What Does Your Car Run On?

What Does Your Car Run On?


What does your car run on?

The body’s currency of energy is Adenosine Tri-phosphate (ATP for short.) Without ATP located within a muscle cell there is no contraction. In the worst possible scenario, if your body was totally devoid of ATP, rigormortis would set in and you would be dead.

ATP is constantly having phosphates chemically cleaved off of an adenosine molecule and replaced back onto an adenosine molecule. This process is what allows a muscle to contract over and over again. The higher the intensity , the faster the ATP is chemically cleaved and resynthesized. In a 40 yard dash, the ATP is depleted very rapidly (probably 30 seconds or less,) while a low intensity, long duration jog uses ATP very slowly, so the body can make new ATP from sugar and fat.

In order to supply the demand for energy the body has 3 different pathways to rebuild ATP. The great thing is you don’t have to make a conscious effort to decide which pathway you will use. Intensity and duration will determine from where and how the ATP is produced.

The 3 Different Energy Metabolisms are:

ATP / CP System: Lasts from about 0-30 seconds used for quick energy bursts

Anaerobic Glycolysis: Lasts an intermediate duration 1-6 minutes, middle distance, moderate intensity

Beta Oxidation: Greater than 16 minutes and used for long distance, slow / low intensity


One important thing to remember:

These energy systems are not compartmentalized, but work interdependently. They are always working, all together, just in different ratios and proportions based upon the intensity and the duration.


Once you can grasp the concepts and principles of the 3 energy metabolism pathways – you can achieve any goal you may have: running a sprint, playing soccer or running a marathon and you can do all of these with an eye on fat loss and improved body composition!

ATP – CP System: Within the mitochondria (the powerhouse of the muscle cell) exists a stored amount of ATP and Creatine Phosphate. As the adenosine molecule constantly cleaves its phosphate off for energy, the creatine phosphate is there to replace or lend one of its phosphates to resynthesize the ATP.

Anaerobic Glycolysis: This system as the name implies is the breakdown “isis” of sugar “glycol” in the absence of oxygen. In all actuality, the only ATP is produced by the burning of sugar but only halfway. It just doesn’t last very long, 1 molecule of sugar only produces about 36 ATPs.

Beta Oxidation: When you exercise aerobically, this energy system takes control. This system produces a limitless amount of energy by breaking down triglycerides and sugar. One triglyceride produces 460 ATP. While the body may run out of sugar, it never runs out of fat. However, there must be oxygen present. No oxygen present and the fat burning ceases.


Just as a recap:

ATP / CP System:

  • Stored energy in powerhouse of muscle cell
  • Readily available, for quick bursts
  • No oxygen needed
  • No metabolism of Sugar / Fat
  • 0-30 seconds

Anaerobic Glycolysis:

  • Burns sugar hallways to produce ATP
  • Faigues easily
  • No oxygen required
  • Lasts about 6 minutes
  • Only produces 36 ATP per molecule of sugar
  • Lasts minutes

Beta Oxidation:

  • Uses fat / sugar for energy
  • Must have oxygen present
  • Lasts forever
  • Really kicks in during activities lasting greater than 16 minutes
  • Provides about 460 ATP per triglyceride
  • Lasts forever


An important point to remember: While sugar is the body’s preferred source of energy for high intensity exercise, the body’s preferred source of energy during recovery is fat.

If you are continually exercising, yet fail to see a decrease in body fat, your Beta Oxidation energy system is not working effectively and efficiently. In layman’s terms, when fat goes to a working muscle, the muscle doesn’t recognize it and continues to use sugar for energy and eventually you run out of sugar (very quickly) and you end up stopping. The key is not to go onto another useless diet, but rather, increase the efficiency and effectiveness of your fat metabolism energy system. Diets and deprivation cannot achieve this, only through resistance training and cardio can this be accomplished.

Only Beta Oxidation burns fat for energy during exercise

I know I’ve preached that there must be oxygen present in order to use fat for energy, but get ready, I’m going to throw a wrench in that thinking. While it’s true that oxygen must be present in order to burn fat during exercise, you always burn fat for energy after exercise.

The energy it takes to resynthesize the ATP used in the muscle cell requires energy, and it comes from fat.

The energy it takes to repair microscopic trauma to the muscle requires energy, and it comes from fat.

The energy it takes to replenish cardiac muscle energy requires energy, and it comes from fat.


With this in mind, you need to lift heavy enough weights that cause failure or near failure in the 8-12 rep range.  Lifting in this range will spur muscle growth and will also deplete enough muscle glycogen that the body will be a fat burning machine in between your lifting sessions while it repairs itself.

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