The aerobic or oxidized mechanism is the process through which the cell degrades the substracts (glucids, lipids and proteins) in the presence of oxygen: it is the cellular breathing[En2][En3]
. All this occurs in the cell, in special organelles
, the mitochondrials[En2][En3], existing in large quantities in muscles.
Thanks to several complicated reactions
and enzymes interventions, the O2 molecule burns the substracts, thus producing water, carbon dioxide[En2][En3]and of course the ATP necessary to muscular work: as a result from a mole of glycogen can be re-synthetized 39 ATP molecules, whilst with the lactacid anaerobic mechanism only 3 ATP molecules can be re-synthetized ; the problem is that although the capacity is very high (theoretically an aerobic activity could last for days), the power developed by this system is the lowest of the three mechanisms.
The oxidative mechanism can use carbohydrates, proteins and lipids. The carbohydrate supplies (ax. 1200-2000 Kcal) are enough to perform around two hours of activity; proteins are used only when the carbohydrate supplies are exhausted and the request of energy is high. Finally lipids are able to provide a considerable energy supply, but, with the same consumption of oxygen, compared to carbohydrates they have a lower performance of approximately 10%.
In a continuous and long-term physical exercise, the aerobic mechanism is more and more solicited as time goes by: after five minutes only more than 90% of the produced energy is of aerobic origin.
Sports : athletics (long-distance competitions, walk, marathon), cycling, triathlon, Nordic skiing, swimming….
