People with higher intelligence do tend to live longer, and the effect is measurable. For every 15 points higher on an IQ test, the risk of dying in a given period drops by roughly 17 percent. That relationship holds across decades of research, multiple countries, and different ways of measuring cognitive ability.
How Much Longer, Exactly?
The most consistent finding in this field comes from studies that test children’s cognitive ability early in life, then track them for decades. A 65-year study from Sweden found that each 15-point increase in early IQ was linked to a 15 percent lower mortality risk in men, even after accounting for the person’s own education level and their father’s education. A separate large study put the figure at 17 percent lower risk of death per 15-point increase in childhood IQ.
To put that in perspective: someone scoring 130 on an IQ test (roughly the top 2 percent) would carry about 34 percent less mortality risk than someone scoring 100 (the population average), all else being equal. That doesn’t translate neatly into “X extra years” because the benefit depends heavily on what era you live in, where you live, and what kills people in your environment. But across populations, it’s a meaningful gap.
What’s Actually Driving the Difference
The obvious explanation is money. Smarter people tend to earn more, live in safer neighborhoods, and have better access to healthcare. That matters, but it doesn’t explain everything. When researchers statistically remove the effects of income and social class, the survival advantage shrinks from 17 percent to about 12 percent per 15 IQ points. So roughly a third of the benefit comes from socioeconomic advantages, but the majority persists even after those are stripped away.
Health behavior fills in much of the remaining gap. People who score higher on cognitive tests are more likely to understand health information, follow medical advice correctly, avoid smoking, eat better, and exercise. They’re also better at evaluating risk, which means they’re more likely to wear seatbelts, less likely to drink heavily, and more responsive to public health messaging. These aren’t trivial advantages. Smoking alone accounts for years of life expectancy difference between groups.
There’s also a more intriguing possibility: that scoring well on a cognitive test reflects something deeper about the body’s overall condition. One theory, called “system integrity,” proposes that a brain that processes information efficiently may simply be part of a body where everything works a little better. Under this view, IQ isn’t causing longer life directly. Instead, both high cognitive performance and physical resilience are outward signs of a body that’s well-assembled at a fundamental level. This idea is still being tested, but it would help explain why the link between intelligence and survival persists even after you account for behavior and wealth.
Which Causes of Death Are Most Affected
Heart disease shows one of the strongest connections to cognitive ability. A meta-analysis of five long-term studies covering more than 17,000 people found that each 15-point decrease in childhood IQ was associated with a 16 percent increase in cardiovascular disease risk. Genetic research points in the same direction: when researchers used a technique that isolates genetic influences on intelligence from environmental ones, they found that genetically predicted higher intelligence was associated with a 24 percent lower risk of coronary artery disease and a 22 percent lower risk of heart attack.
The pattern extends to other causes of death as well. Respiratory disease, stroke, and some cancers all show inverse relationships with cognitive ability, though the strength of the connection varies. Accidents and injuries also appear more frequently among people with lower test scores, likely reflecting differences in risk assessment and occupational hazards.
Intelligence Alone Doesn’t Protect You
The Terman Study, which followed over 1,500 high-IQ children (all scoring above 135) from the 1920s through their entire lives, offers a useful reality check. As a group, these exceptionally intelligent people got divorced, became alcoholics, and died by suicide at roughly the national average rate. Some died young from accidents, disease, or suicide. Being very smart did not make them more emotionally stable or immune to self-destructive behavior.
What did predict longer life within the Terman group wasn’t IQ itself (they were all high-IQ) but personality. Psychologist Howard Friedman of UC Riverside reanalyzed the Terman data and found that conscientiousness, the tendency to be organized, dependable, and disciplined, had the strongest life-extending effect of any personality trait. Self-esteem had no effect at all. Cheerfulness actually appeared to shorten life, possibly because optimistic people were more likely to underestimate health risks.
This finding suggests that what matters most isn’t raw brainpower but whether you consistently act on what you know. A person of average intelligence who takes their medication reliably, gets screened for cancer on schedule, and avoids smoking may well outlive a genius who ignores those things.
What the Numbers Actually Mean for You
Population-level statistics describe averages across thousands of people. They don’t determine any individual’s fate. The 12 to 17 percent mortality difference per 15 IQ points is real but modest compared to the effects of smoking (which roughly doubles mortality risk), severe obesity, or chronic heavy drinking. If you’re reading this article and thinking about your own longevity, the behaviors that extend life are well-established and have nothing to do with test scores: regular physical activity, not smoking, moderate alcohol intake, maintaining social connections, and staying engaged with preventive healthcare.
The research on intelligence and lifespan is ultimately a story about advantages compounding over time. Higher cognitive ability makes it slightly easier to navigate health systems, understand risks, and land in environments that support good health. Those small edges, repeated over decades, add up. But they are edges, not guarantees, and they can be replicated through habits and systems that don’t require a high IQ to maintain.