Couples who spend the night in the same bed show increased REM sleep and synchronized sleep architecture.

In many countries, sharing a bed with a partner is common practice. However, research investigating the relationship between bed sharing and sleep quality is sparse and contradictory. Most studies have compared shared sleep with individual sleep in pairs measuring only body movements. However, Dr. Henning Johannes Drews of the Center for Integrative Psychiatry (ZIP), Germany and his colleagues overcame these limitations by also evaluating the sleep architecture of couples sharing a bed.

The researchers conducted the study among 12 young, healthy, straight couples who spent four nights in the sleep lab. They measured sleep parameters both in the presence and in the absence of the couple using simultaneous dual polysomnography, which is a “very accurate, detailed and comprehensive method of capturing sleep at many levels, from brain waves to movements, respiration, muscle tension, movement, heart activity, “says Dr. Drews. In addition, participants completed questionnaires designed to measure the characteristics of the relationship (eg, length of relationship, degree of passionate love, depth of relationship, etc.)

The results showed that rapid eye movement (REM) sleep increases and is less disrupted in couples who sleep together compared to when they 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.

The team also found that couples synchronize their sleep patterns when they sleep together. This timing, which is not linked to the fact that couples tease each other at night, is positively associated with the depth of the relationship. In other words, the higher the participants rated the importance of their relationship to their life, the stronger the synchronization with their partner.

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 “since these are well-known effects of REM sleep, they are very likely to be seen if we analyze them.”

Interestingly, the researchers found increased limb movement in couples who share the bed. However, these movements do not interrupt the dream architecture, which remains unchanged. Dr. Drew says, “You could say that while his body is a little rebellious when he sleeps with someone, his brain is not.”

Although the results are promising, many questions remain to be answered. “The first thing that is important to evaluate in the future is if the couple effects we found (promoted REM sleep during shared sleep) are also present in a more diverse sample (for example, the elderly or if a couple suffers from an illness) “says Dr. Drew.

Despite the small sample size and exploratory nature of some of the analyzes, this research furthers our understanding of couples’ sleep and its possible implications for mental health. Dr. Drews adds that “sleeping with a partner could actually give you an extra boost regarding your mental health, memory, and creative problem-solving skills.”