A delivery driver spent 28 years at the wheel with the window on his left. By 69, the left side of his face was thickened and furrowed, and the right side looked as if it belonged to a younger man. One side had sat in the sun through the glass. The other had spent those years in the shade of the cab.
His photograph travelled round the world because it shows something we rarely get to see: one person, one set of genes, one birthday, aged at two speeds. How fast we age is far less fixed than the calendar suggests, and most of what speeds up ageing is ordinary and close to hand. Ahead: how much of a face's ageing comes down to the sun, what identical twins reveal about smoking, the two ages when the body seems to age in a burst, and the belief about growing older that went with seven and a half extra years of life.
What sets the speed
Genes matter less than they get credit for. Among 2,872 pairs of Danish twins born before 1900, genes explained about a quarter of the difference in how long they lived. The other three quarters came from everything else.
The speeds pull apart early. In one New Zealand city, 954 people born within the same twelve months were measured three times through their twenties and thirties. By their late thirties some were ageing much faster than others, and the fast agers were already less physically able, slower on thinking tests, and older-looking in photographs.
Ageing also comes in bursts. When 108 adults were tracked molecule by molecule for up to seven years, the changes bunched around two ages, about 44 and about 60. If you once felt you aged a lot in a single year, you may well have been right.
Cells keep their own count. In 1961 Leonard Hayflick showed that human cells divide about 40 to 60 times and then stop for good. Until then they were thought to be immortal. The counter is the telomere, a cap on the end of each strand of DNA that loses a little with every division. Remember the word; it comes up again.
Looking older is more than vanity. Among 1,826 Danish twins over 70, the twin who looked older in photographs was the more likely to die first, and the bigger the gap in looks, the surer the pattern. Looking young for your age went with stronger bodies, sharper minds and longer telomeres.
1. Shade your skin
A tan used to mean the opposite of what it means now. Until the 1920s it was the mark of outdoor labour, and people who could afford to carried parasols. Then Coco Chanel came home from the Riviera sunburnt, and brown became the fashion.
The sun does most of what we call ageing on a face. When 298 women aged 30 to 78 were compared, sun-seekers against sun-avoiders, the sun accounted for about 80% of the visible signs: the spots above all, and a good share of the lines.
It can be slowed. In Australia, 903 adults were asked either to use sunscreen every day or to carry on using it when they felt like it. Four and a half years later, the daily group's skin showed no measurable ageing, and 24% less than the others.
Skin needs some sun: it's how the body makes vitamin D, and in the brighter half of the year, time outdoors gives most people all they need. The ageing comes from the long unprotected hours and the burns. Oily fish, red meat, egg yolks and liver carry vitamin D too.
Glass is only half a shield. Window glass stops most of the rays that burn and lets through a good share of the ones that age, which is how the driver's face came about. Side windows in cars usually let through more than windscreens.
Make shade and a hat as ordinary as brushing your teeth, and sunscreen on the days you'll be out for long. A wide-brimmed does the first half of the job.
2. Let the cigarettes go
Identical twins are the fairest test there is. At a twins' festival in Ohio, 79 pairs were photographed in which only one twin smoked, or one had smoked at least five years longer. Judges who knew nothing about them picked out the smoker's face: heavier upper lids, bags under the eyes, deeper folds from nose to mouth, more lines around the lips, and jowls.
Jeanne Calment, the oldest person on record, lived to 122 and smoked until she was 117. She is the exception the figures allow for, and nobody's plan.
If you smoke, let your face be one more reason to stop, alongside the bigger ones.
3. Give your skin its night shift
Sleep is when skin repairs itself. Sixty women were sorted into good and poor sleepers. The good sleepers scored lower on skin ageing, and when a patch of their skin was stripped with tape, it had recovered 30% better three days later. Their skin bounced back faster from a burst of ultraviolet light too.
One lost night shows. Twenty-three people were photographed after a full night and after a night without sleep, and 65 strangers judged the tired faces less healthy and less attractive.
Treat your bedtime as part of your skincare, the part that costs nothing.
4. Mind the air you live in
Soot settles on faces. Among 400 women in their seventies, those who lived with more soot and traffic particles in the air had 20% more age spots on the forehead and cheeks.
