Behavioral-Social Rhythms and Cardiovascular Disease Risk in Retired Night Shift Workers and Retired Day Workers.

OBJECTIVE: Stability in the timing of key daily routine behaviors such as working/doing housework, sleeping, eating, and engaging in social interactions (i.e., behavioral-social rhythms) contributes to health. This study examined whether behavioral-social rhythms were associated with cardiovascular disease (CVD) risk factors in retired night shift workers and retired day workers and explored whether past night shift work exposure moderated this association. METHODS: A total of 154 retired older adults participated in this study. Multiple logistic regression models were used to examine associations between behavioral-social rhythms and CVD risk factors. Independent variables included Social Rhythm Metric (SRM)-5 score and actigraphy rest-activity rhythm intradaily variability (IV) and interdaily stability (IS). Dependent variables were metabolic syndrome prevalence and its five individual components. RESULTS: More regular behavioral-social rhythms were associated with lower odds of prevalent metabolic syndrome (SRM: odds ratio [OR] = 0.57, 95% confidence interval [CI] = 0.35-0.88; IV: OR = 4.00, 95% CI = 1.86-8.58; IS: OR = 0.42, 95% CI = 0.24-0.73) and two of its individual components: body mass index (SRM: OR = 0.56, 95% CI = 0.37-0.85; IV: OR = 2.84, 95% CI = 1.59-5.07; IS: OR = 0.42, 95% CI = 0.26-0.68) and high-density lipoprotein cholesterol (SRM: OR = 0.49, 95% CI = 0.30-0.80; IV: OR = 2.49, 95% CI = 1.25-4.96; IS: OR = 0.35, 95% CI = 0.19-0.66). Past shift work history did not moderate the association between behavioral-social rhythms and metabolic syndrome. CONCLUSIONS: Behavioral-social rhythms were related to CVD risk factors in retired adults regardless of prior night shift work exposure. Older retired workers may benefit from education and interventions aiming to increase behavioral-social rhythm regularity.

Elusive hypersomnolence in seasonal affective disorder: actigraphic and self-reported sleep in and out of depressive episodes.

BACKGROUND: Hypersomnolence has been considered a prominent feature of seasonal affective disorder (SAD) despite mixed research findings. In the largest multi-season study conducted to date, we aimed to clarify the nature and extent of hypersomnolence in SAD using multiple measurements during winter depressive episodes and summer remission. METHODS: Sleep measurements assessed in individuals with SAD and nonseasonal, never-depressed controls included actigraphy, daily sleep diaries, retrospective self-report questionnaires, and self-reported hypersomnia assessed via clinical interviews. To characterize hypersomnolence in SAD we (1) compared sleep between diagnostic groups and seasons, (2) examined correlates of self-reported hypersomnia in SAD, and (3) assessed agreement between commonly used measurement modalities. RESULTS: In winter compared to summer, individuals with SAD (n = 64) reported sleeping 72 min longer based on clinical interviews (p < 0.001) and 23 min longer based on actigraphy (p = 0.011). Controls (n = 80) did not differ across seasons. There were no seasonal or group differences on total sleep time when assessed by sleep diaries or retrospective self-reports (p's > 0.05). Endorsement of winter hypersomnia in SAD participants was predicted by greater fatigue, total sleep time, time in bed, naps, and later sleep midpoints (p's < 0.05). CONCLUSION: Despite a winter increase in total sleep time and year-round elevated daytime sleepiness, the average total sleep time (7 h) suggest hypersomnolence is a poor characterization of SAD. Importantly, self-reported hypersomnia captures multiple sleep disruptions, not solely lengthened sleep duration. We recommend using a multimodal assessment of hypersomnolence in mood disorders prior to sleep intervention.

Spectra in low-rank localized layers (SpeLLL) for interpretable time-frequency analysis.

The time-varying frequency characteristics of many biomedical time series contain important scientific information. However, the high-dimensional nature of the time-varying power spectrum as a surface in time and frequency limits its direct use by applied researchers and clinicians for elucidating complex mechanisms. In this article, we introduce a new approach to time-frequency analysis that decomposes the time-varying power spectrum in to orthogonal rank-one layers in time and frequency to provide a parsimonious representation that illustrates relationships between power at different times and frequencies. The approach can be used in fully nonparametric analyses or in semiparametric analyses that account for exogenous information and time-varying covariates. An estimation procedure is formulated within a penalized reduced-rank regression framework that provides estimates of layers that are interpretable as power localized within time blocks and frequency bands. Empirical properties of the procedure are illustrated in simulation studies and its practical use is demonstrated through an analysis of heart rate variability during sleep.

