Perez-Lopez A, et al. - Here, researchers figure out if physical activity regulates circulating IL-15 and IL-15Rα in lean and obese individuals. Circulating IL-15 and IL-15Rα are decreased in lean and obese participants who perform physical activity regularly (≥180 min/week), proposing a regulative role of physical activity on the circulating concentrations of IL-15 and IL-15Rα at baseline. Besides, the systemic connection found between IL-15Rα and glucose profile may indicate a role of the alpha receptor in glucose metabolism.