How Understanding VO2 Changed My Workout AND My Life

VO2 max test

By Caitlin Klopp

Hard work comes with its benefits. For me, this comes in terms of running. I personally enjoy running and look at it as a fun way to exercise or socialize with people. That being said, I lean more on the high mileage approach to my training plans. I always do a half marathon in the early spring and then take it from there. I love road cycling and running, occasionally I’ll train for a half ironman, but that’s if I’m feeling really motivated. I say that every race I do is for fun, but deep down inside I thrive off the opportunity to set a new PR and challenge myself even further.

When asked to demo a VO2 Max test I wasn’t totally thrilled. I really had no idea what it all entailed other than a mask over my mouth, a treadmill, and being totally exhausted at the end. Before I agreed to the test I was given a brief description of the tools I would be using; a Metalyzer 3B ergospirometry system by Cortex and the 4Front treadmill by Woodway.

I was also given a quick rundown of what the fitness test was all about. VO2 tests are a way to measure the maximum volume of oxygen your body can use to make energy. When you work out, your body increases the amount of oxygen it consumes to produce energy (why you breathe harder when running faster) but at some point, your body reaches the maximum rate at which it can consume oxygen and convert it into usable energy. The most common analogy is to a car engine, the bigger the engine, the more potential power it has. When the needle reaches the red zone on your cars tachometer on the dashboard, your car starts to make a little noise and is not happy with you. Just like when working out past your VO2 max. Your demand for oxygen is higher than your body can supply, which is why your body fatigues quicker once above that maximum.

In order to find this maximum rate, it was time to start the ten minute test! Our product specialist went over the basics of the breathing mask, heart rate strap, and how I wanted to fatigue on the treadmill (by speed or elevation). From that point on, I was only focused on running and trying to forget that I had a mask on my face. Running with a breathing mask is definitely something I haven’t experienced before, almost feeling restricted of air, but if you can get past it mentally, the results are worth the uncomfortableness.

Before I knew it, the fitness test was over! The vast amount of information gathered was then plotted into a chart. The main number that I was looking at was my max, just how large is this engine I am working with. This will be a better indicator of my potential for endurance activities such as cycling and running. Turns out that based on the classifications by the American Heart Association (AHA) my fitness level is excellent! Way better than I thought I would be! My max from this test was 52ml/kg/min which is well above “good” range for females my age, which is 33-36.9ml/kg/min. Maybe all those runs are paying off! To put that in perspective, Lance Armstrong has a VO2 Max of 84.0ml/kg/min, well above mine. At my VO2 max, my heart rate was at 186 bpm so the workouts are then generated with this as my maximum aerobic heart rate.

The one number that I really found fascinating was the Respiratory Exchange Ratio (RER). This number represents the ratio of the volume of carbon dioxide you exhale versus the volume of oxygen you consume. So when you are warming up, you are consuming more oxygen than carbon dioxide that is released so you are breaking down fats. This would be anything under 0.8 for an RER. When you increase your intensity levels, your body starts to burn more carbohydrates, represented by a RER number of anything above 1. This clicked in my head, all those times my coach would tell me to go for an easy run, it was to burn fat and save the carbohydrates for the interval workouts. Now I’m older, wiser, and eager to start training off a heart rate based program to see the potential this can have on my running results.

Based on my results, the Metalyzer 3B was able to come up with a heart rate based training program for me. This will give me catered workouts based off my RER, VO2 max, max heart rate, and other results from the test. I’m excited because these training plans are unique to me and my current fitness level, not a generic training plan one could find online. I am going to give it a try, follow all the suggested workouts, time frame, and heart rate based intensity levels and see where that takes me in 9 weeks. After 9 weeks, I will complete the VO2 test again and see what progress I have made from this approach to training. Hopefully I will increase my max, giving me a larger engine to work with. This training plan will also teach me to work out smarter by conserving carbohydrate expenditure for intense workouts. If nothing else, I will still maintain my cardiovascular health and enjoy not having to create workouts for myself. Who knows, after 9 weeks I may be right back to my high mileage approach!

To learn more about Woodway's VO2 testing equipment please contact Woodway to speak with a sales representative in your area!