The following text is from the Physical Conditioning Course shared in the SomaTraining Exercise Program organized by Guy VOYER, DO.
What is aerobic fitness?
Aerobic fitness (cardiovascular endurance) is the body’s ability to deliver oxygen to your muscles, which allows them to do work, or engage in activity. The lungs take in oxygen from the air we breathe where it gets perfused into the blood stream; the heart and blood vessels deliver it into the working muscles; and the skeletal muscles utilize the oxygen to execute muscular contractions and produce work. A cardiovascular assessment is a good tool to measure the efficiency of the aforementioned physiological functions.
While there are numerous methods for evaluating aerobic capacity, in most instances treadmill walking/running is appropriate for the majority of individuals. Normative data correlates time on the treadmill with aerobic fitness. It is expressed in milliliters of oxygen consumed per minute, and adjusted for body weight in kilograms ml/min.
There are many factors that can influence VO2 max, e.g. Hereditary, training age, gender, and body composition. Generally, VO2 max declines with age (about 2% per year after age 30) and males typically have a greater oxygen consumption value than females. Nevertheless, the trend is that a higher VO2 max allows one to produce more energy, thereby performing more work. With this in mind, VO2 max is the “gold standard” measure of overall fitness.
How is aerobic fitness assessed?
Aerobic fitness is assessed by having the subject perform exercise at increased loads, for 12 to 15 minutes, while breathing into a mouthpiece which collects information on inspired and expired air. A treadmill, personal bike on a Computrainer, or a stationary bicycle are used. The test starts with an easy-moderate work load which is maintained for 1-2 minutes. The load is increased gradually every 1-2 minutes until reaching the maximum level that the subject can tolerate and/or until the physiological parameters such as heart rate, oxygen consumption have hit a peak plateau. This is done by increasing the cycling resistance or the speed and/or grade of the treadmill. The oxygen update, heart rate, speed and/or watts are measured at the ventilatory threshold and at maximal load, the later would be the subject’s VO2 max.
End of part 1.