It’s been chastening and illuminating to see certain preconceived notions fall by the wayside as my research progresses. An early one was the assumption that good health was a precondition for an active old age. Although I expected to encounter the occasional, extraordinary geriatric Stephen Hawking, it seemed intuitively obvious. And certainly most of the people I’ve spoken with are exceptionally healthy, remaining physically mobile as well as mentally agile. Good luck, good genes.
But many also suffer from chronic or degenerative disease — and it doesn’t keep them from their work.