Moderate-to-vigorous physical activity and reactivity to acute psychosocial stress in preadolescent children

OBJECTIVES

High reactivity to psychosocial stress during childhood increases the risk of future psychological and physiological disorders. The main objective of this study was to investigate associations between children's moderate-to-vigorous physical activity (MVPA) and physiological and psychological reactions to acute psychosocial stress.

DESIGN

Randomized cross-over study comparing two groups.

METHODS

After a 7-day accelerometer-based measurement of MVPA, 110 children aged 10-13 years (48 female) were categorized into a low (<30 min/d) or a high MVPA group (>60 min/d). On separate laboratory appointments, participants completed the Trier Social Stress Test for Children (TSST-C) and a non-stressful control task in randomized order. Stress reactivity was assessed from saliva cortisol, heart rate variability and self-reported anxiety.

RESULTS

In repeated measures analyses of variance, main effects of condition indicated higher stress reactivity in the TSST-C compared to control for cortisol and anxiety, with more pronounced effects in girls compared to boys. Differences in heart rate variability disappeared after controlling for confounding variables. No interactions with MVPA were found. A main effect of MVPA indicated generally lower cortisol reactivity in the high compared to the low MVPA group.

CONCLUSIONS

The TSST-C is suitable for induction of psychosocial stress in the laboratory, but sex-specific differences have to be considered. Children who met the WHO recommendations for MVPA exhibited generally lower endocrine reactivity to both laboratory tasks combined, underlining the potential role of regular physical activity in the regulation of the stress response in early developmental stages. Further studies are necessary to ascertain causal associations.

Early life adversity is associated with attenuated testosterone reactivity to acute stress among adolescents

Understanding how testosterone responds to stress or challenge may be integral to uncovering biological pathways to potentially harmful behaviors like aggression. Yet, studies investigating patterns of testosterone reactivity under stress within adolescent populations are limited. Among those conducted, even fewer have investigated environmental factors which may shape such patterns. Exposure to early life adversity (ELA) has been shown to influence other biological markers of stress reactivity, though how it may be associated with alterations in testosterone reactivity remains underexplored. The current study addresses these gaps by examining salivary testosterone concentrations across the administration of a Trier Social Stress Test for Children in a sample of 87 adolescents (46.4% female, M_age = 13.91 years, SD_age = 1.57). The current study tested two central hypotheses: (1) that testosterone would rise in response to a standardized laboratory stressor, and (2) that greater ELA would be associated with higher baseline (or, pre-stress) testosterone scores and a dampened testosterone response to stress. Adolescents in the current sample showed a robust increase in testosterone following administration of the TSST-C, supporting the limited previous findings which indicate testosterone does mount an acute stress response in adolescents. Contrary to hypotheses, ELA was not associated with significant elevations in baseline testosterone scores. However, ELA was associated with dampened testosterone reactivity, even after controlling for important demographic and biological factors. Methodological implications, including considerations for researchers aiming to capture an acute testosterone response, as well as how our understanding of ELA's role in adolescent biological functioning is extended by our findings regarding testosterone, are discussed.

Secretory immunoglobulin A (s-IgA) reactivity to acute psychosocial stress in children and adolescents: The influence of pubertal development and history of maltreatment

BACKGROUND

Mucosal secretory immunoglobulin A (s-IgA) is an antibody protein-complex that plays a crucial role in immune first defense against infection. Although different immune biomarkers have been associated with stress-related psychopathology, s-IgA remains poorly studied, especially in youth.

OBJECTIVES

The present study investigated how s-IgA behaves in front of acute psychosocial stress in children and adolescents, including possible variability associated with developmental stage and history of childhood maltreatment (CM).

METHODS

94 children and adolescents from 7 to 17 years (54 with a current psychiatric diagnostic and 40 healthy controls) drawn from a larger Spanish study were explored (EPI-Young Stress Project). To assess biological reactivity, participants provided five saliva samples during an acute laboratory-based psychosocial stressor, the Trier Social Stress Test for Children (TSST-C). Samples were assayed for s-IgA, as well as for cortisol. Pubertal development was ascertained by Tanner stage and CM following TASSCV criteria.

RESULTS

We observed s-IgA fluctuations throughout the stressor, indicating the validity of TSST-C to stimulate s-IgA secretion (F(4,199) = 6.200, p <.001). Although s-IgA trajectories followed a reactivity and recovery pattern in adolescents, children exhibited no s-IgA response when faced with stress (F(4,197) = 3.406, p =.010). An interaction was found between s-IgA and CM (F(4,203) = 2.643, p =.035). Interestingly, an interaction between developmental stage, CM history and s-IgA reactivity was identified (F(12,343) = 2.036, p =.017); while children non-exposed to maltreatment exhibited no s-IgA changes to acute stress, children with a history of CM showed a similar response to adolescents, increasing their s-IgA levels after the psychosocial stressor.

CONCLUSION

Acute psychosocial stress stimulates s-IgA secretion, but only after puberty. However, children with a history of maltreatment exhibited a response resembling that of adolescents, suggesting an early maturation of the immune system. Further studies are needed to clarify the validity of s-IgA as an acute stress biomarker, including additional measures during stress exposure.

