Linking bioregulatory systems: reciprocal autonomic activation predicts sleep over 1 year in middle childhood

Race, Ethnicity, and Sleep in US Children

Importance

Although racial and ethnic disparities are well documented in children's mean levels of sleep, particularly duration, evidence is mixed for sleep variability, an important sleep dimension of growing interest. Most research has also focused on comparisons of Black and White children, with limited attention to sleep variability disparities among other racially and ethnically minoritized groups such as Asian, Latinx, and multiracial children.

Objective

To investigate racial and ethnic disparities in children's mean levels of sleep and variability of sleep across multiple dimensions and diverse racial and ethnic groups using actigraphy data.

Design, Setting, and Participants

This cross-sectional study used data from the Adolescent Brain Cognitive Development (ABCD) study, a national cohort study, from 21 study sites across the US. ABCD participants were recruited at baseline (2016-2018) using a multistage, stratified, probability sampling method. The current study used a subsample with reliable actigraphy data collected at 2-year follow-up (2018-2020). Data analysis occurred from July 2023 to October 2024.

Exposures

Parent-reported race and ethnicity at baseline. Sociodemographic, health, and contextual covariates of sleep were also included.

Main Outcomes and Measures

Actigraphy-assessed mean levels of sleep and sleep variability across multiple dimensions (duration, bedtime, risetime, efficiency, and latency) over 3 weeks.

Results

The analytic sample included 3868 children (mean [SD] age, 11.50 [0.67] years; 1913 female [49.5%]), of whom 104 (2.7%) were Asian, 347 (9.0%) were Black or African American, 801 (20.7%) were Latinx, 356 (9.2%) were multiracial, and 2260 (58.4%) were White. Asian, Black, Latinx, and multiracial children exhibited shorter sleep duration and later bedtime than White children. Importantly, compared with White children, bedtime variability was greater among Asian (β = 0.04; 95% CI, 0.01 to 0.07; P = .02), Black (β = 0.11 95% CI, 0.08 to 0.15; P < .001), Latinx (β = 0.08; 95% CI, 0.05 to 0.12; P < .001), and multiracial children (β = 0.08; 95% CI, 0.05 to 0.11; P < .001). Similarly, risetime variability was greater among Asian (β = 0.04; 95% CI, 0.01 to 0.07; P = .01), Black (β = 0.08; 95% CI, 0.04 to 0.12; P < .001), and Latinx (β = 0.06; 95% CI, 0.02 to 0.10; P < .01) children in comparison with White children. Black children exhibited the most profound disparities across mean levels (duration and bedtime) and variability of sleep (duration, bedtime, risetime, and efficiency) than other groups. Asian and multiracial children also exhibited some disparities sleep duration, efficiency, and efficiency variability, when compared with Latinx children.

Conclusions and Relevance

In this cross-sectional study of children's sleep disparities, racially and ethnically minoritized children exhibited disparities in mean levels and variability of sleep compared with their White peers. These findings suggest that policies and practices should target multiple sleep dimensions among diverse racial and ethnic groups to promote equitable pediatric sleep health.

A developmental perspective on sleep consistency: Preschool age through emerging adulthood

OBJECTIVE/BACKGROUND

Beyond sleep duration, the regularity of sleep patterns (e.g., sleep consistency), including variability in sleep timing (e.g., bedtime, wake time) and duration, is a critical marker of sleep health. Sleep consistency is captured using a variety of methods within the literature (e.g., sleep intraindividual variability, social jetlag), but most of the research focuses on adolescents.

METHODS

Drawing on a developmental perspective, this narrative review highlights how normative changes at the individual (e.g., biological, cognitive, and social) and contextual (e.g., home, school, sociocultural) levels may contribute to inconsistent sleep patterns across development.

RESULTS AND CONCLUSIONS

This review emphasizes how inconsistent sleep may increase across pivotal transitions throughout development (e.g., elimination of naps, puberty, summertime, entering college). Finally, recommendations for measuring sleep consistency and areas to address in future research are discussed.

Discrimination and adjustment in adolescence: the moderating role of sleep

STUDY OBJECTIVES

We examined multiple actigraphy-based sleep parameters as moderators of associations between experiences of general and racial discrimination and adolescent internalizing symptoms (anxiety, depression) and externalizing behavior (rule-breaking). Adolescent sex and race were examined as additional moderators.

