No wonder marathon runners have the highest number of mitochondria in their cells! (fullhealthsecrets.com)
The brown cells possess an extremely high number of mitochondria — these cell power stations «burn» white fat by converting it into thermal energy. (sciencedaily.com)
Both longer duration, moderate - intensity exercise and shorter periods of high - intensity exercise increase the size and number of mitochondria inside muscle cells and their efficiency. (cathe.com)