Thought I'd get my bit in. I'm over 70 and still getting consulting jobs - mainly in the field of database development and data management. I laugh when a 50 year old says they're getting old.
Great article and obviously Chip has a good bit of behavioural and health knowledge. Note however that Omega fatty acids are not all the same, 3's and 6's should be in balance but modern diets are more heavy on the 6's - which can be bad.