The study found that exercise prompts the liver to pump out a little-known protein, and that chemically upping the levels of that protein in out-of-shape, elderly animals rejuvenates their brains. This was also shown even for blood transfusions between the animals.
It's really sad that the few times I've been to see any medical doctor it only ended in a pharmaceutical prescription. Never was I sent away with advice to exercise three times a week or switch to a low-carb diet (permanently, not temporary diet). OK I've not been diagnosed with diabetes, but I wonder how many people have been given a prescription to do regular exercise or change their diet? I do know from my Oura Ring (supports what I experience) that I sleep noticeably better during nights after I exercise.
See New clues into how exercise bolsters the brain
Many questions remain unanswered about how, at a cellular level, exercise remodels and alters the brain.