What does Genesis 5:5 mean?

After revealing in the previous two verses that Adam was 130 years old when Seth was born and then lived 800 years after the fact, this verse reveals the inevitable math: Adam lived to be 930 years old. Could that possibly be true? The Bible's claim is that these first generations of humans after the garden and before the flood lived extraordinarily long lives, at least by modern standards.

Over the centuries, some scholars have suggested that the ages listed here do not represent actual years as we understand them. Some have suggested these numbers are in months (12 times the actual age), seasons (4 times the actual age), or tenths of years (ten times the actual age). Others have speculated that there is some form of symbolic or metaphorical intent from the author. The text itself, however, gives no explicit answer one way or the other, nor any particular reason to doubt that these were real people who lived extremely long lives.

Scholars have also speculated that the idealized environment of creation before the flood made it possible for human beings to live so many years. This is not only possible, it coordinates with modern understanding of genetics. In short, the lifespan of a living creature is far more dependent on its environment than its design. This means it's also possible, if not likely, that God's decree to restrict how long He would allow humans to live was specifically meant to limit the damage they could do with their sinful lives (Genesis 6:3).