VO2 Max Test

I’ve been wanting to have a VO2 Max test done for a while. The cost of the test, plus having to find childcare always kept it in the “maybe one day” category. The heart rate training has been working, and I though I could certainly benefit from a VO2 Max test, it wasn’t a priority.

Thanks to Harvey who flooded my beloved Y, I joined Lifetime Fitness a couple of weeks ago. I went to the facility for a tour and after I’d decided to join the uber slick guy selling me the membership started asking me a number of questions, the last of which was, “Do you want to purchase LT Bucks?”

Me: Uhhh, what are LT Bucks?
Him: They’re electronic currency you can buy stuff with. When you join you can buy them for $.50 per $1 LT Buck.
Me: Ah, okay. Like what kind of stuff can I buy?
Him: Massages in the spa.  Hair and nail services. Group classes. Food from the cafe.
Me: Eh, food maybe but I won’t really use the other stuff. I’ll pass.
Him: Metabolic testing.
Me: Wait. What?
(He started grinning. He knew he’d won.)
Me: Like VO2 testing?
Him: Yes.

10 days later, I was standing on a treadmill with a mask strapped to my face.

The test itself was pretty rough, obviously. It’s a twisted version of torture, if you think about it. It’s the only word to describe something that involves increasing difficulty in small intervals, the last of which includes the description, “I am going to die!”

That’s actually what the paper said.

It really did.

Before I go any further, let’s talk about what VO2 Max actually is. It’s the maximum amount of oxygen your body can consume in one minute (in milliliters), per kilogram of body weight. If you want to increase your VO2 Max you can either increase your lung capacity or loose weight.

The keyword here is maximum. This is a maximal test, meaning you push your body as hard as it can be pushed, hence the description, “I am going to die.”

You know you’ve reached that maximum point if you see a plateau in oxygen consumption at the end of the test.

My test went like this, first we did a warm up, a mini version of the test. We started at a 10:10/mile at 1% incline and increased the speed by 1/2 mph every two minutes, before every increase in speed I was asked how I felt on a pain scale of 1-10. 1=Sitting on the couch, eating bon bons; 10= I am going to die. The warm up ended at a 7:30/mile pace at a pain level of 7.

We then took a 5 minute break.

After the break was over, we did the real test. Just like before we started at a 10:10/mile, pain scale of 1 and this time ending at a 6:25/mile, pain scale of 10.

During the warm up and test I ran about 4 miles combined (slightly less, but close to it) and the whole process took an hour. (Please note: this test was personalized for me. If you choose to get your own test done, the process should be similar but the starting/ending paces and inclines will be different, depending on your own individual needs.)

Now, the results.

As of September 14, 2017, my VO2 Max is 57.2.

What does that mean? This means my body can consume up to 57.2 milliliters of oxygen in one minute per kilogram of body weight. Oddly enough since this is a ratio of consumption to body weight, decreasing your body weight increases your VO2 max number. If I had taken this test a month ago, prior to the 9 pounds I gained during our camping trip and Hurricane Harvey, the VO2 Max reading would have been a 60, simply based on the math.

Okay, but what does that mean? Yeah, it really doesn’t really mean anything. The VO2 number itself, is a way of measuring how much oxygen your body can process during exercise and is an indicator of fitness.  Though fun to know, it is simply one of many tools that can help you determine ways to improve. Other factors, such as lactate threshold and running efficiency, also play a major role in developing speed and determining performance.

So why go through the trouble? Because I wanted to know my training zones. I’ve been heart rate training now for about a year and a half and have seen significant progress but as fitness improves zones change and progress slows.

Ironically enough, with all my preaching about slowing down, according to the test I’m doing my easy runs at too low of a heart rate. According to the test I should be training at a heart rate of 160, not 147 if I want to continue to see improvement in cardio-respiratory fitness. Good to know.

The test also gave me some different information other than VO2 Max and my zones. It gave me my max HR (191) and an estimated lactate threshold of 171 bpm. (True lactate threshold can only be determined by a blood test.) Interestingly enough, when I do tempo runs, I run by heart rate not by pace and I always try to maintain a heart rate of 171. This is also the heart rate at which I race a half marathon. I find it no coincidence that this is my estimated lactate threshold since most of my speed training takes place at this heart rate.

It’s an amazing illustration of how the body adapts to the stress placed on it.

I also learned what percentage of fat versus carbs my body is burning in each zone. In my zone 2, I am burning 91% fat and only 9% carbs! I guess all that fat adaption I’ve been doing is paying off.

Furthermore, I am burning 73% fat and 27% carbs at the top of zone 3, which is where I race a marathon. This means I can race a marathon without hitting the wall and explains why I threw away 6 packs of gummies at mile 20 during Boston. My body wasn’t depleting its glycogen reserves. According to the math, I could in theory run 185 miles at an easy pace (the top of zone 2, heart rate 160), or 61 miles at marathon race pace (top of zone 3, 170 heart rate) before I run out of glycogen. I think my legs would give out long before then but it sounds really cool!

This where the wheels fall off. When I hit my threshold of 171, the fat burning stops entirely. I have done such a good job training my body at half marathon race pace that I suck at everything faster than that. At a heart rate of 172, I am burning 100% carbs and could only go 16 miles before hitting the wall.  Important lessons to be learned here, folks.

You can read the full report here.

A Few Technicalities

For the record, the test at lifetime gives you 5 zones but they were broken down slightly differently than other tests I have seen. According to the test my zone 1 doesn’t even start until 140 bpm (and they explained after the test that most of my training should be at the top of zone 1), and zones 2-3 are only a total of 9 bpm combined I am assuming a non-indicated zone prior to their given zone 1 and that zones 2-3 combined are equivalent to zone 3.  Given that information, I re-programmed the zones in my Garmin to the following numbers.

Zone 1 is < 140.
Zone 2 is 140-160.
Zone 3 is 161-170.
Zone 4 is 171-180.
Zone 5 is 181-191.

In addition, after looking at the numbers after the tests, it was noted that my oxygen consumption never plateaued. Remember, I noted earlier that a plateau of consumption at the end of the test indicates that you’ve reached your maximum? My highest level of oxygen consumption was my last breath, meaning I quit too soon. I could have pushed myself through another interval had I not been truly terrified of falling off the treadmill…which was a valid concern.

The Harvey weight and lack of a plateau leads me to believe that 57.2 is, most likely, slightly low.

The moral of the story: I am scheduling a re-test in January when Ironman training really gets started. Between now and then I’m going to get back down to my normal weight (2 pounds to go!) and practice running sprints on the treadmill so I’m have some confidence in my ability to actually stay on it!

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