Oxygen Debt | The Excess Post-Exercise Oxygen Consumption Effect

Brad Taylor
Natural Society
Jul 12, 2012

Everyone knows that exercise leads to a healthy body, strong muscles, reduced stress, and weight loss. But what many people don’t consider is what happens on an internal level after exercise is complete. The number of techniques or strategies which could be implemented into your workout for greater achievement is endless. Some people think that steady, long, low-intensity workouts provide the best results, but this isn’t true. Jogging is a healthy activity, and walking may even be better, but rigorous exercise has a more profound impact on an effect that occurs in your body following exercise known as excess post-exercise oxygen consumption in order to take care of what’s referred to as oxygen debt.

Excess Post-Exercise Oxygen Consumption

EPOC refers to the rate of oxygen consumed in order to return to a homeostasis state and ‘fix’ the body’s oxygen debt. Although a light worker does trigger EPOC, the effect is bound to be more powerful and continue for a longer period of time after a vigorous workout. After performing a low-intensity workout, the body’s demand for oxygen simply isn’t as pertinent.

To attain a higher demand for oxygen and use more oxygen in the process of a workout, a high-intensity, anaerobic exercise should be performed. For every liter of oxygen consumed, approximately 5 calories are burned, making high intensity workouts trigger a greater oxygen debt, EPOC response. Exercising hard enough to cause heavy breathing is the level to aim for.

Oxygen Debt and the Effect of EPOC

In addition to returning to a homeostasis state, the body releases energy at a higher rate. During this time period, the body begins to restore itself.

• Replenishing it’s Energy Resources – Your body needs to replenish it’s energy, especially immediate sources of energy. To do this, your body taps into what’s known as the phosphagen system and restores the creatine phosphate and ATP.  In addition, lactic acid is being reconverted to glucose, and muscle glycogen levels are being restored during this process.

• Re-oxygenating the Blood & Renewing Circulatory Hormones - Energy is expended in order to re-oxygenate the blood for excess oxygen use. In addition, circulatory hormones which become elevated after exercise return to normal levels.

• Decrease in Temperature – Energy is expended in an attempt to go back to normal body temperature.

• Rebound to Normal Heart Rate – In an attempt to return to a normal heart and breathing rate, the body expends energy at an increased level.

When is oxygen debt mostly experienced?

Research suggests that maximal EPOC response is generated through the following list with 1 being the most effective method and 3 being the least effective method. In terms of EPOC response, the amount of elevation of oxygen consumption and the lasting effects are based on the length and intensity of the workout. Here are ways to ignite higher EPOC response.

1. Highly intense resistance workouts
2. Highly intense cardiovascular workouts
3. Highly intense cardiovascular workouts revolving around interval training

High-intensity interval training, or HIIT, is one  intense interval training workout proven to stimulate greater EPOC response.

There are certain aerobic exercises such as cycling that may bring forth a lesser magnitude (amount of increased oxygen consumption) and duration (length of increased oxygen consumption) of EPOC than heavy weight training based on research conducted.

Source: naturalsociety.com