Exercise supports muscle–brain communication via the release of myokines such as IL-6, insulin-like growth factor 1 (IGF-1), brain-derived neurotrophic factor (BDNF), cathepsin B (CTSB), irisin, and leukemia inhibitory factor (LIF), which help prevent mild cognitive impairment (MCI) and musculoskeletal aging [95]. The gene discussed is CTSB; the disease is Cognitive impairment.