Redefining the role of mitochondria in exercise: a dynamic remodeling.

Exercise induced adaptations in muscle are highly specific and dependent upon the type of exercise, as well as its frequency, intensity, and duration. Mitochondria are highly dynamic organelles. Fusion and fission reactions lead to a continuous remodeling of the mitochondrial network, which range from reticulum of elongated and branched filaments to collections of individual organelles. Mitochondrial network dynamics are sensitive to various physiological and pathological stimuli, and mitochondrial morphological changes are no epiphenomena, but central to cell function and survival. There is a strong correlation between mitochondrial network morphology, dynamic-related protein, and energy metabolism. It is expected that alteration in cellular energy status during exercise can also be achieved through mitochondrial network dynamics. In this review, we describe mitochondrial network remodeling response to acute and endurance exercise, which is accompanied by bioenergetics and redox regulation. In addition, potential mechanisms for metabolic and redox signaling involved in mitochondrial dynamic regulation are also reviewed.