In many countries, sharing a bed with a partner is common practice. Yet research on the relationship between bedsharing and sleep quality is both sparse and conflicting. Most studies have compared co-sleep to individual sleep in couples by measuring only body movements. However, Dr. Henning Johannes Drews of the Center for Integrative Psychiatry, Germany, and colleagues overcame these limitations by also assessing sleep architecture in couples who shared a bed.
The researchers conducted the study with 12 young, healthy, heterosexual couples who spent four nights in the sleep lab. They measured sleep parameters both in the presence and absence of the partner using simultaneous dual polysomnography, which is a very precise, detailed and comprehensive method for capturing sleep at many levels. “From brain waves to movement, to breathing, to muscle tension, to movement, to heart activity,” says Dr. Drews. In addition, participants completed questionnaires designed to measure relationship characteristics (e.g. duration of relationship, degree of passionate love, depth of relationship, etc.)
Sleeping Together: More Intense Dreams
The results showed that rapid eye movement (REM) sleep was both greater and less disrupted in couples who slept together than in those who slept individually. This finding is particularly relevant because REM sleep, which is associated with vivid dreams, has been linked to emotion regulation, memory consolidation, social interactions and creative problem solving.
Sleep together and dream together
The team also found that couples synchronize their sleep patterns when they sleep together. This synchronization, which is not related to the partners disturbing each other during the night, is positively associated with the depth of the relationship. In other words, the more participants rated the importance of their relationship in their lives, the stronger the synchronization with their partner.
Better emotional stability during the day
The researchers propose a positive feedback loop in which sleeping together improves and stabilizes REM sleep, which in turn improves our social interactions and reduces emotional stress. Although the researchers did not specifically measure these possible effects, Dr. Drews says that “because these are well-known effects of REM sleep, it is very likely that they would be observed if tested.”
Interestingly, researchers have found increased limb movement in couples who share the bed. However, these movements do not disturb the architecture of sleep, which remains intact. Dr. Drew says, “You could say that while your body is a little messier when you sleep with someone, your brain is not.”
Boost to mental health, memory and problem solving
Despite the small sample size, this research gives us a better understanding of couples’ sleep and its potential implications for mental health. Sleeping with a partner might actually give you an extra boost when it comes to your mental health, memory, and creative problem-solving abilities.”
Henning Johannes Drews et al: Bed-Sharing in Couples Is Associated With Increased and Stabilized REM Sleep and Sleep-Stage Synchronization, Frontiers in Psychiatry (2020). DOI: 10.3389/