history, nutritional status, hormonal function, and injury history?”
That question opens the door to a much more meaningful assessment, because our goal isn’t just to identify low bone density, it’s to understand WHY an athlete may be struggling to maintain healthy, resilient bones in the first place.
Want to Become More Confident Interpreting Bone Health Through a REDs-Informed Lens?
Bone density is a perfect example of why treating REDs requires more than recognizing individual symptoms or memorizing clinical cutoffs.
An athlete may present with a stress fracture, menstrual dysfunction, low bone mineral density, restrictive eating, or poor recovery.
Each finding tells us something, but the real clinical skill is recognizing how those findings may be connected.
Inside my REDs Informed Provider Certification Program®, I teach providers how to screen, assess, and support athletes with REDs using a practical, systems-based framework.
We work through the complicated cases where the numbers don’t tell the whole story, the symptoms overlap, and knowing what to do next requires looking beyond a single test result.
Becoming REDs-informed isn’t about memorizing another list of red flags… it’s about learning how to connect the dots so you can provide better care for the whole athlete.