Activity patterns related to depression symptoms in stressed dementia caregivers.

OBJECTIVES: Self-reported activity restriction is an established correlate of depression in dementia caregivers (dCGs). It is plausible that the daily distribution of objectively measured activity is also altered in dCGs with depression symptoms; if so, such activity characteristics could provide a passively measurable marker of depression or specific times to target preventive interventions. We therefore investigated how levels of activity throughout the day differed in dCGs with and without depression symptoms, then tested whether any such differences predicted changes in symptoms 6 months later. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We examined 56 dCGs (mean age = 71, standard deviation (SD) = 6.7; 68% female) and used clustering to identify subgroups which had distinct depression symptom levels, leveraging baseline Center for Epidemiologic Studies of Depression Scale-Revised Edition and Patient Health Questionnaire-9 (PHQ-9) measures, as well as a PHQ-9 score from 6 months later. Using wrist activity (mean recording length = 12.9 days, minimum = 6 days), we calculated average hourly activity levels and then assessed when activity levels relate to depression symptoms and changes in symptoms 6 months later. RESULTS: Clustering identified subgroups characterized by: (1) no/minimal symptoms (36%) and (2) depression symptoms (64%). After multiple comparison correction, the group of dCGs with depression symptoms was less active from 8 to 10 AM (Cohen's d ≤ -0.9). These morning activity levels predicted the degree of symptom change on the PHQ-9 6 months later (per SD unit ß = -0.8, 95% confidence interval: -1.6, -0.1, p = 0.03) independent of self-reported activity restriction and other key factors. CONCLUSIONS: These novel findings suggest that morning activity may protect dCGs from depression symptoms. Future studies should test whether helping dCGs get active in the morning influences the other features of depression in this population (i.e. insomnia, intrusive thoughts, and perceived activity restriction).

Sleep and Daily Social Experiences as Potential Mechanisms Linking Social Integration to Nocturnal Blood Pressure Dipping.

OBJECTIVE: Socially integrated individuals are at lower risk of cardiovascular disease morbidity and mortality compared with their more isolated counterparts. This association may be due, in part, to the effect of social integration on nocturnal blood pressure (BP) decline or "dipping," a physiological process associated with decreased disease risk. However, the pathways linking social integration with nocturnal BP dipping are unknown. We sought to replicate the association between social integration and BP dipping, and to test whether sleep characteristics (duration, regularity, continuity) and/or daily social interactions (frequency, valence) helped to explain the association. METHODS: A total of 391 healthy midlife adults completed an actigraphy assessment protocol that measured sleep. During four actigraphy assessment days, participants also completed ambulatory BP monitoring and ecological momentary assessment protocols that measured BP and social interactions at regular intervals throughout the day. Social integration was assessed via a questionnaire. RESULTS: Linear regression controlling for age, sex, race, education, and body mass index indicated that higher levels of social integration were associated with greater nocturnal BP dipping, as indicated by a smaller ratio of night/day mean arterial pressure (ß = -0.11, p = .031). Analyses of indirect effects suggested that this association was explained, in part, by greater sleep regularity among more integrated individuals. We did not find evidence for other hypothesized indirect effects. CONCLUSIONS: This was the first study to investigate sleep and social mechanisms underlying the link between social integration and nocturnal BP dipping. Because sleep regularity is modifiable, this pathway represents a potential intervention target to promote nocturnal BP dipping.

Blood Pressure Cuff Inflation Briefly Increases Female Adolescents' Restlessness During Sleep on the First But Not Second Night of Ambulatory Blood Pressure Monitoring.

