VO2 Max: What is it and Why is it Important
Simply put; your VO2 max describes your cardiorespiratory fitness. The actual definition of VO2 max is the maximum volume of oxygen your body can import, transport and utilize in a single minute during intense physical activity.
Why VO2 Max Matters
Exercise physiologists have studied how the human body uses oxygen for a long time, in fact it has been studied for over 100 years. Why does your body need oxygen? Oxygen is the key ingredient that makes aerobic energy production possible. Oxygen helps transform the energy stored in macronutrients like carbohydrates and fats into fuel for your muscle cells.
How is VO2 Max calculated?
In order to directly measure oxygen consumption, you need to wear a special mask connected to a machine capable of analyzing the contents of your respiratory gases. The goal is to measure how much oxygen is in the air you breathe in compared to how much oxygen is in the air you exhale. The difference is how much oxygen your body is using. VO2 Max tests are typically performed in a lab setting and involve running on a treadmill. The speed of the treadmill increases gradually until your reach the intensity at which maximum oxygen consumption rate is achieved. It is a very difficult test and should only be performed when healthy.
Understanding VO2 Max
The first thing to understand is that a higher VO2 max is generally better than a lower VO2 max. A higher VO2 max means that your body is better at taking oxygen from the air and delivering it to your muscles. The more oxygen your muscles can get, the more nutrients you can aerobically transform into fuel (ATP) that your muscles use to contract and perform. The next question is how high should your VO2 Max be? This is all dependent on a few factors and the same value can mean different things for different people. A VO2 max of 40 can be excellent for one person, good for another and poor for a third. That's because the value is dependent on factors such as age and sex.
VO2 max values vary greatly between men and women, and this is largely due to body composition and lean muscle mass. Not only do women tend to store more fatty tissue, but also the location of where the fatty tissue is stored makes a difference. Men tend to store fat in their trunk and abdomen and women tend to storing more fat around the hips and thighs. Understanding these natural differences in average body composition are important for understanding your personal VO2 max. Remember, muscles use oxygen while fat is simply stored energy. Due to these differences in body composition and muscle mass, men tend to have a higher VO2 max than women. So if a man and a woman have the same VO2 max value, the women will have a better fitness level comparatively.
Age is also a factor that impacts our VO2 max values, however its role is a bit more complex. Our performance tends to get worse as we get older, in fact our peak performance is usually around the age of 20. From this point fitness typically declines between 5-20% per decade in healthy individuals between the ages of 20 and 65. There are several factors that contribute to age-related fitness declines. The first is the fact that total body mass tends to increase as we get older, but lean mass tends to decrease. Another factor is that our muscles work less efficiently and this affects the large muscles that power our movement and heart. The good news about VO2 max and aging is that for the most part accelerated fitness declines resulting from sedentary lifestyles can be reversed.