Exercise and the Body (cont.)

Exercise increases levels of GH which promotes protein synthesis, stimulates gluconeogenesis and promotes lipolysis. Lipolysis is the degradation of fat cells. So, once again, exercise also helps burn fat. Thyroid hormones are also elevated with exercise and along with GH stay elevated for quite some time after exercise. The epinephrine that is elevated causes an increase in blood glucose (sugar) and stimulates lipolysis which once again shows that exercise helps burn fat. Exercise also decreases insulin levels, increases blood plasma, decreases cholesterol, LDL and triglycerides. It also increases the good HDL levels which are known to help prevent atherosclerosis and releases endorphins which help sedate pain and give euphoria.

The physical activity depends mainly on three systems of energy for muscle contraction. The first to be used is called the ATP-phosphocreatine system which only lasts for 8-10 seconds. Then the second system kicks in, which is called the lactic-acid (anaerobic) system which lasts approx. 1.3-1.6 minutes. This lactic-acid is formed when there is insufficient oxygen supplied to the muscle cells. The third and last system is the aerobic system which has an unlimited time frame but produces the least energy. With the aerobic system, one burns fat much more readily than the other two systems. Both aerobic and anaerobic systems are boosted with the increase in muscle size/quality and therefore increases the efficiency of energy production.

Increased amounts of exercise requires proper nutrition for longer lasting muscle fuel. There are supplements on the market that one can take as well as certain foods one can eat. Glucose stores in the muscle called muscle glycogen, are the immediate fuel stores for exercise. To build up or restore this type of glucose, one should eat carbohydrates. Studies have shown that the muscles are most susceptible to insulin 2-4 hours after exercise and therefore, that is the best time to replace the muscle glucose stores.

Certain activities can deplete these stores such as:
Anxiety and nervousness
Muscle damage
Exercise past AT
Stress
Hot and humid conditions
Dehydration

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