12 January 2020
Snoozing on a rocking bed can foster better sleep and improve overnight memory recall, reveals a new study that monitored the brainwaves of several participants as they were rocked to sleep.
The secret lies in inducing longer periods of ‘slow wave’ or deep sleep, according to a study published in Current Biology.
“We naturally rock babies to sleep. Yet, we also have plenty of anecdotal reports of adults falling asleep faster when in a train or a car, as well as reported feelings of relaxation in a hammock,” says Aurore Perrault, research co-author.
Researchers from the University of Geneva, and the University of Lausanne, recruited 18 participants who slept in the lab for three nights. The first night was intended to get them used to sleeping in a lab environment. They spent the second night on a rocking bed and the third on a stationary one.
The researchers recorded the participants’ brainwaves using an EEG or an electroencephalograph. In the evenings and mornings, they gave them word pairing exercises to test memory recall.
A whole night of gentle rocking made participants doze off faster, says Perrault. “[The motion] also boosts brain oscillations that are crucial for overnight memory consolidation processes.”
Brain electrical oscillations are micro-events that happen during sleep and which play a role in sleep regulation and memory processing. They can be affected by state of mind, and factors such as noise, heat, drug or alcohol intake prior to sleep, as well as health conditions such as chronic pain.
There are several frequency oscillations associated with sleep. Slow oscillation and spindles — bursts of brain activity that moderate responsiveness during sleep —have been linked with less wakefulness during the night, and memory improvement in the morning.
“Spindles and slow oscillations appear more or less frequently, depending on the sleep stage you are in,” explains Perrault.
The data shows gentle rocking increases the prevalence of slow spindles and oscillations and synchronizes their timing to the rocking cycle, making participants fall faster into deeper sleep, and stay asleep for the whole night.
It’s possible that these benefits can be extended to individuals with sleeping difficulties or insomnia, but a discussion of application is perhaps premature with the research still in its early stages. Perrault says that they first need to test the rocking bed on a larger sample of adults before results can be considered clinically significant.
Perrault, A. et al. Whole-Night Continuous Rocking Entrains Spontaneous Neural Oscillations with Benefits for Sleep and Memory. Current Biology 29, 402–411 (2019)| article