overexertion causes the excess release of acid in the muscle tissue. this can make you feel like crap, especially in people whose detox pathways are impaired. its possible that what some people is a good "die off" reaction is actually a sign of excess acid in the body, a reason not to overdo the workouts.
The buildup of "Lactic Acid" is a result of not enough oxygenated blood supply to the muscles. Continued exercise will result in more efficient exchange of oxygen to lactic acid. Regular aerobic exercise, as opposed to anaerobic, is the best way to build up your stamina as well as kill off candida in the inner recesses of the muscle tissue. The old exercise saying "feel the burn" is referring to this lactic acid buildiup and will improve with time. When candida cells die-off, they release toxins which can cause a new series of symptoms. The best way to eliminate these is exercise, sweating, and drinking plenty of water. Sauna baths are a great way to get rid of these toxins. It is also effective for relief of skin problems due to candida.