Research tells us the human body has been designed to last at least one hundred years. Even at this age we still should be able to function independently and efficiently even as we approach the triple digits. But take a look at the people around in our modern society today. To see or meet a one-hundred year old person who is strong, fit and energetic is a very rare or even mythical prospect.
We have been misled into believing that it is purely a stroke of luck or our genetics that determines how long we may live and if we stay healthy or not as we age. Sort of like good genes and good health lucky you - a healthy long life. Or the flip side bad genes and poor health equals chronic diseases and a shortened life.