Aug 042010

So read this before you get sold a bill o’poo.

RMR testing (Resting Metabolic Rate, tests how many calories your body needs) and VO2 testing (Volume of Oxygen Consumption, tests the fitness of your cardiovascular system) are a good way for fitness clubs to make cash. Which would explain why every Tom, Dick and Scary fitness club has started offering metabolic testing over the past few years.

But, as with personal training, just because they offer a service doesn’t mean they know how to do it. They may have inaccurate testing equipment (the most popular brand of equipment became the most popular because it’s cheaper, not because it works so hot), and the people who operate it may not be fully steeped in the science behind the numbers.

Since most of us wouldn’t even pay a barrista to have their latte made the wrong way, I’m pretty sure we hell-no don’t wanna pay to have a health test done the wrong way. So, here’s how your conversation goes when you pick up the phone.

You say: “Hello, kind sir/miss. I’m doing some shopping around for metabolic testing. Do you offer that?”

(They should probably say yes.)

You say: “Okay, I’ve got a few questions about it.” And they’ll transfer you to the training department or whomever conducts the testing.

1} “How much do you charge for the RMR test?”
“How much do you charge for VO2 testing?”
“Is there a discount if I do both tests at once?”
“Can you tell me what brand of metabolic cart they use?”
“Do they do a lung (pulmonary) function test beforehand?”
6} “Does someone sit down with you afterward and tell you what to do with the results?”
“Okay, and also, what kind of degree does this person have?” (Level and field of study, please.)

If they try to pressure you into setting up an appointment right away—obviously—just tell ’em you’ve got a few more places to call before you decide, so get-out my face, punk. And hang up on dey ass.

That was the quick-reference list. Now for the right answers.

Answers for 1} “How much do you charge for the RMR test?”

You be the judge on this one. Some places may be a bit cheaper, but it may also be because they do the test, hand you the printout, and send you on your way. Which is the equivalent of a lab tech who does a brain scan, hands you the scan, and sends you on your way. Just be sure to ask what you’re getting for the price, and pretty soon you’ll start to get a feel for which deal is better.

From an RMR test alone, you should learn:

> The number of calories your body currently requires per day to function (at rest)

Important sidenote: Since you’re “at rest” during this test, the majority of calories you’re using will come from fat. (Why? Here.) So don’t let them try to tell you their test is so great because it will tell you how much fat calories vs. sugar calories you’re using. It either means they’re not very educated on the subject, or they think you aren’t.

> Whether your metabolism is below, at, or above average for someone your age.

> They should also calculate your Total Metabolic Rate. This is the number of calories your body needs during a regular day, doing your regular activities (not at rest).

Answers for 2} “How much do you charge for VO2 testing?”

Again, just ask what the price includes. I checked out a certain local fitness club’s website, and there was one testing service listed that I’d never heard of, so it caught my attention. Then I read the details. It was just a VO2 test. Whether they came up with another name because “VO2” wasn’t sexy enough, or because they were trying to make it seem more special (i.e., charge more) than “regular” VO2 testing, I cannot speculate. But it was the same ol’ VO2 test.

From a VO2 test alone, you should learn:

> Your heart rate zones. Zone 1 (lowest intensity) through zone 5 (your absolute maximum intensity). They’ll tell you which zones are aerobic, cardio, and where your “anaerobic threshold” is, if you’ve heard that term. (The anaerobic threshold is what heart rate zones are based on.)

> Your VO2 max—literally, it’s the maximum amount of oxygen your body can use at its peak intensity. The more cardiovascularly fit you are, the more efficiently your body uses oxygen. Oh, and heads up, folks—this is also the single most accurate indicator of how long you’ll live.

> How many calories you burn during exercise. In each heart rate zone, you burn a certain number of calories. The higher the zone, the more the calories. Fact: the more cardiovascularly fit you are, the higher the number of calories you burn in all zones.

Answers for 3} “Is there a discount if I do both tests at once?”

It’s common to get a package deal. Both tests involve the same equipment, so it’s easier to have them done at the same time.

Answers for 4} “Can you tell me what brand of metabolic cart they use?”

