It's mostly luck and genetics, but good sleep matters.

My mother died from Alzheimer's at 77 but wrote down her symptoms as early as 60, a full six years before her diagnosis.

Prior to her diagnosis, she walked her dog two miles a day, had an ideal weight, ate organic, never drank or smoke, used her brain constantly, and enjoyed a happy social life.

The only problem I saw with her was she was a very light sleeper.

Her aunt also died from Alzheimer's and was super healthy when diagnosed too.

Meanwhile the 103-year-old lady at my mother's former care facility is still sharp as a tack and reads daily without needing glasses.