Exercise maintains a subset of bone marrow stromal cells that give rise to osteoblasts and lymphoid progenitors. CITATIONS Shen B, Tasdogan A, Ubellacker JM, et al. A mechanosensitive peri-arteriolar niche for osteogenesis lymphopoiesis. Nature. 2021;591 (7850):438–444. The health benefits exercise have been well documented publicized, although whether how improves the fitness immune system, co...