Some I knew had Alzheimer's. Exercising slowed it down a lot. Eventually she stopped going for her daily bike ride and things got worse really fast after that. I would recommend regular exercise, relaxation exercises, meditation and exercising your brain. I don't know if it will reduce the risk of getting Alzheimer's but it would certainly slow it down. Since I have a good chance of getting it based on my family I am going to do what I can to prevent it or slow it down.
A lot of older people don't exercise their body or their mind enough and stress is bad for your body and mind.