Sarcopenia, an age-related degenerative skeletal muscle disorder characterized by progressive loss of muscle mass, diminished strength, and impaired physical function, poses substantial challenges to global healthy aging initiatives. The pathogenesis of this condition is fundamentally rooted in mitochondrial dysfunction, manifested through defective energy metabolism, disrupted redox equilibrium, imbalanced dynamics, and compromised organelle quality control. This comprehensive review elucidates the central role of exercise-induced mitochondrial hormesis as a critical adaptive mechanism counteracting sarcopenia. Mitohormesis represents an evolutionarily conserved stress response wherein sublethal mitochondrial perturbations, particularly transient low-dose reactive oxygen species (ROS) generated during muscle contraction, activate cytoprotective signaling cascades rather than inflicting macromolecular damage. The mechanistic foundation of this process involves ROS functioning as essential signaling molecules that activate the Keap1 nuclear factor erythroid 2 related factor 2 (Nrf2) antioxidant response element pathway. This activation drives transcriptional upregulation of phase II detoxifying enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GPx), thereby enhancing cellular redox buffering capacity. Crucially, Nrf2 engages in bidirectional molecular crosstalk with peroxisome proliferator activated receptor gamma coactivator 1 alpha (PGC-1α), the principal regulator orchestrating mitochondrial biogenesis through coordinated induction of nuclear respiratory factors 1 and 2 (NRF1/2) along with mitochondrial transcription factor A (Tfam), collectively facilitating mitochondrial DNA replication and respiratory complex assembly. Concurrently, exercise-induced alterations in cellular energy status, specifically diminished ATP to AMP ratios, potently activate AMP activated protein kinase (AMPK). This energy-sensing kinase phosphorylates PGC-1α while concomitantly stimulating NAD dependent deacetylase sirtuin 1 (SIRT1) activity, which further potentiates PGC-1α function through post-translational deacetylation. The integrated AMPK/PGC-1α/SIRT1 axis coordinates mitochondrial biogenesis, optimizes network architecture through regulation of fusion proteins mitofusin 1 (Mfn1), mitofusin 2 (Mfn2) and optic atrophy protein 1 (OPA1), and enhances clearance of damaged organelles via selective activation of mitophagy receptors BCL2 interacting protein 3 (Bnip1) and FUN14 domain containing 1 (FNDC1). Exercise further stimulates the mitochondrial unfolded protein response (UPRmt), increasing molecular chaperones such as heat shock protein 60 (HSP60) and HSP10 to preserve proteostasis. Within the mitochondrial matrix, SIRT3 fine-tunes metabolic flux through deacetylation of electron transport chain components, improving phosphorylation efficiency while attenuating pathological ROS emission. Distinct exercise modalities differentially engage these pathways. Aerobic endurance training primarily activates AMPK/PGC-1α signaling and UPRmt to expand mitochondrial volume and oxidative capacity. Resistance training exploits mechanical tension to acutely stimulate mechanistic target of rapamycin complex 1 (mTORC1) mediated protein synthesis while modulating dynamin related protein 1 (Drp1) phosphorylation dynamics to support mitochondrial network reorganization. High intensity interval training generates potent metabolic oscillations that rapidly amplify AMPK/PGC-1α and Nrf2 activation, demonstrating particular efficacy in insulin-resistant phenotypes. Strategically designed concurrent training regimens synergistically integrate these adaptations. Mitochondrial-nuclear communication through tricarboxylic acid cycle metabolites and mitochondrially derived peptides such as mitochondrial open reading frame of 12s rRNA-c (MOTS-c) coordinates systemic metabolic reprogramming, with exercise-responsive myokines including fibroblast growth factor 21 (FGF-21) mediating inter-tissue signaling to reduce inflammation and enhance insulin sensitivity. This integrated framework provides the scientific foundation for precision exercise interventions targeting mitochondrial pathophysiology in sarcopenia, incorporating biomarker monitoring and exploring pharmacological potentiators including nicotinamide riboside and MOTS-c mimetics. Future investigations should delineate temporal dynamics of mitohormesis signaling and epigenetic regulation to optimize therapeutic approaches for age-related muscle decline.