That's somewhat surprising. I wonder if the reverse holds - do rich people in poorer regions have shorter life expectancies than in richer regions?
According to the original paper, life expectancy in the lowest quartile "were not significantly correlated with access to medical care, physical environmental factors, income inequality, or labor market conditions."
https://jama.jamanetwork.com/article.aspx?articleid=2513561
The big correlates seem to be income and behavior (e.g. smoking, obesity).
Looking at studies surrounding exercise, even simply walking 30 minutes every day leads to better quality life in terms of health including preventing cognitive decline. Exercise is also associated with preventing the shortening of telomeres which scientist believe are connected with aging.
But doesn't seem too "incredible", it's mostly the typical notion of "diminishing returns" we see everywhere.
Mere environment matters a lot.
Update: What is wrong with that? Look how rich segregate themselves and where they used to live.
Also ask any sociologist or comparative historian.