I could easily imagine that longevity isn't significantly prolonged on average, but that the average person says fitter longer.
An example from canon would be Picard who was 59-74 played by the (fit for his age) 47-62 year Patrick Stewart.
In "The First Duty", Boothby (Starfleet Academy Groundskeeper) tells Picard, now in his mids 60s, that he is the age Boothby was when Picard was at the Academy, approximately 40 years earlier.
So we have Boothby being over 100 and physically fit and able to do a reasonably strenuous role.