For decades, scientists believed lifestyle and environment dominated in determining lifespan – there is still consensus that modifiable factors like physical activity, diet, sleep, stress, and social connection play a major role in both lifespan and healthspan, or the number of years a person enjoys good health as they age – but recent research suggests genes may have a greater impact than previously thought.
In investigating the influence of genetics on longevity, studies over the past two or three decades have found a relatively modest impact of between 15% and 33%, but the latest findings, published in Science, suggest those estimates were possibly skewed by the historical era in which the data were collected and that the impact of genes on longevity could be much higher.
Everyday Health reports that previous twin and family studies relied heavily on data from people born in the late 19th and early 20th centuries, when deaths from causes unrelated to biological ageing – infections, accidents, violence, and natural disasters – were 10 times more common than today, said first author of the new study, Ben Shenhar, a doctoral candidate and researcher at the Weizmann Institute of Science in Rehovot, Israel.
Those historical conditions created misleading signals, he said. “You would sometimes see twins where one died at 30 and the other lived to 95. Today, that would be extremely unusual, but back then it wasn’t.”
To get a more accurate assessment, Shenhar and his colleagues developed a mathematical modelling approach designed to separate deaths caused by external events from deaths driven by biological ageing.
When they applied that model, the picture changed substantially. The researchers estimate that inherited genetic factors account for roughly 50% to 55% of expected lifespan, which is about double earlier estimates.
“This study convincingly showed that earlier estimates of the genetic contribution to lifespan were too low,” said Charles Brenner, PhD, Alfred E. Mann Family Foundation Chair in the Department of Diabetes and Cancer Metabolism at the Beckman Research Institute of City of Hope, California, who wasn’t involved in the research.
The findings also confirmed earlier research on the powerful role that genetics play in dementia: “They found the heritability of deaths from dementia is around 70%,” he added.
On the other hand, up to 45% of dementia cases may be preventable through healthy lifestyle choices, including diet and exercise, which just goes to show: genes do not dictate exactly how long a person will live – but inherited risk may shape the overall range of ageing-related lifespan more than scientists once believed.
“Our findings do not suggest that lifestyle is not important for longevity, not at all. Even if 50% of lifespan is heritable, that still leaves another 50%,” said Shenhar.
Which genes help longevity?
For most people, longevity is shaped by many genes working together, each contributing modest effects that interact with lifestyle and environment over time.
But some people may win the “genetic lottery” by inheriting a small number of rare variants that may powerfully extend their lifespan.
Research into centenarians shows that these variants don’t prevent ageing itself. Instead, they appear to delay the onset of age-related diseases.
APOE2 Gene Variant One of the most consistently replicated longevity genes is APOE, which regulates cholesterol transport. “The APOE2 allele is significantly enriched in long-lived individuals and appears to offer neuroprotective and cardiovascular benefits,” Shenhar said.
FOXO3A Gene Another key gene linked to exceptional longevity is FOXO3A, which regulates cellular stress responses, DNA repair, and insulin signalling. Variants in this gene have been found in “long-lived” populations around the world, possibly because they help cells withstand stress that would otherwise lead to deterioration, Shenhar said. Additional studies are needed to confirm the impact of this gene on longevity and age-related illness.
CETP Gene CETP is linked to larger, healthier cholesterol particles, which helps protect against vascular ageing, said Shenhar.
What genes harm longevity?
Some inherited conditions dramatically increase the risk of serious disease earlier in life, effectively lowering the baseline for longevity.
APOE4 Gene Variant: Unlike the APOE2 variant that promotes longevity, the APOE4 variant is associated with increased risk of Alzheimer’s and heart disease, highlighting how different versions of the same gene can influence ageing in opposite directions.
BRCA1 and BRCA2: Mutations in these genes impair the cell’s ability to repair DNA, raising the lifetime risk of aggressive breast and ovarian cancers, often at younger ages than average, said Shenhar.
Familial Hypercholesterolemia (FH): This inherited condition prevents the body from clearing LDL (“bad”) cholesterol efficiently, leading to dangerously high levels from birth, and heart attacks in people as young as their 20s or 30s if untreated.
Family history and your longevity
Knowing their family history, which could offer clues about genetic inheritance, can help guide conversations between patients and healthcare teams about prevention and screening, said Brenner, pointing to evidence-based screening tests that are already part of routine care, including mammograms for breast cancer and colonoscopies for colorectal cancer.
Women with a strong family history of breast cancer – particularly those with a known BRCA1 or BRCA2 mutation – may need earlier screenings than women at average risk. Women at high risk of breast cancer may also benefit from breast MRI in addition to mammography; genetic counselling may also be appropriate.
