Extracellular mitochondria: a potential player involved in exercise health benefits

Exercise is widely recognized as an effective nonpharmacological therapy for noncommunicable diseases, with its health benefits mediated in part by exerkines. Recently, extracellular mitochondria (ex-Mito) have been suggested as a player in mediating intercellular communication. While it is known that the health benefits of exercise involve the remodeling of mitochondria in multiple organs, the impact of exercise on circulating ex-Mito is poorly understood. Most existing studies have focused on cell-free circulating mitochondrial DNA, skeletal muscle-derived extracellular vesicles, or platelet-derived mitochondria, without focusing on other types of ex-Mito. The cellular origin of exercise-induced circulating ex-Mito and the role of each form (vesicle-enclosed, free, or as mitochondrial components) in mediating exercise's therapeutic effects are yet to be elucidated. This review aims to delve into the role of ex-Mito as potential players in exercise-related health benefits, paving the way for future research aimed at uncovering the molecular culprits of this nonpharmacological therapy, including mitochondrial transfer and transplantation.