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There is considerable in the media and the psychological literature on the role of sleep quality in everything from work to mental health. However, many adults, of course, sleep not as individuals, but in couples. Therefore, it would seem worthwhile to extend the study of sleep and well-being to the study of the patterning of sleep within couples.

You may be thinking that the quality of yours and your partner's sleep reflects the quality of your relationship. However, there's a flip side to this: In long-term close relationships, partners comes to resemble each other in basic biological systems, a phenomenon known as coregulation. Theoretically, according to this line of thinking, the closer you are to your partner, the more your daily rhythms should come to resemble each other’s. You’ll both breathe deeply at the same time, toss and turn the same way, and maybe even dream together as you spend more time between the sheets together ( , that is).

Does this mean that the owl (a late night person) may become more of a lark (a morning person), and the lark an owl, as partners influence one other over time? Or do things work out the other way? If the similarity hypothesis of close relationships is correct, lark should attract lark and owl attract owl. You and your partner may have met, if this holds true, at a 6 am spinning class at your gym or, conversely, on the dance floor at 2 in the morning.

However, if you truly care about someone, and your biological rhythms aren’t quite in sync, it’s just as likely that you’ll try to find a way to compromise between your very different daily (or nightly) patterns. Perhaps you’ll make these adjustments in small units—a half-hour earlier to bed, or a half-hour earlier at the breakfast table—until you’ve found somewhat of a balance.

Even if you don't consciously seek a partner with the same sleeping preferences as yours, or consciously try to align more closely to the habits of your partner, the principle of coregulation predicts that your biological rhythms will still tend to sync up over the course of time. This might be especially true for partners who are emotionally in sync as well.

In other words, if you’re closer to your partner emotionally, will your sleep-wake patterns get closer too?

This question led University of Pittsburgh sleep researcher Heather Dunn and colleagues to conduct a study of 46 married couples (averaging 30 years of age), examining the effect that relationship satisfaction would have on patterns of coregulation.

Following from the notion that coregulation occurs in response to bonds between partners, Dunn and her team investigated whether so-called “securely attached” partners would establish closer sleep patterns. This proposal relates to the theory of attachment style, which states that adults model their relationships on the mental images they have of how they were treated by their parents or caregivers when they were infants. Most people actually do develop a secure attachment style, in which they feel they can rely on their adult partners because they could rely on their parents or caregivers as constant sources of nurturance. Children who were neglected can develop an avoidant attachment style, in which they struggle to form close bonds with a long-term partner as adults. If the child is treated in an inconsistent manner in which life with their is unpredictable, they're more likely to develop an avoidant attachment style.

Returning to how attachment style might relate to sleep coregulation between partners, the idea is that people who are securely attached should be the most likely to bring their sleep patterns into harmony. This should be particularly true, Dunn and colleagues believed, when the individual is highly satisfied with the quality of the relationship. Everything should hum along smoothly throughout the hours of sleep when couples are optimally tuned to each other psychologically.

That coregulation occurs at all was shown by the fact that 75% of couples in the study were in fact closely aligned in their nightly sleep patterns, more so than randomly matched pairs of men and women from within the sample. The matching of periods of sleep and wakefulness between partners showed no relationship with the quality of their sleep or whether they described themselves as morning or evening people (larks or owls).

Next, the researchers tackled the question of whether, among those couples closer to the lower end of the coregulation spectrum, one or both partners were either less satisfied with their relationship, insecurely attached, or some combination of the two. Looking first at wives, the data showed that there was no relationship between their own attachment style and sleep coregulation. However, the more satisfied the wives, the more they and their husbands snoozed in sync. From the wife’s point of view, if she’s satisfied with the relationship, she’ll display sleep patterns that match her husband.

If the wife wasn’t satisfied with her relationship, however, she and her husband slept in greater harmony if the husband was anxiously attached. It’s as if the husband’s search for closeness with his wife—to satisfy his attachment needs—compensated for her lower within the relationship. Maybe he was likely to snuggle more closely to her, which, in turn, influenced her body’s tendency to regulate her biological rhythms closer to his. Interestingly, though, men’s overall relationship satisfaction did not correlate with sleep coregulation. It’s possible that, as Dunn and her team speculate, “Women are more [physiologically] attuned to the emotional quality of the ” (p. 938).

We don’t know whether getting your nightly habits to attune to your partner’s will make you consciously happier. At some deeper level below awareness, perhaps, you and your partner may be adjusting in ways to each other in ways you didn’t even realize in your waking life.

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Reference

Gunn, H. E., Buysse, D. J., Hasler, B. P., Begley, A., & Troxel, W. M. (2015). Sleep concordance in couples is associated with relationship characteristics. Sleep: Journal Of Sleep And Sleep Disorders Research, 38(6), 933-939.

Copyright Susan Krauss Whitbourne 2015