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Understanding Post-Exercise Oxygen Consumption

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Excess post-exercise oxygen consumption (EPOC) is described as an increase in the rate of oxygen intake, designed to erase the oxygen debt after a period of strenuous activity or exercise. In other words, it's the reason we have a hard time catching our breaths when we've just run for several minutes on the treadmill. Our bodies are given a constant supply of oxygen, but when we engage in physical activity that strains the muscles and increases the heart rate, our bodies use up that latent supply of oxygen quickly and must resort to alternate processes to keep things flowing. One of the ways we help to replace that oxygen debt is by taking deep and often shallow breaths following a brisk walk, jog or weight-lifting session. In addition to this, the body has many elements in place to assist the process of post-exercise oxygen consumption.

Recovering Oxygen Debt

Oxygen consumption must be increased in order to replace the debt caused by exercise and vigorous activity. Under normal conditions, myoglobin, a pigment in the blood, serves as a small storehouse for oxygen. Pyruvate is used to create energy in the body, and glycogen is stored up and ready for a situation that will require a burst of energy, such as exercise. When these stores of oxygen are used up, the body processes must temporarily switch gears and take a new plan of action. When myoglobin is depleted, the muscles begin to work without oxygen. This process is commonly referred to as anaerobic. Because the supply of oxygen is now limited, components such as ATP, or adenosine triphosphate help to convert pyruvate into lactic acid. Lactic acid can then be converted into glucose or glycogen for use by the body as energy, or released into carbon dioxide and water as the body is moving strenuously. Once the body's vigorous activity has slowed down or ceased, depleted storage of ATP, myoglobin and glycogen will need to be replenished. The amount of time that replenishment takes depends upon how strenuous the activity was, and how much oxygen will be necessary for complete restoration. It will take anywhere from two hours up to several days for components such as the storage of glycogen to be recovered.

Increasing Oxygen Efficiency

The amount of oxygen debt created exertion can be greatly lessened based on a number of factors. Maximum oxygen uptake is another phrase for aerobic capacity, and it's determined by things such as age, sex and weight. Females, people who are obese or overweight, and those who are older tend to have a smaller aerobic capacity, thus they may become 'out of breath' more quickly than others when exerting themselves. Changes in diet and proper muscle or weight training can decrease the amount of oxygen debt created during a workout. When this is accomplished, people experience less exhaustion while working out, weight training or even taking that walk to the mailbox!

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