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Table of Contents

  • The Biggest Effects Come From Removing What's Holding Scores Down
  • Education: The Most Consistently Documented Causal Effect in Adults
  • Sleep: The Most Underrated Short-Term Factor
  • Exercise: Real but Moderate Gains Over Time
  • What Doesn't Work, Despite the Marketing
  • The Honest Summary by Magnitude
  • The Takeaway
  • References
Jul 6, 2026Β·General IQ & Intelligence

What Raises Your IQ Score the Most?

Does working out actually make you smarter? Discover how exercise impacts your IQ score and cognitive performance. Read our guide and try the RIOT test!

Dr. Russell T. WarneChief Scientist
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What Raises Your IQ Score the Most?

This is one of the most searched questions in the intelligence literature and one of the most frequently answered badly. The popular internet version of the answer is usually a list of brain games, supplements, and lifestyle hacks that overstate the evidence considerably. The actual scientific answer is more grounded, more specific about timing and magnitude, and more useful for anyone who genuinely wants to understand what moves the needle on cognitive performance and the results on IQ tests.

The short version: the interventions with the largest documented effects on IQ are not cognitive training apps or nootropics. They are education, early childhood nutrition, and for individuals in states of deficiency or deprivation, correcting those deficits. For adults in reasonably healthy conditions, the factors with the clearest evidence are sustained aerobic exercise, adequate sleep, and continued intellectual engagement. And the scale of what's achievable differs dramatically depending on whether you're starting from deficit or baseline.


The Biggest Effects Come From Removing What's Holding Scores Down



Before discussing what raises IQ, it's worth being precise about a distinction the literature makes consistently. The largest measured IQ gains don't come from enrichment above a healthy baseline β€” they come from correcting deficits that have been suppressing cognitive development below its potential. The size of those corrections can be enormous.

Iodine deficiency is the single largest cause of preventable cognitive impairment worldwide. Iodine deficiency results in a global loss of 10–15 IQ points at a population level and constitutes the world's greatest single cause of preventable brain damage. The mechanism is clear: adequate iodine is required for thyroid hormone production during fetal and early childhood brain development, and even mild gestational iodine deficiency produces measurable cognitive and educational deficits that persist into adolescence. A study of children with moderate iodine deficiency found a Full-Scale IQ deficit of 15.13 points compared to adequate-iodine peers, with significant impairments across 6 of 13 WISC-III subtests. Correcting iodine deficiency through supplementation or salt iodization in affected populations produces some of the largest average cognitive gains documented in any intervention study.

Early childhood malnutrition and stunting operates through a similar mechanism. A meta-analysis of studies in low- and middle-income countries found that each unit increase in height-for-age z-score in infants under 2 years was associated with a 0.24 standard deviation increase in cognitive ability at ages 5–11, measured across IQ, executive function, reasoning, language, and academic performance. The implication is that adequate nutrition during the first 1,000 days of life or when the brain is growing most rapidly has lasting cognitive consequences that no subsequent intervention can fully reverse.

For individuals in developed countries without nutritional deficiency, the starting point is different and the gains from correction are correspondingly smaller. This doesn't mean nothing works β€” it means expectations need to be calibrated appropriately.


Education: The Most Consistently Documented Causal Effect in Adults

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Dr. Russell T. WarneChief Scientist

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Table of Contents

  • The Biggest Effects Come From Removing What's Holding Scores Down
  • Education: The Most Consistently Documented Causal Effect in Adults
  • Sleep: The Most Underrated Short-Term Factor
  • Exercise: Real but Moderate Gains Over Time
  • What Doesn't Work, Despite the Marketing
  • The Honest Summary by Magnitude
  • The Takeaway
  • References
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For individuals past the critical early developmental window, the intervention with the most consistent, causally documented effect on IQ is formal education.

Using compulsory schooling reforms as natural experiments β€” policy changes that forced some cohorts to stay in school longer than others, creating a near-random assignment to additional education β€” researchers have established a causal estimate: an additional year of schooling at age 18 causes approximately 1/4 of a standard deviation increase in IQ, equivalent to roughly 3–4 IQ points. Norwegian data using the same design documented 3.7 IQ points per additional year. Swedish data replicated this finding. These are not correlational estimates that might reflect smarter people choosing to stay in school longer β€” they are causal estimates derived from policy variation that affected students regardless of their own choices.

