As I proceed through the aging process I tend to worry and obsess about my future well being. I watch my friends lose mobility and function and find it quite distressing. However I have become aware of how to help oneself (somewhat) through this phase of life. Mobility begets mobility. And mental activity begets mental stability and alertness, by and large. While one still has one's faculties he/she must continue to use them actively. Undertake a rigerous physical activity program and maintain it. And keep mentally active. As long as you can.