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DexaFit Seattle If your body could talk, what would it tell you? making it easy to monitor & take action

We deliver immediate, personalized insights about your body, fitness, and metabolism using medical-grade technologies considered the gold standard by science.

𝗧𝗪𝗢 𝗣𝗘𝗢𝗣𝗟𝗘 𝗖𝗔𝗡 𝗛𝗔𝗩𝗘 𝗧𝗛𝗘 𝗦𝗔𝗠𝗘 𝗩𝗢₂M𝗔𝗫A𝗡𝗗 𝗡𝗘𝗘𝗗 𝗩𝗘𝗥𝗬 𝗗𝗜𝗙𝗙𝗘𝗥𝗘𝗡𝗧 𝗖𝗔𝗥𝗗𝗜𝗢 𝗧𝗥𝗔𝗜𝗡𝗜𝗡𝗚.That's because VO₂max is only one part of the...
10/12/2026

𝗧𝗪𝗢 𝗣𝗘𝗢𝗣𝗟𝗘 𝗖𝗔𝗡 𝗛𝗔𝗩𝗘 𝗧𝗛𝗘 𝗦𝗔𝗠𝗘 𝗩𝗢₂M𝗔𝗫
A𝗡𝗗 𝗡𝗘𝗘𝗗 𝗩𝗘𝗥𝗬 𝗗𝗜𝗙𝗙𝗘𝗥𝗘𝗡𝗧 𝗖𝗔𝗥𝗗𝗜𝗢 𝗧𝗥𝗔𝗜𝗡𝗜𝗡𝗚.

That's because VO₂max is only one part of the test.

VO₂max tells us your maximal aerobic capacity.
Your ceiling.
Important number.

But most of your training doesn't happen at your ceiling.
It happens underneath it.

And during a VO₂ test, we're watching what happens on the way there.

At DexaFit Seattle, you exercise through a graded test while our MGC Diagnostics Meridian clinical-grade metabolic cart measures your respiratory gas exchange.

We're measuring oxygen consumption, carbon dioxide production and ventilation as workload increases.

That lets us identify more than VO₂max.

We're also looking for VT1 and VT2, your first and second ventilatory thresholds.
Those thresholds can tell a very different story.

Imagine two people who both have a VO₂max of 45.
One reaches VT1 relatively high in their available aerobic range.
The other reaches it much earlier.

Same VO₂max.
Different sustainable range.
Different training problem.
And potentially a different program.

This is also why we're cautious with generic heart-rate zones.
An age equation can estimate your maximum heart rate.
A percentage can divide that estimate into neat little colored boxes.
What it cannot know is exactly where your physiology changes.

Research has repeatedly shown that fixed percentages of HRmax or VO₂max can put different people into different physiological intensity domains.

That's one reason “Zone 2” becomes so confusing.

A 2025 expert consensus on Zone 2 recommended placing it immediately below the first lactate or ventilatory threshold rather than assuming one universal percentage works for everyone.

That's essentially what we're trying to find during your test:
Where does your body actually transition?

And once we've identified that transition, we can connect it to the heart rate and workload you can use outside the lab.

One important detail:
Those heart rates aren't permanently carved in stone.

Fitness changes.
Heat, fatigue, hydration and cardiac drift can affect heart rate during training.
And as you adapt, your thresholds themselves can move.

That's why testing gives you an anchor, and retesting tells you whether the physiology has actually changed.

So yes, we give you your VO₂max.
But the number at the top isn't the only reason to do the test.

Sometimes the most useful information is everything that happened before you got there.

And if you want more than the test numbers, our Cardio Xone Blueprint takes your VO₂ data, VT1, VT2 and limiting factors and turns them into practical training priorities.

The goal is not just to know your VO₂max. It is to understand what is actually limiting you and what to do next.

𝗠𝗲𝗮𝘀𝘂𝗿𝗲 → 𝗨𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱 → 𝗣𝗿𝗶𝗼𝗿𝗶𝘁𝗶𝘇𝗲 → 𝗔𝗰𝘁 → 𝗥𝗲𝘁𝗲𝘀𝘁.