Early childhood education shows even larger effects in disadvantaged populations. A longitudinal study from an Indian birth cohort found that structured early childhood education of 18–24 months was associated with higher total IQ scores of 4.66 points compared to no early childhood education, with effects persisting to age 12 after controlling for maternal cognition, socioeconomic status, and stunting. High-quality birth-to-5-year early childhood education programs in disadvantaged low- and middle-income environments yield an estimated 13.7% annual return, with a benefit-cost ratio of 7.3.

The relationship between education and intelligence is also bidirectional. Mendelian randomization evidence finds strong causal effects in both directions β€” greater intelligence increases educational attainment, and greater educational attainment increases intelligence β€” with similar magnitudes in each direction. Education doesn't just expose you to more information; it trains the analytical habits, working memory processes, and abstract reasoning strategies that IQ tests directly measure.


Sleep: The Most Underrated Short-Term Factor



If there's one factor that the IQ preparation literature consistently underemphasizes, it's sleep. The evidence for what sleep deprivation does to cognitive performance β€” across domains that IQ tests directly assess β€” is substantial and sobering.

A 2024 study using EEG and spatial working memory tasks across a 36-hour sleep deprivation protocol found that after 24 hours of deprivation, both behavioral performance and neural ERP amplitudes declined significantly, with effects progressing across measurement points. A large randomized study of 182 participants found that one night of total sleep deprivation led to performance impairments across attention, arithmetic ability, episodic memory, and working memory, which are all domains directly sampled by a professional IQ battery.

A three-month longitudinal study of medical students found that sleep-deprived students showed significant reductions in tonic alertness, selective and sustained attention, and cognitive inhibition. The cognitive domains hit hardest by sleep deprivation, including attention, working memory, and executive function, are precisely the domains most heavily weighted in modern IQ assessments.

The practical implication is direct: a test-taker who sleeps well the night before an IQ assessment and one who doesn't are not measuring the same cognitive baseline. The well-rested score is more accurate. The sleep-deprived score is a depressed reading, not a true one. This applies in both directions: adequate sleep before testing is likely to recover several IQ points that chronic mild sleep restriction has been quietly suppressing.


Exercise: Real but Moderate Gains Over Time



I covered the exercise-IQ relationship in detail in the previous article in this series, so I'll be brief here. The relevant summary is this: sustained aerobic exercise produces real, measurable improvements in cognitive function through hippocampal neurogenesis and BDNF elevation, with the largest effects documented in children and adolescents. A 2025 Bayesian network meta-analysis of 15 RCTs found small-to-moderate improvements in general intelligence (SMD = 0.59), fluid intelligence (SMD = 0.43), and crystallized intelligence (SMD = 0.64) attributable to exercise interventions.

In adults, the effects are smaller and concentrate primarily on processing speed, working memory, and executive function rather than on fluid reasoning broadly. The realistic IQ gain from sustained aerobic exercise for a healthy adult is likely in the 2–5 point range under favorable conditions β€” meaningful, but not transformative. What exercise does more reliably is protect cognitive function over time, particularly in aging populations where it shows some of the strongest evidence for slowing decline.


What Doesn't Work, Despite the Marketing



Given how much money is spent on cognitive enhancement products, it's worth being direct about what the evidence does not support.

Commercial brain training apps β€” Lumosity, Elevate, and similar products β€” consistently fail to demonstrate transfer of training to untrained cognitive tasks. The distinction between near transfer (getting better at the trained task) and far transfer (getting better at general cognitive ability) is crucial here, and the evidence for far transfer from brain games is weak to nonexistent. The FTC charged Lumosity with deceptive advertising in 2016 specifically because the company overstated the cognitive benefits of its product beyond what the science supported.

