Some keep running after the race is over:
https://www.nytimes.com/2017/12/16/business/asked-about-retiring-they-have-a-simple-answer-why.html
Surprising: "Ms. Weinstock said she expected that this trend would continue into the next decade. The Bureau of Labor Statistics says the labor force participation rate for those 75 and older rose from 6.4 percent in 2006 to 8.4 percent in 2016 and is likely to reach 10.8 percent by 2026."
https://www.nytimes.com/2017/12/16/business/asked-about-retiring-they-have-a-simple-answer-why.html
Surprising: "Ms. Weinstock said she expected that this trend would continue into the next decade. The Bureau of Labor Statistics says the labor force participation rate for those 75 and older rose from 6.4 percent in 2006 to 8.4 percent in 2016 and is likely to reach 10.8 percent by 2026."