VO₂ Max Testing | $175
Cardio Xone Blueprint available
DexaFit Seattle
https://www.seattle.dexafit.com/appointments

𝗛𝗘 𝗟𝗢𝗦𝗧 𝟱.𝟯 𝗣𝗢𝗨𝗡𝗗𝗦 𝗢𝗙 𝗙𝗔𝗧.A𝗡𝗗 𝗚𝗔𝗜𝗡𝗘𝗗 𝟲.𝟯 𝗣𝗢𝗨𝗡𝗗𝗦 𝗢𝗙 𝗟𝗘𝗔𝗡 𝗠𝗔𝗦𝗦.If that's the only test you saw, you'd probably call the ex...
10/10/2026

𝗛𝗘 𝗟𝗢𝗦𝗧 𝟱.𝟯 𝗣𝗢𝗨𝗡𝗗𝗦 𝗢𝗙 𝗙𝗔𝗧.
A𝗡𝗗 𝗚𝗔𝗜𝗡𝗘𝗗 𝟲.𝟯 𝗣𝗢𝗨𝗡𝗗𝗦 𝗢𝗙 𝗟𝗘𝗔𝗡 𝗠𝗔𝗦𝗦.

If that's the only test you saw, you'd probably call the experiment a success.

Then you look at the VO₂ test.
49.1 → 41.4 ml/kg/min.
About a 16% decline.

Same person.
Same roughly 100 days.

Very different story depending on which system you measured.

Alfie Hammersham is currently documenting a year-long experiment in which he fasts three complete days every week.

After his first approximately 100 days, his DEXA results looked impressive:
Body fat: 29.9% → 26.8%
Fat mass: −5.3 lb
Lean mass: +6.3 lb
Body weight remained about 180 lb.

But here's where interpretation matters.
DEXA lean mass does not mean he built 6.3 pounds of skeletal muscle.
Lean tissue includes muscle, but it also includes body water, glycogen, organs and other non-fat tissue.

DEXA is an excellent body-composition tool.
It still has to be interpreted correctly.

His scans were reportedly performed under similar morning, fasted conditions, which is exactly the kind of standardization we want.

But hydration and glycogen can still influence lean-mass measurements, especially during an experiment built around repeated fasting.

We also can't say fasting caused whatever tissue change occurred.
Training, protein intake, total energy intake and prior training status all matter.

Then there's the VO₂ result.
His measured VO₂max declined from 49.1 to 41.4.

He reports reducing training volume, which could absolutely contribute.
But even that number deserves context.

If the follow-up test happened during or shortly after one of his fasting periods, lower carbohydrate and glycogen availability may also have limited how long he could sustain the final stages of the test.

At higher intensities, carbohydrate availability matters more.
If his legs reached their metabolic limit earlier, he may have stopped before fully expressing his cardiorespiratory capacity.

That means a lower VO₂ result could reflect:
deconditioning,
acute fuel availability,
or some combination of both.

Without knowing his exact test preparation, fasting state, carbohydrate intake, peak RER, peak heart rate and workload from both tests, we can't separate them confidently.
And that's exactly why measurement alone isn't enough.

The DEXA wasn't wrong.
The VO₂ test wasn't contradicting it.

They were measuring different systems, under conditions that also need to be understood.

At DexaFit Seattle, we use DEXA to assess body composition and an MGC Diagnostics Meridian clinical-grade metabolic cart to measure respiratory gas exchange during VO₂ testing.

Different tools.
Different physiological questions.

And neither number gets to tell the whole story by itself.

Measure → Understand → Prioritize → Act → Retest.

DEXA | VO₂ Max | RMR
DexaFit Seattle
https://www.seattle.dexafit.com/appointments

𝗔 𝗦𝗧𝗨𝗗𝗬 𝗦𝗔𝗬𝗦 𝗖𝗢𝗟𝗟𝗔𝗚𝗘𝗡 𝗔𝗗𝗗𝗘𝗗 𝗠𝗢𝗥𝗘 𝗧𝗛𝗔𝗡 𝟯 𝗣𝗢𝗨𝗡𝗗𝗦 𝗢𝗙 𝗙𝗔𝗧-𝗙𝗥𝗘𝗘 𝗠𝗔𝗦𝗦.Cool.But did those people actually build that much muscl...
10/09/2026

𝗔 𝗦𝗧𝗨𝗗𝗬 𝗦𝗔𝗬𝗦 𝗖𝗢𝗟𝗟𝗔𝗚𝗘𝗡 𝗔𝗗𝗗𝗘𝗗 𝗠𝗢𝗥𝗘 𝗧𝗛𝗔𝗡 𝟯 𝗣𝗢𝗨𝗡𝗗𝗦 𝗢𝗙 𝗙𝗔𝗧-𝗙𝗥𝗘𝗘 𝗠𝗔𝗦𝗦.

