Today we will be looking at the three energy systems we use for our daily activities (this will be a very general look at the systems. If you’d like more info on anything, please leave a comment so I can follow-up). Today’s article will not have much of a practical component to it, but more educational. We’ll apply this education to next week’s applicable article.
Let’s get right into it!
Adenosine Triphosphate is the molecule that our body uses as energy. One of the three phosphate (P) molecules breaks off; resulting in an adenosine diphosphate (ADP) molecule, a phosphate ion, and energy. It is this energy we use for nearly all the processes in our body.
Aerobic System – Our highly efficient but slower system
We’ll start with the aerobic system. Even though it is the most complex, it is the easiest to sum up, because most of us have a general sense of what’s involved. “Aerobic” implies that oxygen is required to produce energy from this system. Once oxygen is brought into the equation, our cells have to work harder to create the energy, thus resulting in a longer amount of time before that energy is available. Along with the oxygen, our aerobic system uses fats and carbohydrates to create the ATP (adenosine triphosphate) our cells need for energy. Our aerobic system is like highway driving. It takes a while to get up to speed, but once we’re there, we are moving as efficiently as possible. The aerobic system may take a couple minutes to become fully operational during exercise, but it’s capacity lasts as long as there is oxygen and glucose available.
Anaerobic Lactic System – Our mid-capacity system
The anaerobic systems do not make use of fat breakdown, thus avoiding the need of oxygen. This results in less chemical processes, and quicker access to energy. The lactic system breaks down glucose molecules to produce ATP, supplying our muscles with faster energy than the aerobic system. However, a trade-off for this quicker energy is the production of lactic acid. The problem with lactic acid is that it releases hydrogen ions into our muscles and bloodstream, creating an acidic environment which causes that burning feeling when you’re exercising at high intensities. If too many hydrogen ions are present in our cells, we have to decrease our intensity to a point where we can tolerate/remove the hydrogen ions.
Anaerobic Alactic System – Our instantaneous but short lived system
This system doesn’t breakdown fats or carbohydrates for energy. In fact, everything this system needs is already stored within our muscles in the form of stored ATP and creatine phosphate (CP). During the initiation of intense exercise, the stored ATP within our muscle is used for instantaneous energy. As mentioned before, this results in many ADP molecules sitting in our muscles. This ADP is converted back to ATP by borrowing the phosphate ion from the stored CP. These processes are very fast, allowing us to give maximal efforts for an all-out bout of 10-15 seconds.
One Fine Machine
These three systems work together at all times; allowing us to run four blocks to catch the bus (lactic), sprint after the bus as it pulls away from the stop (alactic), and jog 20 minutes to get home using our own two feet (aerobic). The intensity of the activity determines which system predominates, but rest assured they are all working to some degree. In next week’s article, we will use this knowledge to look at the marketed “fat burning zones” on treadmills; and whether slow is better for “burning fat”.