IQ and death: why smarter people live longer

Reading time: 5 minutes

In my article about neuromyths, I debunked the commonly-held belief that IQ tests results only represent your ability to take IQ tests. In reality—and despite their flaws—IQ tests are predictive of many things. And, in particular, IQ tests can help predict your chances of dying.

In a cohort study conducted in 2009 with almost a million Swedish men who took a mandatory IQ test during their military service when they were around 18 years old, researchers followed-up with participants during 20 years after they took the test to see who was still alive and who had died. The graph below speaks for itself.

IQ and death: why smarter people live longer

As you can see, the graph shows the relation between IQ score—split into nine levels—on the x-axis, and risk of death in the 20 years following the IQ test on the y-axis. There is an impressive, staircase-like correlation between IQ score and risk of death. The people with higher IQ scores were less likely to be dead at the follow-up.

One million people of the same gender and the same age, and an almost perfect correlation between IQ and risk of death. But researchers decided to take it a step further, and to check if this result was mediated by other factors such as blood pressure, body mass index, or cigarette smoking. And they found that it wasn’t. All things made equal, individuals in the study tended to live longer if they were considered smarter as measured by the IQ test they took when they were 18.

The link between intelligence and longevity

The researchers admit in their paper that while the correlation is pretty clear, the actual causes aren’t. But there are a few hypotheses as to why smarter people tend to live longer.

  • Being smarter improves your quality of life. It may mean a better job, which could come with better quality healthcare, and living in a nicer area. Basically, more money means a better lifestyle.
  • Being smarter in general means being smarter with your health. For example, IQ is negatively correlated with smoking and getting into car accidents (as you will see if you click these links, most large-scale studies have been done on Swedish men during and after their military service). You’re less likely to put yourself in danger. You take better care of yourself, so you live longer.
  • A lower IQ can be a sign of a bad childhood. It can be a signal that things haven’t gone well for you as you developed. Maybe you’re from a deprived background, or you had malnutrition or an illness as a child. This may have affected your IQ by stopping your brain from developing to its full potential, and it also might as a result affect your life expectancy.
  • The genes that affect your brain may also affect the rest of your body. Some luckier people may just have better-built systems. The genes that build a healthier brain may also build healthier hearts, lungs, and so on.

These are just a few hypotheses that have been brought forward in the science community, but the truth is… We don’t know for sure. We know IQ can be used as a predictor for many things—as mentioned in this article, it can be used as a predictor for smoking, getting into car accidents, or dying in general—but we don’t know exactly why this is the case.

But you don’t need to know why to start using this correlation to your advantage. The great news is that IQ is not fixed, and there are many science-based ways to increase it, even as an adult.

Four ways to get smarter

One of the reasons why many people are against IQ tests is because they believe IQ is supposed to be a fixed measure of intelligence. It’s not. It’s just a snapshot of one’s intelligence taken at a specific point in life. Anyone can get smarter by stimulating their brain in the right way. And no, listening to Mozart won’t work. Unfortunately, raising your IQ will take a bit more effort than that.

  1. Meditation. Many studies have shown that meditating has positive effects on cognition. You can start seeing these effects with as little as 20 minutes of daily meditation. If you’re struggling to build a meditation habit, try an app such as Headspace or Calm and go through their introductory meditation course.
  2. Playing an instrument. Research by the University of Zurich showed that becoming proficient in a musical instrument can raise the IQ of both adults and children. And I’m not talking about insignificant gains. Playing music can raise your IQ by 7 points or more.
  3. Learning a new language. You know how hard it is to learn a new language? It’s because it’s actually changing the fundamental connections inside your brain. By navigating a new set of complex rules, learning a new language forces cortical thickening and increases the volume of your hippocampus. The great thing is that it also helps you with other language tasks like reading, negotiating, and problem-solving.
  4. Sleeping. Ha, finally one that doesn’t require too much effort. Research from the Loughborough University’s Sleep Research Centre found that every hour less than eight hours of sleep a night can knock off a full point from your IQ. In fact, not sleeping enough can make people perform at work at the same level as someone with a learning disability.

Other tactics you can use to increase your IQ include playing chess and exercising. Next time someone tells you IQ tests are bullshit, remember: they are just a snapshot of how well you’re taking care of your brain, right now. Put another way, IQ tests are a measure of your current intelligence. Intelligence is not fixed, and it can be fostered with the right strategies. Anyone can get smarter—and live longer.

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