Health2026-07-21
Sudoku at 3AM: Why Puzzles Help Insomnia
When counting sheep fails, I reach for a number grid. Here is how sudoku became my unlikely insomnia remedy and what the research actually says about it.
I have been an insomniac for as long as I can remember. Not the dramatic kind that involves staring at the ceiling and weeping into the darkness. The boring kind. The kind where you lie in bed, reasonably comfortable, and your brain just refuses to power down. It runs through tomorrow's to-do list, replays that awkward thing you said in 2019, and occasionally wonders whether you left the garage door open. Standard fare.
For years, my solution was my phone. I would scroll Twitter, read Wikipedia articles about obscure wars, or watch YouTube videos until my eyes burned. It worked in the sense that I eventually fell asleep. It did not work in the sense that I was getting four hours of low-quality rest and waking up feeling like a ghost piloting a meat suit made of regret.
Then, about six months ago, a friend told me she does sudoku when she cannot sleep. No screen. Just a book, a pencil, and a grid of numbers. I was skeptical. Sudoku is work. It is math-adjacent. How is that going to help you relax?
Turns out, it is exactly why it works.
There is a concept called "cognitive load theory" that explains a lot about insomnia. When you cannot sleep, your brain is usually in what psychologists call a "hyperaroused" state. You are thinking about too many things at once. Your brain is a web browser with seventeen tabs open, and three of them are playing videos. The problem is that you cannot just tell your brain to stop. The classic advice — "just relax" — is like telling someone to not think about a pink elephant. It backfires immediately.
Sudoku works because it provides a single, contained cognitive demand. You cannot solve a sudoku puzzle while also worrying about your mortgage. The puzzle demands just enough mental bandwidth to crowd out the anxiety, but not so much that it keeps you alert. It is the Goldilocks zone of brain engagement.
I started keeping a sudoku book on my nightstand about four months ago. Here is what I noticed. First, the transition from "phone brain" to "puzzle brain" is immediate. There is no glow, no notification, no infinite scroll. Just a grid and a number two that you are pretty sure goes in the top-right corner but you need to double-check the row. It is meditative in a way I did not expect.
Second, I started falling asleep faster. Not dramatically faster — I am not cured — but consistently faster. My rough estimate is that I went from lying awake for 60-to-90 minutes to about 20-to-30 minutes. That is a huge quality-of-life improvement. It means I lose less time to the spiral. I do a puzzle or two, and somewhere around the second or third grid, my brain decides it is safe to power down.
There is actually some research backing this up. A 2019 study from the University of Cambridge found that older adults who regularly did word and number puzzles had better cognitive function, but the insomnia connection is more anecdotal. Occupational therapists sometimes recommend puzzles as part of "sleep hygiene" routines because they provide a structured, low-stimulation activity that bridges wakefulness and sleep. It makes sense. Your brain needs a ramp, not a cliff.
A few tips if you want to try this. Get a physical book. Screens mess with melatonin production, so the whole point is to avoid them. Use a pencil, not a pen, because you will make mistakes and erasing is part of the calming ritual. Start with easy puzzles. Hard ones will frustrate you and keep you awake. I do "medium" difficulty and it hits the sweet spot. And stop when you feel drowsy. The goal is not to finish the puzzle. The goal is to fall asleep.
I still have bad nights. Insomnia does not really go away. But having a pencil and a grid of numbers next to my bed has made those bad nights shorter and less miserable. And honestly, that is enough.