METHODS

Participants were 272 adolescents (Mage = 17.3 years, SD = 0.76; 51% male; 59% White/European American, 41% Black/African American). Sleep was assessed using actigraphs for 7 consecutive nights from which sleep duration (minutes), efficiency, and variability in minutes over the week were derived. Youth reported on their experiences of general discrimination, racial discrimination, anxiety, depressive symptoms, and rule-breaking behavior.

RESULTS

Both types of discrimination were associated with poorer adjustment outcomes. Longer sleep duration, greater sleep efficiency, and less variability in sleep duration were protective in associations between race-specific and general discrimination and internalizing symptoms. Findings for duration and efficiency were more pronounced for females such that the adverse effects of discrimination were minimized among females with longer and more efficient sleep. Greater variability in sleep exacerbated rule-breaking behavior among adolescents experiencing general or racial discrimination. Associations did not differ by adolescent race.

CONCLUSIONS

Short and poor-quality sleep may exacerbate internalizing symptoms for adolescents experiencing discrimination, particularly females. Variability in sleep duration was a key moderator of associations between discrimination and internalizing symptoms as well as rule-breaking behavior. Findings illustrate that actigraphy-assessed sleep parameters play a key role in ameliorating or exacerbating adjustment problems associated with discrimination.

Vigilant or avoidant? Children's temperamental shyness, patterns of gaze, and physiology during social threat

Temperamental shyness is characterized by fear, wariness, and the perception of threat in response to social novelty. Previous work has been inconsistent regarding attentional patterns to social threat among shy children, with evidence for both avoidance and vigilance. We examined relations between children's shyness and gaze aversion during the approach of a stranger (i.e., a context of social novelty), and tested whether these patterns of gaze moderated relations between shyness and autonomic reactivity and recovery. Participants included 152 typically-developing children (M_age  = 7.82 years, SD = 0.44 years) who had their respiratory sinus arrhythmia (RSA) recorded during baseline, social novelty, and recovery. Children's shyness correlated with increases in self-reported nervousness from baseline to social novelty, providing support for perceived threat. Results revealed that children's proportion of gaze aversion from social novelty was related to shyness in a U-shape pattern such that both low levels of gaze aversion (i.e., attentional vigilance) and high levels of gaze aversion (i.e., attentional avoidance) were related to higher levels of shyness. Further, we found that children's shyness was directly related to decreases in RSA from baseline to social novelty, whereas quadratic gaze to social novelty moderated the relation between shyness and RSA recovery. Specifically, shyness was related to greater RSA recovery among children who exhibited attentional vigilance during the novel social interaction. Our findings provide support for both avoidance of, and vigilance to, social threat among different shy children, and these gaze strategies may be differentially related to physiological regulation during novel social encounters.

Quality of father-child relationships as a predictor of sleep developments during preschool years

Substantial developmental changes in sleep occur during the preschool period, but few studies have investigated the factors that forecast these developments. The aim of this study was to examine whether three aspects of father-child relationships in toddlerhood predicted individual differences in developmental patterns of change in five actigraphy-derived sleep variables during the preschool period (N = 67; sleep assessed yearly between 2 and 4 years). In a predominantly White and middle-to-higher income sample, paternal mind-mindedness and quality of father-child interactions were assessed during father-child free play at 18 months and fathers self-reported on their involvement in childrearing at age 2. Multilevel growth modeling revealed that children whose father made more mind-related comments during father-child interactions had a higher proportion of sleep taking place during nighttime as well as shorter daytime and total sleep duration at 2 years. This was, however, followed by a relative leveling off (i.e., less rapid change) of these sleep features between 2 and 4 years. Given previous studies documenting that nighttime sleep proportion increases while daytime and total sleep duration decrease during preschool years, the findings suggest that children who are exposed to more paternal mind-mindedness may reach more mature sleep patterns earlier in development.

Linking autonomic nervous system reactivity with sleep in adolescence: Sex as a moderator

The purpose of the present study was to investigate relations between autonomic nervous system (ANS) reactivity across the parasympathetic and sympathetic branches and multiple sleep parameters in adolescence. Participants were 244 adolescents (Mage  = 15.79 years old, SD = 9.56 months; 67.2% White/European-American, 32.8% Black/African-American). Parasympathetic activity was indexed by respiratory sinus arrhythmia (RSA) withdrawal and sympathetic activity was indexed by skin conductance level reactivity (SCL-r), which were examined in response to a laboratory-based stressor (star-tracing task). Sleep was assessed with actigraphs in adolescents' homes for seven consecutive nights. Two sleep parameters were examined: sleep duration indexed by actual sleep minutes and sleep quality indexed by sleep efficiency from sleep onset to wake time. Regression analyses showed that more RSA withdrawal (lower RSA during task than baseline) was associated with shorter sleep, and more SCL-r (higher SCL during task than baseline) was associated with poorer sleep efficiency. Moderation analyses showed that associations linking RSA withdrawal with fewer sleep minutes and poorer sleep efficiency, and SCL-r with fewer sleep minutes were significant only for boys. Results illustrate that higher daytime physiological reactivity (increased RSA withdrawal and SCL-r) is negatively associated with sleep duration and efficiency for adolescents, especially boys.

