North Coast Miller
Level 9 Valued Member
- Do lactate production rates predict performance? If so, How so?
- does lactate (or other cofactors) supplementation provide performance increases to those interested?
Lactate levels and pH generally do not track with local reduction in force potential or fatigue, or recovery of either following exertion. This is outdated understanding based on in vitro testing at non physiologic temps. Muscle fatigue is most negatively effected by accumulation of inorganic phosphate from CrP ATP metabolism - its source is fundamentally alactic. There is an ongoing residual cost anytime high threshold motor units are being called upon. Two phases are required - the elimination of this inorganic phosphate (glycolysis assists with this) and rephosphorylation of Creatine accomplished via surplus ATP produced in mitochondria. This can be from glucose or lipids, and explains why only rest can truly restore CrP stores.
Metabolic harm seems to be a function of ROS levels overwhelming resident antioxidant defenses. These defenses are scalable, the upper limit of which seems to be almost beyond belief in elite endurance athletes. ROS exposure triggers all manner of positive downstream adaptive response to exercise. The poison is in the dose. ROS are only formed from the oxidation of pyruvate, not from the simple presence of lactate, which increases anytime an effort exceeds lipid aerobic ATP supply.
To the best of my knowledge, lactate supplementation is only used in head trauma care to reduce the amount of damage to the brain.
Some research has demonstrated that lactate combined with very mild muscle tissue damage is enough to trigger muscle growth, even without exercise - more research needed.
Activation of the Cori Cycle converting lactate back to glucose causes downstream anabolic signalling.
None of this reduces the effectiveness of certain training methodologies, but the stated theoretical underpinnings may need to evolve, or not. Most people don't care why something works well.