I've been dating the same guy for 2 years and we rarely spend the night with each other, mainly because he can never fall asleep or stay asleep when we do. I sleep much better when he is with me despite his tossing and turning all night, but I don't want to keep him from sleeping. I've always thought that married couples who don't sleep in the same bed have issues, but maybe there's nothing wrong with sleeping alone. Is it important for couples to sleep together or does it matter?
Thank you for your question. It is not surprising that you would feel some concern about what sleeping together means for your relationship; does it mean that you and your partner are becoming less intimate? “Co-sleeping” has been used as a measure of relationship intimacy, so some relationship researchers share that belief.1
Despite the fact that 61% of American adults co-sleep with intimate partners,2 researchers conduct most laboratory sleep research with individuals sleeping alone on single beds. As a result, we know surprisingly little about how co-sleeping impacts quality of sleep. Based on what little we do know about dyadic sleeping arrangements, intimate partners have been found to influence each other’s circadian rhythms, which are our sleep-wake cycles. When couples’ sleep rhythms match, their marital quality is better—when their rhythms are mismatched (one is a night owl and the other is a lark), then relationship quality suffers.3
There is some research demonstrating that co-sleeping affects men and women differently. A number of years ago, married couples that were characterized as having “good” sleeping habits were asked to sleep alone. Spouses who slept alone (compared to when they co-slept) spent more time in “Stage 4 sleep” and less in REM (rapid eye movement) sleep, particularly if they were women. Women also woke less often than men during co-sleeping than when they slept alone.4 Stage 4 sleep (a.k.a. “Delta” sleep) is when we are most deeply asleep—without it, we often do not feel rested upon awakening. Therefore, people tend to wake a little more often when they co-sleep, and spend more time in REM than deep sleep, especially if they are men. This could be one explanation as to why your boyfriend does not sleep as well, or feel as rested as you when you co-sleep. The question remains, however, as to whether alone versus co-sleeping results in "better" sleep, and whether this has an impact on daytime relationship functioning.
In another study, spouses completed a survey several times a day about their relationship satisfaction and sleep and awake behaviors. They also wore wrist bands equipped with technology that monitored their activity patterns (for a full week). When men had poor sleep, they reported having bad interactions with their spouses the next day. For women, an opposite effect was found. When women had a negative daytime interaction with their spouse, they slept worse that night. Sleep disturbances can impact our ability to regulate our emotions and manage our interactions with others, and the researchers propose that women have greater interpersonal “capacity” than men due to how they have been socialized—therefore sleep disturbances do not impact them the same way.5 The researchers also found that when couples fight, it takes longer for them to fall asleep. When they are happy, they fall asleep faster.5
The take home message here is that your partner’s experience with co-sleeping may be very different than yours, and your day to day interactions can impact your sleeping experience. For your boyfriend, bad sleep one night can mean negative interactions with you the next day, and those negative interactions with you during the day (if you are a woman) then lead to bad sleep for you that night. This is a vicious cycle. If it helps to sleep separately in order to offset this cycle, and things between you both during the day are generally positive, then I would not worry about what this means for intimacy. Find other ways to demonstrate your love and affection for each other, and then consider sleeping with a nice, comfy body pillow if that makes your own sleep better.
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1de Munck, V. C., & Korotayev, A. V. (2007). Wife-husband intimacy and female status in cross-cultural perspective. Cross-Cultural Research, 41, 307-335.
2Troxel, W. M., Robles, T. F., Hall, M., & Buysse, D. J. (2007). Marital quality and the marital bed: examining covariation between relationship quality and sleep. Sleep Medicine Reviews, 389-404.
3Lange, A., Waterman, D., & Kerkhof, G. A. (1998). Sleep/wake patterns of partners. Perceptual & Motor Skills, 86, 1141–2.
4Monroe, L. J. (1969). Transient changes in EEG sleep patterns of married good sleepers: The effects of altering sleeping arrangement. Psychophysiology, 6, 330-337.
5Hasler, B. P., & Troxel, W. M. (2010). Couples’ nighttime sleep efficiency and concordance: Evidence for bidirectional associations with daytime relationship functioning. Psychosomatic Medicine, 72, 794.801.
Dr. Jennifer Harman - Adventures in Dating... | Science of Relationships articles | Website/CV
Dr. Harman's research examines relationship behaviors that put people at-risk for physical and psychological health problems, such as how feelings and beliefs about risk (e.g., sexual risk taking) can be biased when in a relationship. She also studies the role of power on relationship commitment.