For years, you’ve probably heard that “genes are only 20–30% of your lifespan” and the rest is lifestyle and luck. A new twin study, covered by ScienceAlert in early 2026, suggests that may not be the full story: when you remove deaths from accidents and injuries, your genes may shape your lifespan much more than we thought.

That can feel unsettling—almost as if your future is pre-written. But the real message is more nuanced and, in many ways, empowering: genes set the playing field, but how you play still matters.

Close-up of two older adults holding hands, symbolizing aging and longevity
Long life is shaped by a complex dance between genes, environment, and the choices we make every day.

In this article, we’ll unpack what this new research actually means, how much your genes may influence your lifespan, and—most importantly—what you can still do to tilt the odds toward a longer, healthier life.

“Genetics loads the gun, but environment pulls the trigger.” — Often attributed to behavioral geneticists summarizing gene–environment interplay

What the New Twin Study Really Found

ScienceAlert reported on an “unparalleled” analysis of twin data that re-examined how genes influence lifespan. Twin studies are powerful because:

  • Identical twins share ~100% of their genes.
  • Fraternal twins share on average ~50% of their segregating genes.
  • Both types usually grow up in similar environments.

Traditionally, such studies have suggested that heritability of lifespan (the proportion of variation in lifespan explained by genetic differences) sits around 20–30%. The new analysis went a step further by:

  1. Focusing on large twin registries and long-term follow-up.
  2. Separating deaths due to accidents and injuries from deaths more likely influenced by biology and aging.

Once the researchers “set aside” those accidental or external-cause deaths, they found that:

  • The similarity in lifespan between identical twins increased.
  • This pushed estimates of genetic influence on lifespan to be substantially higher than earlier numbers.
  • In other words, genes may matter more when we’re looking specifically at aging and disease, not random events.

The takeaway: compared with older estimates, your genetic starting point for longevity may be more influential than once thought—especially if you avoid early or accidental causes of death.


Genes vs. Lifestyle: How Much of Your Lifespan Is Really Under Your Control?

The idea that genes matter more can feel demotivating—particularly if you come from a family with heart disease, diabetes, or cancer. But a higher genetic influence does not mean lifestyle is irrelevant. It means:

  • Some people are born with a higher “baseline risk” for certain age-related diseases.
  • Others may be more protected but can still shorten their lifespan with unhealthy habits.
  • Healthy behaviors can delay or reduce the expression of genetic risks.
“Genes are not destiny; they are a draft. Lifestyle and environment are the editors.” — Paraphrasing the concept of gene–environment modification often discussed in longevity research

Large observational studies—like the Harvard cohorts on diet and lifestyle, or research on “Blue Zones” (regions with many centenarians)—show that people who:

  • Do not smoke
  • Stay physically active
  • Eat mostly whole, plant-forward diets
  • Maintain healthy weight and blood pressure
  • Have strong social connections

tend to live years longer on average than those who do not, even within the same genetic backgrounds. These lifestyle factors don’t erase genes, but they shift risk curves in your favor.


How Your Genes May Shape Longevity

The updated twin findings don’t point to a single “longevity gene.” Instead, they reinforce that lifespan is influenced by many small genetic effects, often acting together. Research to date suggests genes can affect:

  • Cardiovascular health – genes related to cholesterol metabolism, blood pressure, clotting.
  • Cellular repair and aging – DNA repair mechanisms, telomere maintenance, responses to oxidative stress.
  • Metabolism and weight – how you handle glucose, store fat, respond to overfeeding.
  • Immune function – how you respond to infections and chronic inflammation.
  • Brain resilience – susceptibility to neurodegenerative diseases like Alzheimer’s.
Scientific representation of DNA structure symbolizing genetics and longevity research
Longevity is polygenic: hundreds or thousands of small genetic variants each nudge your risk up or down.

This aligns with modern “polygenic risk score” research: rather than one decisive mutation, most people carry a mix of variants that move risk slightly in either direction.

Importantly, many of these genetically influenced pathways are modifiable:

  • Blood pressure can be lowered with diet, movement, stress management, and medication when appropriate.
  • Inflammation can be reduced through weight management, sleep, and certain dietary patterns.
  • Glucose control can be improved with physical activity and targeted eating strategies.

A Real-World Case: Same Genes, Different Lifespans

In clinical practice, I’ve often seen patterns similar to those reported in twin studies. Consider a composite example based on several twin pairs followed in cardiovascular clinics:

Identical twin brothers, both with a strong family history of heart disease:

  • Twin A worked a sedentary office job, smoked for 20 years, and rarely exercised. He developed significant coronary artery disease in his late 50s.
  • Twin B also had a desk job but cycled daily, ate mostly home-cooked meals, and never smoked. He reached his late 60s before any notable cardiovascular issues—and even then, the disease was milder.

Genetically, they were almost identical. Their risk profile on paper was the same. But lifestyle delayed the onset and severity of disease in one twin by roughly a decade.


What You Can Do: Practical Longevity Strategies in a Genetically Shaped World

With genes playing a bigger role than we once thought, the goal isn’t to “outrun” your DNA, but to work with it intelligently. Here are evidence-informed steps you can take.

