Like a baby, being rocked can help you sleep, but it might also improve your memory, new research suggests.
Two studies, one in humans and the other in mice, report that being rocked has real benefits for sleep.
Fewer arousals during the night
"Having a good night's sleep means falling asleep rapidly and then staying asleep during the whole night," said study author Laurence Bayer, of the University of Geneva in Switzerland.
"Our volunteers – even if they were all good sleepers – fell asleep more rapidly when rocked and had longer periods of deeper sleep associated with fewer arousals during the night. We thus show that rocking is good for sleep," he said in a news release from the journal Current Biology.
Bayer has already shown that continuous rocking during a 45-minute nap helped people fall asleep faster and sleep more soundly.
In the new study, the researchers recruited 18 healthy young adults. The first night in the sleep lab got them used to sleeping there.
The next two nights, participants slept on a gently rocking bed or an identical bed that wasn't moving. Participants fell asleep faster while rocking. Once asleep, they also slept more deeply and woke up less.
Brain activities synchronised
To assess memory, participants studied word pairs. The researchers then measured their accuracy in recalling those paired words in an evening session compared with the next morning.
People did better on the morning test when they were rocked during sleep, the researchers found.
Additionally, the studies found that rocking affects the brain during sleep. Continuous rocking helped to synchronize brain activities that are important in both sleep and memory.
A study in mice found that rocking helps sleep in other species.
Researchers led by Paul Franken of the University of Lausanne in Switzerland used shakers to rock the cages of mice as they slept.
The scientists found that rocking reduced the time it took the mice to fall asleep and increased sleep time as it did in humans. The mice, however, didn't sleep more deeply.
New approaches for treating insomnia
Researchers suspected that the effects of rocking were tied to rhythmic stimulation of the vestibular system, which contributes to the sense of balance and spatial orientation.
When they looked at mice with disabled vestibular systems, the animals experienced none of the beneficial effects of rocking.
These findings may be relevant in developing new approaches for treating insomnia and mood disorders. They may also help older adults, who often suffer from poor sleep and memory.
It will be essential to explore the precise deeper brain structures that are affected by rocking, the researchers said.
Here's the "rocking bed" used in the study:
Image credit: iStock