As noted by the article, it was only recently discovered that the central nervous system had lymphatic drainage (see [1]). I’m simply connecting the results of

As noted by the article, it was only recently discovered that the central nervous system had lymphatic drainage (see [1]). I’m simply connecting the results of this mouse study with what we know about the lymphatic system, skeletal muscle, and the apparent benefit of exercise on Alzheimer’s disease risk, to form a hypothesis. I strongly suspect it’s true, but I cannot represent it as fact. Edit: Here is a more direct answer to your question: 1) Increased localized pressure from contracting muscle pushes lymph away through a vessel. 2) Reduced localized pressure from relaxing muscle allows new lymph to refill the evacuated vessel portion. 3) Lymphatic vessels have valves that keep all this flow moving in the same direction. 4) Given that the lymphatic system is connected to the central nervous system, increased muscular contraction could increase drainage of the brain. [1] https://www.nature.com/articles/nature14432 https://www.nature.com/articles/nature14432