Sleep Concordance in Couples is Associated with Relationship Characteristics

Coregulation of biological systems is a defining feature of normative attachment in close adult relationships. Sleep is a shared, intimate biological process between couples; however, sleep is usually examined at the individual level. We examined minute-by-minute concordance in couples' actigraphy-defined sleep-wake patterns, and how attachment style and marital satisfaction relate to concordance.

Couples completed measures of avoidant and anxious attachment styles and relationship functioning and wore wrist actigraphs for 10 days. Minute-by-minute concordance of sleep and wake (i.e., the percentage of epochs in which both partners were asleep, or both were awake) was calculated for each sleep period. Mixed modeling was used to account for measurement occasions across time.

Percent concordance ranged from 53-88% and was not associated with couples' sleep quality or circadian preference. For wives, neither anxious nor avoidant attachment was associated with sleep-wake concordance. For husbands, anxious attachment style was associated with higher concordance, but was moderated by wives' marital satisfaction. High marital satisfaction in wives was associated with higher concordance, regardless of husbands' attachment style. In couples in which wives reported low satisfaction, concordance was higher when husbands had an anxious attachment style. Avoidant attachment style in husbands was not related to concordance.

Sleep concordance provides a unique measure of couples' cosleep and varies depending on attachment style and relationship satisfaction.