1. Reduce Early and Preventable Risks First

The twin analysis found genes matter more when early, accidental deaths are removed. That’s a clear signal to:

  • Wear seatbelts and helmets consistently.
  • Avoid driving under the influence of alcohol or drugs.
  • Follow safety protocols at work and around machinery.
  • Address mental health early to reduce self-harm risk.

2. Know Your Family History—and Act on It

A detailed family history is a low-tech window into your genetic risk. Consider:

  1. Listing major conditions in close relatives (parents, siblings, grandparents).
  2. Noting the age at diagnosis or death when known.
  3. Sharing this list with your healthcare provider.

This may lead to earlier or more frequent screening (e.g., for cancers, heart disease, or diabetes), which can make a profound difference in outcomes.

3. Focus on High-Impact Lifestyle Pillars

Certain habits show up across almost all longevity research:

  • Move regularly: Aim for at least 150 minutes/week of moderate exercise plus some strength training.
  • Eat mostly minimally processed foods: Emphasize vegetables, fruits, legumes, whole grains, nuts, and healthy fats.
  • Don’t smoke: If you do, quitting remains one of the biggest single “longevity wins.”
  • Sleep 7–9 hours: Prioritize routines that support consistent, restorative sleep.
  • Build social connection: Loneliness is associated with higher mortality risk, comparable to some traditional risk factors.
Group of older adults walking outdoors together for exercise and social connection
Movement and social connection are two of the most consistent lifestyle factors linked with healthy, longer lives.

4. Consider Targeted, Not Trend-Driven, Testing

Direct-to-consumer genetic tests often overpromise on lifespan prediction. Instead, talk with your clinician about:

  • Evidence-based screenings (cholesterol, blood pressure, glucose, cancer screenings).
  • Genetic counseling if there’s a strong pattern of early disease in your family.
  • Whether specific genetic tests (e.g., BRCA for certain cancers) are appropriate.

Common Obstacles—and How to Work Around Them

Knowing your genes matter more can trigger two unhelpful reactions: fatalism (“why bother?”) or panic (“I need every supplement on the market”). Neither is necessary—or supported by evidence.

Obstacle 1: “Longevity Habits Feel Overwhelming”

Trying to overhaul everything at once usually fails. Instead:

  • Pick one habit to improve for the next 4–6 weeks.
  • Make it small and specific: “Walk 10 minutes after dinner on weekdays,” not “exercise more.”
  • Attach it to something you already do (a classic “habit stacking” strategy).

Obstacle 2: “My Family History Makes Me Feel Doomed”

A strong family history can indeed mean higher risk—but you’re not powerless. Studies of people with high genetic risk for heart disease, for example, have shown that healthy lifestyles can cut that risk substantially.

Practical steps:

  • Use your family history as motivation for earlier screening.
  • Focus on the “big rocks” (smoking, movement, diet, blood pressure).
  • Seek support—from clinicians, counselors, or support groups—if anxiety about health becomes overwhelming.

Obstacle 3: “Conflicting Information Everywhere”

Longevity is a hot topic, and not all sources are reliable. To filter noise:

  • Look for references to peer-reviewed studies and reputable institutions (e.g., NIH, WHO, major universities).
  • Be skeptical of anyone promising dramatic lifespan extension from a single supplement or hack.
  • When in doubt, discuss claims with a healthcare professional who understands your personal context.
Doctor talking with an older patient while reviewing health information on a tablet
Partnering with a trusted healthcare professional can help you navigate genetic information without fear or fatalism.

How This Fits with the Broader Longevity Research

The ScienceAlert report on the new twin analysis adds an important piece to a larger puzzle. Other lines of research include:

  • Genome-wide association studies (GWAS): Identifying small genetic variants linked with living to 90, 95, or 100+.
  • Studies of centenarians: Some families show clustering of long-lived individuals, suggesting shared protective genes.
  • Epigenetic research: Exploring how lifestyle and environment can modify gene expression over time.
  • Biomarker work: Looking at “biological age” measures based on blood tests, DNA methylation, or imaging.

Together, these lines of evidence point in the same direction:

  • Genes may play a larger-than-expected role in who reaches very old ages.
  • Lifestyle can still compress disease into a shorter period late in life, improving “healthspan.”
  • We’re far from being able to predict individual lifespans with precision.

Turning Genetic Insight into Compassionate Action

The new twin research, as highlighted by ScienceAlert, challenges the comforting idea that genes are only a small slice of your lifespan story. It suggests that, once we factor out random tragedies, our genetic wiring may matter more than we hoped.

But that doesn’t mean you’re trapped. It means that:

  • You can approach your health with curiosity instead of blame.
  • You can use family patterns as early warning systems, not death sentences.
  • You can focus energy on high-yield actions that improve both lifespan and day-to-day quality of life.
Older adult smiling while walking outdoors in nature, symbolizing healthy aging and longevity
You can’t change the genes you were born with—but you can still shape how you live within them.

If this topic stirs anxiety, that’s understandable. It also presents an invitation: to schedule a check-up, to start a small movement habit, to cook one more meal at home each week, or to reach out to someone you care about.

You may not control the length of every chapter ahead—but you have real influence over how those chapters feel, and how well you live them.

Next step: Choose one small, specific health action you can take in the next 48 hours, tell someone about it for accountability, and treat it as your quiet vote for a longer, healthier life—whatever your genes may be.