The end of life

Since you were born, your body has grown, and developed. Your cells have divided and created new cells. Cells can repair damage, and are remarkably able to heal themselves, if something goes wrong inside them. But there's a limit to how many times cells can divide. In older people, there are fewer and fewer new cells being formed.

More of them are getting worn and damaged, without being replaced. Eventually, the body can't function anymore. You die. How old will you become? For how long will you get to live an active and healthy life?...

Nobody knows. Largely it's inherited; if your relatives lived long, then you have probably inherited genes that give you a good chance of that too. But what does it mean to die? When a person stops breathing, and the heart stops beating, is she then dead? Not long ago, it was like that.

Cardiac death meant you were dead. But today, there are machines that can keep the heart beating and the lungs breathing, so that the body keeps living, even if the brain is so damaged, that it has completely stopped working. That's why there's a more modern term: brain dead. When the brain is dead, the person is dead. But why would anyone want to keep a body alive, with machines, if the person is dead?

Well, there may be some of the organs that are still healthy and working well, and can be moved with surgery. By transplanting organs like this, a dead person can save another person's life. A hundred years ago, it would sound like science fiction, to move a heart or a liver, from one human to another. But today it's a fairly common operation. -- A successful transplant obviously prolongs the life for the receiver of the organ. This is one of the reasons people live longer than a hundred years ago.

Yet there are other, more important explanations, too. We: Eat better Drink cleaner water Take vaccines And we can get antibiotics for diseases that used to kill millions of people. In Africa, particularly, this change has been huge in recent decades. For these added reasons... ... the fight against malaria, and...

antiretroviral drugs, which slow down HIV... All these help many more children to survive their first years, escaping malnutrition, malaria, or diarrhea from dirty water. This is a fantastic development. So, on average we live longer. But there's still a lot to be done, in order to enable more people to live until they are old: Everyone needs clean water, and enough food.

Most of us need to eat more healthily, and exercise. That would reduce cancer and diabetes. We need to find better treatments for cancer, cardiovascular diseases, malaria, and dementia. If we manage to do all that, then the life expectancy of a newborn, globally, will increase even more. We might even expect to be as old as 110, or a bit more than that.

But there seems to be a limit at about that age. It appears as if cells can't age anymore than that. There are researchers who have started to experiment with extending this limit, so that we could get even older. How old can we be then? A hundred and fifty?

Two hundred? How old we can get, is something scientists are trying to figure out. But how old we want to become, is a more philosophical question. What would it be like to live for hundreds of years, and what would the World look like if we did.