A simple observation. Doing a few push ups feels like it pushes blood into my head, which makes me feel good. It doesn't last long but it's making me think about ways to use this. Would doing a few push ups every day be expected to lead to long term improvements in blood flow into the brain? Postural changes from eg. lying down to standing up are heavy orthostatic stress for me and repeating them is a fast way to feel worse. But maybe if done gently and in a way that makes them tolerable that would allow one to train the blood vessels and valves importing in brain blood flow. Does this idea have merit?