Just learned an interesting bit on lactic acid. Lactic acid is produced through the cori cycle during anaerobic exercise. For an athlete, during explosive exhausting exercise lactic levels in the plasma can go up 10x whats normal. (note lactic levels usually don't change much during everyday activities if you're a healthy person.)
This is all background. What i found interesting was that while lactate acid concentration in the blood takes 6-8 hours to clear from the plasma (return to normal levels) if you rest right after your exercise, when you take a light but lengthy jog, a cool down jog, lactic acid in the plasma drops rapidly. This is because the lactate acid ends up being used by working muscles. In muscles it is converted back to pyruvate and this pyruvate is directed into the TCA cycle.