Cool.

But did those people actually build that much muscle?
That's where this gets interesting.

A recent protein meta-analysis created a pretty spectacular headline: collagen ranked ahead of whey for improvements in fat-free mass during resistance training.

There are several reasons to be cautious about that conclusion.
But one jumped out at us immediately:
The collagen studies measured body composition using BIA.

You know the machines.
Stand barefoot on some metal pads. Maybe grab two handles. A tiny electrical current travels through you.
And shortly afterward the machine announces, with impressive decimal-point confidence, exactly how many pounds of muscle and fat you supposedly have.

Here's what actually happened.
The machine measured electrical impedance.
It did not measure your muscle.
It did not measure your fat.
It measured how an electrical current traveled through your body and then used assumptions about body water plus prediction equations to estimate everything else.

Those equations can work reasonably well across groups of people.
For an individual trying to determine whether they actually gained two pounds of muscle?
That's a much bigger ask.

Hydration matters. Food matters. Exercise matters. Glycogen matters. Fluid distribution matters. The equation used matters. Your body type can matter. Even your body position matters!

Which creates another problem:
Being consistently wrong would actually be easier to work with.
If a machine were always off by exactly three pounds, we could still measure change.

The trouble is that the error doesn't necessarily stay put.

Now compare that with what we use.
DEXA sends two different X-ray energies through the body and measures how those energies are attenuated by tissue. From that information it separates the body into:
• bone mineral
• fat mass
• lean soft tissue

And it does it regionally, so we can look at your arms, legs and trunk instead of asking an equation to reconstruct your body from an electrical pathway.

DEXA isn't magic either.
Hydration can still influence lean-mass measurements. Positioning matters. Scanner calibration matters. Test conditions matter. The knowledge and skill of your tech matters.

And despite what you may see online, DEXA does not directly measure skeletal muscle. Lean mass and muscle are not interchangeable terms.

That's why we standardize repeat testing as much as possible and why interpretation matters.

But if we're trying to answer:
Did you lose fat?
Did you preserve lean tissue while losing weight?
Did your last three months of lifting actually produce measurable change?
We want the measurement method with the strongest signal we can reasonably obtain, not another number generated from an electrical estimate of body water.

And this circles back to that collagen study.
If a small study reports an unusually large increase in “fat-free mass” using BIA, our next question isn't:
Where can we buy the collagen?
It's:
What exactly did they measure?

Measurement matters.
Especially when the headline depends on it.

YOUR WATCH SAYS YOUR VO₂MAX IS 45.But what did it actually measure?Not oxygen consumption.Not carbon dioxide production....
10/08/2026

YOUR WATCH SAYS YOUR VO₂MAX IS 45.

But what did it actually measure?

Not oxygen consumption.

Not carbon dioxide production.

Not ventilation.

Not your ventilatory thresholds.

A recent study followed 20 runners through 12 weeks of half-marathon training while they wore a Garmin Forerunner 265.

Researchers also put them through a criterion treadmill VO₂max test before and after training.

At the beginning:

Garmin: 43.95
Measured VO₂max: 41.10

Twelve weeks later:

Garmin: 45.00
Measured VO₂max: 42.43

The Garmin estimate ran high both times.

It also predicted an average half-marathon finish of about 130 minutes.

The runners averaged about 137.5.

Does that mean your Garmin is useless?

Not even close.

Wearables are extraordinary tools for collecting frequent training data.

But they're doing a different job.

Your watch can measure things like heart rate, pace and movement.

From those signals, along with information about you and your training, an algorithm estimates VO₂max.

It does not measure respiratory gas exchange.

The publicly available abstract for this study also doesn't identify which metabolic cart was used for the criterion testing, so we wouldn't pretend to know more about that setup than the paper tells us.

At DexaFit Seattle, we use an MGC Diagnostics Meridian clinical-grade metabolic cart during a graded exercise test.

We're measuring the respiratory gases and airflow involved in the exercise response.

