So What is VO2 Testing All About, Anyway?

One of the questions we often hear is how someone actually benefits from VO2 test testing. We thought we’d take this opportunity to explore the question in some detail. So, hang on, because it's a thrill-a-minute!

Aerobic and Anaerobic
No doubt you’ve heard the terms “Aerobic” and “Anaerobic” thrown around in conversation. For anyone aspiring to peak endurance performance – or just wanting to drop a few pounds and stay in shape – they’re ultra important. Luckily, the concepts are relatively simple:

• The Aerobic system burns mostly fat
• The Anaerobic system burns mostly carbohydrates

As a source of fuel, fat is certainly the most abundant, providing hours of energy. Carbohydrates, in the form of muscle and liver glycogen, deliver energy – but at a higher cost. Glycogen is consumed faster than it can be replaced. Your body also utilizes protein as a fuel source – but its contribution to energy output is minuscule, so for this discussion we’ll focus on fats and carbohydrates.

Now, one thing to keep in mind is that the systems are not either on or off. In other words, we’re always burning some mixture of fats and carbohydrates to produce energy. That’s why energy gels, nutrition bars, and other products providing concentrated carbohydrates are used on long rides and runs – we need to keep replenishing our carbohydrates (we’ll talk about nutrition in more detail in a later post).

So the key for endurance athletes and those looking to stay fit and trim is to burn the most abundant fuel available – fat! Or, as we’ve learned, a higher percentage of fats relative to carbohydrates.

But how do we control what fuels we burn?

It’s All In The Zones
Unlocking your metabolism is as easy as strapping on a heart rate monitor and exercising within specific zones. A key heart rate indicator is Anaerobic Threshold (AT). AT indicates the point at which your body can no longer deliver oxygen to your muscles in quantities necessary to burn fat as a primary fuel source. As the stores of muscle glycogen are depleted, your energy begins to wane – and if you’re able to continue exercising through the fatigue, eventually liver glycogen is utilized…and that’s pretty much when you either “hit the wall” or “bonk.” Not a good feeling!

There are variety of methods for determining Anaerobic Threshold – problem is, most methods are merely averages of people in your age and weight group. Studies show these can be wrong for any given individual by 40 to 50%!

A Better Way
The only way to know your true Anaerobic Threshold and target heart rate zones is to measure how much oxygen your body is using as you increase the intensity of your workout. And we just happen to have state-of-the-art of laboratory equipment that does just that, measuring both VO2 and VCO2.

Through a simple, graded exercise test, we can target Anaerobic Threshold and determine a range of zones corresponding to recovery, aerobic or endurance, tempo, and interval workouts. Plus we can tell you the percentage of fat relative to carbohydrates you’re burning at any given heart rate. Talk about targeted training!

Beyond the Aerobic Zone
Of course, as an athlete, you know you have to take things outside the endurance zone – T-Pace intervals, Fartleks, time trials, track intervals – in order to push your body to new levels of fitness. It just comes down to knowing when and how much intensity to add. And that’s where having a good coach can make all the difference. More on that later!

Stay true to your zones!

Jon and Barry
Endurance Geeks