Lactate and Its Training Implications. Part 1.

May 5, 2013

During competition, the athlete that can outlast their opponent(s) wins. The supplement industry makes a fortune from athletes trying to get ahead in their game. Some athletes have turned to pharmacological supplementation to enhance their development and recovery. For some athletes the side effects of such methods may be undesirable and so they look at other training methods to get ahead in their sport. One such method is to train as close to or at the athlete’s lactate threshold as possible.

The lactate threshold is the point at which the body is unable to get rid of the excess lactate being created and it starts to build up in the blood. At least, this is how it is determined by blood tests. This doesn’t say how much is actually in the muscle. Once blood lactate levels pass this threshold fatigue, and pain set in. We have all been there. The burning sensation in our legs and trying to catch our breath, after running away from the neighbor’s dog, are symptoms of passing lactate threshold. In order to understand what lactate does, we need to understand a little bit of its biochemistry.

Chemical reactions are made up of reactants and products. When conditions are right reactants combine together to form products. Reactions are typical written out like this: A+B → C+D,

where A and B are reactants and C and D are the products. In physiological systems such as muscles, products can have an inhibitory effect on the chemical reactions by effectively shutting down the enzymes that run them. Lets go back to anaerobic glycolysis now and see how this pertains to it. Anaerobic glycolysis converts sugar in the form of glucose to ATP which is the usable source of energy in the muscles.

The anaerobic glycolysis reaction looks like this when simplified: Glucose → ATP+Pyruvate

Where glucose is the reactant and ATP and pyruvate are the products. When the human body is in an aerobic state, meaning that there is plenty of oxygen in the muscles to produce ATP, pyruvate is taken directly into the mitochondria. If pyruvate is not taken into the mitochondria it builds up in the cytoplasm of the muscle cell and can lead to inhibition of anaerobic glycolysis. If anaerobic glycolysis is inhibited, then the amount of ATP decreases. When this occurs muscles loose the ability to contract due to fatigue. One way the muscle cell is able to maintain anaerobic ATP production is to convert pyruvate to lactate. As the conversion of pyruvate to lactate continues, pain and eventual fatigue set in. Fatigue sets in because when lactate levels get too high in the cell, the reaction that produces it is inhibited. This then causes pyruvate to increase in the cell which then inhibits anaerobic glycolysis.

This may look like it is not necessarily a good thing, but remember that this is really only one side of the issue. In part 2 I’ll discuss what the fate of lactate is and how we can utilize it in our training.


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