If you can slow the biological process of aging, even a minor slowdown in the rate at which we age yields improvements in virtually every condition of frailty and disability and mortality that we see at later ages.

The last thing you ever want to do is extend the period of frailty and disability and make people unhealthy for a longer time period. So lifespan extension in and of itself should not be the goal of medicine, nor should it be the goal of public health, nor should it be the goal of aging science.

You can open up a centenarian's brain, and you'll see some areas that look like that of a 50-year-old or of a 110-year-old. You can have variation in the basic process of aging, called senescence, in different parts of the same body.

Once you avoid the things that accelerate aging like smoking, obesity, excessive alcohol consumption, and excessive sun exposure, you've done about as much as you can to influence your aging process.

Our concepts of aging really should be blurring because there are plenty of people who make it to older ages who aren't really any different in many ways than people who are decades younger.

Researchers have been looking for biomarkers of age for a long time and have failed. People sell tests out there to measure your biological age, and none of them work. There's no evidence that you can measure biological age with any reliability.