OBJECTIVE: Ambulatory blood pressure monitoring (ABPM) increases restlessness during adults' sleep in laboratory settings, but there is little evidence of an association among adolescents or in naturalistic environments. This study examined activity levels before and after blood pressure cuff inflation during sleep to determine whether and for how long ABPM increased restlessness during sleep in healthy adolescents. METHODS: Two hundred thirty-four healthy adolescents (mean age = 15.72 [1.30] years; 54% female; 57% Black) completed two consecutive nights of hourly ABPM and wrist-worn actigraphy. Activity counts during sleep, averaged across 5-minute bins, were compared in the 20 minutes before and after blood pressure cuff inflation using a four-level mixed model (bins within hours within nights within participants). Interactions of bin with night, sex, and race were examined. Covariates included age, sex, and race. RESULTS: Activity counts in the 5-minute bin immediately after cuff inflation were 10% to 14% higher than all other bins before ( p < .001) and after ( p < .001) cuff inflation. This effect differed by night and sex, as activity levels during 5-minute post-cuff inflation were elevated only on night 1 ( p values < .001) and only in female participants ( p values < .001). Effects did not differ by race. CONCLUSIONS: Cuff inflation during ABPM briefly increased adolescent female participants' restlessness during sleep. Habituation occurred after one night, so two nights of ABPM may minimize impact on sleep. If only one night of ABPM is feasible, excluding 5 minutes of actigraphy data after each cuff inflation may accommodate the impact of ABPM on restlessness during sleep.

Age Trends in Actigraphy and Self-Report Sleep Across the Life Span: Findings From the Pittsburgh Lifespan Sleep Databank.

OBJECTIVE: Sleep changes over the human life span, and it does so across multiple dimensions. We used individual-level cross-sectional data to characterize age trends and sex differences in actigraphy and self-report sleep dimensions across the healthy human life span. METHODS: The Pittsburgh Lifespan Sleep Databank consists of harmonized participant-level data from sleep-related studies conducted at the University of Pittsburgh (2003-2019). We included data from 1065 (n = 577 female; 21 studies) Pittsburgh Lifespan Sleep Databank participants aged 10 to 87 years without a major psychiatric, sleep, or medical condition. All participants completed wrist actigraphy and the self-rated Pittsburgh Sleep Quality Index. Main outcomes included actigraphy and self-report sleep duration, efficiency, and onset/offset timing, and actigraphy variability in midsleep timing. RESULTS: We used generalized additive models to examine potentially nonlinear relationships between age and sleep characteristics and to examine sex differences. Actigraphy and self-report sleep onset time shifted later between ages 10 and 18 years (23:03-24:10 [actigraphy]; 21:58-23:53 [self-report]) and then earlier during the 20s (00:08-23:40 [actigraphy]; 23:50-23:34 [self-report]). Actigraphy and self-report wake-up time also shifted earlier during the mid-20s through late 30s (07:48-06:52 [actigraphy]; 07:40-06:41 [self-report]). Self-report, but not actigraphy, sleep duration declined between ages 10 and 20 years (09:09-07:35). Self-report sleep efficiency decreased over the entire life span (96.12-93.28), as did actigraphy variability (01:54-01:31). CONCLUSIONS: Awareness of age trends in multiple sleep dimensions in healthy individuals-and explicating the timing and nature of sex differences in age-related change-can suggest periods of sleep-related risk or resilience and guide intervention efforts.

Association of Depressive Symptoms with Sleep Disturbance: A Co-twin Control Study.

BACKGROUND: Few studies have comprehensively evaluated the association of depression with sleep disturbance using a controlled twin study design. PURPOSE: To cross-sectionally evaluate the association of depression with both objective and subjective sleep disturbance. METHODS: We studied 246 members of the Vietnam Era Twin Registry. We measured depressive symptoms using the Beck Depression Inventory-II (BDI) and assessed major depression using structured clinical interviews. Twins underwent one-night polysomnography and 7-day actigraphy to derive measures of objective sleep and completed the Pittsburgh Sleep Quality Index for subjective sleep. Multivariable mixed-effects models were used to examine the association. RESULTS: Twins were all male, mostly white (97%), with a mean (SD) age of 68 (2). The mean (SD) BDI was 5.9 (6.3), and 49 (20%) met the criteria for major depression. For polysomnography, each 5-unit higher BDI, within-pair, was significantly associated with 19.7 min longer rapid eye movement (REM) sleep latency, and 1.1% shorter REM sleep after multivariable adjustment. BDI was not associated with sleep architecture or sleep-disordered breathing. For actigraphy, a higher BDI, within-pair, was significantly associated with lower sleep efficiency, more fragmentation and higher variability in sleep duration. BDI was associated with almost all dimensions of self-reported sleep disturbance. Results did not differ by zygosity, and remained consistent using major depression instead of BDI and were independent of the presence of comorbid posttraumatic stress disorder and antidepressant use. CONCLUSIONS: Depression is associated with REM sleep disruption in lab and sleep fragmentation and sleep variability at home, but not with sleep architecture or sleep-disordered breathing.

