1. Our body use two types of metabolism during exercise to provide the fuel needed for our muscles.
- Anaerobic metabolism: Anaerobic respiration is the creation of energy through the combustion of carbohydrates in the absence of oxygen. Also produces energy and uses glucose, but it produces less energy and does not require oxygen. This is useful in tissues which have a high energy demand such as in working muscles, in which there is not enough oxygen to produce all the energy needed by using aerobic respiration alone. Anaerobic respiration takes place in the cell cytoplasm and produces lactic acid. Anaerobic metabolism occurs when our lungs can't put enough oxygen into the bloodstream to keep up with the demands of your muscles for energy. Generally, this occurs only for short bursts of activity, such as when you do a sprint . When there isn't enough oxygen in the bloodstream, glucose can't be fully broken down to carbon dioxide and water. Instead, lactic acid is produced.
- Aerobic metabolism: Is the way your body creates energy through the combustion of carbohydrates and fats in the presence of oxygen. Combustion means burning, which is why this is called burning sugars, fats... for energy. Exercises that use aerobic metabolism, are for example, walking, running... aerobic metabolism fuels most of the energy needed for long duration activity. It uses oxygen to convert nutrients (carbohydrates, fats, and protein) to ATP. This system is a bit slower than the anaerobic systems because it relies on the circulatory system to transport oxygen to the working muscles before it creates ATP. Aerobic metabolism is used primarily during endurance exercise, which is generally less intense and can continue for long periods of time. As exercise begins, ATP is produced via anaerobic metabolism. With an increase in breathing and heart rate, there is more oxygen available and aerobic metabolism begins and continues until the lactate threshold is reached. If this level is surpassed, the body can't deliver oxygen quickly enough to generate ATP and anaerobic metabolism kicks in again. Since this system is short-lived and lactic acid levels rise, the intensity can't be sustained and the athlete will need to decrease intensity to remove lactic acid build-up.
- DIFFERENCES: The key difference between the two is that aerobic metabolism occurs in the presence of oxygen, while anaerobic metabolism doesn't. Anaerobic metabolism is not as efficient as aerobic metabolism. A molecule of glucose can only produced 3 ATP molecules under anaerobic metabolism, while it produces 39 with aerobic metabolism. ATP is what fuels the muscles. Anaerobic metabolism can only use glucose and glycogen, while aerobic metabolism can also break down fats and protein. Intense bouts of exercise in the anaerobic zone and exercises with a heart rate over 85, will result in using anaerobic metabolism to fuel the muscles. Other differences are:
- - Anaerobic metabolism cannot continue indefinitely. In contrast, aerobic metabolism can continue forever, only under theoretical conditions.
- - Carbohydrate, fat, and proteins are used as sources of aerobic metabolism while only carbohydrate is involved for anaerobic metabolism.
- - Aerobic metabolism involves low to moderate intensity activities, whereas anaerobic metabolism involves only high intensity activities.
- - Anaerobic metabolism takes place in the cytoplasm of cells while aerobic metabolism occurs in mitochondria.
- - Aerobic metabolism produces more energy than anaerobic metabolism
- - Aerobic metabolisms contribute more (around 90%) for the supply of energy while anaerobic metabolism contributes less.
- - End product of anaerobic metabolism is lactic acid while that of aerobic metabolism is carbon dioxide and water.
