A lot of people are under a misguided assumption that just because we're living longer now than before, we're living those extra years in good health. We're not. More people are living longer due to medical and other advacements over the years but we're living more of those years in poor health. And remember this: the reason life expectancy has improved over the years is because we've been eliminating the reasons of premature death (war, famine, disease).