A meta-analysis of accelerometer sleep outcomes in healthy children based on the Sadeh algorithm: the influence of child and device characteristics

STUDY OBJECTIVES

Children often experience sleep problems, with a negative impact on mood, behavior, cognitive function, and other aspects of mental and physical health. Accelerometers are widely used to assess sleep, but general reference values for healthy children do not yet exist. The aim of this meta-analysis was to determine mean values for wake after sleep onset (WASO), sleep efficiency (SE), total sleep time (TST) and sleep onset latency (SOL), and to determine the effect of child and accelerometer-characteristics.

METHODS

A search included studies with healthy children, 0-18 years, reporting WASO, SE, TST, and/or SOL, calculated with the Sadeh algorithm. Meta-analyses with random effects produced pooled estimate means per outcome. Meta-regression analyses determined the effect of age, sex, placement site and accelerometer type.

RESULTS

Eighty-three studies (9,068 participants) were included. Pooled means were 63 min (95% CI 57 to 69) for WASO, 88% (95% CI 87 to 89) for SE, 477 min (95% CI 464 to 491) for TST and 19 min (95% CI 17 to 22) for SOL. Heterogeneity was high (95%-99%). TST decreased with age and there was an age-effect on SOL. SE differed between wrist and ankle (used in age 0-24 months) placement, and between piezoelectric and MEMS-type accelerometers. No differences were found between boys and girls, although this number of studies was small.

CONCLUSIONS

We found differences in almost all investigated outcomes and heterogeneity was high. Therefore, we advise to use a study-specific control sample until more robust reference values are available. Future research should narrow the methodological heterogeneity and produce larger datasets, needed to establish these reference values.

A latent change score approach to understanding dynamic autonomic coordination

Children's self-regulation is a core adaptive system in child development. Physiological indices of regulation, particularly the autonomic nervous system (ANS), have garnered increased attention as an informative level of analysis in regulation research. Cardiography supports the simultaneous examination of both ANS branches via measures of pre-ejection period (PEP) and respiratory sinus arrhythmia (RSA) as indicators of sympathetic and parasympathetic activity, respectively. However, despite their heavily intertwined functions, research examining autonomic coordination across sympathetic and parasympathetic systems is scarce. Moreover, extant efforts have favored static, mean level reactivity analyses, despite the dynamic nature of ANS regulation and the availability of analytic tools that can model these processes across time. This study drew on a sample of 198 six-year-old children from a diverse community sample (49.5% female, 43.9% Latinx) to examine dynamic autonomic coordination using bivariate latent change score modeling to evaluate bidirectional influences of sympathetic and parasympathetic activity over the course of a challenging puzzle completion task. Results indicated that children evidenced reciprocal sympathetic activation (i.e., PEP attenuation and RSA withdrawal) across the challenge task, and these regulatory responses were characterized by a temporally leading influence of PEP on lagging changes in RSA. The current findings contribute to our understanding of children's autonomic coordination while illustrating a novel analytic technique to advance ongoing efforts to understand the etiology and developmental significance of children's physiological self-regulation.

Quantity versus quality of objectively measured sleep in relation to body mass index in children: cross-sectional and longitudinal analyses

BACKGROUND/OBJECTIVES

Although sleep duration is well established as a risk factor for child obesity, how measures of sleep quality relate to body size is less certain. The aim of this study was to determine how objectively measured sleep duration, sleep timing, and sleep quality were related to body mass index (BMI) cross-sectionally and longitudinally in school-aged children.

SUBJECTS/METHODS

All measures were obtained at baseline, 12 and 24 months in 823 children (51% female, 53% European, 18% Māori, 12% Pacific, 9% Asian) aged 6-10 years at baseline. Sleep duration, timing, and quality were measured using actigraphy over 7 days, height and weight were measured using standard techniques, and parents completed questionnaires on demographics (baseline only), dietary intake, and television usage. Data were analysed using imputation; mixed models, with random effects for person and age, estimated both a cross-sectional effect and a longitudinal effect on BMI z-score, adjusted for multiple confounders.

