rewrite this title A Simple Technique to Help You Fall Asleep

Dr. Joe Whittington, 47, has been an emergency room physician for two decades, but he can still find it tough to quiet his mind after leaving the hospital.

As he tried to doze off after one particularly chaotic shift, he kept thinking about a victim of a motorcycle crash whose vital signs had tanked, a patient who developed sepsis and another whose heart had suddenly stopped beating.

His tendency to replay the night’s events — and his irregular work hours — often made it tricky for him to fall asleep. Over the years, he tried deep breathing, meditation and melatonin, before finally stumbling upon a technique called cognitive shuffling.

The sleep strategy helps to “force my mind out of that loop and into a state where I can finally rest,” said Dr. Whittington, who has shared it on his Instagram account, which has more than 750,000 followers.

“Cognitive shuffling” has been touted on social media for years, but does it really work? We spoke with sleep experts and the scientist who created the technique to learn more.

What is cognitive shuffling?

Cognitive shuffling is a mental exercise that involves focusing your mind on words that have no association with one another, as a way of signaling to your brain that it’s time to fall asleep. The task is meant to be engaging enough to distract you from the thoughts that may be impeding sleep, but not so interesting that your brain perks up.

You start by taking a random word — “Pluto,” for example. Then think of as many words as you can that begin with the same first letter, like so: “Plane, poodle, play, peaches.” When you run out of “P” words, you can move on to the next letter of your original word, which is “L,” and do the same thing: “Love, light, lemur, linger.” Take a second or so to visualize each word.

Research suggests that when people naturally drift off, their minds are often peppered with vivid images or distant thoughts, said Luc P. Beaudoin, a cognitive scientist and adjunct professor at Simon Fraser University in Canada who developed the cognitive shuffling technique. The goal is to help your mind mimic that process, he added.

“These images don’t create a clear story line and may help your brain to disengage from problem solving or worry loops,” said Dr. Beaudoin, who markets an app based on the technique.

How did the idea come about?

Dr. Beaudoin created cognitive shuffling more than 15 years ago in part because he was suffering from insomnia and wanted to find a solution.

In 2016, he and his colleagues decided to study it. They recruited about 150 students and assigned one group to do cognitive shuffling. A second group was asked to spend 15 minutes in the early evening jotting down their worries and any potential solutions, a method that psychologists refer to as constructive worry. A third group was told to do both.

After about a month, the researchers found that each of the methods was equally effective. But the participants who had tried both were more likely to rate cognitive shuffling as more helpful and easier to use.

Dr. Beaudoin’s study, which was featured in 2016 at the Associated Professional Sleep Societies conference in Denver, caught the eye of a journalist at Forbes who then wrote about it. Soon the concept circulated widely online.

Should you try it?

Possibly.

There’s not enough evidence to support using cognitive shuffling as a primary treatment for insomnia, said Dr. Jorge I. Mora, the associate chief of clinical affairs in the division of sleep medicine at the University of Pennsylvania.

“We need to study this more to be able to fully say, yes, this should be a consistent tool, like C.B.T.-I. is,” said Dr. Mora, referring to cognitive behavioral therapy for insomnia, a treatment that has been shown to help people who often struggle to fall or stay asleep.

But there is no harm in giving cognitive shuffling a try, provided that it is used as a complement to evidence-based methods, experts said.

“When it works, wow, it can really help some people,” said Shelby Harris, a clinical psychologist in the New York City area who specializes in behavioral sleep medicine.

As the technique has grown in popularity, people have created their own unique variations. Dr. Harris sometimes suggests that her patients come up with random cupcake combinations, like red velvet with vanilla frosting or chocolate with cream cheese frosting, until they drift off.

If you try cognitive shuffling and it isn’t working and you’re getting frustrated — or if you’re no sleepier after 20 minutes — Dr. Harris recommended getting up and finding something else to calm your mind.

She suggested doing a quiet activity in dim light — like stretching, coloring or working on a jigsaw puzzle — and then returning to bed when you feel sleepy.

“I even read old cookbooks — I collect them — and earmark things I eventually want to make,” Dr. Harris said. “It helps pass the time and acts as a place holder for the busy brain.”