Has it occurred to you that perhaps your concentration is diminishing because you are engaged in too many activities? That can adversely affect both focus and stress levels. Although I think you're being a bit premature here, if cognition and focus diminish with age, then perhaps we need to be more selective in our preoccupations. Make more room by getting rid of some of the clutter so you can focus on the good stuff. And as has already been mentioned, regular daily meditation of even modest duration helps the relaxation response and can aid focus and concentration during the course of the day. Consider Herbert Benson's groundbreaking little book from the '70s: The Relaxation Response.Quote from nitro:
...What I am saying is that I am noticing distinct degradation in my capacity to concentrate for extended periods of time. I doubt it is anything I can cure with mental gymnastics. My daily regimen already includes a tremendous amount of that, as I am an avid reader, I program, am a chess player and bridge player, etc. But in all these areas, I see degradation in level of performance...
