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Page 42
| Instead, they quickly convert to anaerobic (without oxygen) activity as the pulse races, the heart pounds and they pant trying to catch the breath while becoming fatigued from a lack of oxygen. |
| The adrenal glands also manufacture the hormone corticosterone to help liver, muscles and other tissues make glycogen out of the carbohydrates we eat and then store it. Corticosterone is also responsible for breaking glycogen down into sugar and helping cells absorb it when energy is needed. Muscles burn glycogen to make energy, but use up oxygen as lactic acid forms in the muscles while they "burn." Oxygen is needed to convert leftover lactic acid back into glycogen for future use. Without enough oxygen, too much lactic acid remains in the muscles so they cramp and become stiff. |
| That is not all. Metabolic wastes such as free radicals (molecular fragments that lose an electron during oxidation) cause harmful oxidation during strenuous exercise or physical work. If they kept to themselves, free radicals would not be much of a problem. However, they grab electrons from stable molecules and damage cells, enzymes, proteins and the DNA itself in the process. An excessive amount of free radicals are released by the immune system during a chronic disease or an infection to attack harmful organisms in the body, but they can also attack the body itself Physical and emotional stress, poor diet, toxic chemical exposure and drug use also increase their numbers. This ups your risk of illness, including cancer, and accelerates aging. |
| To compound the problem, with physical fatigue several other mechanisms needed to provide the body with energy malfunction. For one thing, ATP (adenosine triphosphate), an enzyme produced in the cells and responsible for storing energy in muscles, is lost too quickly. This is a real problem since people with |
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