How Lifestyle Shapes the Face of Ageing: Insights from Identical Twins
Somewhere on the internet right now there is a photograph of two 61-year-old women sitting side by side. They are identical twins. One of them looks about a decade older. The caption travelling with it usually claims one twin smoked for sixteen years and sunbathed at every opportunity, and Snopes has had to keep pointing out that the caption invents most of that.
The photograph is real, though. It comes from a study that says something far more useful than any caption ever could.
Same DNA, Different Faces
In 2009, plastic surgeon Bahman Guyuron conducted a compelling study at the Twins Days Festival in Twinsburg, Ohio — a gathering of thousands of twins every August. His team photographed and surveyed 186 pairs of identical twins, then had an independent panel estimate each twin’s apparent age based solely on their photos.
The results were striking. The longer a twin had smoked, the older she appeared. More sun exposure also correlated with an older-looking face, and these effects became more pronounced with age. Interestingly, twins who had experienced a divorce appeared nearly two years older than their siblings on average.
One particularly intriguing finding defies typical wellness industry narratives: while a higher body mass index (BMI) made twins under 40 look older, after 40, a higher BMI was associated with a younger appearance. This suggests that facial volume, which tends to decrease with age, contributes to perceived youthfulness — so aggressively pursuing thinness in your fifties may not be the best strategy.
These women shared identical genetic code; the differences in their facial ageing were shaped entirely by environmental factors and lifestyle choices.
Genes Are Not Off the Hook
It’s important to address a common misconception: while lifestyle clearly impacts ageing, genes still play a significant role. Popular narratives often downplay genetic influence, citing twin studies that estimated lifespan heritability at roughly 20 to 25 percent, with some family pedigree studies suggesting as low as 6 percent.
However, a landmark paper published in Science in January 2026 challenged these figures. The authors highlighted that older generations suffered many deaths from accidents and infections unrelated to genetics, which skewed heritability estimates downward. After adjusting for these factors, they found the heritability of intrinsic lifespan likely exceeds 50 percent.
So, while genes matter more than some folk wisdom allows, two crucial points remain: first, heritability estimates concern how long people live, not how old they look — these are separate questions with different evidence bases. Second, heritability describes variation across populations, not a fixed destiny for any individual.
A Face Is a Status Report
New Zealand’s Dunedin Study provides further nuance. Tracking nearly a thousand individuals born in the same year, researchers assessed biomarkers across cardiovascular, metabolic, renal, immune, dental, and pulmonary systems at ages 26, 32, and 38. They then calculated each person’s true physiological ageing rate.
The variation was astonishing: some showed almost no physiological decline per calendar year, while others aged internally nearly three years for every chronological year (PNAS, 2015). Independent raters, shown only facial photographs, consistently judged those ageing faster on the inside as looking older externally.
By age 45, the fast-aging group also exhibited more cognitive difficulties, advanced brain ageing markers, and diminished sensory-motor function (Nature Aging, 2021). This suggests that looking young after 60 can be a visible status update on how well the body’s internal systems have been maintained over time.
Punishment Has a Ceiling
This evidence challenges assumptions that more effort in fitness always yields better youthfulness. The Copenhagen City Heart Study followed 1,098 joggers and 3,950 non-joggers over 12 years. They found that light joggers had the lowest mortality rates, while strenuous joggers’ mortality was statistically indistinguishable from sedentary individuals.
The optimal “sweet spot” was about one to two and a half hours of jogging per week, spread over two or three sessions, at a slow to average pace. However, it’s important to treat this finding cautiously: the study was observational, jogging intensity was self-reported, and the sample of strenuous joggers was small, leading to wide confidence intervals. A direct rebuttal was even published in the same journal.
Still, the burden of proof lies with claims that extreme physical punishment buys youth—and current evidence does not support it.
The Unglamorous Stuff
Sleep consistently emerges as a key factor in ageing. A study of 60 women found that good sleepers had lower intrinsic skin ageing scores and recovered about 30 percent more skin barrier function after deliberate disruption. While the study was small and funded by a cosmetics company, its findings align with broader research emphasizing the restorative power of sleep.
Strength training also plays a significant role, with some nuances. A 2025 meta-analysis of 24 trials involving 951 older adults diagnosed with age-related muscle loss showed that resistance training reliably improved grip strength, walking speed, and leg strength. Notably, muscle mass itself changed little, indicating that functional improvements often outpace visible physical changes.
Ultimately, the twins in that photograph were running identical genetic “software.” One simply spent three decades making slightly different decisions in ordinary moments: choosing to wear a hat, prioritizing a good night’s sleep, opting for a walk instead of a late espresso, and avoiding late nights. These small, consistent lifestyle choices over decades appear to be the real secret to aging well.
For more insights, read Here.
