We tend to live more sedentary lives these days, in general. Keeping moving is important. I'm turning 50 next year and whilst I could probably do a little more exercise manage to keep fairly active. About the greys...No stopping it.
I think my most balanced age was about 33 years old, however I think I'm doing ok these days in the key areas you mention; Mentally, physically, spiritually.
Good post.
RE: Grey Hairs and Handstands | getting fit and aging