Most nootropic supplements β€” including ginkgo biloba, omega-3 supplements in non-deficient populations, and the vast majority of marketed "brain pills" β€” show no reliable effect on IQ in healthy adults with adequate baseline nutrition. Omega-3 supplementation in populations already meeting dietary requirements does not raise IQ scores. In populations with genuine deficiency, correction does help β€” which is consistent with the deficit-correction principle above, not with the enrichment-above-baseline claim that supplement marketing relies on.

Listening to classical music β€” the so-called Mozart Effect β€” was based on a single 1993 study showing a temporary, small improvement on one spatial reasoning task after listening to Mozart. It did not replicate reliably, the effect was short-lived, and it has no meaningful application to long-term IQ development. The research consensus abandoned the Mozart Effect claim more than a decade ago.


The Honest Summary by Magnitude



Ranked by documented effect size on IQ-relevant cognitive measures:

Largest effects: Correcting iodine deficiency (10–15 IQ points at population level); correcting early childhood malnutrition; treating lead poisoning (which suppresses IQ by 1–5 points per 10 ΞΌg/dL blood lead concentration).

Large effects: Formal education, particularly in the early years: approximately 3–4 IQ points per additional year of schooling based on causal estimates. High-quality early childhood education in disadvantaged populations: 4–7 points.

Moderate effects: Sustained aerobic exercise over months: approximately 2–5 points, concentrated on processing speed and executive function. Correcting chronic sleep deprivation: recovering 2–5 points that deprivation has suppressed.

Small but real effects: Acute aerobic or resistance exercise immediately before testing: improved processing speed and working memory within the session. Bilingualism and continued language learning: associated with executive function advantages, particularly cognitive flexibility.

No reliable effect in healthy populations: Brain training apps, most commercial supplements, listening to music, passive mental stimulation without active learning demands.


The Takeaway



The factors that raise IQ scores the most are not the ones the supplement industry or brain-training market wants to sell you. They are adequate nutrition in early development, formal education that builds abstract reasoning skills, sufficient sleep, and sustained aerobic exercise β€” in roughly that order of magnitude. For adults in healthy conditions, the realistic ceiling for environmental intervention on general cognitive ability is probably 5–10 points under optimal conditions. That's meaningful β€” but it's a very different claim from the 20–30 point improvements implied by some cognitive enhancement marketing.

The most honest framing is this: your measured IQ on any given day reflects your genuine cognitive capacity minus whatever environmental deficits are currently suppressing it. Sleep deprivation, chronic stress, poor nutrition, and sedentary lifestyle are all suppressors. Addressing them doesn't create new cognitive capacity; it removes the ceiling that's been keeping your actual performance below your potential.

If you want to measure your current baseline before or after making any of these changes, the RIOT gives you a domain-level profile that shows exactly where your performance sits across fluid reasoning, working memory, processing speed, and other key cognitive indices.


References



  1. PubMed Central. (2012). Fortified Iodine Milk Improves Iodine Status and Cognitive Abilities in Schoolchildren. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4812403/

  2. PubMed Central. (2022). Iodine Intake and Related Cognitive Function Impairments in Elementary Schoolchildren. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9599038/

  3. arXiv / Signaling and Employer Learning. (2021). Causal Effect of Education on IQ: Norwegian compulsory schooling reform estimates. https://arxiv.org/pdf/2103.04123

  4. medRxiv. (2025). Persisting influence of structured early childhood education exposure on pre-adolescent cognition β€” Evidence from an Indian birth cohort. https://www.medrxiv.org/content/10.1101/2025.10.20.25338401.full.pdf

  5. PubMed Central. (2024). Non-Linear Effects of Acute Sleep Deprivation on Spatial Working Memory: Cognitive Depletion and Neural Compensation. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11763834/

PubMed Central. (2021).
Quantifying Cognitive Impairment After Sleep Deprivation at Different Times of Day.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8076531/


  • PubMed Central. (2021). Sleep deprivation effects on basic cognitive processes: attention, working memory, and executive functions. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8340886/

  • PubMed Central. (2025). Optimal exercise modalities and dose for enhancing intelligence in children and adolescents: a Bayesian network meta-analysis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12851973/