Lactate and Its Training Implications. Part 2.
May 9, 2013
The term lactate is often used interchangeable with that of lactic acid. The difference between the two is that lactic acid has a hydrogen atom that lactate does not. At normal pH in the human body, lactic acid loses the hydrogen atom and becomes lactate.
The mitochondria uses both pyruvate and lactate as reactants to form ATP. Lactate enters the mitochondria a different way than pyruvate does and is then converted back into pyruvate. Aerobic glycolysis then proceeds and ATP is produced.
It has been reported that in humans, lactate has a half life of 21 to 40 minutes. This means that to remove half of the lactate it takes from 21 to 40 minutes. The better trained and individual is, lower the half life. Let’s say for an untrained individual with a lactate clearance rate half life of 40 minutes, after 4 hours post exercise 96.9% of the lactate will have been removed. For a highly trained individual with a lactate clearance rate half life of 21 minutes, their 2 hour post exercise levels of lactate would have been reduced by 96.9%. Training affects the rate at which lactate is taken up into the mitochondria and used by actually increasing the number of mitochondria per muscle cell. People often think of endurance training as the only way to increase the mitochondria in muscle cells, however lactate threshold training can do the same in less amounts of time.
Traditionally maximal oxygen uptake (VO2max) has been treated as the most important aspect for success in prolonged exercise. VO2max is a measure of how much oxygen is taken up by the body tissues during exercise. Scientists have recently reported that lactate threshold is a better predictor of endurance performance. The higher the lactate threshold, the better ability an athlete has of dealing with lactate and maintaining a higher intensity during exercise. This higher intensity can directly translate into improved performance.
Training at, or above this lactate threshold creates a lot of lactate, something that we can all agree on. The cell sees this as a stimulus to produce a greater number of mitochondria to metabolize the lactate. This increases the lactate removal during exercise, and lessens its effects on the athlete. Certain training centers for elite athletes have exercise physiologists that monitor blood lactate during exercise to determine the physiological intensity of the exercise. By carefully controlling the intensity and thus indirectly the production of lactate athletes can train smarter and longer with improved results. Now not everyone has access to the equipment required to test blood lactate levels during exercise, nor do athletes necessarily want to be pricked by a needle (how else are they going to get the blood out?), so there has to be a different way to estimate where the lactate threshold is.Researchers have found that 90% of maximal heart rate and 70% of VO2 max are good indicators of exercise intensity that can indicate lactate threshold approach. One thing that researchers did notice was that lactate threshold training was specific to the type of exercise being performed. In other words, it won’t transfer too well between different activities.
To take advantage of this type of training use the exercise you will be competing in and train with a heart rate monitor. If you are a cyclist train on your bike at or near 90% of your maximum heart rate. If you are a runner, run. Its that simple. Now go get better.
2.Exercise Physiology: Human Bioenergetics and Its Applications 4th ed. G.A. Brooks, T.D. Fahey and K. M. Baldwin. McGraw Hill. 2005.