Sleeping with a partner affects your sleep cycle in a surprising way: study

Sleeping with a partner requires browsing by sharing the cover, different sleeping times and changing the wake-up times. New research suggests that the bed-sharing tests really pay off, especially when you both fall asleep.

In a sample of 12 heterosexual couples who have been a couple for an average of 23.5 years, scientists found that sleeping together was related to 10% more REM sleep compared to sleeping apart. During REM sleep, processes such as sleep and memory consolidation are set in motion. Co-sleepers also had longer, quieter pieces of REM sleep when they slept together.

The nights were not particularly calm: couples also moved more when they slept together compared to when each person slept alone. But despite that breakdown, they entered sleep stages at roughly the same time.

When couples slept apart, they spent about 36.6 percent of the night, going through the sleep stages at the same time. Because all humans go through the stages of sleep, that’s not particularly surprising: Naturally, there will be a little overlap.

Remarkably, this overlap significantly increased when couples slept together, growing to 46.9 percent.

The study was published Thursday in Frontiers in psychiatry.

Henning Johannes Drews is the lead author of the study and a postdoctoral researcher at the Center for Integrative Psychiatry in Germany. Explain that these findings are a departure from conventional wisdom and previous research on sleeping with a partner.

“There is, even in the medical community, the notion that if you sleep with a partner, you might subjectively think that you slept well or better, but objectively, your sleep is more disturbed,” says Drews. Reverse. “I would like people to take away that if you want to share a bed with your partner, there is nothing to say against that.”

“It might even be very good for you because of REM sleep stabilization.”

Couples who slept together had fewer REM sleep interruptions compared to when they slept apart. Eva Blanco / EyeEm / Shutterstock

One night in the sleep laboratory. This study addresses the dangers of sleep along with polysomnography, a type of sleep study that records brain waves, movement, and oxygen levels in the blood. That means that the couples had to sleep in a laboratory while being monitored by scientists (it is not the most natural place to sleep with their partner).

Couples slept in the lab for four nights over two weekends. One weekend, they slept in two separate rooms on single beds. The following weekend, they slept in a room on two beds together. They were given two sets of sheets and two blankets, so grabbing the deck probably wasn’t a big factor here.

When the couples slept together, they told scientists that their sleep quality improved. However, the scientists found no difference in measures such as total sleep time or the time it took for people to fall asleep. They found increases in the amount of REM sleep and the architecture of that REM sleep.

When couples slept together, there were, on average, 5.4 REM interruptions during the night. When they slept apart, 8.5 interruptions to REM sleep. That translated into longer uninterrupted REM sleep periods – they lasted an average of about 22 minutes when couples slept together compared to 13.4 when they slept apart. Still, this measure varied greatly depending on the topic of study, making it not a perfect comparison.

Drews has two explanations of work for reducing REM sleep interruptions. The first is purely biological. During REM sleep, the body’s ability to regulate temperature is affected. A partner can help keep body temperature stable, he argues.

The second is psychological: a couple could make us feel more secure.

“REM sleep is in fact disturbed and reduced by psychosocial stress,” says Drews. “Therefore, relaxing and safe environments promote REM sleep. The presence of a partner could help create such a safe environment.”

Synchronizing sleep One of the most puzzling findings of the study was the appearance of synchronization of sleep between couples.

For one thing, that could simply be because couples simply go to sleep at the same time and wake up (perhaps with each other) throughout the night, causing them to line up.

But even when scientists excluded wake incidents, they still found that 47.5 percent of epochs (short periods of time within a sleep study that allow scientists to compare sleep stages) were in sync with each other.

Right now, Drews suggests that it is the depth of the relationship that could explain why couples tend to sync up when they sleep.

Having a deeper relationship strongly correlated with this REM sleep timing, the study suggests. That’s just a trend – it can’t be fully confirmed with experimental data.

Because this is a small pilot study, the data is not accurate enough to apply to everyone. He also only looked at healthy, straight couples. As for the studies that apply to non-heterosexual couples, Drews says he is not yet aware of any documents that use objective sleep measures for homosexual couples. Finally, sharing a bed is probably not a way to to get better your dream, says Drews, especially if you know you prefer to sleep alone.

This study suggests that sharing a bed doesn’t have to mean losing a good night’s sleep. In some cases, you can rest more than you might expect.


Background / Objectives: Sharing a bed with a partner is common among adults and impacts the quality of sleep with possible implications for mental health. However, the findings so far are conflicting, and particularly polysomnographic data on couples sleeping together is extremely rare. The present study aimed to investigate the effects of the presence of a bed partner on the neurophysiology of individual and dyadic sleep.

Methods: Healthy young heterosexual couples underwent a sleep-based polysomnography of two sleeping arrangements: individual sleep and shared sleep. Individual and dyadic sleep parameters (i.e. synchronization of sleep stages) were collected. The latter were evaluated by means of cross-recurrence quantification analysis. In addition, subjective sleep quality, relationship characteristics, and chronotype were monitored. The data was analyzed comparing shared sleep versus individual sleep. In addition, the interaction effects of sleep disposition with gender, chronotype or relationship characteristics were tested.

Results: Compared to individual sleep, co-sleeping was associated with approximately 10% more REM sleep, less fragmented REM sleep (p = 0.008), longer uncomfortable REM fragments (p = 0.0006), and more limb movements (p = 0.007). None of the other stages of sleep was significantly altered. Social support interacted with sleep disposition in such a way that people with suboptimal social assistance showed the greatest impact of sleep disposition on REM sleep. Sleep architectures were more synchronized between couples during shared sleep (p = 0.005) even if waking phases were excluded (p = 0.022). Furthermore, the dream architectures engage significantly in a delay of ± 5 min. The depth of the relationship represented an additional significant main effect with respect to timing, reflecting a positive association between the two. Neither REM sleep nor timing were influenced by gender, chronotype, or other relationship characteristics.

conclusion: Depending on the disposition to sleep, the architecture and the synchronization of the couple’s sleep show alterations that are modified by the characteristics of the relationship. We discuss that these disturbances could be part of a REM sleep self-improvement feedback loop and sociality and a mechanism through which sociality prevents mental illness.