Our body is designed for 200-300 years of life. Only it is necessary to lead a correct way of life.
the bible says so. there are characters in the bible that says he live more than 800 years old. i think that was moses. either moses or abraham. but why would you want to live that long? all you friends are already dead by the time you're 80. relieve yourself. there are more sufferings already. scratching your ass everyday with all the skin diseases is not that easy while you are 80.
I think that this is possible only for the elect, the one who understands why he should live so long and he can do something useful for others around this time.