“It’s just the second law of thermodynamics,” goes the argument, “which says that entropy tends to increase”—in other words, things become more disordered, and fall apart with time. All good things must come to a messy, high-entropy end, whether they’re steam engines, universes, or animals. This argument is flawed because it omits a crucial phrase:

These are often hidden from view and politically neglected, but the indirect costs of diseases like cancer and dementia frequently exceed the direct ones. The total cost is enormous: unpaid care alone in the UK is estimated to be worth about the same as the entire healthcare budget. Once again, this was never planned—but love and a sense of

Smokers can’t even claim to live fast and die young: they experience about the same number of years in ill health at the end of life as non-smokers, meaning a greater fraction of their shorter lives overall.

This ubiquity means that, even though you might consider it an “external” factor, it makes sense to consider CMV as a part of human aging.

This means that now, uniquely in human history, we have become victims of our own success—the rout of malevolent microbes, the rise of public health, healthier lifestyles, modern medicine and increasing education and wealth have conspired to bring us face-to-face with a new scourge: aging. No matter where you live in the world, you’re very likely

DNA methylation, meaning “methyl groups” made of a carbon and three hydrogen atoms that stick to your DNA. It’s been known since the 1980s that DNA methylation tends to decrease overall with aging, but it was only with the sequencing of the human genome in the late nineties and the development of special “chips” which could measure methylation at

The root cause, the aging process itself, we ignore entirely.

It seems that most age-related changes are aggravated by inflammation one way or another.

We, by contrast, have a risk of death which doubles every eight years. This doesn’t start out so bad: aged 30, your odds of dying that year are less than 1 in 1,000. However, if you keep on doubling something it can start small but, eventually, get very large very quickly: at 65, your risk of death that year is 1 percent; at 80, 5 percent; and by