Is Sudoku Good for Your Brain? What Studies Show

Probably yes, in a modest way, but not in the way most headlines claim. Large studies find that adults who do puzzles like sudoku often score better on memory and reasoning tests, and people who keep up mentally active hobbies in later life have a somewhat lower dementia risk. Those studies show an association, not proof that sudoku causes the benefit. No trial has shown that sudoku prevents dementia, raises IQ or makes you better at tasks outside the puzzle. It is a good, cheap way to keep your mind busy, and that is about as far as the evidence goes.

Below is what each of the main studies measured, what it found, and where its limits are. We cite the papers directly, so you can check every number.

The short version

Puzzle solvers score better on memory and reasoning tests

The most cited sudoku study comes from the PROTECT online cohort run by the University of Exeter and King's College London. Helen Brooker and colleagues asked 19,078 cognitively healthy adults aged 50 to 93 how often they did number puzzles such as sudoku, then gave them a battery of 14 cognitive tests. People who did number puzzles more often did better on every measure, and those who never did them did worst (Brooker et al., International Journal of Geriatric Psychiatry, 2019). A companion paper found the same pattern for word puzzles (PMID 30443984).

You may have seen the line that puzzle fans have a brain "10 years younger". That figure comes from the university press release, and it describes word puzzles on a grammatical reasoning test, not sudoku. The release converts score differences into "years", which the papers themselves do not headline.

The bigger caveat is direction. This is a snapshot, so it cannot tell whether puzzles sharpen people or whether sharper people enjoy puzzles. The lead author said so herself: "We can't say that playing these puzzles necessarily reduces the risk of dementia." Independent experts made the same point in the Science Media Centre reaction.

Sudoku leans on working memory

When you hold "this cell can only be 3 or 7" in your head while scanning a box, you are using working memory. Jeffrey Grabbe tested this directly and found that sudoku performance tracked working memory scores in both younger and older adults (Grabbe, Activities, Adaptation & Aging, 2011). That tells us sudoku exercises the skill. It does not show that practising sudoku improves working memory elsewhere.

You can lower the load by writing candidates down, which is what pencil marks are for, or raise it by solving without notes.

Does sudoku help prevent dementia?

No study shows that sudoku prevents dementia. What exists are cohort studies linking mentally active leisure to lower risk.

• Wu et al. 2023. A Monash University team followed 10,318 Australians aged 70 and over for about ten years. People who regularly did active mental activities such as games, cards, chess, puzzles and crosswords had an 11% lower dementia risk (hazard ratio 0.91), and adult literacy activities like writing letters or journals went with a similar reduction (JAMA Network Open, 2023).
• Verghese et al. 2003. In 469 people over 75 followed for a median of five years, each extra "activity-day" per week of cognitive leisure lowered dementia risk by about 7% (hazard ratio 0.93). Reading, board games, playing music and dancing stood out (New England Journal of Medicine, 2003).
• Lancet Commission 2024. The commission's list of 14 modifiable risk factors does not include puzzles, but its first recommendation is to encourage cognitively stimulating activities in midlife (Livingston et al., The Lancet, 2024).

Both cohort studies share the same weakness. The early, silent stage of dementia can make people drop hobbies years before diagnosis, so part of the link may run backwards. The honest reading: keeping mentally active is sensible and low-risk, and sudoku is one of many ways to do it.

Will sudoku make you smarter?

You will get better at sudoku. Evidence that the gain spreads to other kinds of thinking is weak. A review of the brain-training literature by Daniel Simons and colleagues found that training improves the trained task, sometimes closely related tasks, and rarely anything further away (Psychological Science in the Public Interest, 2016). Timothy Salthouse reached a similar view on the "use it or lose it" idea: active people score higher, but little evidence shows activity slows age-related decline (Salthouse, 2006). A study of crossword experts even found that years of crossword experience did not protect against age-related declines in reasoning speed (Hambrick et al., 1999).

Sudoku vs brain-training apps

In 2014, more than 70 scientists signed a consensus statement from the Stanford Center on Longevity saying there was no compelling evidence that commercial brain games improve everyday cognition. The AARP's Global Council on Brain Health called the evidence for "brain games" "weak to non-existent" and recommended activities that are new and challenging instead (GCBH, 2017).

One randomized trial compared the two directly. D.P. Devanand's team gave 107 people with mild cognitive impairment either crossword training or computerized cognitive games for 78 weeks. The crossword group did slightly better on the main cognitive score and on daily functioning (NEJM Evidence, 2022). The trial was small, the margin was narrow, and it tested crosswords, not sudoku. It does suggest ordinary puzzles hold their own against purpose-built apps.

Stress, sleep and anxiety

Many people find sudoku calming, and that is a fine reason to play. The research base here is thin. The one randomized trial we found gave 64 hemodialysis patients 20 minutes of sudoku three times a week for four weeks, and their anxiety scores fell compared with controls (Heydari et al., International Urology and Nephrology, 2026). That is a small, unblinded study in a specific patient group. We found no robust study on sudoku and sleep. If you play before bed, a dark theme and an app without ads or pop-ups at least removes the obvious distractions.

How to get the most out of it

• Keep it hard enough. The studies above point toward activities that stay challenging. Once a level feels automatic, move up one of the difficulty levels or learn a new technique such as the X-Wing.
• Make it regular. The dementia cohorts measured habits over years, not one-off sessions. A daily puzzle is an easy habit to keep.
• Mix it up. The strongest associations in Wu et al. and Verghese et al. covered a range of activities: reading, writing, music, games. Sudoku is one good ingredient.
• Do not skip the basics. The Lancet Commission's risk factors include hearing loss, high blood pressure, physical inactivity and social isolation. A puzzle habit does not replace any of those.

For how sudoku compares with word puzzles, see sudoku vs crossword.