Sleeping With a Partner Associated With Increased REM Sleep, Synchronization of Sleep Architecture

Couples sleeping together, as opposed to separately, was associated with increased rapid-eye movement (REM) sleep and greater sleep synchronization, potentially caused by a positive feedback loop, according to study findings published today in Frontiers in Psychology.

As the researchers note, although sharing a bed with a partner is common in most countries, there is a lack of research investigating bed sharing and sleep quality. Moreover, of the studies that have compared co-sleep with individual sleep, analyses only measured body movements and results have proven contradictory to sleep quality and associated mental health.

Researchers sought to address these data limitations by assessing both sleep quality and architecture in individual sleep and co-sleep. Participants included 12 young, healthy heterosexual couples who spent 4 nights in the sleep laboratory. The study measured individual sleep and co-sleep via dual simultaneous polysomnography, which lead study author Henning Johannes Drews, MD, of the Center for Integrative Psychiatry, touted as a “very exact, detailed and comprehensive method to capture sleep on many levels—from brain waves to movements, respiration, muscle tension, movements, heart activity."

The study cohort also completed questionnaires designed to measure relationship characteristics, such as duration, degree of passionate love, and relationship depth.

In the study findings, co-sleeping was associated with approximately 10% more REM sleep, less fragmented REM sleep (P = .008), longer undisturbed REM fragments (P = .0006), and more limb movements (P = .007) compared with sleeping individually.

Notably, the increased movement of limbs found in co-sleeping did not impair sleep synchronization, with those undergoing co-sleep shown to be more synchronized (P = .005) even if wake phases were excluded (P = .022).

"One could say that while your body is a bit unrulier when sleeping with somebody, your brain is not," said Drews. Sleep synchronization was also shown to be positively associated with relationship depth.

In reference to the findings observed in co-sleep, the researchers proposed a positive feedback loop where sleeping together enhances and stabilizes REM sleep. This could further prove beneficial for couples sleeping together, as REM sleep is known to improve social interactions and reduce emotional stress.

"Sleeping with a partner might actually give you an extra boost regarding your mental health, your memory, and creative problem-solving skills," added Drews.

Although promising, Drews highlights that future studies are warranted to examine more couples. "The first thing that is important to be assessed in the future is whether the partner-effects we found (promoted REM sleep during co-sleep) are also present in a more diverse sample (eg, elderly or if one partner suffers from a disease),” said Drews.

Reference

Drews HJ, Wallot S, Brysch P, et al. Bed-sharing in couples is associated with increased and stabilized REM sleep and sleep-stage synchronization. Front Psychiatry. Published online June 25, 2020. doi:10.3389/fpsyt.2020.00583