On Saturday, June 22nd, my wife and I attended a wedding invite of a close relative.  Among the guests was one close relative whom we have not met for several years.  She asked for my age.  I told her I am now 75. She is 65 and her husband 70.  She mentioned that now her husband is suffering from amnesia - unable to remember and always forgetting.  Gosh, I sympathise with her plight.

I believe that brain atrophy can be avoided if we do constant exercise, to keep body and mind fit and strong.  
This means not only indulging in cardiovascular exercises and sweating it out, but also exercising the mental muscles by regular reading, writing and indulging in creative activities: in my case constructing wooden toys for my grandchildren.  They enjoyed the toys I constructed for them and I enjoyed seeing happily playing with something I have built.  Yes, use it or lose it - with reference to your body muscles and mental muscles.