When you walk, take the quieter street over the main road. Indoors, an takes fine particles out of the room you sleep in.
5. Watch the sugar
Sugar leaves a mark as well. It sticks to the collagen that keeps skin firm, and the stiffened fibres are hard to repair. When 602 people had their age guessed from photographs, those with higher blood sugar were judged older, and that held among people without diabetes.
Low-carb, keto and carnivore eating all take the sugar out at the source.
Find the largest source of sugar in your day, and start with that one.
6. Mind what you drink
Alcohol reaches those telomeres. In 245,354 people, more drinking went with shorter telomeres, and a genetic check pointed to the alcohol itself as the cause, most strongly in the heaviest drinkers.
Water may matter more than it gets credit for. Among 15,752 adults followed for 25 years, those whose blood ran saltier in middle age, a sign of drinking too little, were up to 50% more likely to be biologically older than their years.
Make water the drink you reach for first.
7. Keep your fitness
Fitness is one of the clearest signs of how fast a body is ageing. When 122,007 adults took a treadmill test and were followed for about eight years, the least fit were five times more likely to die than the fittest. Being unfit carried a risk as large as smoking, diabetes or heart disease, or larger. Every step up the fitness ladder helped, with no upper limit in sight. The gain showed in people over 70 as well, so the ladder is still there to climb.
Find the pace that leaves you a little breathless, and visit it most days.
8. Ease the long stress
Long stress reaches right down into your cells. Among healthy mothers, some of them caring for a chronically ill child, those under the heaviest stress had telomeres shortened by the equivalent of at least ten extra years.
Some of it runs in reverse. When single hairs were mapped along their length, a few that had turned grey had regained their colour, and the changes ran in step with stress in the person's life.
Find the one thing that reliably calms you, and give it ten minutes every day.
9. Keep your people close
Friendship shows up in the figures on who lives longest. Across 148 groups and 308,849 people, those with stronger relationships were 50% more likely to be alive at the next count.
Put one person in your diary this week, before the week fills up with everything else.
10. Check what you believe about growing older
"Senate" and "senior" both come from the Latin senex, old. The Romans named their ruling council after its old men.
What you expect of old age seems to shape the one you get. Among 660 people aged 50 and over, those who held a brighter view of their own ageing lived seven and a half years longer than those with a gloomier one, and the views had been recorded up to 23 years earlier. The gap held after health, money and loneliness were taken into account. Becca Levy, who led that work, tells the rest in .
Notice the next time you say "I'm too old for that", and ask whether it's true.
Does eating less slow it?
A little, in the one long test we have. For two years, 220 healthy adults either cut their calories or ate as usual. By one measure the cutters' pace of ageing slowed slightly. By two others nothing changed.
Everyone in that test was healthy and well fed to begin with, which matters: eating less is a poor idea for anyone already thin, frail or recovering.
What the menopause does to skin
As oestrogen falls, skin gets thinner and drier, loses some of its spring, and holds less collagen. It's a real change, and it arrives on top of everything above, which makes the shade and the sleep matter even more in those years.
What about creams and collagen?
One cream has good evidence behind it: tretinoin, a prescription relative of vitamin A. In eight tests it improved sun-damaged skin more than a dummy cream, with irritation as the price.
Collagen powders sold for skin are another story. Across 23 tests in 1,474 people they looked helpful, until the tests paid for by companies were set aside. In the independent ones, and in the best-run ones, they did nothing for hydration, elasticity or wrinkles.
When a mark needs a look
Years of sun bring more than lines. A new mole, or one that changes its shape, its colour or its size, bleeds or itches, is worth having checked soon.
More windows than you think
The driver had no say over his birthday. One window changed half his face.
You have more than one window, and you choose where you sit. Pick one today and start there. The years will come either way, and how they land is partly up to us.
Is the sweet thing usually in a glass? The Hidden Cost of Your Daily Sugary Drink — what a daily soda or juice does to your liver, your teeth and the ends of your DNA.
Tired all day and wide awake at night? Stuck in Survival Mode: What Chronic Stress Does to the Body — what long stress does from heart to gut, and what sounds the all-clear.
Know someone who keeps saying they're getting old? Send them this, and take them for a walk on the shady side of the street.
Disclaimer: This article is general information. For advice about your own health, talk to a qualified health professional.
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