Hi Pennycandy,
Like most of the Bible it's accounts of people living to almost 1000 years old is pure fantasy from all the available evidence I've seen. These stories are contemporary with other known cultures who left us written records from these times and none of them report humans living to such extreme ages. Even if other cultures did claim that people lived this long it would not be provable either but it is interesting that since no such claims are made it is very unlikely that people were even living to be 200 years old or someone would have noted it somewhere even as a folk tale or exaggeration. Most of the Archeological evidence leads us to believe people in these times lived about as long as we do today if they were lucky, healthy, and had enough food. If the Watch Tower's theory about people in ancient times being closer to perfection and hence having longer life spans was true then there should have been a lot of evidence of many people gradually dying at a younger and younger ages counting down from the upper 100's regardless of their cultures. The recorded reigns of Egyptian Kings for instance all show lifespans exactly in line with what one would expect from normal modern humans living under the conditions prevailent then in ancient Egypt.
Think of the unique familial relationships which would have been noted by someone in talking about living alongside their own GreatGreatGreatGreat Grandparents/Grandchildren yet there is no mention of such. Why would Noah have only taken his children and their wifes on the Ark when clearly there should have been his Parents, Grandparents, Great Grandparents, etc. to include, not to mention his numerous generations of Grandchildren, Uncles, Aunts, Cousins etc. Surely they were not all evil since Noah got his righteousness from somewhere? Noah does not even mourn the loss of all these close relatives who would surely have been alive if everybody was living past 500 years or more. The Bible is illogical even within it's own context in this regard. People living to nearly 1000 years old is clearly sheer nonsense.