Lactic acid is not the responsible of muscle soreness the day after intense exercise, nor is the responsible of fatigue. The myth is still alive 30 years after we know the truth. The story of this scientific mistake is well described in Loren Cordain's book: It was born in 1919 when during an experiment with frog muscles lactic acid was found after intense exercise and wrong conclusions were assumed. |
Why lactic acid does appear after intense exercise and what is its role? The answer lies in how glucose is metabolized during high intensity exercise.
In the absence of intense exercise glycogen, which is stored within muscle, is first used as a source of energy. Then, energy is mainly obtained by oxidation of glucose, producing carbon dioxide and water. However, during high intensity exercise energy is | required so fast that the body cannot keep with the demand of oxygen, so anaerobic glycolysis takes place, producing lactic acid. Anaerobic glycolysis allows obtaining fast energy from glucose, being the dominant process during the first 20 to 30 of max effort. |
Lactic acid is actually helpful! As shown in the flowchart, lactic acid is reused by conversion to glycogen and glucose. In addition, it counteracts the effect of excessive acidity (see M Lean, Food Science, Nutrition & Health)
So, what does produce soreness the day after? Muscle damage is the main reason.
What about having sugary drinks after the exercise? Actually, it helps but for different reason. Intake of carbs and proteins, especially right after the exercise, speeds up recovery, as they are needed to return the system to normal conditions and repair tissue damage (see Loren Cordain, The Paleo Diet For Athletes).
Does stretching helps to avoids soreness? This is another myth, which will be covered in another article.
What about having sugary drinks after the exercise? Actually, it helps but for different reason. Intake of carbs and proteins, especially right after the exercise, speeds up recovery, as they are needed to return the system to normal conditions and repair tissue damage (see Loren Cordain, The Paleo Diet For Athletes).
Does stretching helps to avoids soreness? This is another myth, which will be covered in another article.