Are puzzles good
for your brain?

Yes, in the sense that they are an engaging way to use attention, memory and reasoning for a few minutes. Probably not, in the sense most people mean: there is no good evidence that puzzles raise intelligence or prevent dementia. Here is what the studies show, in order of how much they can bear.

The association is real and large

The PROTECT study asked 19,078 healthy adults aged 50 to 93 how often they did word puzzles and number puzzles, and tested them on nine measures of cognition.^{[1] [2]} The more often people puzzled, the better they scored, on every test. Frequent solvers performed like people eight to ten years younger on measures of reasoning and short-term memory. The relationship held for both word and number puzzles.

Why association is not cause

PROTECT measured habits and cognition at the same moment. It cannot tell whether puzzles sharpen people or sharper people are drawn to puzzles. Both are probably true to some degree. The authors say so. The study is strong evidence that puzzling and good cognition go together in later life; it is not evidence that starting puzzles will change your test scores.

What happens when you train

The largest review of brain-training research, covering 132 studies, concluded that training reliably improves the trained task and sometimes very similar tasks, with little evidence of transfer to distant tasks or daily life.^[3] Puzzles are training. Do a lot of sudoku and you get better at sudoku and perhaps at other constraint-elimination tasks. Expect improvement to stay close to home.

One randomised trial stands out: 107 adults with mild cognitive impairment did either web-based crosswords or computerised cognitive games for 78 weeks.^[4] The crossword group declined less on a standard cognitive scale, did better on daily functioning and lost less brain volume on MRI. That is a real experimental result in favour of a puzzle, in a specific population, against an active comparator rather than against nothing.

The bigger picture: reserve and risk

In the Rush Memory and Aging Project, people who reported more cognitive activity across their lives declined more slowly, and the difference was not explained by the amount of disease found in their brains at autopsy.^[5] This is the idea of cognitive reserve: an engaged life builds capacity to cope with age-related change. Puzzles are one small form of engagement among education, work, reading, learning and social life.

The 2024 Lancet Commission lists fourteen modifiable risk factors that together account for around 45 percent of dementia cases.^[6] Puzzles are not on the list. Hearing loss, high LDL cholesterol, depression, inactivity, diabetes, smoking, hypertension, obesity, alcohol, head injury, social isolation, air pollution, vision loss and low education are. If you have time for one change, the evidence points there first. The Global Council on Brain Health recommends cognitively stimulating activity that is novel, challenging, engaging and enjoyable, and rates learning a genuinely new skill above any brain game.^[7]

A fair answer

Do puzzles because you enjoy them. They are a good way to spend a few minutes thinking, they keep skills in use, and frequent puzzlers do tend to test well. Do not do them as medicine, and do not let them crowd out the things with stronger evidence. If you want the daily habit, Brisk’s six-question challenge takes two minutes, mixes words, numbers and patterns, and promises nothing about your brain.