Sympathetic and Parasympathetic Nervous System Functioning and Experiences of Peer Exclusion: Links to Internalizing Problems in Early Adolescence

Is autonomic functioning distinctly associated with anxiety and unsociability in preschoolers?

There are many benefits of peer interactions for children's social, emotional, and cognitive development, and isolation from peers may have negative consequences for children. Although biological processes may underlie social withdrawal broadly, distinct patterns may be associated with withdrawal behaviors depending on their underlying motivation (e.g., shy versus disinterested). This study investigated the role of autonomic nervous system activity, as assessed via skin conductance level (SCL) and respiratory sinus arrhythmia (RSA) in predicting changes in unsociability (e.g., lack of interest in peers) and anxious-fearfulness (e.g., discomfort among peers). Data were collected using a community sample of 92 US preschool children (45.7% female; Mage = 45.51 months, SDage = 3.81 months) at two time points one year apart. Gender differences were also explored. Baseline physiology was assessed while viewing a neutral video clip, and reactivity was assessed while viewing social exclusion and post-aggression discussion videos. For all children, coinhibition (i.e., SCL inhibition accompanied by RSA inhibition) to the post-aggression discussion video and blunted SCL activation to the exclusion video were prospectively associated with higher levels of anxious-fearfulness one year later. For boys only, baseline reciprocal sympathetic activation (i.e., SCL activation and RSA inhibition) was prospectively related to higher levels of unsociability one year later. For girls only, RSA inhibition in response to the post-aggression discussion video was prospectively related to higher levels of unsociability one year later. Findings contribute to a growing literature on autonomic reactivity in preschoolers' adjustment and suggest possible differences in the physiological processes underlying unsociability and anxious-fearfulness.

The Role of Autonomic System Coordination in Relations Between Peer Factors and Aggressive Behavior in Early Childhood

This study tested biological sensitivity to context theory in the peer context. Respiratory sinus arrythmia (RSA-R) and skin conductance level (SCL-R) reactivity to a peer stressor were collected for participants (N = 86; M age = 45.99 months old; 70.2% White) in the summer (Time 1). Children's peer risk (i.e., physical and relational victimization) and protective (i.e., received prosocial behavior) factors were examined in the fall (T2) and relational and physical aggression were measured at T2 and in the spring (T3). Interactions were tested in regression analyses. Interactions emerged between relational victimization, RSA-R, and SCL-R in the prediction of T3 relational aggression and between received prosocial behavior, RSA-R, and SCL-R in the prediction of T3 relational and physical aggression, respectively. There was a positive relation between T2 relational victimization and T3 relational aggression for children with a coactivation pattern (i.e., increased RSA and SCL activity to a bullying stressor) but no relation for any other physiological pattern. Conversely, there was a negative relation between T2 received prosocial behavior and both forms of aggression at T3 for children with a reciprocal pattern (i.e., increased RSA and decreased SCL or decreased RSA and increased SCL activity) but no protective benefit of received prosocial behavior on subsequent aggression for children with a coactivation pattern. For children with a coinhibition pattern (i.e., decreased RSA and SCL activity), received prosocial behavior was negatively related to subsequent physical but not relational aggression. In sum, a coactivation pattern in response to stress may represent a vulnerability factor.

Daily Mood Reactivity to Stress during Childhood Predicts Internalizing Problems Three Years Later

The mental health toll of common school problems that many children encounter every day is not well understood. This study examined individual differences in mood reactivity to naturally occurring school problems using daily diaries, and assessed their prospective associations with youth mental health, three years later. At baseline, 47 children ages 8 to 13 years described common problems at school and mood on a daily basis, for 8 weeks. Thirty-three youth returned for follow-up three years later at ages 11 to 17 years. Children and parents also completed one-time questionnaires about youth mental health at baseline and follow-up. There were individual differences in the within-person associations between school problems and same-day and next-day mood. A greater tendency to react to school problems with more negative mood or less positive mood on the same day predicted more parent-rated internalizing and externalizing problems and child ratings of depression symptoms three years later, relative to baseline levels of symptoms. Daily diaries can help to identify specific targets of psychosocial interventions in real world settings.

Diving in the Arctic: Cold Water Immersion's Effects on Heart Rate Variability in Navy Divers

Introduction

Diving close to the Arctic circle means diving in cold water regardless of the time of year. The human body reacts to cold through autonomous nervous system (ANS)-mediated thermoregulatory mechanisms. Diving also induces ANS responses as a result of the diving reflex.

Materials and Methods

In order to study ANS responses during diving in Arctic water temperatures, we retrospectively analyzed repeated 5-min heart rate variability (HRV) measures and the mean body temperature from dives at regular intervals using naval diving equipment measurement tests in 0°C water. Three divers performed seven dives without physical activity (81–91 min), and two divers performed four dives with physical activity after 10 min of diving (0–10 min HRV recordings were included in the study).

Results

Our study showed a significant increase in parasympathetic activity (PNS) at the beginning of the dives, after which PNS activity decreased significantly (measure 5–10 min). Subsequent measurements (15–20 min and onward) showed a significant increase in PNS activity over time.

Conclusion

Our results suggest that the first PNS responses of the human diving reflex decrease quickly. Adverse effects of PNS activity should be considered on long and cold dives. To avoid concurrent sympathetic (SNS) and PNS activity at the beginning of dives, which in turn may increase the risk of arrhythmia in cold water, we suggest a short adaptation phase before physical activity. Moreover, we suggest it is prudent to give special attention to cardiovascular risk factors during pre-dive examinations for cold water divers.