RESULTS

The estimate of the effect on BMI z-score for each additional hour of sleep was -0.22 (95% CI: -0.33, -0.11) in cross-sectional analyses and -0.05 (-0.10, -0.004) in longitudinal analyses. A greater effect was observed for weekday sleep duration than weekend sleep duration but variability in duration was not related to BMI z-score. While sleep timing (onset or midpoint of sleep) was not related to BMI, children who were awake in the night more frequently (0.19; 0.06, 0.32) or for longer periods (0.18; 0.06, 0.36) had significantly higher BMI z-scores cross-sectionally, but only the estimates for total time awake (minutes) were significant longitudinally (increase in BMI z-score of 0.04 for each additional hour awake).

CONCLUSION

The beneficial effect of a longer sleep duration on BMI was consistent in children, whereas evidence for markers of sleep quality and timing were more variable.

Marital conflict and trajectories of adolescent adjustment: The role of autonomic nervous system coordination

The present study investigates how coordination between stress responsivity of the parasympathetic nervous system (PNS) and sympathetic nervous system (SNS) moderates the prospective effects of marital conflict on internalizing and externalizing symptoms across adolescence. Although an important avenue for psychophysiological research concerns how PNS and SNS responses jointly influence adjustment in the context of stress, these processes have rarely been studied in adolescence or longitudinally. Participants were 252 youth (53% female, 66% European American, 34% African American) who participated in laboratory assessments when they were 16, 17, and 18 years old. PNS activity (measured via respiratory sinus arrhythmia [RSA]) and SNS activity (measured via skin conductance level [SCL]) were assessed during a resting baseline and in response to a laboratory-based challenge (star tracing). Parents and adolescents both reported on marital conflict and adolescents reported on their internalizing and externalizing symptoms. At higher levels of marital conflict, coactivation of PNS and SNS activity, characterized by increased RSA and increased SCL from baseline to challenge, predicted elevated internalizing symptoms and an increase in externalizing behavior across adolescence. Coinhibition, or decreased activity across both systems, also predicted an increase in internalizing symptoms over time. At lower levels of marital conflict, internalizing and externalizing symptoms were relatively low. Findings extend primarily cross-sectional work with younger children by demonstrating that coordination between the two branches of the autonomic nervous system (ANS) moderates the longitudinal effects of marital conflict on psychological and behavioral maladjustment among adolescents. (PsycINFO Database Record

High-Frequency Heart Rate Variability Reactivity and Trait Worry Interact to Predict the Development of Sleep Disturbances in Response to a Naturalistic Stressor

BACKGROUND

High-frequency heart rate variability (HF-HRV) reactivity was proposed as a vulnerability factor for stress-induced sleep disturbances. Its effect may be amplified among individuals with high trait worry or sleep reactivity.

PURPOSE

This study evaluated whether HF-HRV reactivity to a worry induction, sleep reactivity, and trait worry predict increases in sleep disturbances in response to academic stress, a naturalistic stressor.

METHOD

A longitudinal study following 102 undergraduate students during an academic semester with well-defined periods of lower and higher academic stress was conducted. HF-HRV reactivity to a worry induction, trait worry using the Penn State Worry Questionnaire, and sleep reactivity using the Ford Insomnia Stress Reactivity Test were measured during the low stress period. Sleep disturbances using the Pittsburgh Sleep Quality Index were assessed twice during the lower stress period and three times during the higher stress period.

RESULTS

Greater reductions in HF-HRV in response to the worry induction predicted increases in sleep disturbances from the lower to the higher academic stress period. Trait worry moderated this association: individuals with both higher trait worry and greater HF-HRV reactivity to worry had larger increases in stress-related sleep disturbances over time, compared to participants with lower trait worry and HF-HRV reactivity. A similar, but marginally significant effect was found for sleep reactivity.

CONCLUSION

This study supports the role of HF-HRV reactivity as a vulnerability factor for stress-induced sleep disturbances. The combination of high trait worry and high HF-HRV reactivity to worry might identify a subgroup of individuals most vulnerable to stress-related sleep disturbances.

