I saw some runner who was a 2:2X Marathon runner when he was in his 30s barely being able to run a mile in 8 minutes at 63. He is not running much anymore, however he isn't fat or injured, and he is still quite active.
While some runners who would never have broken 3 hours on a Marathon no matter the training being able to run sub 45minutes 10k at 60.
Is aging really hitting some people that hard ? Or what am I missing ?