Sleep moderates the effects of Tibetan yoga for women with breast cancer undergoing chemotherapy.

This study examined self-reported and actigraphy-assessed sleep and depression as moderators of the effect of a Tibetan yoga intervention on sleep and depression among women undergoing chemotherapy for breast cancer. This is a secondary analysis of an RCT examining a 4-session Tibetan yoga program (TYP; n = 74) versus stretching program (STP; n = 68) or usual care (UC; n = 85) on self-reported sleep (Pittsburgh Sleep Quality Index (PSQI), actigraphy-assessed sleep efficiency (SE)) and depression (Centers for Epidemiological Studies Depression Scale; CES-D) for women undergoing chemotherapy for breast cancer. Data were collected at baseline and 1-week and 3-month post-intervention. Baseline PSQI, actigraphy-SE, and CES-D were examined as moderators of the effect of group on PSQI, actigraphy-SE, and CES-D 1 week and 3 months after treatment. There was a significant baseline actigraphy-SE × group effect on PSQI at 1 week (p < .001) and 3 months (p = .002) and on CES-D at 3 months (p = .049). Specifically, the negative association of baseline actigraphy-SE with subsequent PSQI and CES-D was buffered for women in the TYP and, to a lesser extent in STP, compared to those in the UC. Baseline PSQI and CES-D were not significant moderators of the effect of group on any outcome. Behaviorally assessed sleep may be a more robust indicator of which patients are most appropriate for a yoga intervention than self-reported sleep quality. Women with poor sleep efficiency may derive the greatest benefit in terms of sleep quality and mood from a yoga intervention.

Social Integration and Sleep Quality during the COVID-19 Pandemic: Prospective Evidence from a Study of Retired Older Adults.

BACKGROUND: Growing evidence has documented the adverse impact of the global COVID-19 pandemic on sleep quality among older adults. Given the negative consequences of poor sleep, it is critical to identify factors that provide older adults with resilience against worsening sleep quality. Social integration may represent one such resilience factor. PURPOSE: This study evaluated the association of social integration and sleep quality during the COVID-19 pandemic. METHODS: 113 retired older adults completed assessments of their social integration after the onset of the COVID-19 pandemic, and of their sleep quality before and after the onset of the COVID-19 pandemic. RESULTS: Higher levels of social integration were associated with better sleep quality during the COVID-19 pandemic, even when statistically controlling for pre-pandemic sleep quality. Sex-stratified analyses showed that this association was driven by women in our sample. CONCLUSIONS: Social integration may confer resilience against poor sleep quality, especially in older adult women. Additional research is warranted to assess candidate mechanisms and moderators of the link between social integration and sleep quality.

Physiological sleep measures predict time to 15-year mortality in community adults: Application of a novel machine learning framework.

Clarifying whether physiological sleep measures predict mortality could inform risk screening; however, such investigations should account for complex and potentially non-linear relationships among health risk factors. We aimed to establish the predictive utility of polysomnography (PSG)-assessed sleep measures for mortality using a novel permutation random forest (PRF) machine learning framework. Data collected from the years 1995 to present are from the Sleep Heart Health Study (SHHS; n = 5,734) and the Wisconsin Sleep Cohort Study (WSCS; n = 1,015), and include initial assessments of sleep and health, and up to 15 years of follow-up for all-cause mortality. We applied PRF models to quantify the predictive abilities of 24 measures grouped into five domains: PSG-assessed sleep (four measures), self-reported sleep (three), health (eight), health behaviours (four), and sociodemographic factors (five). A 10-fold repeated internal validation (WSCS and SHHS combined) and external validation (training in SHHS; testing in WSCS) were used to compute unbiased variable importance metrics and associated p values. We observed that health, sociodemographic factors, and PSG-assessed sleep domains predicted mortality using both external validation and repeated internal validation. The PSG-assessed sleep efficiency and the percentage of sleep time with oxygen saturation <90% were among the most predictive individual measures. Multivariable Cox regression also revealed the PSG-assessed sleep domain to be predictive, with very low sleep efficiency and high hypoxaemia conferring the highest risk. These findings, coupled with the emergence of new low-burden technologies for objectively assessing sleep and overnight oxygen saturation, suggest that consideration of physiological sleep measures may improve risk screening.

