Glycolysis involved in glycolysis. The burning sensation in muscles during hard exercise can be attributed to the release of hydrogen ions during the shift to glucose fermentation from glucose oxidation to carbon dioxide and water, when aerobic metabolism can no longer keep pace with the energy demands of the muscles. These hydrogen ions form a part of lactic acid. The body falls back on this less efficient but faster method of producing ATP under low oxygen conditions. This is thought to have been the primary means of energy production in earlier organisms before oxygen reached high concentrations in the atmosphere between
Aerobic exercise authorities suggest at least twenty minutes performed at least three times per week. Cooper himself defines aerobic exercise as the ability to use the maximum amount of oxygen during exhaustive work. Cooper describes some of the major health benefits of aerobic exercise, such as gaining more efficient lungs by maximising breathing capacity, thereby increasing ability to ventilate more air in a shorter period of time. As breathing capacity increases, one is able to extract oxygen more quickly into the blood stream, increasing elimination of carbon dioxide. With aerobic exercise the heart becomes more efficient at functioning, and blood volume, hemoglobin