Those who have mitochondrial dysfunction of the skeletal muscle can experience two main types of fatigue. One is the result of increased acidosis inside the muscle cells and has as a marker increased lactate in the blood. This is a result of muscle cells trying to create ATP when there is insufficient oxygen. Endurance athletes (such as marathoners) can experience this type of fatigue. They refer to it as “hitting the wall."8, 9 It is also referred to as “metabolic fatigue.”46
The second type of fatigue is the result of a large build-up of Reactive Oxygen Species (ROS) and depletion of ATP in the muscle cells. As far as we can determine from a careful search of the medical literature, this second type of fatigue is unique to patients with known inherited genetic mitochondrial diseases of skeletal muscle, AIDS patients undergoing treatment with antiretroviral drugs (who have severe mitochondrial dysfunction),47and CFS/ME patients experiencing post-exertional “malaise.” It is this second type of fatigue that has the most permanent serious consequences for patients.
Mitochondrial Dysfunction, Post-Exertional Malaise and CFS/ME