Find your Fitness Level

Let's talk VO2 Max. AKA Aerobic Fitness.

V02 Max represents the volume (V) of oxygen (O2) your body can use while performing aerobic activity- running, cycling, swimming, etc. You want your body to be able to use a lot of oxygen because it delays the onset of fatigue while performing these activities. AKA you want a higher VO2 Max. 

So what's a good VO2 Max? It depends on the person. Everyone is different, but from my experience I usually see anything from 40-60 mLO2/Kg/Min (we'll get into what that unit means later). Obviously, the higher end of this range is ideal, but if you are just starting a fitness program, the key is to get a baseline number and track your progress.

Getting your VO2 Max can be complicated. You may have seen the Gatorade commercial that shows an athlete hooked up to some sort of breathing apparatus and sprinting on a treadmill. It looks something like this:

Photo Cred: trifitcoaching.com

This procedure reports your actual VO2 Max by using a maximal treadmill test. However, this test isn't usually readily available to the general population and is sometimes (and when I say sometimes, I mean all of the time) uncomfortable. Imagine plugging your nose and being asked to breath through a snorkel. Now add maximal exercise (sprinting on a treadmill until you LITERALLY cannot sprint any longer). That's maximal treadmill testing.

Besides  being uncomfortable this test is expensive. The equipment used in this procedure costs thousands of dollars and is usually only found in research or university settings. 

Because of this, researchers have developed various protocols and predictive equations that provide a predicted VO2 Max. These protocols are a lot less invasive and uncomfortable. Many times they can be self-administered and call for readily available tools (heart rate monitor, treadmill, etc.). These are called sub-maximal tests.

Here's an easy protocol to find your predicted VO2 Max:

Rockport One Mile Walk Test

1. Walk one mile as fast as possible

• You really do have to WALK!

2. Collect Ending Heart Rate (HR)

• Take heart rate for 15 seconds after crossing the mile mark. Multiply this number by 4 to get beats per minute.

3. Collect Mile Time in Decimal Minutes (T)

• Use the equation Decimal Minutes= minutes +(seconds/60)

4. Use Prediction Equation to find predicted VO2 Max

• VO2 Max= 132.853 - (0.3877 x Age) - (0.0769 x Wt) - (3.2649 x T) - (0.1565 x HR) + (6.315 x Gender)

• Wt in lbs
• Gender: Male=1 Female=0

If you don't want to solve the equation on your own you can enter in the above information here: https://www.walkingwithattitude.com/fitness-tools/rockport-fitness.

Now let's talk about the units of VO2 Max. As mentioned before, VO2 is measured in mLO2/Kg/min. Simply put, this states how many milliliters of oxygen each kilogram of your body uses per minute while performing aerobic activity. You want your body to be able to use a greater amount of oxygen so you can perform aerobic activities for a longer period of time or so you can perform higher intensity activities without your heart rate skyrocketing.

Wait, how is heart rate related? Great question. You can see from the equation above that heart rate is one of only two variables we use when predicting VO2 Max. Each time your heart beats, it pumps out a certain amount of blood (thank you, Captain Obvious). In this blood is oxygen. The blood takes the oxygen to the muscles where it is used in metabolic processes during aerobic activity. If you are only able to use a small percentage of this oxygen in your blood, your heart has to beat faster (more often) to increase the amount of blood flow (and oxygen in that blood) to the muscles to satisfy its metabolic needs. Sound complicated?

If you have a higher VO2 max, your heart doesn't have to beat as fast (as often) because you are absorbing a higher percentage of oxygen from each heart pump.

Make sense? I hope not. It took me 4 years to learn that, so if you got it from one blog post I'm going to greatly question my abilities.

Now let's make this applicable:

Take a look at where your predicted VO2 Max falls. Is it better than what you thought it would be? Good for you. Is it worse? 

The great news is there's always room for improvement. Start by looking at the next category up from where your result falls. Make that your goal. Gradually increase your aerobic activity based on your fitness level. Try to participate in moderate-intensity aerobic activity for at least 150 minutes per week (or vigorous-intensity for 75 minutes per week). Then perform the test again and see your progress!