Exercise testing as a diagnostic entity in mitochondrial myopathies

Exercise intolerance is one of the most common symptoms in patients with mitochondrial myopathies (MM). At the whole body level, this is characterized by a reduction in maximal oxygen consumption (VO2max) with an excessive carbon dioxide production (VCO2), increased rating of perceived exertion and a hyperdynamic circulatory response at a given exercise intensity. Fewer patients with MM display overt muscle atrophy and weakness even in the …