Henry Family Blog

OK, on to my new class, Exercise Physiology.  I am relieved I made it through Physiology.  It was a lot of information in a short amount of time.  Now I get to apply that knowledge to exercise.  Wooo…whooo!!  It is starting to make sense now. 

For those of you who like to learn with me…you will enjoy these more than the last posts.  If you wonder how you use your energy..read on.

We have three energy systems; the phosphagen system, the lactic acid system and the oxygen system.

The Phosphagen System

This system is also called ATP-CP.  It is when you do high intensity exercise.  You have Creatine Phosphate stored in small amounts in your muscles.  This is the energy that gives you the initial burst of energy.  Say if you had to run across the room really fast..this is what allows you to do it.  It is normally no more than the first 30 seconds of exercise.  It is considered anaerobic because it does not require oxygen. 

The Lactic Acid System

These last two systems are considered glycolysis.  The Lactic acid system is also called anaerobic glycolysis.  The difference between the two is whether or not oxygen is available.  In this system, oxygen is not present.  It starts off with carbohydrates (glucose) degrading and turning into pyruvic acid.  since there is no oxygen the pyruvic acid turns into lactic acid.  This is the burn that you feel in your muscles.  It also is associated with fatigue.  The energy it provides is maximal and last from 1 minute after the onset of exercise to about 3 minutes after the onset.

The Oxygen System

This system starts off the same as the Lactic Acid system.  It starts with glucose and turns into pyruvic acid.  The difference is that oxygen is present, therefor it is also call aerobic glycolysis.  Since oxygen is present, after pyruvic acid it turns to Acetyl Coenzyme A.  Then, it enters the Kreb’s cycle and the Electron Transport System.  both of these produce ATP which is energy.  CO2 is produced and diffused into the blood and exhaled by the lungs.  Oxidation also occurs which removes the electrons in the Kreb’s cycle in the form of Hydrogen (H+).  These electrons enter the Electron Transport System.  This system forms H2O (Water)  The H from the Kreb’s cycle and the O2 from what we breathe. 

Along this whole way, ATPs are produced.  This is what provides energy.  This system works after about 3 minutes from the onset of exercise.

These three systems are Carbohydrate Metabolism.

Do you wonder about Fat and Protein Metabolism?  I bet you do. 

Fat Metabolism

Fat only metabolizes in an aerobic system.  Fat can be Beta Oxidized and enter the Kreb’s cycle or enter the electron transport System.  both systems produce energy.  So yes, you need fat for energy.  Here is the kicker.  Fat is the slowest to metabolize.  In the long run it does produce the most energy but it is definitely the slowest. 

Protein Metabolism

Protein metabolism plays a minor role in energy production while at rest.  It also only contributes 5-10% of energy during prolonged exercise.   It is used mostly under extreme circumstances…e.g. starvation, carbohydrate depletion or an extreme endurance event.

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