I've been doing a lot of reading about exercise lately and came across the remarkable career of Robert Marchand (1911-2021). He started cycling seriously in 1978 (yes, at age 67). But it took him until 2012 to set his first world-record - the one-hour record for the over 100 group.
He set is last world record in 2017 at age 105 and continued racing until at least 2018.
He passed away at 109.
https://en.wikipedia.org/wiki/Robert_Marchand_(cyclist)
"After he turned 106 Marchand's doctors advised him to stop competing for world records. He obliged, but refused to quit racing completely."
Boy, I'll bet he argued good and long before he obliged.