An inactive control of the 'Trier Social Stress Test' for Youth 10-17 years: Neuroendocrine, cardiac, and subjective responses

The Trier Social Stress Test for children (TSST-C) adapted from TSST is one of the most commonly used laboratory paradigms for investigating the effects of stress on cognitive, affective and physiological responses in children and adolescents. Considering that laboratory procedures generate a significant amount of stress to children and adolescents, even in the absence of a stress paradigm, it is important to validate TSST-C against an inactive control condition in which the stress components were absent. Using a randomized design, we tested an inactive control condition, which replaced the TSST-C with a benign video clip (nature scenes viewed while standing), thus removing the stress associated components of the TSST-C. Eighty-eight youth between the ages of 10 and 17 years were randomly assigned to complete the TSST-C or the Inactive Control (IC). Subjective anxiety rating, salivary cortisol, systolic and diastolic blood pressure, and heart rate were collected at eight time points. Subjects in the Inactive Control condition showed no significant changes in blood pressure and heart rate, and decreased anxiety rating and salivary cortisol level throughout the study. Subjects in the stress condition (TSST-C) showed increased anxiety ratings, salivary cortisol, systolic and diastolic blood pressure, and heart rate immediately following TSST-C stress induction. Our findings validated that the TSST-C induced a systemic stress response, and that the Inactive Control can be a promising standardized control condition for the TSST-C and a tool for future psychobiological research. Our results also showed that anxiety reactivity decreased with age while HR reactivity increased with age. Cortisol reactivity did not fall in a linear relationship with age but rather via a quadratic curve, suggesting the mid-age adolescents had the highest cortisol responses to stress compared to their younger and older peers, potentially due to a dual factor of pubertal development and self-control and emotion regulation capacity.

Stress system dysregulation in pediatric generalized anxiety disorder associated with comorbid depression

Because chronic stress is an important risk factor for anxiety states and depressive disorders, we studied hypothalamus-pituitary-adrenal (HPA) axis and sympathetic system activity via changes in cortisol and alpha amylase activity levels in pediatric generalized anxiety disorder (GAD) patients (n = 26) with comorbid depression and a healthy comparison group (n = 26). Morning plasma cortisol and diurnal profiles of salivary cortisol and salivary alpha amylase (sAA) activity were assessed, also reactivity of HPA-axis, sAA activity, and heart rate following a psychosocial stressor (Trier Social Stress Test for children). GAD patients with comorbid depression showed increased morning plasma and salivary cortisol levels, ameliorating throughout in-patient treatment, and higher sAA activity in their diurnal profile. Both HPA and sympathetic activity positively correlated with the severity of anxiety and depression. We also demonstrated a blunted HPA and sympathetic response to acute stress in patients. This pattern of neuroendocrine and sympathetic changes seems to be distinct from the one previously reported in pediatric patients with only social anxiety or depressive disorders. We propose morning plasma and saliva cortisol levels as potential physiological indicators for supporting the evaluation of symptoms' severity and treatment progress in children with GAD and comorbid depressive disorder.

Does the arrival index predict physiological stress reactivity in children

Knowledge about children's stress reactivity and its correlates is mostly based on one stress task, making it hard to assess the generalizability of the results. The development of an additional stress paradigm for children, that also limits stress exposure and test time, could greatly advance this field of research. Research in adults may provide a starting point for the development of such an additional stress paradigm, as changes in salivary cortisol and alpha-amylase (sAA) over a 1-h pre-stress period in the laboratory correlated strongly with subsequent reactivity to stress task (Balodis et al., 2010, Psychoneuroendocrinology 35:1363-73). The present study examined whether such strong correlations could be replicated in 9- to 11-year-old children. Cortisol and sAA samples were collected from 158 children (83 girls) during a 2.5-h visit to the laboratory. This visit included a 1-h pre-stress period in which children performed some non-stressful tasks and relaxed before taking part in a psychosocial stress task (TSST-C). A higher cortisol arrival index was significantly and weakly correlated with a higher AUCg but unrelated to cortisol reactivity to the stressor. A higher sAA arrival index was significantly and moderately related to lower stress reactivity and to a lower AUCi. Children's personality and emotion regulation variables were unrelated to the cortisol and sAA arrival indices. The results of this study do not provide a basis for the development of an additional stress paradigm for children. Further replications in children and adults are needed to clarify the potential meaning of an arrival index.

Acute psychosocial stress and children's memory

We investigated whether children's performance on working memory (WM) and delayed retrieval (DR) tasks decreased after stress exposure, and how physiological stress responses related to performance under stress. About 158 children (83 girls; Mage = 10.61 years, SD = 0.52) performed two WM tasks (WM forward and WM backward) and a DR memory task first during a control condition, and 1 week later during a stress challenge. Salivary alpha-amylase (sAA) and cortisol were assessed during the challenge. Only WM backward performance declined over conditions. Correlations between physiological stress responses and performance within the stress challenge were present only for WM forward and DR. For WM forward, higher cortisol responses were related to better performance. For DR, there was an inverted U-shape relation between cortisol responses and performance, as well as a cortisol × sAA interaction, with concurrent high or low responses related to optimal performance. This emphasizes the importance of including curvilinear and interaction effects when relating physiology to memory.

Stress and the developing adolescent brain

Adolescence is a time of continued brain maturation, particularly in limbic and cortical regions, which undoubtedly plays a role in the physiological and emotional changes coincident with adolescence. An emerging line of research has indicated that stressors experienced during this crucial developmental stage may affect the trajectory of this neural maturation and contribute to the increase in psychological morbidities, such as anxiety and depression, often observed during adolescence. In this review, we discuss the short- and long-term effects of periadolescent stress exposure on the structure and function of the brain. More specifically, we examine how stress at prepubertal and early adolescent stages of development affects the morphological plasticity of limbic and cortical brain regions, as well as the enduring effects of adolescent stress exposure on these brain regions in adulthood. We suggest that, due to a number of converging factors during this period of maturation, the adolescent brain may be particularly sensitive to stress-induced neurobehavioral dysfunctions with important consequences on an individual's immediate and long-term health and well-being.