The key ideas

Ageless: The New Science of Getting Older Without Getting Old

Andrew Steele, 2020

Why is a tortoise as vigorous at a hundred and seventy as at thirty, while we grow weaker with every decade? Biologist Andrew Steele shows that aging is a process with causes rather than a law of nature, and scientists can already change its speed in the laboratory. This book explains what breaks in an aging body, which treatments are being tested, and what you can do yourself while waiting for them.

Who it is for

For anyone who wants to understand why we age and why scientists seriously discuss treating old age, and anyone looking for honest advice on staying healthy longer.

Aging is not a morally acceptable solution to any problem.

A world where old age appeared one day

Imagine a world where people do not age. At twenty and eighty, your heart is equally strong and your mind equally clear, and your chance of dying this year does not depend on your age. Suddenly, a new disease appears. It slowly takes away strength, memory, and sight, makes bones fragile, and eventually kills almost everyone it touches.

Scientist Andrew Steele proposes this thought experiment. He is certain that people in that world would devote all their efforts to fighting the disease, and nobody would call it necessary because it was natural. Yet this is simply a description of aging. By Steele’s calculations, of roughly a hundred and fifty thousand people who die on Earth each day, more than a hundred thousand die from age-related causes.

Steele began as a physicist, then moved into biology and decided that aging was the most important scientific challenge of our time. His book explores why we age, why some animals barely age, and what scientists can already do about aging in the laboratory. It also explores what you can do yourself right now while new medicines are still being tested.

We begin with a graph that, Steele says, brought him into this field.

Every eight years, the risk doubles

In 1825, English actuary Benjamin Gompertz, a specialist who calculates for insurance companies how long their customers will live, was examining mortality tables. He noticed a strange pattern. An adult’s chance of dying in the coming year rises not little by little, but doubles roughly every eight years.

Steele shows what this means in practice. In your mid-thirties, your chance of dying within a year is about one in a thousand. By your mid-sixties, it is one in a hundred. In your mid-nineties, one in six. It resembles debt at compound interest: the sum grows almost unnoticed at first, then suddenly becomes unmanageable.

Age brings disease. Cancer, heart disease, stroke, dementia, and type 2 diabetes are rare in youth and become more frequent over the years. Steele stresses that this is no coincidence: all these diseases share one root, and that root is aging itself.

Yet medicine, Steele says, treats them individually. Oncologists fight cancer, cardiologists heart disease, neurologists dementia, and each defeated disease simply makes room for the next. Life expectancy has roughly doubled since 1800, from forty to eighty years. This happened mainly because people stopped dying young from infections, hunger, and injuries. Nobody treated aging itself.

This leads to the book’s central move. If the diseases of old age grow from one root, treating the root makes more sense than plucking off leaves individually. Steele calls this an extension of ordinary medicine rather than science fiction. His goal is longer healthy life, not immortality.

For you, a simple point follows. “What do you expect, it’s your age” is neither an explanation nor a life sentence. It names a process that can be studied, measured, and, as we will see, slowed.

Read in Livria

About the author

Andrew Steele is a British scientist and science communicator. After earning a doctorate in physics at Oxford, he moved into biology and worked at the Francis Crick Institute in London.

All books by this author: Andrew Steele

Terms from the book

  • dementia
  • Williams
  • mitochondria
  • Yamanaka
  • Senolytics
  • Telomeres
  • Actuary: A specialist who uses mortality and disease statistics to calculate risks for insurance companies and pension funds.
  • Gompertz: Benjamin Gompertz (1779–1865), a British mathematician and actuary. In 1825, he described how an adult’s risk of death rises ever faster with age, a pattern called Gompertz’s law.
  • Harriet: A Galápagos tortoise that died in Australia in 2006 at around 175 years old.
  • Negligible senescence: A scientific term for species whose risk of death does not rise with age and whose fertility does not decline. It describes certain tortoises and fish, for example.
  • Blanding’s turtles: North American freshwater turtles named after naturalist William Blanding. Long-term observations found that older females retain their fertility.
  • Kirkwood: Thomas Kirkwood, a British biologist and aging researcher. In 1977, he proposed the disposable soma theory: organisms spend resources on growth and reproduction rather than endlessly repairing themselves.
  • McCay: Clive McCay (1898–1967), an American nutrition researcher at Cornell University. In the 1930s, he showed that rats eating less lived longer.
  • Calorie restriction: A diet containing substantially fewer calories than usual but enough of all necessary nutrients. It extends life in many animals.
  • Kenyon: Cynthia Kenyon, an American biologist. In 1993, her group showed that changing the daf-2 gene doubled nematodes’ lifespan.
  • Nematodes: Roundworms. Caenorhabditis elegans, about a millimeter long, lives for a few weeks and is frequently used in aging research.
  • daf-2: A nematode gene through which cells receive signals from insulin and related hormones. When it works less strongly, the worms live longer.
  • Laron syndrome: A rare inherited condition in which cells barely respond to growth hormone. People with it are short; one of the best-known groups lives in Ecuador.
  • Senescent cells: Aging cells that have stopped dividing but have not died. They release substances that cause inflammation in neighboring tissues.
  • Mayo Clinic: A major US medical and scientific center in Rochester, Minnesota.
  • Fibrosis: The growth of dense scar tissue in an organ, impairing its function. Lung fibrosis makes breathing difficult.
  • Thymus: A gland behind the breastbone where immune cells called T lymphocytes mature. It shrinks with age.
  • Parabiosis: An experiment in which two animals are surgically joined so they share a blood circulation.
  • Conboy: Irina and Michael Conboy, biologists studying how blood influences tissue aging. They currently work at the University of California, Berkeley.
  • Reprogramming: Returning an adult cell to an embryo-like state in which it can again become any type of cell.
  • Cloning: Producing an animal from a cell of an adult organism rather than from two parents. The best-known example is Dolly the sheep, born in 1996.

All terms

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