It鈥檚 not just babies who like being rocked to sleep. Adults that are gently rocked fall asleep quicker and have a higher quality nap.
So say a team led by Sophie Schwartz and of the University of Geneva, Switzerland, who asked 10 men to take two 45-minute afternoon naps, one on a bed that rocked gently and one on a static bed.
Patterns of brainwaves monitored by an EEG while they slept revealed that it took 3 minutes to fall asleep when being rocked, about 30 to 40 per cent faster than in a static bed.
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Rocking also helped the volunteers sleep more deeply; they spent 25 to 30 per cent longer in 鈥淣2鈥� sleep, the deepest stage you reach in a nap. The quality of N2 sleep improved too, as shown by a higher density of brain activity bursts called spindles. Spindle density is linked to memory improvement and insulation from noise disturbance.
The team say rocking may help to synchronise sleep-related brainwaves in the thalamus and the cortex, possibly via input from the vestibular system in the inner ear, which monitors motion and balance.
Journal reference: Current Biology, DOI: 10.1016/j.cub.2011.05.012
When this article was first posted, we failed to mention that Sophie Schwartz was one of the leaders of the team. The time taken for men being rocked to fall asleep was also given incorrectly, and we referred to the hypothalamus rather than the thalamus in the final paragraph.