Oxygen consumption.

How much O₂ your body is actually using as workload increases.
Carbon dioxide production.

How much CO₂ you're producing as intensity changes.

Ventilation.
How much air you're moving and how your ventilatory response changes as the work gets harder.

And that gives us much more than a VO₂max number.

We can identify VT1 and VT2, the physiological transitions that help tell us where different types of training actually occur.

That lets us connect heart rate and workload to the physiology underneath them.

So we don't see wearables and metabolic testing as competitors.
Your watch can give you thousands of data points between assessments.

A metabolic test can give those numbers context.

The distinction is simple:
Your watch estimates VO₂max from other signals.
We measure the respiratory physiology the estimate is trying to predict.

Use the watch.
Measure when the answer matters.

VO₂ Max Testing | DexaFit Seattle
https://www.seattle.dexafit.com/appointments

10/07/2026

WHAT A VO₂ MAX TEST ACTUALLY FEELS LIKE

If you have never done a VO₂ max test, the picture you have in your head is probably worse than the test really is.

The actual working part of the test is usually lasts about 8–15 minutes. We book 45 minutes for the full visit so there is time to get you set up, warm up, perform the test and actually explain what the results mean.

You’ll wear a snug mask over your nose and mouth that measures the oxygen you use and the carbon dioxide you produce while you exercise. Way better then those nose clips and moth places some places still use.

You can test on the treadmill or bike.

The effort starts manageable and gradually increases until you reach your limit, and you are the one who decides when the test is done. You go till you can't.
You are not expected to arrive already fit, and you do not have to be a runner.

The point is to see how your cardiovascular system responds as the work gets harder.

And VO₂ max is only one part of what we measure.

We also identify your ventilatory thresholds, including the points where your breathing begins to change and where harder work becomes increasingly difficult to sustain, and many many other useful data points.

Those thresholds help answer much more useful training questions:

How easy should your easy cardio actually be?

Where does moderate work become hard?

How hard should your intervals be?

What part of your cardiovascular fitness is most likely holding you back?

After the test, we sit down with you and walk through what we measured. Your results are also available through the DexaFit app so you can refer back to them later.

You do not need to be an athlete.

You just need to want a better answer than guessing.

If you want to know where your cardiovascular fitness stands right now and what would make the biggest difference next, this test gives you that starting point.

Already have a recent VO₂ test from us or another lab? Cardio Xone Interpretation is $199 and identifies the cardiovascular constraint most worth working on next and provides guidance on getting there.

Need the testing too? Cardio Xone is $375 and includes the VO₂ assessment plus the deeper interpretation.

Book at seattle.dexafit.com.

Every October a certain number of people look at a costume, look in the mirror, and decide to do something about it.That...
10/05/2026

Every October a certain number of people look at a costume, look in the mirror, and decide to do something about it.

That's a perfectly good reason to start. It just deserves better information than a mirror can give you.

The mirror and the scale are both estimating, and they tend to push people toward the same fix: eat less. So someone who actually needs more muscle spends eight weeks dieting, ends up smaller and softer, and can't figure out why it didn't work.

A DEXA scan shows what's really there, with lean mass and fat mass broken down region by region. You'll see what the thing you keep noticing is actually made of. Two people who feel exactly the same about their costume can need opposite plans.

Four weeks is enough time to start moving in the right direction, and a scan now gives you a baseline for everything after. Whatever you do between now and January, your next scan will show you exactly what it did.

If you've never been scanned with us, the New Client Special is $99. That covers your DEXA scan and a posture report, and we'll sit down with you and walk through the results before you leave.

Book your baseline: https://www.seattle.dexafit.com/appointments

Or grab the free Floor Card: https://app.bodysciencecoach.com/the-floor-card

10/05/2026

A test is worth booking when the result would change what you do next.

So before you schedule one, picture the number coming back higher or lower than you expect. Would you train differently? Adjust how much you eat? Track your progress another way, or retest sooner? If the answer is yes, that test is worth your time and money.

We built the 90-Day Reserve Plan workbook to help you sort this out. It walks you through setting up your next 90 days of training and nutrition. On the last page, you'll find a list of every part of that plan that's currently built on a guess.

