I love the way the advances in sports science that were once only affordable by elite and sponsored athletes have trickled down to be accessible to club and age group cyclists. One of these advancements is the VO2 max test.
In order to perform at its best, your body has to do a number of things. This includes the whole energy cycle of taking in oxygen from the air, delivering that oxygen effectively to the working muscles, delivering fuel (body fat and glucose) to those same muscles, using the oxygen to oxidize that fuel in the muscle cells and release energy, and then removing the waste products effectively.
What Is the Basic VO2 Max Measurement
A VO2 max test, in its simplest form, simply measures how much oxygen you take in. Basically, the more oxygen you can take in and deliver to the working muscles, the more energy can be released. The faster or harder you work, the faster you breathe and the more oxygen is delivered.
A VO2 max test, therefore, has a simple test protocol of getting you to work harder and harder while measuring the rate of air consumption until this plateaus. This then gives you a value as to the maximum amount of oxygen that your body can deliver. The final figure is usually measured in milliliters per minute and then normalized by dividing by your body weight (mL/min/Kg). A typical figure might be fifty-five milliliters per minute per kilogram, depending upon your body dimensions, age, lung capacity, and respiratory health. But what then?
What You Do With the VO2 Max
On its own, this VO2 figure has limited use. Not surprisingly, elite athletes have generally been found to have a higher VO2 max than non-elite people, and that has no doubt helped them to get where they are. The only way to change this number for yourself is by increasing your breathing rate, increasing lung size, or losing a bit of weight. It may also be that if you have a history of respiratory problems that this is an important measurement to monitor on a regular basis as part of a longer-term fitness program. However, for the club or age group cyclist who is already taking part in regular activity, this number is unlikely to change by much.
More Advanced VO2 and EMR Measurements
Another type of VO2 max test measures the power and heart rate during the increase or ramp of effort in addition to the point at which oxygen or air consumption plateaus. This additional information can then be used to estimate different heart rate or exercise zones.
The point at which your oxygen consumption plateaus can be approximated to an aerobic threshold since exercise above this level cannot be supported by any more oxygen and you will go into oxygen debt, or anaerobic exercise. If you are doing hard interval sets, then this will give you the threshold level that the effort part of the interval needs to exceed. This will be more reliable that using the heart rate, which tends to lag behind the effort.
Another type of VO2 max test should more accurately be called an Exercise Metabolic Rate (EMR) test. The protocol for this test includes a ramp, as before, but this time the concentration of expired carbon dioxide is also measured. An algorithm inside the test unit is able to use the rate air consumption, percentage of oxygen, and percentage of carbon dioxide to measure what type of fuel your body is using. This is because oxidation of body fat and body sugar release different amounts of carbon dioxide.
A full EMR test will therefore give a lot of information such the amount of body fat and body sugar you are burning, the amount of energy you are releasing and comparison to the load to determine how efficient you are, a variety of exercise zones depending upon the point at which exercise becomes anaerobic, and power and heart rate. A typical chart will look like this diagram:
The table that should accompany the EMR test chart is a gold mine of information. Since the body has a limited reserve of sugar (usually around 2000Kc and an additional 240Kc per hour if you top up with energy drinks), you can use the information to give an estimate of your pacing for an event. Ride too fast, and you will use up all the body sugar and bonk, or hit the wall. Ride more slowly and you will burn mainly body fat, which is sustainable for a long time. If you are doing a timed event, then you can use the information to work out an optimum pace to complete just as sugar reserves are running low.
It is also possible through a focused exercise and nutrition plan (remember, the body will specifically adapt to imposed demands) to shift the chart to the right. This will increase your ability to burn body fat and help enable you to ride faster and longer.
If you just wish to establish some exercise zones, there are many ways you can do this yourself without a VO2 max test. If you have the EMR type of test and obtain all the data, there is a wealth of information that you can use to help reach your goals.
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