I am trying to get my treadmill fixed so I can go back to vigorous exercise.
Drinking fresh beetroot juice or a concentrated, high-nitrate beetroot blend an hour or two before moderate-vigorous exercise has been shown to boost blood flow and oxygen to the frontal lobes of the brain, which can help boost the neurogenesis there that physical exercise already stimulates. There was a study on that done with the elderly who had mild cognitive decline but not full-fledged dementia.
I am also trying to regrow the nucleus accumbens, a motivation-related dopaminergic part of the brain and physical exercise is the only thing I can find that may help heal it. I have been, for a very long time, on at least two medications known to shrink it over time, and I am working with my doctor to try reducing the dose of one and taking breaks from the other while reducing its dose as well. I have symptoms of a damaged nucleus accumbens and frontal lobes. Probably basal ganglia and hippocampus as well.
If you are concerned about your brain and cognitive function but are not on any pharmaceutical medications, you have a great advantage if you are wanting to try promising herbs like Brahmi, or Ginseng or Rhodiola (dopamine and neurogenesis), or Ashwagandha (interesting studies on dementia through its action on the liver) (But not all of them at the same time) of not having to worry about interacting with drugs, which can get scary and complicated.
The supplements Acetyl L Carnitine and Citicoline may help heal and protect the brain as well.
You probably already know about Turmeric.
But you are an avid researcher and have probably read up on everything like this anyway.
Do you drink a large glass of warm water with turmeric powder, Himalayan salt and a squeeze of lemon or lime as the first thing to consume after waking up?
Ernst often prefers homeopathy in general and has warned about over-reliance on even the tonic medicinal herbs, with regard to "forcing the body" to change too often.