Tuesday, May 15, 2012

Puking in my VO2 Mask

It was time to redo my VO2 testing (more info on VO2Max testing from Runner's World) at the gym. I actually had thought we'd last tested 3 months ago, but when we did the test and pulled up the old data we saw that it was 68 days ago. I tried to push myself during the test as close to my max heart rate as I could get and yet not throw up. And yes, I managed to avoid puking in my VO2 mask, but I got close enough that my trainer and I were both googling for videos of people puking into VO2 masks to include in my blog entry. Sadly, or fortunately for all of you, depending on your perspective, I scoured the internet and could find no such videos. Boo.

Here's what happened at my last test. And what did we hope to see this time?

  • We didn't expect my aerobic base to really move, because I'm pretty efficient at my base so it would take a lot of work to move that, and it hasn't been long enough.
  • We didn't expect my anaerobic threshold to move either, because I haven't been doing extremely high intensity speedwork at a very very high heart rate.
  • We did hope to see that the big negative slope in efficiency that we saw between the aerobic base and anaerobic threshold last time would have leveled off some. This would be because of spending a lot more time training at Zone 2 and Zone 3, those uncomfortable zones. This would allow me to race at higher heart rates and faster paces without burning through my glycogen (carb) reserves as quickly.


I'm not an exercise physiologist, kinesiologist, or any other -ologist expertly trained in VO2 testing and its results. I'm an average runner, who passed the test to be an RRCA-certified running coach, and understands a lot of the rudimentary things about VO2. But I may misstate things here, so always do your own research and consult with someone smarter than me!

The Actual Testing

So the test works like this. You wear a super sexy blue mask. And you wear this mask for 10-11 minutes in the middle of the gym in my case in front of the whole world. 
This is what the testing looks like. P.S. This is not a self-portrait.
Then, my trainer Donnie, who is trained and certified within his gym to analyze the raw data, starts the treadmill at 3 mph. So word of warning, get the test done with someone who is actually trained in it. Not someone who owns the equipment and runs the machine and makes the computer do all the work. Because you really want a professional reading the test data and helping you interpret so that you know what it means!

The wires hooked up my mask read the oxygen and carbon dioxide levels to figure out when and how I use the oxygen in my body efficiently. 1-2 minutes at a time we move up to 3.5 mph. 4.0 mph. 4.5 mph. 5 mph. Then we start raising the incline, 2%, 4%, 6%. At 8%, it's starting to hurt, but I'm trying to keep that heart rate in check. Unlike the last test, we actually reach 10%. And I hold on, at 12 minute per mile pace and 10% incline, for about 20 seconds. Until I have to jump off and cling to the sides as I almost spew into my very tight mask.


One easy way to sum it all up is comparing my VO2Max number.

  • Before: 36.5
  • After: 42.1

That's a huge jump! 17% increase in only 68 days! I had a VO2Max that was expected for a normal female, or in my case a female marathoner with bad genetics. Boo. And now I have a VO2Max that sounds a lot more like a standard athlete. Yippee!

From a Runner's World article about improving VO2Max:
"If you want a high VO2 max, choose your parents carefully. One group of scientists concluded that heredity determines up to 50 percent of your endurance ability. Still, that leaves 50 percent that can be influenced by training. While an outrageous VO2 max isn't the only ticket to running greatness--Frank Shorter's and Alberto Salazar's maxes were in the low 70s--increasing it can boost your race times. A five-point jump, for example, can translate into a seven percent improvement, or 90 seconds for a 20-minute 5-K. And a moderately fit runner can increase VO2 max by as much as 25 percent."

Further, the % of calories that come from fat at higher heart rates has gone up. That means I'm more efficient at higher heart rates in Zones 2 and 3. So I can go longer pushing at those heart rates, burning fat calories. See the numbers in Zone 2 - before I burned 37% of calories as fat calories, whereas now I burn 42%. Even better is that strong negative slope of declining efficiency in Zone 2 has almost completely leveled out! And my efficiency in Zone 3 went up quite a bit too. I knew this from anecdotal evidence because I had spent about the last 6 miles of the NJ Marathon, when I was working to finish with a PR, at Zone 3 thanks to cardiac drift. But with increased fat-burning efficiency, I could do that where I could not have before!

More data for those who like data like I do...

Final Conclusions

What does this all mean for upcoming races? So where do I go from here?

  • It means that I can hang out anywhere in Zone 2 for quite a while and still have a very high fat-burning efficiency. Before, I knew to hang out no higher than low Zone 2.
  • I can race for about an hour at low- to mid-Zone 3 where before I would have sputtered out of energy.
  • I can use the calories per minute burned calculation to verify that I'm taking in enough nutrition during ultramarathons. I need about 200-250 calories per hour in a race to keep the engine fueled well it appears.
  • Do not ever hit Zone 4! Look at how many calories I burn per minute there! 13. And it's all carbs. So a half hour of that burn equals more than an hour of happy fat-burning effort. I'd burn through my energy reserves quick. And even if the heart rate zings up and hits Zone 4 briefly, you can keep burning pure carbs for a while after it pops back down. In an ultra, this would get me to a quick DNF. So no Zone 4!

So Friday it's time for a trip, and Saturday I'll be running Jemez 50K with all this new data loaded into my Garmin Forerunner 910, and all this knowledge driving my efforts and my paces! Jemez, here I come!


  1. I love data! I'd love to do this! I'm not sure what it means, but the last time I took data from a half marathon, my heart rate averaged 85-95% max the entire time (2:15-ish hours at about 175-185), which equates to 2 hours of zone 4/5 time there.

    And you're going to rock this race!!! I'm so excited to see the race recap. :)

    1. With all your training and racing, you may want to consider it! At the least, the data is a great way to quantify improvements in fitness from the start to end of a training season. Good luck at your upcoming races!!

  2. Why didn't you have your picture taken with the sexy blue mask on your face??? =)

    1. Because that guy looks a lot better in it than I do. Helllloooo, Hannibal Lechter!

  3. You may spew in your oxygen mask at 10k feet...