Aerobic Energy System

Glycolosis breaks down glucose which produces pyruvic acid. • Aerobic Glycolysis transports pyruvic acid from

the cytoplasm to the mitochondria where it is broken down in the Krebb’s Cycle.o When pyruvic acid is broken down it

produces CO₂

*Glycolysis, whether anaerobic or anaerobic, occurs in the cytoplasm and yields slightly different products dependent upon the presence of O₂* Anaerobic: 2 ATP, Lactic Acid (H⁺ + pyruvic acid) Aerobic: 2 ATP, Pyruvic Acid, H₂O (H⁺ + O₂)

Anaerobic vs. Aerobic Glycolysis

Cori CycleRemoves lactic acid from the muscle fibre, taking it to the liver to be metabolized back into pyruvic acid and then glucose.

The Aerobic Energy System is our most important energy system because it provides energy for the majority of our daily activities.• Provides energy for activities of a duration greater than 3

minutes, dependent upon intensity level

• The more intense the activity, the sooner your aerobic system will have to take over for the Anaerobic Lactic System

• It is our primary source of energy for exercise lasting longer than 10 minutes

In order to function properly, the aerobic energy system requires:• sufficient mitochondria to meet energy

requirements

• sufficient oxygen supplied to mitochondria

The Aerobic Energy System is the most efficient of the three systems yielding the most energy per metabolized molecule.• Unlike the Anaerobic Systems the Anaerobic System

can metabolize all macronutrientso Carbohydrates (glucose): 36 ATPo Fats (fatty acids): 169 ATPo Protein (amino acids):

Efficiency

Krebs Cycle• Occurs in the mitochondria

• Pyruvic acid, glucose, fat and protein are reduced into coenzymes (FADH₂ & NADH + H⁺)o these coenzymes are used to fuel ATP re-synthesis in the

Electron Transport Chain & Oxidative Phosphorylation

Yield: ATP, CO₂, coenzymes

Electron Transport Chain & Oxidative Phosphorylation

• Located in the mitochondria• This is where aerobic ATP re-synthesis occurs• the H⁺ from the coenzymes are removed and combined with O₂ to form H₂Oo the energy released during these reactions is

harnessed and used to re-synthesize ATP, attaching Pi to ADP.

Limitations

1. Requires continuous oxygen and adequate fuel sources

2. ATP utilization must be slow, allowing oxygen to be supplied where necessary

Aerobic PowerVO₂max: measuring the maximal volume of oxygen that can be consumed in a given amount of time during maximal effort.

Factors contributing to a high VO₂max:• high arterial oxygen content• Increased cardiac output• a large tissue oxygen extraction

Effects of TrainingEndurance training is the best way to improve your Aerobic Energy System. Endurance training will have the following effects:

1. Increase vascularization within muscles2. Increase the number & size of mitochondria within muscle fibres3. Results in the use of fats before glycogen during exercise