Similarly, colorectal cancer screening is typically recommended starting at age 45 for people at average risk. But those with a family history of colorectal cancer may need to begin earlier or be screened more frequently.
Lfestyle choices impact lifespan and interact with genes
Even if genetics account for about half of ageing-related lifespan, lifestyle still matters and may matter more the older you get, noted Shenhar, adding that while it could take decades for unhealthy habits to translate into serious disease for someone in their 30s, for someone in their 80s, the margin for error was smaller, and the impact could be more immediate.
One reason lifestyle matters is epigenetics, the system that controls how and when genes are “read”.
“Daily habits can influence whether certain genes are activated and which ones stay quiet,” said David Rehkopf, PhD, a Professor of Epidemiology and Population Health at Stanford University, California.
An individual’s epigenetic profile reflects both genetic inheritance and environmental exposures. “It’s a mechanism through which genes and environment jointly influence health, but importantly, it’s changeable over the course of life,” said Rehkopf.
That means daily habits can influence how genetic risk plays out. “If someone has an unhealthy epigenetic profile now, changes they make can help it shift in a healthier direction over time,” he said.
Big 4 lifestyle pillars of longevity
No single habit determines longevity on its own. “All of the major lifestyle factors – diet, physical activity, sleep, and stress – play a role,” Rehkopf added. “It’s not about getting an A-plus in one category. It’s about balance, because they all matter for everyone.”
1. Exercise: move more, sit less
Physical activity is one of the behaviours most consistently linked to living longer. Research suggests, for example, that just 10 extra minutes of exercise a day may lower the risk of early death by 15% to 35%.
But research using wearable devices suggests that sedentary time matters, too.
In a large study of older women, those who spent more than 11.5 hours per day sitting had a higher risk of death than those who sat less, even if they regularly got moderate-to-vigorous exercise.
2. Nutrition: eat more plants
Diet appears to influence longevity largely by shaping the risk of chronic diseases that shorten life.
In a large modelling study, researchers concluded that if a 40-year-old eating the average American diet switched to a healthier diet and sustained those changes throughout their lifetime, they could potentially live nearly 10 years longer.
The biggest benefits were tied to higher intake of whole grains, fruits, vegetables, legumes, and nuts, and lower intake of processed meat and sugary drinks.
3. Sleep: ensure the brain gets its nightly ‘rinse cycle’
Sleep appears to influence longevity primarily by shaping long-term health rather than acting as a standalone driver of lifespan. Adequate sleep allows the body and brain to process metabolic waste, recharge, and support the immune system, among numerous other functions.
One large study published in 2024 tracked how well people consistently met healthy sleep metrics – things like getting seven to eight hours per night, waking up feeling rested, and having few sleep disturbances. The results suggested that people with the best sleep hygiene might expect to live two to five years longer than people with the poorest sleep outcomes.
4. Stress: learn to manage cortisol levels
Chronic stress raises cortisol levels and is associated with inflammation, heart disease, and metabolic dysfunction. Experts believe that, over time, biological wear and tear may accelerate ageing, including faster shortening of telomeres – the “protective caps” on DNA that help keep them stable.
Telomeres naturally shorten as cells divide, but factors such as chronic stress, inflammation, and oxidative damage can speed up that process, which has been linked to earlier onset of age-related diseases.
Shorter telomeres are tied to higher risks of conditions like heart disease and metabolic disorders, making them one of several biological markers tied to how the body ages over time.
Community and social connection also matter
Research on long-lived populations in the world’s “Blue Zones” suggest that longevity isn’t just shaped by habits like diet or exercise, but by daily social connection. People in these communities tend to eat together, spend more time with family and friends, and remain socially engaged well into older age.
Strong social ties have been linked to lower risks of heart disease, cognitive decline, and premature death, while chronic loneliness has been associated with higher mortality risk comparable to other major health threats.
Shared meals and regular social interaction may also help buffer stress, support healthier sleep, and reinforce routines that that promote long-term health.
Environment impact on longevity
Lifestyle choices don’t happen in a laboratory. Air quality, neighbourhood safety, access to healthcare, education, and income all shape what choices are realistically available, said Rehkopf, but pointed out that in many case, people can’t do much about that.
“While individual responsibility matters, many choices are constrained by broader social and economic conditions. As a society, we need to make it possible for people to be healthy if they want to be,” he said.
Everyday Health article – Genes or Lifestyle: Which Matters More for Longevity? (Open access)
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The Longevity Diet: How nutrition affects ageing and healthy lifespan – US analysis
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