After struggling through a fall season where my HR zones were continually being "adjusted," I decided that I'd like to get a VO2 max test. A VO2 max test measures many things, but the results of the test will give you your zones based on science instead of guesswork and formulas. VO2 max refers to the maximum amount of oxygen that an athlete can use during intense exercise. The test gives you your VO2 max number, which is a good indication of your aerobic endurance potential, but it also gives you a ton of other information about how many and the kind of calories you currently burn during exercise at different intensities, as well as HR information as related to zones.
I asked Lauren for a recommendation because I knew that she was really happy with the test she took last spring, and ended up scheduling with Melissa Dalio from endura coaching. I contacted her via email about the test and we scheduled it for last week. My initial impression of Melissa via email was fantastic - she seemed organized and detailed and everything I needed to do to prepare for the test was very clear. I was told not to exercise the day before or the day of the test and not to eat for 3 hours before the test. One mistake I think that I made which may have slightly affected my numbers was how I ate throughout the day. When I'm hungry I get REALLY cranky, and I was so worried about feeling hungry after not eating for 3 whole hours that I'm pretty sure I overate quite a bit at lunch that day. When we started the test, not only was I not hungry, but I actually still felt full. Melissa told me that this may have slightly affected my fat-burn vs carb-burn numbers. Otherwise, I felt rested and ready to go.
When I showed up for the test, Melissa had me start walking on the treadmill to warm-up while she took down a bunch of information about me (age, height, weight, rough idea of training paces, all kinds of stuff). I'd guess that I walked for about 15 minutes and then eased into a slow jog. One thing she did that was great was set up a video camera so I could see myself running from the side on the TV that was mounted right in front of the treadmill - live gait analysis. We talked for a few minutes about some minor things as related to my gait, and then she turned off the camera and we got ready to start the test. She paired my HR monitor with her machine and set me up with the mask that you wear that measures your breathing. (She was also awesome enough to take a bunch of pictures and even a video of my suffering).
The test starts at a very easy pace. Data is gathered in increments of a minute, so she let me know beforehand all the secret hand signals to let her know that I was getting tired or close to being done, and she told me that she'd have me finish out the minute (if possible) to get complete data. Every minute, she upped the pace by about :30-:40/mile, and once I got pretty close to running flat-out, she added elevation instead of increasing pace. Melissa let me know before we started that most people end the test and say they could have gone one more minute. She also kept manual notes of HR/pace/cadence on a clipboard while I ran. I made it 14 minutes and then we shut it down. After that, I walked for about 10 minutes to cool down while she printed out and worked through the data. Here are the results of the test (it's all gibberish but click on it if you're a science nerd like me):
And here are my zones (running only):
Just for fun, compared to my running zones that I used all fall (hot mess, straight ahead):
So, what does all the science mean? A lot. (Disclaimer: I'm using my memory and the packet Melissa gave me to translate all of this so it's highly likely that I might be getting some of it wrong. Hopefully you internet scientists will straighten me out).
First of all, my VO2 max number is amazing. Like really seriously surprisingly amazing, now that I've done some more research about what all this means. My number, as a 31-year-old 5'6" 140lb female, was 51.5. Here's a chart to help you recognize how awesome I am (like you needed it).
Right. So the first thing I learned is that my aerobic potential is literally off the charts, which is a great piece of information to be armed with, mentally, on day 1 of IM training.
The next piece of information is less happy - even at low intensities, my body is burning almost all carbohydrates and no fat. This is really bad news for an endurance athlete. In zone 2, I burn 4.7 Kcal/min of fat and 8.7 Kcal/min of carbohydrate. Ideally, those numbers would be at least switched. At my lactate threshold - the place where your body can recycle lactic acid as quickly as it is making it (top of zone 4, HR 170) - I burn 0.6 Kcal/min of fat and 14.4 Kcal/min of carbohydrate. One of the many reasons that athletes spend so much time training in the dreaded zone 2 is because that's how you teach your body to burn fat. I'm not sure of the statistic and I'm way too lazy to google it, but I believe that you have enough fat stored in your body to take you through a ridiculously long amount of exercise - like 24 hours or something crazy. In contrast, you have enough carbohydrates stored to take you through about 90 minutes of exercise. So athletes train at this low intensity to overload their slow-twitch muscle fibers which is where the fat burn happens which increases endurance (i.e. the thing you need to get through an Ironman). Right now my body really sucks at that but it's really amazing at burning carbs. Or, as Melissa put it, in my endurance house right now, my foundation is small but my house is REALLY tall (and I should be able to run much faster than I do, sigh). Fortunately, I'll be spending most of the next 7 months in zone 2, which should help my body become an aerobic fat-burning monster.
The other really critical piece of information that I got is related to nutrition. When you are exercising for a long time, you need to replace the calories you are burning. You can't replace the fat calories but you can replace the carbohydrate calories (I think). In zone 2, I burn 281 Kcal/hour of fat and 523 Kcal/hour of carbohydrate. Ideally, you'd like to replace every calorie you burn of carbohydrates but that is theoretically impossible because you'd probably power puke your brains out on the bike (not recommended). However, Melissa let me know that I should be aiming for at least 250-300 calories per hour, which is quite a bit more than the 200 per hour I've been working off of for the past several months on the bike, and not even close to the 100 per 45 minutes that I've used for every long run I've ever done. Which means I've probably been under-fueling for long workouts, which has probably been contributing to my very tall and skinny house.
I'm really happy that I did this for quite a few reasons, not the least of which is because I'm addicted to the science related to exercise. Being firmly aware of what my body needs and is doing makes me feel much more confident about starting up IM training. I'd like to go back in a few weeks and do this test on the bike, as there are formulas that can translate these numbers back and forth but they aren't exact. If you're a local athlete, I definitely recommend Melissa for this test, and I'm sure I'll be back in her studio quite a few times this season. Make sure to tell her that the blog with all the ass shots sent you.
Have you ever had a VO2 max test done? Did you lose your lunch? Is your house wide and short or tiny and tall like mine?