What's Your Max VO2?

How much oxygen you take in and deliver to the working muscles (volume oxygen uptake) is a term frequently used by exercise physiologists and personal trainers when discussing exercise intensity, level of fitness, aerobic power, metabolism and performance capability, but what this means to the average person and why it is important is often misunderstood.

 

Our bodies need a constant supply of energy in order to sustain life, contract muscles, pump our blood, support tissues and much more. The form of energy the body uses for these processes is called ATP (short for adenosine triphosphate). Much like gasoline being a fuel source for automobiles, ATP is the fuel source for energy production. ATP cannot be stored in large quantities and must be continually manufactured by processes that involve the breakdown of carbohydrates, fat and to some extent, protein. To make ATP from these nutrients, a certain amount of oxygen is required; hence, oxygen is ultimately the determining factor for our body’s energy capabilities.

 

Oxygen consumption (V02) is often expressed as a rate of use per minute. A person who has a high V02 is capable of using more oxygen per minute at the cellular level than someone who has a lower V02. The person with a higher V02 has a greater aerobic capacity. They are considered the fitter individual. People with a higher V02 not only perform day to day tasks easier, they also have the ability to work harder during exercise, exercise longer without fatigue, and burn more calories at rest than a person whose aerobic capacity is lower. If a person is working at their fullest potential and taking in all the oxygen their body can deliver to the working muscles per minute, they have reached what is called their Max V02 - an ultimate measure of aerobic power and performance capability.

 

V02 is often confused with rate of breathing; however, true V02 is indirectly related to the amount of air you take in which each breath irrespective of how hard you are breathing. When you inhale, the breath you take into your lungs is about 20% oxygen, and .03% carbon dioxide. When you exhale, the percentage of oxygen in expired air is lower and the percentage of carbon dioxide is higher. It is lower on the exhalation because your body uses a certain amount of oxygen at the cellular level to produce energy while, at the same time, creating an increased amount of carbon dioxide as a by-product (waste material) of cellular respiration. In terms of fitness, the more oxygen your body can take in and deliver to the working muscles, the greater your ability to perform exercise and sustain activity at a higher intensity - level of fitness in enhanced. The more you huff and puff (breathing harder) with without being able to deliver oxygen to the working muscles, the greater likelihood of fatigue – level of fitness is diminished.

  

Oxygen consumption reflects energy expenditure, or the amount of calories you burn with exercise. At rest, your body does not need an abundance of oxygen. It sits idle much like an automobile waiting for someone to turn the key. Assuming you are healthy, respiration at rest is slow and shallow. The number of calorie burned will be minimal. When you start to move around and increase activity, the demands for oxygen increase. The heart starts pumping harder, breathing increases, circulation increases, and cellular respiration increases in direct response to the demands of work intensity. How the body adapts is by BURNING MORE CALORIES! If exercise continues in duration or increases in demand, the amount of oxygen the body uses per minute is even greater. Energy expenditure will be higher and the number of calorie burned per minute will be greater! A novel explanation as to why exercise is so very important on weight loss regimes.

 

The absolute best way to increase V02 is to exercise consistently and efficiently at least three to five days per week with varying intensities of activity. The goal is to train your body to adapt to imposing demands in a gradual fashion before fatigue set in. If you start out too hard or try to push yourself to fast, the body cannot keep up with the demands for oxygen at the cell level. You will end up exhaling more oxygen with each breath than you take in to the muscle cells. Cardiovascular, or aerobic activities are an absolute necessity to include in the workout regime. You might choose walking at a varied pace, using a treadmill at different inclines and speeds, hiking hills and valleys, riding a bike, or attending an aerobic group exercise class. Challenging but not exhausting is key!