‘Hammock’ effect or ‘rocking’ helps adults fall asleep faster

You’re lying in a hammock on a warm afternoon. You rock softly back and forth. In no time you’re … snoring. This is no real surprise—after all, we’ve all rocked our babies asleep. But researchers wanted to know how rocking works.

So, they did a study. They recruited 12 healthy males—all of who were said to be “good sleepers.” Each volunteer twice took an afternoon nap in a dark room on a custom-made bed that could rock. For one nap, the bed was still. For the other, it rocked gently.

The Swiss researchers reported in journal Current Biology that “gentle rocking can improve one’s quality of sleep.” The finding may offer hope for those suffering from sleep problems, the authors suggested.

HealthDay News reported, “like infants, adults find it easier to nap on a slowly swinging bed.”

“It is a common belief that rocking induces sleep: we irresistibly fall asleep in a rocking chair and, since immemorial times, we cradle our babies to sleep,” study co-author Sophie Schwartz, of the University of Geneva, said in a news release from the journal’s publisher.

“Yet, how this works had remained a mystery. The goal of our study was twofold: to test whether rocking does indeed soothe sleep, and to understand how this might work at the brain level.”

The investigators found that rocking worked by lengthening the duration of stage N2 sleep, which is a form of non-rapid eye movement sleep that accounts for about half of a good night’s sleep.

The rocking also promoted brain activity associated with deep sleep.

Looking ahead, the study authors noted that more research is needed to determine whether or not rocking can improve more than just naps. This type of motion, they pointed out, may help in the treatment of troubling sleep disorders, including insomnia.

The researchers added that rocking may also benefit memory consolidation and potentially help people who’ve suffered from brain damage by improving brain repair mechanisms.

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