Taking a VO2 max test

by Jason Devaney

I am a 55.3. What’s your number?

Since I started training for triathlons in April, I’ve employed one simple method during workouts: Go out and swim, bike or run. The only goal I had for each workout was to go as far as possible at a pace I could sustain. I never measured my heart rate or paid any attention to the physiology of what I was doing.

With this in mind, I recently drove to Total Performance, Inc. in Lutherville, Md. to visit with triathlon coaches Krista Schultz and David Glover of ENDURANCEWORKS, LLC. The reason for my visit was to take a VO2 max test.

A what?

A VO2 max test.

In short, the test calculates your aerobic and anaerobic thresholds, plus your VO2 max number. That number, which takes into effect respiration and body weight, is the “maximum volume of oxygen the body uses during one minute of maximal exercise,” according to VO2maxtesting.net.

Still confused? I am a bit perplexed myself. But what I do understand is that the results sheet that Krista handed to me (and explained in excellent detail) is very telling.

Before I go any further, I’ll reveal my VO2 max number: 55.3! To put that in perspective, the computer predicted – based on my weight – that I would be a 44.4. And, at nearly 30 years old, I fall in the 40-48 bracket. So I was pretty happy with my final result. In addition, I could have kept going during the test and I’m convinced that my number is closer to 60. More on that in a bit.

Back to the results sheet. Aside from the VO2 max figure, one thing I learned about from my test was RER (respiratory exchange ratio). RER is the ratio of carbon dioxide you exhale versus the amount of oxygen you take in at a given exercise intensity. A lower RER means that you are able to break down more fats (an unlimited fuel source) rather than carbohydrates (a limited fuel source).  An RER of 0.85 means that you are burning approximately 50 percent fat and 50 percent carbohydrate. As exercise intensity increases, your body must rely more and more on carbohydrates as a fuel source. Anything over 1.00 means you are basically are burning primarily carbohydrates.

After one minute of the test – which involved strapping some high-tech gizmos onto my face and head to measure my breathing as I ran on a treadmill – my RER was 0.83. At 1:31 it had jumped to 0.97, then 0.99 at 3:00. About a minute later, I was 1.01.

This makes perfect sense to me because when I run, I tire very quickly. Usually in the first mile I feel very tired but shortly after that, I’ll settle into a groove and cruise the rest of the way. If I can teach my body to tap into its fat stores earlier and stop using carbohydrates to much, I can remedy this.

Another important figure I took away from the test was my anaerobic threshold, also known as the lactate threshold (LT). My heart rate at the LT was 171 beats per minute and it occurred when my RER number jumped (and stayed for the remainder of the test) above 1.00 at the 6:30 mark.

Lactate threshold, according to David, is the point above which lactate, a byproduct of muscle activity from the breakdown of carbohydrates, begins to accumulate more rapidly in the blood. Exercising above the LT is not sustainable for a long period of time, but you can increase this number with training.

So that was quite telling.

But onto the actual test.

When I arrived shortly before noon, I met with Krista and we shared a few stories about driving in Washington, D.C. traffic, competing in triathlons and everything in between. David then walked in and after a few more pleasantries, I went into the locker room and emerged a few minutes later in running shorts and shoes and a Universal Sports t-shirt (obviously).

Krista weighed me and strapped a heart rate monitor onto my chest, and then had me run at a medium clip for 5-7 minutes on the treadmill to warm up. She discussed the entire test to me during this time, and squashed some of my anxieties with her thorough explanation. I had done some research about VO2 max tests before meeting with them, but I still did not really know what to expect.

After my warmup we stopped the treadmill and I hopped off to grab a drink of water. We talked for a few more minutes as Krista and David answered a few more of my questions (like what they thought my VO2 max number might be). Then the fun began.
Krista fitted a headpiece on me with white straps and clear plastic pieces hanging down from the sides. Then she gave me the mouthpiece, which fit like a sports mouth guard and connected to the headpiece via the clear plastic straps. It had a plastic tube extending from my mouth which she then hooked up to a hose that connected to the computer, and it was held up by a Velcro strap hanging from a metal arm. She completed the preparation by clipping my nose shut with blue rubber nose clips. This would force me to breathe out of my mouth, allowing the sensors to do their thing.

It was all very high tech.

Now that I was back on the treadmill, Krista started the belt and after a few minutes of walking to make sure the computer was functioning properly and to get me comfortable with the equipment, she kicked up the speed to 6 miles per hour and the testing began.

For the first few minutes, she increased the speed of the belt by a few clicks to make me work harder every 60 seconds. Then she started doing this in increments of 30 seconds as the test wore on, trying to max me out and get the highest possible numbers.

With David taking photos and Krista manning the machine and calling out commands, the test went on for 11 and a half minutes. They were both very happy that my VO2 max number kept climbing, and they let me know it.

“42.7!” Krista exclaimed at the 8:01 mark. “You’re doing great! Keep pushing! Let’s get it to 50!”

David chimed in a few times too: “Great job Jason! Keep it going! Don’t let up!”

At 10:31, the machine said I was at 51.5. Wow! I figured I’d be in the 40s, but 50? Thirty seconds later I was 52.8. Still climbing! Krista said I was still increasing and I could keep going, but at any point I could signal to her to stop the machine if I was too tired.

The treadmill was at 12 percent incline and the speed was at 7.5. I had no issues with keeping up with the belt speed-wise, but the hill I was being forced to run up was really taking a toll on me.

The 11:31 reading came through.

“55.3!” Krista yelled. “Wow! Can you keep going? You’re still increasing!”

As pumped up as I was, the incline was really getting to me. I was so gassed and as much as I wanted to keep going, I knew I had stop. My VO2 max number was still increasing so I definitely did not reach my true max (it will plateau once you reach it), but I needed to stop. I signaled to Krista that I was done.

She quickly unhooked me and stopped the treadmill.

Before the testing began, David and Krista both said to me that a lot of people, once they finish the test, say that they could have kept going. I laughed and thought to myself, “Nah, that won’t be me.”

I was wrong.

No more than two minutes after I finished, I uttered those same words. Both coaches got a kick out of that one.

The three of us talked about my test results for probably 30 minutes afterward, and then again over lunch, and I really learned a lot of great information. Scientific numbers aside, I learned that there is a lot more to working out than simply going for a run. Or heading out on my bike or swimming laps.

I learned that if I can control the tempo and pace of my workout, I can actually increase my performance – which will lead to a faster Jason in 2010 and beyond.

Author’s note: Krista Schultz  and David Glover run ENDURANCEWORKS, LLC an endurance sports coaching and services company. specializes in personal training, triathlon coaching and VO2 max testing. Visit them on the web at enduranceworks.net.

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