Sleep-Wake Concordance in Couples Is Inversely Associated With Cardiovascular Disease Risk Markers.

Aim: To determine whether interdependence in couples' sleep (sleep-wake concordance i.e., whether couples are awake or asleep at the same time throughout the night) is associated with two markers of cardiovascular disease (CVD) risk, ambulatory blood pressure (BP) and systemic inflammation. Methods: This community-based study is a cross-sectional analysis of 46 adult couples, aged 18-45 years, without known sleep disorders. Percent sleep-wake concordance, the independent variable, was calculated for each individual using actigraphy. Ambulatory BP monitors measured BP across 48 h. Dependent variables included mean sleep systolic BP (SBP) and diastolic BP (DBP), mean wake SBP and DBP, sleep-wake SBP and DBP ratios, and C-reactive protein (CRP). Mixed models were used and were adjusted for age, sex, education, race, and body mass index. Results: Higher sleep-wake concordance was associated with lower sleep SBP (b = -.35, SE = .01) and DBP (b = -.22, SE = .10) and lower wake SBP (b = -.26, SE = .12; all p values < .05). Results were moderated by sex; for women, high concordance was associated with lower BP. Men and women with higher sleep-wake concordance also had lower CRP values (b = -.15, SE = .03, p < .05). Sleep-wake concordance was not associated with wake DBP or sleep/wake BP ratios. Significant findings remained after controlling for individual sleep quality, duration, and wake after sleep onset. Conclusions: Sleep-wake concordance was associated with sleep BP, and this association was stronger for women. Higher sleep-wake concordance was associated with lower systemic inflammation for men and women. Sleep-wake concordance may be a novel mechanism by which marital relationships are associated with long-term CVD outcomes.

Sleep Concordance in Couples is Associated with Relationship Characteristics.

STUDY OBJECTIVES: 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. DESIGN: 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. RESULTS: 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. CONCLUSIONS: Sleep concordance provides a unique measure of couples' cosleep and varies depending on attachment style and relationship satisfaction.