Aerobic Capacity (VO2max)

What a VO2 Max test can tell you:

Your aerobic capacity, as measured with a VO2 max test, is the maximal amount of oxygen your body can consume during maximal intensity exercise. It is the product of your maximal cardiac output and your arterial-venous oxygen difference. This value is directly indicative of your level of cardiovascular fitness. VO2 max can be expressed in milliliters of oxygen per kilogram of body weight per minute, which is known as relative VO2 max, or in liters of oxygen per minute, which is known as absolute VO2 max. Relative VO2 max is better for comparing your results to those of others because it takes into account your weight, however, both values can be useful for personal comparison if you choose to return to our facilities for an additional test. If you want to improve your VO2 max, you can improve your cardiac output with aerobic training. Cardiac output is reliant on systolic volume and heart rate. An athlete can improve their systolic volume through aerobic exercise training which will lead to ventricular hypertrophy. Additionally, a number of physiologic changes will improve oxygen delivery. These factors include: increased capillary density in the muscle, a greater blood volume with a higher red blood cell count, higher levels of hemoglobin and myoglobin, increased levels of aerobic enzymes, increased size and density of mitochondria, more efficient ATP synthesis, and improved blood direction to active muscle.

What to Expect:

For an aerobic capacity test, you should arrive to our facilities in appropriate active wear having had only a light meal. This maximal exercise test is run on a treadmill and there are a number of different protocols which can be selected. One of the most common protocols is the standard Bruce protocol, which involves increases in speed and treadmill grade at the end of each three minute stage. Depending on your age and fitness level, a warm up speed will be selected. After you have been briefed by a technician on protocol you will be implemented with a heart rate monitor that is worn around the rib cage. A metabolic cart will be measuring the contents of the air you exhale through an expiratory tube connected to a secured facemask; you will be breathing in unaltered air from the room. After the equipment has been applied, you will begin your test and a program on the attached computer will measure your volume of oxygen consumption, volume of carbon dioxide production, respiratory exchange ratio, and heart rate. The test will end when you reach volitional exhaustion or when one of the following criteria is met: 1) the increase in your carbon dioxide production is significantly larger than the related increase in oxygen consumption (RER ≥ 1.15) 2) there is a plateau of your heart rate with increased exercise intensity, or 3) there is a plateau of your VO2 with increased intensity. Aerobic capacity tests generally end within 15 minutes.

How Aerobic Capacity (VO2 max) is calculated:

Your VO2, as measured by the metabolic cart, will be plotted on a graph against time. The increase in VO2 during activity remains fairly linear until your maximal oxygen consumption level is reached at which point the slope of the plotted line will begin to plateau. The highest value of VO2 during your test will be noted and reported in the form of relative and absolute VO2 max. You will also be presented with a summary and explanation of your results.