Stay on top of your cardiovascular health. Even moderate diet and lifestyle changes can have a significant impact on the last decade of your life. These things compound over decades.
I've hard about cognitive reserve and how healthy lifestyle choices can build that. But I never read about ways to minimize the number of years you have to live with dementia. I wish I could sign an order that would grant me a dignified death once I'm deemed no longer fit to make that decision.
Technically there's an extreme version of this where someone's lifestyle is so bad that they're unlikely to live past 60, but the last 10-20 years of that life would not be fun.
That depends. I'd rather die at 70 after a year of dementia than live to 85 where the last five of those I have dementia. I want to minimize the number of years with dementia, not maximize the number of years without.