CD8A and infectious disease: Notably, catecholamines NE and EPI peaked post-exercise, and NE was selectively associated with CD8<sup>+</sup> T cell mobilization.<h4>Discussion</h4>In conclusion, acute HIIT mobilizes functional, virus-reactive CD8<sup>+</sup> T cells with features indicative of enhanced migratory and activation potential, supporting translational use from tumor immunology to infectious disease.