My mother had Alzheimer's for 20 years. I would not recommend it for more than 10 years no matter how healthy you are.
I have one copy of the APOE4 gene and am ~40lbs overweight and probably drink too much, and will definitely double my weight and triple my alcohol consumption if I get it.
I have always said the heathier you are when you begin to die, the longer it takes to die.