Blood factors transfer the benefits of exercise to the aged brain independent of physical activity. Here, we show that the liver-derived exercise factor (exerkine) glycosylphosphatidylinositol (GPI)-specific phospholipase D1 (GPLD1), a GPI-degrading enzyme, reverses aging- and Alzheimer's-related memory loss by targeting the brain vasculature.https://pubmed.ncbi.nlm.nih.gov/41713415/