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

Racial differences in sympathetic nervous system indicators: Implications and challenges for research

Growing evidence indicates the presence of racial differences in sympathetic nervous system (SNS) functioning, yet the nature of these differences is unclear and appears to vary across different indices of SNS activity. Moreover, racial differences among commonly used indices of SNS activity are under-investigated. This systematic review examines racial differences among widely used resting SNS indices, such as electrodermal activity (EDA), pre-ejection period (PEP), and salivary alpha-amylase (sAA). Our review reveals that Black participants have consistently been found to display lower resting EDA compared to White participants. The few studies that have investigated or reported racial differences in PEP and sAA yield mixed findings about whether racial differences exist. We discuss potential reasons for racial differences in SNS activity, such as index-specific factors, lab confounds, psychosocial environmental factors, and their interactions. We outline a framework characterizing possible contributors to racial differences in SNS functioning. Lastly, we highlight the implications of several definitional, analytic, and interpretive issues concerning the treatment of group differences in psychophysiological activity and provide future recommendations.

Sleep and disparities in child and adolescent development

Sleep is a robust predictor of child and adolescent development. Race/ethnicity, socioeconomic status (SES), and related experiences (e.g., discrimination) are associated with sleep, but researchers have just begun to understand the role of sleep in the development of racial/ethnic and SES disparities in broader psychosocial adjustment and cognitive functioning during childhood and adolescence. In this article, we discuss poor sleep as a potential mechanism contributing to the development of such disparities, and better sleep as a potential protective factor that diminishes such disparities. We conclude by offering recommendations for research to advance understanding of sleep as a key bioregulatory system that may underlie or protect against detrimental developmental outcomes related to socioeconomic adversity and belonging to a historically minoritized group.

Psychophysiological and affective reactivity to vicarious police violence

Little is known about how vicarious police violence, or instances of police violence observed but not directly experienced, impacts health among Black individuals. Using a lab-based paradigm in a sample of young adults (N = 101), this study examined: (a) psychophysiological reactivity to instances of vicarious police violence, particularly the assault and shooting of Black individuals; (b) affective reactivity to instances of vicarious police violence; and (c) how racial identity, one important moderator, influences psychophysiological and affective responses to vicarious police violence. Using electrocardiography and impedance cardiography, participants' cardiac sympathetic and parasympathetic physiological responses were continuously monitored. Three sets of high-quality color photographs (neutral, non-violent distress, violence) were viewed on a computer. Participants rated their affect after each set using the Positive and Negative Affect Schedule (PANAS). Following this task, racial identity was assessed using the Multidimensional Inventory of Black Identity-Short Form. Findings indicated that vicarious police violence was associated with greater sympathetic reactivity and negative affect relative to the neutral and non-violent distress conditions. Additionally, higher levels of racial centrality exacerbated the association between vicarious police violence and negative affect. Findings suggest that Black individuals may wish to limit their consumption of media depicting the assault and shooting of other Black individuals, with the caveat that the best solution is ultimately the cessation of police violence.

The effect of using activity workstations on heart rate variability during complex cognitive tasks

ObjectivesThe purpose of the current study was to examine the effects of using an activity workstation on the physiological stress response as measured by heart rate variability while completing cognitively demanding tasks. Participants: Eleven college students (6 females; age: 19.4 ± 0.9 years) participated in the study. Methods: The participants completed three psychologically stressful cognitive tasks while seated at a traditional desk and while using an activity workstation. Heart rate variability was recorded and analyzed with power spectrum density and time-domain analysis. Results: Using activity workstations while completing stressful cognitive tasks did not negatively affect task performance. There was; however, a reduction in low frequency heart rate variability but no change in cardiac sympathovagal balance. Conclusion: The results indicate that using activity workstations while completing difficult tasks reduces sympathetic reactivity to stress in college students. This suggests that using activity workstations could provide a coping mechanism for stress.

Linear and nonlinear associations between the sleep environment, presleep conditions, and sleep in adolescence: moderation by race and socioeconomic status

OBJECTIVE/BACKGROUND

The role of the sleep environment and presleep conditions that may influence adolescents' sleep are understudied. The aims of the current study were to examine linear and nonlinear associations between the sleep environment and presleep conditions and adolescents' daytime sleepiness and sleep/wake problems.

METHOD

Participants included 313 adolescents (M_age = 17.39 years, SD = 10.38 months; 51.4% girls, 48.6% boys; 59.1% White/European American, 40.3% Black/African American) from a wide range of socioeconomic backgrounds living in the southeastern United States. Adolescents completed surveys assessing the sleep environment (eg, light, bedding), four presleep conditions (ie, general worries, family concerns, arousal, somatic complaints), and sleep (daytime sleepiness, sleep/wake problems).

