Old 01-20-12, 11:08 AM
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Fat Boy
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Originally Posted by plantrob View Post
That doesn't sound right to me. Going anaerobic doesn't mean you don't use O2 - it just means that the energy in excess of what can be provided by the aerobic system has to be delivered by the anaerobic metabolism. Still, there may be other reasons why developing the anaerobic side comes at the expense of the aerobic end.
Going anaerobic does mean that the muscles you are using are being fueled directly from your carbohydrate stores in a way that does not take oxygen. One of the by products of this is lactate, which can also be used by muscles (and your brain) as a fuel. Anyway, when burning these anaerobic (i.e. without air or O2) fuels, you create a lot of H+ ions. That is what burns and causes muscle tissue to break down. If you had the oxygen, you would create H2O and have water released as the by-product of the fuel burning, by the way.

If you only train at the anaerobic level, then your body becomes so used to burning carbohydrates directly, that it starts to ignore the fact that it can burn fats stores aerobically to fuel lower intensity work. Burning fats is a more labor intensive process for your body, so it will tend towards taking the easy path of burning carbs, even at lower intensities. Pretty soon, you're burning an inordinate amount of carbs and producing excessive H+ ions even at relatively low intensities (i.e. while sitting in) which starts to rob you of your high end.

We all tend to shut down once lactate reaches a certain concentration (12-15mmo/L or so). So the more fats you use (i.e. the better trained your aerobic system), the higher power you're able to produce on the aerobic side and the less you rely on the anaerobic system. When you do engage your anaerobic system fully, you're making more total power before you shut down because you're producing fewer waste by-products (which can be correlated to blood lactate concentration).

Does that make any sense?
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