The Effect of a Slowly Rocking Bed on Sleep.
Level 3 - non-randomized controlled study
Controlled within-subject crossover experiment; randomization of night order is not specified in the abstract.
PubMed 29391413 · doi:10.1038/s41598-018-19880-3
What was done
Eighteen healthy males aged 20–28 years underwent nocturnal polysomnography under three separate night conditions: bed rocking until sleep onset (C1), bed rocking for the first 2 hours of sleep (C2), and a stationary baseline night (B). Researchers measured sleep onset latency, sleep architecture, slow oscillations, sleep spindles, and sleep-dependent memory performance using a word-pair learning task.
What was found
Rocking motion did not facilitate faster sleep onset or increase slow-wave oscillations. Active 2-hour rocking (C2) increased N2 sleep duration and total sleep spindle count during the stimulation window, but these increases did not persist over the entire night. Participants reported subjectively preferring the rocking nights. Overnight memory performance improved across all conditions with no significant difference between moving and stationary nights. Specific numerical values and effect sizes were not provided in the abstract, other than a baseline sleep efficiency of 96%.
Why it matters
Prior nap studies suggested vestibular stimulation enhances sleep depth and memory, but these data show that full-night nocturnal sleep architecture and memory consolidation in healthy, good sleepers are largely unaffected by slow bed rocking.
Limits
The study was small (n = 18) and limited exclusively to young healthy males. Baseline sleep efficiency was already at ceiling levels (96%), potentially masking benefits that might appear in poor sleepers. The abstract does not specify whether condition order was randomized or counterbalanced, nor does it provide quantitative effect estimates or variance measures.
Cited by
- context Slow rocking of a bed helps individuals fall asleep.