Skeletal muscle is increasingly recognized as a dynamic secretory organ capable of translating contractile, metabolic, mechanical and inflammatory stimuli into systemic biological signals. Among these signals, myokines and myokine-associated exerkines mediate communication between skeletal muscle and distant organs, influencing glucose and lipid metabolism, immune regulation, bone remodeling, neuroplasticity, vascular function and tissue regeneration. Representative mediators considered include IL-6, IL-15, myostatin, follistatin, decorin, FNDC5/irisin, FGF21, myonectin/CTRP15, BDNF, cathepsin B, SPARC, apelin and extracellular-vesicle cargo. However, current evidence remains fragmented across individual molecules, exercise modalities, sampling windows, assay platforms and disease contexts. This narrative mechanistic review proposes the concept of the “myokine adaptome” as an integrated, context-dependent signaling network through which skeletal muscle contributes to systemic homeostasis in health and disease. We synthesize evidence on cellular triggers of myokine release, including AMPK-PGC-1α signaling, mTORC1-dependent mechanical sensing, calcium flux, redox signaling, inflammatory pathways and extracellular-vesicle-mediated communication. We further examine how exercise modality, aging, obesity, type 2 diabetes, sarcopenia, osteoporosis, cardiovascular disease, COPD, cancer/cachexia and chronic inflammation reshape myokine production and target-organ responsiveness. The central argument is that myokine biology should be interpreted not as a catalog of isolated mediators, but as a dynamic adaptive code defined by signal amplitude, temporal pattern, molecular composition, delivery route and recipient-tissue sensitivity. Its novelty is operational rather than nominal: it requires source confidence, temporal kinetics, co-signal context, delivery route and functional decoding to be evaluated together. This framework may improve biomarker design, disease-specific exercise prescription and therapeutic strategies aimed at restoring adaptive muscle–organ communication. The framework is further strengthened by testable predictions concerning adaptive pulsatility, modality-specific signatures, source attribution, recovery quality, disease-specific decoding and the superiority of multi-marker panels over single-molecule readouts.

Exercise adaptation and training maladaptation arise from overlapping metabolic, redox, inflammatory, endocrine, and tissue-remodeling processes, so the translational question is not whether biomarkers change but when, where, and for which decision they become informative. This narrative review develops a decision-linked framework for minimally invasive biomarkers across the recovery–overload continuum and treats biomarker meaning as a molecule–matrix–time–decision relationship rather than as a stand-alone peak. The framework is organized around five coupled layers: stimulus architecture, signaling and release biology, sampling matrix and pre-analytics, bout-relative kinetics, and the monitoring decision to be supported. Current evidence indicates that no single biomarker reliably separates productive remodeling from delayed recovery, tissue strain, non-functional overreaching, or early maladaptation. Classical chemistry remains useful for bounded tasks, especially delayed tissue strain and stress reactivity; cfDNA appears promising for rapid load sensitivity; targeted metabolite panels are strongest for recovery phenotyping; and circulating RNAs and extracellular-vesicle cargo add mechanistic depth but remain constrained by pre-analytical fragility and incomplete standardization. The central practical implication is that overload is better interpreted as progressive loss of signal resolution than as threshold-crossing and that sparse temporally staggered panels are more likely to aid monitoring decisions than isolated markers or untimed high-dimensional profiles. Progress will depend on purpose-specific panels, transparent analytical standards, and prospective validation against symptoms, performance, and established measures across sex, hormonal, circadian, and training contexts.

Skeletal muscle is increasingly recognized as a dynamic secretory organ capable of translating contractile, metabolic, mechanical and inflammatory stimuli into systemic biological signals. Among these signals, myokines and myokine-associated exerkines mediate communication between skeletal muscle and distant organs, influencing glucose and lipid metabolism, immune regulation, bone remodeling, neuroplasticity, vascular function and tissue regeneration. However, current evidence remains fragmented across individual molecules, exercise modalities, sampling windows, assay platforms and disease contexts. This narrative mechanistic review proposes the concept of the “myokine adaptome” as an integrated, context-dependent signaling network through which skeletal muscle contributes to systemic homeostasis in health and disease. We synthesize evidence on cellular triggers of myokine release, including AMPK-PGC-1α signaling, mTORC1-dependent mechanical sensing, calcium flux, redox signaling, inflammatory pathways and extracellular vesicle-mediated communication. We further examine how exercise modality, aging, obesity, type 2 diabetes, sarcopenia, osteoporosis, cardiovascular disease, COPD, cancer/cachexia and chronic inflammation reshape myokine production and target-organ responsiveness. The central argument is that myokine biology should be interpreted not as a catalogue of isolated mediators, but as a dynamic adaptive code defined by signal amplitude, temporal pattern, molecular composition, delivery route and recipient-tissue sensitivity. This framework may improve biomarker design, disease-specific exercise prescription and therapeutic strategies aimed at restoring adaptive muscle-organ communication. The framework is further strengthened by testable predictions concerning adaptive pulsatility, modality-specific signatures, source attribution, recovery quality, disease-specific decoding and the superiority of multi-marker panels over single-molecule readouts.

Exercise adaptation and training maladaptation arise from overlapping metabolic, redox, inflammatory, endocrine, and tissue-remodeling processes, so the translational question is not whether biomarkers change, but when, where, and for which decision they become informative. This narrative review synthesizes biomarkers across the recovery-overload continuum and proposes a decision-linked framework organized around five coupled layers: stimulus architecture, signaling and release biology, sampling matrix and pre-analytics, bout-relative kinetics, and the monitoring decision to be supported. Current evidence indicates that no single biomarker reliably separates productive remodeling from delayed recovery, tissue strain, non-functional overreaching, or early maladaptation. Classical chemistry remains useful for bounded tasks, especially delayed tissue strain and stress reactivity; cfDNA appears promising for rapid load sensitivity; targeted metabolite panels are strongest for recovery phenotyping; and circulating RNAs and extracellular-vesicle cargo add mechanistic depth but remain constrained by pre-analytical fragility and incomplete standardization. Biomarkers should therefore be interpreted as temporally staggered layers rather than isolated peaks, with greater concern assigned to persistent cross-window elevation than to a transient rise. Progress will depend on sparse, purpose-specific panels, transparent analytical standards, and prospective validation against symptoms, performance, and established measures across sex, hormonal, circadian, and training contexts.