RESULTS

Sleep environment disruptions and worse presleep conditions were positively associated with sleepiness and sleep/wake problems in a linear fashion. Nonlinear associations emerged such that levels of sleepiness increased rapidly between low and average levels of the sleep environment and two presleep conditions (worries, arousal); the slope leveled off between average and high levels. Moreover, linear effects of environmental disruptions, family concerns, somatic complaints, and presleep arousal on sleep/wake problems were moderated by race and/or SES, indicating that positive associations between some presleep conditions and sleep/wake problems were more pronounced for Black and lower SES youth.

CONCLUSIONS

Results support the importance of the sleep environment and multiple presleep conditions and assessments of both linear and nonlinear effects for a better understanding of factors that may contribute to sleep. Additionally, results indicate the sleep environment and some presleep conditions may be more consequential for disadvantaged youth.

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.

Maturation of the Cardiac Autonomic Nervous System Activity in Children and Adolescents

Background

Despite the increasing interest in cardiac autonomic nervous activity, the normal development is not fully understood. The main aim was to determine the maturation of different cardiac sympathetic‐(SNS) and parasympathetic nervous system (PNS) activity parameters in healthy patients aged 0.5 to 20 years. A second aim was to determine potential sex differences.

Methods and Results

Five studies covering the 0.5‐ to 20‐year age range provided impedance‐ and electrocardiography recordings from which heart rate, different PNS‐parameters (eg, respiratory sinus arrhythmia) and an SNS‐parameter (pre‐ejection period) were collected. Age trends were computed in the mean values across 12 age‐bins and in the age‐specific variances. Age was associated with changes in mean and variance of all parameters. PNS‐activity followed a cubic trend, with an exponential increase from infancy, a plateau phase during middle childhood, followed by a decrease to adolescence. SNS‐activity showed a more linear trend, with a gradual decrease from infancy to adolescence. Boys had higher SNS‐activity at ages 11 to 15 years, while PNS‐activity was higher at 5 and 11 to 12 years with the plateau level reached earlier in girls. Interindividual variation was high at all ages. Variance was reasonably stable for SNS‐ and the log‐transformed PNS‐parameters.

Conclusions

Cardiac PNS‐ and SNS‐activity in childhood follows different maturational trajectories. Whereas PNS‐activity shows a cubic trend with a plateau phase during middle childhood, SNS‐activity shows a linear decrease from 0.5 to 20 years. Despite the large samples used, clinical use of the sex‐specific centile and percentile normative values is modest in view of the large individual differences, even within narrow age bands.

Sleep and development in adolescence in the context of socioeconomic disadvantage

INTRODUCTION

Sleep problems are associated with negative developmental outcomes in youth, and identification of vulnerability and protective factors is needed to explicate for whom and under which conditions adolescents may be most at risk. Towards this end, we examined socio-economic status (SES) as a moderator of associations between multiple sleep parameters and adolescents' socio-emotional adjustment and cognitive functioning.

METHODS

Participants were 272 adolescents (M age = 17.3 years; 49% girls) and their parents, residing in the Southeastern U.S.A. The sample was socioeconomically diverse and included 41% Black/African American and 59% White/European American youth. Using a cross-sectional design, adolescents' sleep was assessed with actigraphy (total sleep minutes; efficiency indicated by % of time asleep from sleep onset to wake time) and self-reports of sleep quality (sleep-wake problems). Mothers reported on youths' internalizing and externalizing symptoms, and cognitive functioning was assessed with a standardized test battery.

RESULTS

Moderation effects were found and illustrated that, for youth from families with lower SES, shorter and less efficient sleep and subjective sleep problems were associated with higher levels of internalizing and externalizing symptoms as well as lower cognitive performance. Conversely, longer and better-quality sleep protected against socio-emotional and cognitive difficulties otherwise observed for socioeconomically disadvantaged youth. Fewer relations between sleep and adjustment emerged for adolescents from families with higher SES.

CONCLUSIONS

Results reinforce a growing literature indicating that the relation between sleep and adjustment is stronger for youth from families with lower SES, who may especially benefit from better sleep.

Trajectory of heart period to socioaffective threat in shy children

Although shyness is characterized by distinct psychophysiological correlates, we know very little about the development of these correlates. In this longitudinal study, we examined how children's shyness was associated with trajectories of heart period (HP) to socioaffective threat across four assessments spanning approximately 2 years. Children (M_age  = 6.39 years) viewed age-appropriate, socioaffective videos at each visit while having their HP measured concurrently. A growth curve analysis revealed that low shy children had a relatively lower HP at enrollment, but experienced increases in HP across visits, while high shy children exhibited relatively stable low HP across visits while viewing threat-related socioaffective video stimuli. These patterns did not exist for HP during resting baseline or HP to nonthreatening video stimuli. These findings suggest that longitudinal patterns of HP among shy children may reflect a stable, characteristic way of responding to socioaffective threat, and possibly a physiological mechanism underlying shyness in some children.