After analyzing blood from a 115-year-old woman, scientists have come up with some interesting ideas on how long a person can live.

What they found was the woman only had about two stem cells in her blood, when you're born you have about 20,000.

Scientists say that shows no matter how much we think we can do things that make us go on forever, we can't.

They say it is possible to take blood donated early in life and use that to increase stem cells when you're older, but it wouldn't do anything for your organs.

So, would you want to live forever if you could?