Your goal decides which of those guesses to replace with real data first. If you're trying to lose fat and keep your muscle, a guessed body composition can send the whole plan in the wrong direction, so DEXA is the smart place to start. If you're training to finish a long hike with energy left over, knowing your aerobic fitness will help you more.

Here's what each test tells you:

DEXA measures your fat and lean mass, with bone density context.
RMR measures how many calories you burn at rest, so your nutrition plan starts from your real number.
VO2 testing measures your aerobic fitness and finds the heart rate zones that should guide your training.

Grab the workbook and work through it. The list on the last page will show you which test to start with.

Get the workbook:
It’s free and the link is in the comments

Your floor protects something specific, so it helps to know which measurement tracks it.Each test on these slides answer...
10/03/2026

Your floor protects something specific, so it helps to know which measurement tracks it.

Each test on these slides answers a different question. Swipe through and pick the one that lines up with what you're protecting this season.

Already have recent results? Those show you exactly where you're starting from. Without them, a baseline scan now gives your January numbers something to compare against.

Once you know what you're protecting, the Floor Card helps you build the floor itself.

Most planners start by asking you to write down the plan, and that's usually the step that stalls once life gets busy. The Floor Card starts with a brainstorm. List everything you could do, big or small. Rate each one 1 to 10 for how much it helps, then again for how easy it is on a packed day, and add the two together.

The totals show you your best option and a realistic default week. The card also pulls out a bad-day version small enough that "I couldn't" stops being an honest answer.

That bad-day version is what keeps you moving. When a week blows up, you drop down a level and still get something done, and October has plenty of weeks like that.

Free, and it takes about five minutes: https://app.bodysciencecoach.com/the-floor-card

Skip ahead to January for a second.Say the busy season went sideways and you're rebuilding something from scratch.Which ...
10/02/2026

Skip ahead to January for a second.

Say the busy season went sideways and you're rebuilding something from scratch.
Which loss would actually bother you?

For most people it's the muscle that took eight months to put on, or the aerobic base that finally made long runs feel controlled. Whatever came to mind first is what your floor is built to protect.

This question is about what's hardest to rebuild, and that's often a different answer than the lowest number on your report. Aerobic fitness drops off within a few weeks of backing off, and it comes back about as quickly. Muscle is slow to build, and after 40 it gets harder to win back every year.

Then there's eating, the one people forget to pick. Once your meals are on autopilot, keeping them there costs you almost nothing. Lose that routine and everything else slides with it, because your training and recovery both run on it.

A lighter week can't protect everything at once, so give it one priority. Guard whatever took the most to build, and fit the rest around it at whatever size your calendar allows.

That's where the card starts. You name the one thing, list everything you could do to protect it, and score each one twice: how much it helps, and how easy it is on a bad day. Three options come out, including one small enough that you'll still do it in your worst week.

Free, about five minutes: https://app.bodysciencecoach.com/the-floor-card

Every October I hear the same thing happening to clients.Someone spends the summer lifting four days a week with their f...
10/01/2026

Every October I hear the same thing happening to clients.

Someone spends the summer lifting four days a week with their food mostly dialed in. Then work ramps up, the light goes before dinner, and the full plan stops fitting. Nobody swaps in a smaller version, so it slides to zero by mid-month. Come January, they spend three months rebuilding what they already had in September.

So this month we're talking about floors. A floor is the minimum you commit to for a busy stretch you can already see coming. Pick the one thing you built this year that you'd hate to lose by accident, then decide what kind of week protects it. Maybe that's two lifts and a long Sunday walk. You choose it now, while you still have the bandwidth to think clearly.

Whether you're halfway through a program or haven't started one yet, the question is the same.

That's what the card is for, and it doesn't leave you staring at a blank line. You list everything you could do to protect that one thing, big and small, then score each one twice: how much it helps, and how easy it is on a crowded day.

Three come out. The best option on your page, your realistic default, and a bad-day version small enough that there's no honest version of "I couldn't."

That last one is the trick. A plan with one option goes to zero the first week it doesn't fit.

Free, five minutes: https://app.bodysciencecoach.com/the-floor-card

Address

111 W. John Street Suite 203A
Seattle, WA
98119

Opening Hours

Monday 8:45am - 6pm
Tuesday 8:45am - 4:30pm
Thursday 8:45am - 4:30pm
Friday 8:45am - 4:30pm
Saturday 8:45am - 2pm

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