Day-to-day associations between sleep characteristics and affect in community dwelling adults.

Despite the high co-occurrence of sleep and mood disturbances, day-to-day associations between sleep characteristics (sleep duration, continuity, and timing) and dimensions of mood (positive affect and negative affect) remain unclear. The present study aimed to test whether there is a daily, bidirectional association between these sleep characteristics and affective states, while addressing methodological limitations in the extant literature by using actiography and ecological momentary assessment methods. Participants were community dwelling, midlife adults (aged 30-54 years, N = 462, 47% male) drawn from the Adult Health and Behavior Project-Phase 2 study. Participants' sleep patterns were assessed with actiography over a 7-day monitoring period, and on 4 of those days, participants completed an ecological momentary assessment protocol that included hourly assessments of positive affect and negative affect during their wake intervals. Using hierarchical linear modelling, we tested whether participants' sleep characteristics on a given night predicted next-day affect and vice versa. We also explored whether nocturnal sleep characteristics would differentially associate with affect at different times of day (morning, afternoon, and evening) while controlling for multiple health behaviours. We found that when participants reported higher positive affect on a given day, they slept later that night (B = 0.22, p = .010). Although we found no other statistically significant associations in our primary analyses (all p > .05), we found several sleep-affect associations specific to time of day (B ranges: 0.01-0.18, all p ≤ .02), which warrants further study. Overall, our findings suggest that healthy adults may be resilient to daily fluctuations in their sleep and mood.

Longitudinal Association Between Depressive Symptoms and Multidimensional Sleep Health: The SWAN Sleep Study.

BACKGROUND: Depressive symptoms and sleep disturbances disproportionately affect midlife women. While there may be a bidirectional association, few studies have examined whether depressive symptoms are longitudinally associated with subsequent sleep. Sleep is typically considered unidimensional, despite emerging evidence that multidimensional sleep health provides novel information on the sleep-health link. PURPOSE: The current study examined whether higher depressive symptoms were longitudinally associated with poorer multidimensional sleep health. METHOD: Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale across six to nine annual assessments in 302 midlife women from the Study of Women's Health Across the Nation. Six months after their last assessment, actigraphy (mean ± standard deviation = 29.3 ± 6.9 days) and self-report were used to assess sleep health components: efficiency, duration, mid-sleep timing, regularity, alertness, and satisfaction, which were dichotomized and summed to create a composite multidimensional sleep health score. Mixed-effects models were used to evaluate the longitudinal associations between depressive symptoms and multidimensional sleep health, as well as individual sleep health components, adjusting for covariates. Exploratory analyses stratified models by race/ethnicity. RESULTS: Higher depressive symptoms were associated with subsequent poorer multidimensional sleep health (p < .0.001) and lower alertness (p < .0001) and satisfaction with sleep (p < .0001). CONCLUSIONS: Our finding that higher average depressive symptoms were associated longitudinally with actigraphy-measured poorer sleep health in midlife women is novel and converges with the larger body of evidence that these two common symptoms are strongly associated. The bidirectional relationship between these two prevalent symptoms needs to be studied in prospective longitudinal studies.

Patient characteristics associated with sleep disturbance in breast cancer survivors.

BACKGROUND: Disturbed sleep is common among breast cancer survivors. Identifying patients at risk for disturbed sleep and its sequelae will aid in improving screening and intervention strategies to improve sleep and cancer-related quality of life (QOL). METHODS: Women with stages I-III breast cancer undergoing neoadjuvant or adjuvant chemotherapy (N = 415) reported subjectively assessed sleep quality (PSQI) and actigraphy-assessed wake after sleep onset (AAS-WASO), total sleep time (AAS-TST), and sleep efficiency (AAS-SE), sociodemographic, and clinical characteristics and completed questionnaires assessing physical and mental health QOL at study entry and 3, 6, 12, and 15 months later. RESULTS: Being from a racially/ethnically underserved population was associated with poorer sleep in all indices (p's < .04). Lower income was associated with poorer subjective sleep and greater AAS-WASO (p's < .02). BMI was associated with lower AAS-SE (p < .001). Baseline subjective sleep complaints were positively associated with depression, fatigue, and health-related QOL and cancer-related symptoms across follow-up (p's < 0.05). Baseline AAS-WASO was positively associated with anxiety and negatively associated with physical health-related QOL at the 3-month follow-up (p's < .001). Baseline AAS-WASO and AAS-SE were associated with mental health-related QOL at the 6-month follow-up (p's < .05). CONCLUSIONS: In keeping with previous health disparity research, racially/ethnically underserved populations, lower household income, and higher BMI were associated with increased risk for disturbed sleep. Sleep disturbance may have long-term effects on multiple aspects of QOL for women undergoing treatment for breast cancer. Results may inform strategies to identify patients at greatest risk for disturbed sleep and its sequelae.

