When you can’t fall asleep because you’re too stressed, counting sheep might not be enough. Instead, experts suggest a simple mental trick that can quiet even the busiest thoughts. They know because they use it themselves.

The technique is called “cognitive shuffling,” and it’s a mental exercise that gives your brain something neutral and mildly engaging to focus on, so it can drift toward sleep instead of churning. Here’s what to know—and how to tell if it might work for you.

What is cognitive shuffling?

The concept was introduced more than a decade ago by Dr. Luc Beaudoin, a cognitive scientist, who was initially inspired by his own struggles with insomnia.

Here’s how it works: Once you go to bed—following your normal routine—pick a word that doesn’t carry much meaning to you and is five to 12 letters long. “The word should be emotionally neutral, so not something tied to stress or strong feelings,” says Patricia B. Pedreira, a health psychologist and postdoctoral associate at Duke University Medical Center who specializes in behavioral sleep medicine. “We want to avoid words like ‘money’ or ‘deadline’ or anything that might trigger worry chains.” Some of her favorites: blanket, garden, bedtime, and kitchen.

With your word in hand, work through it letter by letter, generating as many unrelated words as you can think of for each one. For example, if you chose “bedtime,” your shuffling might look like this: B: butterfly, basket, bagel. E: envelope, Egypt, emerald. (In practice, you’d keep going until you run out of ideas.) “The key is keeping them unrelated,” Pedreira says. “If your brain starts making connections or building a story, it defeats the purpose.”

Each time you name a new word, spend a few moments visualizing it. If you landed on the word “goat” for G, for example, “you’d briefly visualize the goat,” Pedreira says. “You don’t have to worry too much about creating an elaborate mental picture with perfect detail. Just a mental snapshot is OK.” Hold the image for a few seconds, and then move on to the next letter.

Ideally, you won’t finish the whole word—you’ll have drifted off to dreamland. “You might fall asleep mid-letter, you might make it through the whole word, you might lose track of where you are,” Pedreira says. “That’s actually fine. The point isn’t to complete the word perfectly.” If you do make it to the end of your word still wide awake, just pick another one and start again.

And if you find yourself getting stuck or looping back to the same words, the issue might be your starting pick. Try to avoid words with repeating letters, suggests Nina Kaiser, a psychologist in San Francisco who teaches cognitive shuffling to the kids and adults she treats. Once you’ve cycled through every word you can think of that starts with O, hitting another O later in the word means generating that same list all over again—and your mind is more likely to drift. That rules out “Google,” for example, with its two Gs and two Os, and makes a word like “planet,” with six distinct letters, a strong pick. 

Why it works

When your brain is busy reliving or processing what happened over the course of the day, those thoughts can keep you stuck in an alert, problem-solving mode that’s incompatible with sleep. “Your job is to change the channel and refocus on something that’s more likely to help you fall asleep,” Kaiser says. “You’re refocusing on something that’s going to be boring as opposed to stimulating—you’re giving your brain a specific task instead of just trying to say, ‘Don’t think about the thing you’re worried about.’” 

The technique also gives you something to do besides tossing and turning as you watch the minutes tick by. “It provides an alternative to lying in bed ruminating,” Pedreira says. “It gives people something active and constructive to do instead of watching the clock.”

There’s a neurological reason it works, too. During the day, your brain is dominated by faster brain waves associated with focused, attentive thinking; as you fall asleep, those give way to slower, more meandering ones. “It’s a gentle shifting into a more loose, gentle, kind of random-flowing state,” says Sarah Gray, a psychologist and instructor at Harvard Medical School who specializes in cognitive behavioral therapy for insomnia. Cognitive shuffling helps your brain make that shift instead of staying stuck in problem-solving mode.

That’s also why the technique tends to work better than counting sheep, Gray says. Counting is so monotonous that the mind quickly loses interest, leaving room for the day’s stressors to come rushing back. Cognitive shuffling, by contrast, gives the brain just enough to do—coming up with a word, holding a letter, generating items, picturing each one—without revving it up. The visualization piece is especially key: Briefly imagining each object gives the brain enough to occupy itself that intrusive thoughts can’t easily slip back in. “It really does help the brain get distracted and shift its focus to something a little softer and looser,” she says.

Who will benefit most

Cognitive shuffling works best for people who are having trouble falling asleep because of rumination and racing thoughts. “I see this a lot in people who are otherwise healthy sleepers, but they bring stress to bed with them,” Pedreira says.

In other words, it’s not a fix for everything that disrupts sleep. Cognitive shuffling won’t address chronic insomnia disorder, sleep apnea, restless leg syndrome, circadian rhythm disorders, or insomnia tied to medication side effects or hormonal changes—all of which need medical management. It also tends not to work as well for people with aphantasia, a condition in which it’s difficult or impossible to generate mental imagery, Pedreira says. The same goes for anyone who finds visualization mentally effortful in a way that feels alerting rather than relaxing.

One thing to watch out for: Don’t turn cognitive shuffling into homework. “If someone approaches it with the idea that ‘I must do this perfectly, I must visualize with perfect detail,’ that defeats the purpose,” Pedreira says. “This technique should really feel easy and gentle, not like a test.”

If you don’t drift off in the first few minutes, don’t panic—and definitely don’t start watching the clock. “It’s actually very normal to be awake and have a bit of an active brain for 10 to 15 minutes,” Gray says. The trouble starts when people fixate on not falling asleep instantly, because the worry itself keeps them up. That’s exactly the window cognitive shuffling is built for: Something low-key to do while your brain settles, instead of one more thing to stress about.