Adropin Responses to Exercise: Physiological Determinants and Implications for Metabolic and Vascular Adaptation

Background and Objectives: Adropin is a peptide involved in metabolic regulation and vascular function, but its role in exercise adaptation remains uncertain. This narrative review synthesizes evidence on adropin responses to exercise, factors that may influence these responses, and their relationships with metabolic and vascular adaptation. Materials and Methods: A structured literature search was conducted in PubMed, Embase, and Cochrane Library from database inception to August 2026, supplemented by reference-list screening. Two reviewers independently assessed full texts and selected relevant articles. Disagreements were resolved through discussion with a third reviewer. Human exercise studies, observational studies of physiological factors, and experimental studies of metabolic and vascular mechanisms were synthesized narratively. Results: Human studies generally reported increased circulating adropin after aerobics, interval, resistance, and combined training. These increases were associated with improvements in cardiorespiratory fitness, glucose regulation, endothelial function, or arterial stiffness. However, acute responses were not consistently observed, and differences in populations, exercise protocols, and sampling conditions limited comparisons. Age, adiposity, metabolic status, hormonal factors, and nutrition were associated with baseline adropin concentrations, but direct evidence that these factors modify training responses remained limited. Experimental studies support effects on skeletal muscle substrate utilization, insulin signaling, and endothelial nitric oxide production. These findings provide biological plausibility but do not establish that exercise-induced changes in circulating adropin mediate human adaptations. One small, randomized trial reported an exploratory indirect effect on arterial stiffness through adropin. Small samples, uncontrolled comparisons, measurement differences, and reliance on observational and preclinical evidence limit interpretation. Conclusions: Adropin is an exercise-responsive biomarker candidate and a potential biological mediator whose causal role remains unresolved. Current evidence does not establish an optimal exercise modality or dose for increasing adropin. Standardized measurements and studies that establish temporal relationships and test mediation are needed to determine whether adropin provides information beyond established metabolic and vascular outcomes.