White Matter Integrity Underlying Depressive Symptoms in Dementia Caregivers.

OBJECTIVE: We sought to determine whether the aspects of white matter connectivity implicated in major depression also relate to mild depressive symptoms in family dementia caregivers (dCGs). METHODS: Forty-one dCGs (average age=69 years, standard deviation=6.4) underwent a 7 Tesla 64-direction (12-minute) diffusion-weighted imaging sequence. We compared the fractional anisotropy (FA) of 11 white matter features between dCGs with (n=20) and without (n=21) depressive symptoms (Patient Health Questionnaire-9 scores ≥5). RESULTS: Caregivers reporting depression symptoms had lower FA in tracts connecting to the posterior cingulate cortex (Cohen's d = -0.9) and connecting dorsolateral prefrontal with rostral cingulate regions (Cohen's d = -1.2). CONCLUSIONS: Posterior cingulate and dorsolateral prefrontal-to-rostral cingulate white matter, implicated in prior studies of major depression, appear relevant to mild depression in dCGs.

The association between physical activity and a composite measure of sleep health.

PURPOSE: Physical activity has been associated with several individual dimensions of sleep. However, the association between physical activity and sleep health, a construct that emphasizes the multidimensional nature of sleep, has not been explored. This analysis examined the relationship between physical activity and a composite measure of sleep health. METHODS: A total of 114 adults (66% female, 60.3 ± 9.2 years) were included in the analyses. Participants reported daily light-intensity physical activity (LPA) and moderate- and vigorous-intensity physical activity (MVPA) via diary, while wearing a pedometer (Omron HJ-720ITC) to measure daily steps. Sleep health was measured using the RU_SATED questionnaire, which addresses regularity of sleep patterns, satisfaction with sleep, daytime alertness, and sleep timing, efficiency, and duration. Multiple linear regression, binary logistic regression, and analysis of covariance (ANCOVA) were utilized for analyses. RESULTS: Mean sleep health score was 9.6 ± 2.4 (0 [poor]-12 [good]). Participants reported 62.9 ± 66.0 and 51.2 ± 51.2 min/day of LPA and MVPA, respectively, and took 5585.5 ± 2806.7 steps/day. Greater MVPA was associated with better sleep health (ß = 0.27, P = 0.005) and sleep health scores differed between those reporting < 30 min/day and ≥ 60 min/day of MVPA (P = 0.004). Greater MVPA was associated with higher odds of having good sleep satisfaction (OR = 1.58 [1.14-2.20], P < 0.01), timing (OR = 2.07 [1.24-3.46], P < 0.01), and duration (OR = 1.48 [1.02-2.18], P = 0.04). Pedometer-based physical activity and LPA were not related to sleep health or its individual dimensions. CONCLUSIONS: In middle- to older-aged adults, higher-intensity activity, but not lower-intensity or volume of activity, was associated with greater sleep health. These data suggest that physical activity intensity may be important for sleep health.

Field-based Measurement of Sleep: Agreement between Six Commercial Activity Monitors and a Validated Accelerometer.

