Your 82-Year-Old Grandmother Was Diagnosed with Alzheimer's Disease 4 Years

Your 82-year-old grandmother was diagnosed with Alzheimer's disease 4 years ago.Your mother is very concerned about the potential of being diagnosed with Alzheimer's disease herself.She has been an avid runner for many years and vigorously exercises at least five times a week for 20 to 30 minutes a day.What would you tell your mother?

A) Exercise surely will help, but there is no evidence that it does.
B) She should keep exercising.Studies show an inverse relationship between physical activity and the risk of developing Alzheimer's disease.
C) For any benefit to accrue from exercise, she will also need to closely monitor her alcohol intake.
D) Very strenuous exercise actually increases the likelihood of experiencing Alzheimer's disease.