This is not handbags. I’m not being a snob. The equipment they use is called a metabolic cart. And one of the biggest reasons all testing is not the same, is because all metabolic carts are not the same.

These are the brands to look for:

Sensor Medics and Medical Graphics. That’s about it.

You may think this is complete geekdom, but once you understand why, you’ll see red flags before going to a place that uses a cheaper cart.

A real metabolic cart has to be carefully calibrated before each test. Imagine if you put a ten-pound weight on a scale, and then programmed the scale to think that was “zero.” The scale would constantly measure everyone at ten pounds heavier. Chicks would walk out of your bathroom suicidal or convinced they were pregnant.

When it comes to metabolic carts, they’re not measuring weight, they’re measuring air. What you’re breathing in and out. So they use samples of air to get calibrated. When the machine’s turned on, the first thing it does is suck in a little bit of room air. It tells the operator how much oxygen and CO2 it measured, and asks if that’s correct.

Well hell, I don’t know about you, but I can’t just sniff out oxygen and CO2 percentages. That’s why proper metabolic carts use air tanks for calibration—the air tanks have known percentages of each, and the operator checks the cart’s measurements against them.

But the metabolic cart’s not just testing content of air. It’s testing volume. As in, how much you suck in and blow out. So the cart has to calibrate for airflow, too. That’s why the sample of air must be completely still. Zero airflow. On a proper metabolic cart, just the whoosh of air from walking past the sucker while it’s calibrating will cause Armageddon. (Armageddon = it errors out and makes you start the calibration over again.)

The lesson in all this jibber-jabber is: if the calibration is off, the test will be wrong.

The PhD tested a client once using a brand of cart called New Leaf, and because New Leaf carts don’t calibrate accurately (they try to self-calibrate by just sucking in whatever air’s around, whatever the content percentages are, whether it’s moving air or not), the poor dude’s VO2 read as 0 for the first ten minutes of the test. In other words, he was dead for the first ten minutes. “And when he should’ve been at 50 (VO2 measurement),” PhD says, “the machine was saying he was at, like, 20 or something.”

On a scale where 0 is dead, and 60-70 is an elite athlete, that’s a Grand Canyon margin of error. Especially when you consider that this test is what your heart rate zones are based on—if the test is wrong, your heart rate zones will be wrong.

Much like when you make a copy of a copy of a copy, the New Leaf machine would progressively get so out of calibration, the tests became useless. So every three or four months, they had to send the entire cart back to the manufacturer and exchange it for a new one.

From the PhD: “The bottomline is, you’re going to be paying about the same for the testing anywhere you go. They can either buy (a cheap cart) for $5,000-10,000, or (an accurate cart) for $30,000. So if you’re paying the same wherever you go, why not go to the place that has the right equipment?”

The test-giver’s education will factor in here, too. More on that later.

Answers for 5} “Do they do a lung (pulmonary) function test beforehand?”

This is just a quick check. They’ll have you blow air into a machine—like a breathalyzer that’s not looking for booze. It’s just to see if your lungs are okay to go, or if you’ve got some impairment like bronchitis, emphysema, asthma, etc, that would make a test dangerous.

Let’s be real, if you’re already hitting spin class five days a week with no problem (wheeziness), then chances are, your lungs are in good shape. This one’s more of an issue for people who are just getting into exercise.

P.S. The cheaper testing equipment is not able to do lung function testing.

Answers for 6} “Does someone sit down with you afterward and tell you what to do with the results?”

Like I mentioned before, whether it’s the RMR or the VO2, these tests require interpretation—even if you’ve been through it before.

Once they have the results, they should be able to tell you:

> How many calories to eat to lose weight, and it should be something sustainable, not drastic. Otherwise, the weight will just come back (Why? Refer back to that RMR post).

> How many calories you need to be burning in your workouts, and specifically, what exercises will do that. After all, that’s the reason you’re on this train—so you can finally know, once and for all, exactly what you need to do with your nutrition and exercise. Translating random numbers on a paper into specific food and activities isn’t exactly DIY.