OBJECTIVE: To examine agreement between multiple commercial activity monitors (CAMs) and a validated actigraph to measure sleep. METHODS: Thirty adults without sleep disorders wore an Actiwatch Spectrum (AW) and alternated wearing 6 CAMs for one 24-h period each (Fitbit Alta, Jawbone Up3, Misfit Shine 2, Polar A360, Samsung Gear Fit2, Xiaomi Mi Band 2). Total sleep time (TST) and wake after sleep onset (WASO) were compared between edited AW and unedited CAM outputs. Comparisons between AW and CAM data were made via paired t-tests, mean absolute percent error (MAPE) calculations, and intra-class correlations (ICC). Intra-model reliability was performed in 10 participants who wore a pair of each AW and CAM model. RESULTS: Fitbit, Jawbone, Misfit, and Xiaomi overestimated TST relative to AW (53.7-80.4 min, P ≤ .001). WASO was underestimated by Fitbit, Misfit, Samsung and Xiaomi devices (15.0-27.9 min; P ≤ .004) and overestimated by Polar (27.7 min, P ≤ .001). MAPEs ranged from 5.1% (Samsung) to 25.4% (Misfit) for TST and from 36.6% (Fitbit) to 165.1% (Polar) for WASO. TST ICCs ranged from .00 (Polar) to .92 (Samsung), while WASO ICCs ranged from .38 (Misfit) to .69 (Samsung). Differences were similar between poor sleepers (Pittsburgh Sleep Quality Index global score >5; n = 10) and good sleepers. Intra-model reliability analyses revealed minimal between-pair differences and high ICCs. CONCLUSIONS: Agreement between CAMs and AW varied by device, with greater agreement observed for TST than WASO. While reliable, variability in agreement across CAMs with traditional actigraphy may complicate the interpretation of CAM data obtained for clinical or research purposes.

Sleep Duration and Blood Pressure: Recent Advances and Future Directions.

PURPOSE OF REVIEW: This review discusses the recent literature on subjectively and objectively assessed sleep duration in relation to hypertension risk and out-of-clinic blood pressure (BP) measures and highlights critical areas for future research. RECENT FINDINGS: Sleep duration, particularly short sleep, may influence BP through disturbed autonomic balance, hormonal imbalances, increased adiposity and metabolic dysfunction, and disrupted circadian rhythms. Observational studies indicate that short and long sleep are associated with hypertension risk, reduced nocturnal dipping, and elevated morning BP, but evidence is stronger for short sleep. Experimental sleep restriction increases BP, while sleep extension may lower BP in prehypertensive individuals. Women and racial/ethnic minorities are more prone to the detrimental effects of short sleep on BP. Additional studies are warranted to clarify the association of objectively assessed sleep with BP level and diurnal pattern and to determine the sex- and race-specific effects of sleep restriction and extension on BP.

Disturbed Sleep as a Mechanism of Race Differences in Nocturnal Blood Pressure Non-Dipping.

PURPOSE OF REVIEW: Disturbed sleep may be a mechanism of race differences in nocturnal blood pressure non-dipping. In support of this proposal, we summarize recent research from three literatures: (1) race differences (Black compared with White individuals) in nocturnal blood pressure non-dipping, (2) the association between disturbed sleep and nocturnal blood pressure non-dipping, and (3) race differences in disturbed sleep. RECENT FINDINGS: Black individuals are nearly twice as likely to have blood pressure non-dipping profiles compared with White individuals. This may be explained, in part, by sleep; shorter sleep duration, greater sleep fragmentation, less slow-wave sleep, and obstructive sleep apnea have each been associated with nocturnal blood pressure non-dipping. These sleep disturbances, in turn, are more common in Black compared with White individuals. Studies focused on nocturnal blood pressure non-dipping rarely assess sleep, and experimental evidence linking disturbed sleep with nocturnal blood pressure non-dipping in Black individuals is lacking. While mounting evidence from independent literatures suggests that disturbed sleep is a plausible, modifiable mechanism of race differences in nocturnal blood pressure non-dipping, definitive conclusions are premature given the current state of science.

Maternal Sleep in Pregnancy and Postpartum Part I: Mental, Physical, and Interpersonal Consequences.

PURPOSE OF REVIEW: Sleep is a critical restorative behavior which occupies approximately one third of people's lives. Extensive data link sleep health with disease and mortality risk in the general population. During pregnancy and following childbirth, unique factors contribute to overall sleep health. In addition, there are unique implications of poor sleep during these time periods. RECENT FINDINGS: Poor maternal sleep may contribute to risk for adverse birth outcomes as well as poor maternal physical and mental health in pregnancy, postpartum, and longer term during childrearing. Moreover, the extent to which notable racial disparities in sleep contribute to disparities in adverse perinatal health outcomes remains to be fully explicated. Part I of this two-part review details these implications of poor sleep for mental health, physical health outcomes, and relationship functioning, while Part II delves into biological mechanisms as well as treatment approaches.