An exercise tolerance test can be useful in detecting performance intolerance. Metabolic defects can become apparent even at low performance levels due to an inordinate lactate increase.
Dysfunctions of the aerobic metabolism can be detected at an early stage in patients with performance intolerance or other mild, systemic symptoms of mitochondrial disorders thanks to ergometry, spiroergometry and lactate identification.
This method also appears to be especially pertinent in the follow-up examination/evaluation of therapeutic effects – provided that children are mobile and can use the bicycle ergometer.

Bicycle ergometry: conspicuous result