Answers for 7} “Okay, and also, what kind of degree does this person have?” (Level and field of study, please.)

By now I know you all are like, “metabolic, schmetabolicasdfjklzzzz….,” so if you only pay attention to one thing, make it this one.

Even if the place has less than stellar equipment, at least a capable PhD will be able to spot fishy results and know what to do about them. Again, not snobbery. The in-depth classes on metabolism have, like, 70 pre-requisites and are located at the far end of post-graduate-land. But without that high level of understanding, it can be a case of “the machine’s off, but the trainer doesn’t know it,” says the PhD.

Basically, you want someone who knows more than the machine does. Not someone who relies on the machine and the machine alone.

So stick with test-givers who have at least a Masters degree. As yoozh, the quality of a degree varies with the person who has it. Even crappy schools offer Masters degrees, so if your health is really depending on this, a PhD would be ideal.

Plus, bonus: the higher their level of education, the more likely they are to use the right equipment. *ding*

One last tidbit. The results of these tests aren’t permanent. If you’re a non-exerciser-turned-exerciser, you’ll see improvements in your numbers in a matter of weeks (assuming you’d pay for another test so soon). If you just want to become faster and stronger, you’ll wanna have the test done annually. As you get better, your results and the exercise based on them will become obsolete.

I know it seems totally weird that there’s a “right” and “wrong” way to do a medical test (nobody’s getting all consumer-beware on cholesterol testing), but that’s the effect the fitness industry has on the health industry. Things get simplified, warped, to make more money.

But look on the bright side: now you have these questions to use. And once you’ve asked a few places, you can scurry back to this post to check their answers. Have no fear. Tom and Dick not so Scary.

  13 Responses to “All metabolic testing, not equal.”

Comments (13)
  1. Just found your site through google, I’ll keep up with this one for sure

  2. Just did some research and Medical Graphics and New Leaf are kind of like sister companies. New Leaf uses Med Graphics materials and even on the website its said that Med Graphics is for use in hospitals and universities and that New Leaf is the portable version. While I agree that there can be a lot of user error with any type of testing and that people should be able to know what they’re doing and how to explain it, I’m still trying to see how New Leaf is a crappy option?

    • Excellent question.

      You’re right, New Leaf is owned by Med Graphics. New Leaf is basically the cheaper, lesser-featured (“portable”) version of the original metabolic cart. We mention in the post some of the specific features the New Leaf lacks that impact its accuracy.

      Why does it lack them? The original version of a metabolic cart can cost anywhere from $25,000 – $40,000. The New Leaf can be bought for $4000 – $8000. It’s basically a way for them to tap into a cheaper market. Universities and hospitals—places where they do research and require accuracy—are the usual buyers of Med Graphics. Fitness clubs, however, aren’t typically willing to spend that kind of money on a metabolic cart (let alone do metabolic testing, anyway), so the cheaper cart is usually what you’ll find there.

      Thanks for the question!

    • UPDATE:

      Last fall, LifeTime Fitness actually purchased New Leaf from Medical Graphics. It just didn’t occur to me to mention it on the blog…. until this second. Duh.

      You can read about the sale here:

  3. Hi. I did an RMR test recently and it says that my RME is 2059 calories. Which I was surprised about since I’m hypothyroid. It also said that 100% of my calories burned are from carbs could this be why I’m not losing weight? If so how can I change that. Read your link that says at rest you burn fat so I’m confused.

    • Hi there. Yup, you’re right. Those results do not sound likely. If you would like to send us a pdf of your results from the test(s) (the raw data printout from the metabolic cart) we could interpret the information for you. Our contact form doesn’t take attachments, however, so I’ll shoot you an email and you can simply reply to that. Thanks!

  4. I have been researching this for a couple weeks and this is BY FAR the most helpful article I’ve found. I was so confused as to where to go since the pricing seems to vary so much. Thanks for the help!

  5. I work at Lifetime Fitness and I’m about to get a activity metabolic assessment. I was wondering if it’s worth $115 or can I go to a physician and get the same test done for less.

