During anaerobic exercise, you burn carbohydrates (and a minimal amount of protein). Actually, for the first 5-10 seconds of high intensity work, you burn ready stores of ATP. Then your body synthesizes more ATP by breaking down carbohydrates thru glycolysis and the krebs cycle (anaerobic glycolysis is the *incompete* breakdown of fuel for purposes of synthesizing ATP.)
During aerobic exercise, your body synthesizes ATP by breaking down fuels through glycolysis, the krebs cycle, and the electron transport chain. All of this amounts to the *complete* breakdown/oxidation of fuels.
Fats can be broken down completely for ATP production only through this oxidation process, whereas carbos can result in ATP production (although less efficiently) without complete oxidation. So to burn fats, you need to do aerobic exercise.
Aerobic --> in the presence of oxygen --> fats and carbos can be burned Anaerobic--> without the presence of oxygen --> carbos can be burned, not fat.
Linda L. again
There are two major energy pathways for anaerobic exercise - the phosphagen system, and the lactate system.
The phosphagen system uses creatine phosphate as an energy substrate. While this process can supply tremendous amounts of energy very quickly (such as that used to throw a shotput), the energy store is depleted in about 30 seconds or less.
The lactate system can supply energy more quickly than the aerobic pathways by the incomplete breakdown of glucose (anaerobic glycolosis). While it can't generate as much energy as quickly as the phosphagen system, it can produce energy for longer periods of time (about 2-3 minutes) before the byproducts (lactic acid) affect the cell environment sufficiently that the process slows.
The anaerobic energy pathway involves the complete breakdown of glucose, as well as fats and protein. The reactions take longer, but tremendous amounts of energy can be released, and the process can continue as long as the substrates hold out.
It should be noted, though, that none of the pathways function in isolation - while all three are always helping supply energy for activity, usually one predominates.
For example, when you are running on a treadmill for an extended period, your aerobic pathway is supplying the bulk of the energy for your run. However, the moment you stepped on the belt your energy requirement increased dramatically, and far faster than your aerobic energy pathway could ramp up to meet it. Thus, the anaerobic pathways helped provide the bulk of the energy during that transitional time, until your aerobic energy pathways had adjusted to the new workload.
[Correction - pathways...]
The *AEROBIC* energy pathway involves the complete breakdown of glucose...
(sorry about that).
-- --------"It's my personal opinion that people need to be more clear about what is fact and what is in fact their personal opinion." -- me