Falling asleep is easy for some people; not so much for others. If you’re in the latter camp, perhaps you rely on strategies such as counting sheep or drinking warm milk or chamomile tea before bed (with varying degrees of success). Now you can add a new tactic to your list, or, rather, an old one that was recently backed by some science—something parents around the world have been doing for millennia to lull their babies to sleep: rocking.
In a Swiss study in Current Biology, 18 healthy young adults slept one night in a bed that gently rocked and another night in a bed that was motionless (in random order), while their brain activity was monitored. Turns out that when they slept in the rocking bed, they fell asleep faster, slept more deeply, woke up less often, and reported better sleep quality, compared to when they slept in the stationary bed. They also had better memory the morning after sleeping in the rocking bed, recalling three times as many word pairs that they were presented with the night before.
In addition, the researchers found that the continuous rhythmic sensory stimulation of the rocking synchronized activity in the thalamus and cortex, parts of the brain that are key in both sleep and memory consolidation.
Some of the same researchers published a study in the same journal in 2019, in which—picture this—mice who were rocked fell asleep faster and had fewer awakenings. When the researchers measured the vestibular center that’s involved with balance, they found that the sleep benefits were related to this spatial sensory system. Of course, what helps a little mouse go to sleep and stay asleep may have minimal or no relevance to humans, but it’s known that neural information is transmitted between the vestibular center and the thalamus and cortex in all mammals, including mice and humans.
More research is needed to confirm these rock-a-bye benefits, whether they would last over time, and whether they apply to people who have actual sleep problems. But if you have too many sleepless nights and want to give rocking a try, various “rocking bed” options can be found online, though mostly in prototype stage; one company makes an expensive rocking bed frame that retrofits to your existing mattress. The least expensive option is a hammock, though that might only help you fall asleep, not stay asleep, since the rocking motion will quickly cease (and you have to propel it yourself)—unless you attach an automatic rocking device to it (sold by some vendors online). Hammocks come in all sorts of materials and sizes; hammocks on stands are more stable than those anchored to walls or ceilings.
Also see Are You Sleep Smart?