    • Well, you’ve put your finger right on the issue—you can’t get the test from a physician. (V02 is the single most accurate indicator of mortality and you can’t get a VO2 test from a physician.) Even if physicians did do this sort of testing, it would be costly. (Like, closer to $1000.)

      But any test is only worth the money if you get the right information. Like we mentioned, if the equipment or person operating it is less than stellar, you won’t get accurate results and you’ve just wasted that $115. Getting the right information means having the right equipment (brand names for good equipment: Medical Graphics, Sensor Medics, Parvo), and an experienced clinician (a Masters in Exercise Physiology with at least a few years of experience).

      And the only way you can find out if Lifetime has these things is by straight up asking them. Although in our experience, the PhD worked at a medical fitness center where countless clients of his were folks who had already tried going to Lifetime for metabolic tests, and been given inaccurate results.

      Your best bet for metabolic testing is usually a university or medical fitness center. If you’re in the Twin Cities area, The Marsh in Minnetonka has the right equipment and some qualified people.

      Thanks for reading. :)

  6. I just found your blog after doing a VO2 test at a facility staffed by well-meaning, courteous personnel. Unfortunately, it would seem that they were somewhat weak in the science behind the test, and utilized a New Leaf portable unit rather than one of the higher-end metabolic carts described in your article. While I now understand that the accuracy of data from this test could be suspect. But I have a more immediate problem: the results that the facility emailed to me are woefully incomplete (they failed to provide my VO2 max!) and are significantly less detailed than the results that others have received from tests conducted with New Leaf hardware. I already have a sunk cost (shame on me for not doing my homework and discovering your article before wasting my time and money), but I do wish to salvage the situation. The data that they did provide includes a chart illustrating peak O2 consumption, but I doubt the validity of that result as well. The charted value is 8625 (no units provided, but I presume that they mean ml/min). My body mass is 69.4 kg, so by dimensional analysis (and utilizing no real knowledge of how VO2 max is really calculated), that works out to a VO2 max of 124.3. This means that I should strongly consider breaking every world record in every sport that has a finish line. However, in practice, I would congratulate myself for finishing a 10K anywhere near the 40:00 mark, so either the New Leaf machine was grossly miscalibrated or I am grossly miscalculating from the sparse data provided, or both. I’d welcome any thoughts on the matter as I lick my wounds from wasting $130 and a full day’s time to travel into the city for this farce of a test.

    • Hi Andy.

      Sorry to hear about your experience. Sometimes the data from the test isn’t bad, but the staff responsible for interpreting and delivering the results can misinterpret them. However, it sounds like the actual data from your test isn’t accurate. Your VO2 math is correct, and no, it is not possible to have a VO2 max of 100. Given that the data and interpretation from the test were worthless, I would recommend that you go back in and ask for your money back. You have good grounds. If you would like to send us a pdf of the results I might be able to support your case for a refund. (If so, just let us know and we’ll give you an email address to use.)

      Wish I could be of more assistance. Thanks for checking out the blog.

      Joel French, Ph.D.

  7. I just had the worst experience with a trainer at Lifetime Fitness yesterday during a metabolic test. During the test I noticed that the heart rate that was being recorded on the computer was not realistic. I was just warming up, at 2% incline and 2.6 mph, and my heart rate was already at 140 bpm. At the end of the warm-up, I had reached 150 bpm! I was wearing the mask so I could not say anything, but at the end of the ten minutes warm-up, I told the trainer that it looked like my heart monitor was not working properly. She had not noticed that the heart rate was too high for the kind of effort I was making. Which is scary! Anyway she did not want to change heart monitor and we ended up having to measure the heart rate with the sensor on the tread-mill every two minutes (on my suggestion). At the end of the test, I asked her what she was going to do with this test. She told me she would fix the heart rate manually in the software. I became suspicious and started to ask if she was sure the oxygen had been measured accurately. She started to get confused. I think she had no clue on what she was doing, she had been taught to blindly trust the computer with no common sense. I have a PhD and I am a scientist, I could not believe at the poor answer she was giving me! Had I not noticed that the heart rate was way off, she would have continued with the test, and put together the assessment! I am determined to get my money back from Lifetime. Wish me luck!

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