The study investigated the role of the circular RNA circTSN (hsa-circ0003789) as a biomarker during the rehabilitation of patients with chronic obstructive pulmonary disease (COPD). Using peripheral blood RNA sequencing in 4 patients before and after a 12-week exercise intervention and subsequent confirmation of expression in 18 patients, circTSN was shown to be responsive to exercise. Mechanistically, circTSN functions as a molecular sponge for miR-144-3p, thereby influencing the expression of inflammatory genes in airway epithelial cells, including GATA6, IL-6, IL-1β, and TNF-α. This mechanism links the pulmonary epithelium to systemic inflammation. In a COPD mouse model, an indirect correlation between circTSN and miR-144-3p was demonstrated, suggesting the importance of this axis for lung adaptation to exercise. Thus, CircTSN may serve as a molecular sensor linking changes in the lung to the systemic response during exercise therapy. This discovery provides new insight into the mechanisms by which exercise benefits COPD patients and highlights the potential of circTSN as a target for monitoring and therapy.