lactic

Don't hate lactic acid. It's been labelled as metabolic waste, when it is in fact a metabolic by-product, and a very useful one too. You probably mean lactate: lactic acid is very quickly converted to lactate and disperses in the blood where it is metabolised by highly oxidative tissue (cardiac muscle and liver) and used for energy.
It was always assumed that blood-lactate levels were a direct indication of the level of anaerobic glycolysis taking place. More recent research suggests that it is removal rates that dicate blood lactate levels as much as the speed of lactate generation. BTW, it isn't lactic acid that makes your muscles sting- it is acidosis casued by free hydrogen ions generated during glycolysis. I seem to remember reading that very high lactate levels can make you sick- may I suggest altering your training to become more accustomed to them? If you do this already maybe you're just unlucky. Is it harming your performance? What about nutritional strategies, maybe other factors are to blame.
As to the poor soul with chronic fatigue I would suggest talking to a sports doctor. I can only guess that chronic fatigue causes slow clearance of 'background' lactate, as lactate generation would have to be considerable to cause a rise above baseline levels. For example, red blood cells are *only* capable of anaerobic glycolysis, and therefore are always producing lactate. However, as I pointed out earlier this is normally metabolised by the liver and heart and used for energy. As I said, this is only a guess. Perhaps there is a sports MD around here somewhere. If not there are people I could ask. Contact me off-list if I can help.

L.