Children's Autonomic Nervous System Reactivity Moderates the Relations between Family Adversity and Sleep Problems in Latino 5-Year Olds in the CHAMACOS Study

Sleep problems are common for young children especially if they live in adverse home environments. Some studies investigate if young children may also be at a higher risk of sleep problems if they have a specific biological sensitivity to adversity. This paper addresses the research question, does the relations between children’s exposure to family adversities and their sleep problems differ depending on their autonomic nervous system’s sensitivity to challenges? As part of a larger cohort study of Latino, low-income families, we assessed the cross-sectional relations among family demographics (education, marital status), adversities [routines, major life events (MLE)], and biological sensitivity as measured by autonomic nervous system (ANS) reactivity associated with parent-rated sleep problems when the children were 5 years old. Mothers were interviewed in English or Spanish and completed demographic, family, and child measures. The children completed a 15-min standardized protocol while continuous cardiac measures of the ANS [respiratory sinus arrhythmia (RSA), preejection period (PEP)] were collected during resting and four challenge conditions. Reactivity was defined as the mean of the responses to the four challenge conditions minus the first resting condition. Four ANS profiles, co-activation, co-inhibition, reciprocal low RSA and PEP reactivity, and reciprocal high RSA and PEP reactivity, were created by dichotomizing the reactivity scores as high or low reactivity. Logistic regression models showed there were significant main effects for children living in families with fewer daily routines having more sleep problems than for children living in families with daily routines. There were significant interactions for children with low PEP reactivity and for children with the reciprocal, low reactivity profiles who experienced major family life events in predicting children’s sleep problems. Children who had a reciprocal, low reactivity ANS profile had more sleep problems if they also experienced MLE than children who experienced fewer MLE. These findings suggest that children who experience family adversities have different risks for developing sleep problems depending on their biological sensitivity. Interventions are needed for young Latino children that support family routines and reduce the impact of family adversities to help them develop healthy sleep practices.

Trajectories of sleep and cardiac sympathetic activity indexed by pre-ejection period in childhood

Fragmented and insufficient sleep has been implicated in disrupted autonomic nervous system activity during resting state conditions in typically developing children. Towards explication of these relations over development, the current study tested reciprocal relations between the development of sleep parameters (efficiency, duration, latency) and cardiac sympathetic nervous system (SNS) activity indexed by pre-ejection period (PEP) during waking-resting state conditions throughout middle and late childhood. Whether sleep derives changes in PEP or vice versa was examined. A longitudinal design was employed and latent growth modelling was used to examine the research questions. During the first assessment, 282 children aged 9.44 years (65% European American, 35% African American) participated. Two more assessments followed, with a 1-year lag between consecutive study waves. Sleep was examined with 7 nights of actigraphy in the child's home. Controlling for many potential confounds (sex, race/ethnicity, body mass index and family socioeconomic status), higher sleep efficiency and more sleep minutes predicted increases in PEP (less SNS activity) over 3 years. PEP did not predict changes in sleep efficiency or duration over time and there were no significant effects for sleep latency. Findings highlight the probable direction of effects between these two key bioregulatory systems. High levels of cardiac SNS activity are associated with many negative health outcomes, and thus these findings may have important implications.

Intraindividual variability of sleep/wake patterns in relation to child and adolescent functioning: A systematic review

Substantial research attention has been devoted to understanding the importance and impact of sleep in children and adolescents. Traditionally, this has focused on mean sleep variables (e.g., a child's "typical" or average sleep duration), yet research increasingly suggests that intraindividual variability (IIV) of sleep/wake patterns (sometimes referred to as sleep variability or night-to-night variability) regularly occurs and may have implications for adjustment. A systematic search of five electronic databases identified 52 empirical studies published between 2000 and 2015 that examined correlates of sleep IIV in children and adolescents, with a recent increase in the publication rate of such studies. Identified studies were often atheoretical and included post hoc analyses, though IIV in select aspects of sleep does appear to be associated with increasing age/pubertal status, non-White race, physical and neurodevelopmental conditions (e.g., attention-deficit/hyperactivity disorder; autism), psychopathology symptoms (e.g., anxiety, depression, inattention), body weight, stress, aspects of cognitive functioning, and poorer sleep functioning/habits. The limited intervention work examining sleep IIV in adolescents is promising, though studies are needed using more rigorous intervention designs. Clinical sleep recommendations may not only need to address overall sleep duration and sleep habits but also the stability of sleep duration and timing. It will be important for future research examining sleep IIV in children and adolescents to use a developmental framework in advancing theory pertaining to the causes, mechanisms, moderators, and outcomes of sleep IIV in youth, and a conceptual model is proposed to help guide such efforts.