Background - The Generalised Unsafety Theory of Stress, a novel stress explanation, considers the stress response as a default mode of the body, which is always active independently from stressors...Show moreBackground - The Generalised Unsafety Theory of Stress, a novel stress explanation, considers the stress response as a default mode of the body, which is always active independently from stressors unless it is inhibited based on perceiving safety. GUTS suggests there are compromised domains where stress is chronically released despite a lack of clear stressors, and the organism is unable to inhibit the stress mechanism mostly because of perceiving generalised unsafety around. One of these compromised domains is believed to be urban environments as they cannot provide sufficient signs of safety, and they mainly consist property of strangers. Natural environments in contrast are believed to provide signs of safety and therefore decrease stress levels. Using meta-analysis, this current research aimed to find and summarize evidence from existing studies reporting that urban environments are associated with increased levels of stress, Method - In total, 12 studies, collected from Web of Science database, were included in six meta-analyses conducted on heart rate variability (high frequency, low frequency/high frequency), saliva cortisol, blood pressure (systolic and diastolic), and heart rate data of healthy adult participants during and after exposure to urban and natural environments. Results - Statistically significant increased heart rate was found after a walk in the urban environment (g = 0.37, 95% CI: 0.20; 0.50, p <0.0001). High frequency heart rate variability was significantly lower after an urban walk(unknown baseline balance group: g = -0.33, 95% CI: -0.55; -0.11; baseline balanced: g = -2.52, 95% CI: -3.25; -1.78). Low frequency heart rate variability was significantly higher during the urban walk (unknown baseline balance group: g = 0.33, 95% CI: 0.49; 1.80; baseline balanced: g = 2.52, 95% CI: 1.78; 3.26). Subgroup analyses and funnel plots for heart rate variability showed a possible small-study effect in the baseline balanced groups. Blood pressure and cortisol measurements showed no significant effect and were ambiguous because of high heterogeneity and small number of included studies. Conclusions - Heart rate variability and heart rate measures indicated a higher stress level in urban than in natural environments providing an example of prolonged stress without stressors, explainable by GUTS. For blood pressure and cortisol no such evidence was provided. However, the results should be carefully interpreted because of high between-study heterogeneity and other limitations of these studies. Further research into stress measurements and effects of natural and urban environment on stress are required to provide reliable evidence.Show less
Objective: The present study aims to better understand possible multidirectional interactions between depressive symptoms, sleep quality and stress response. Although a significant amount of...Show moreObjective: The present study aims to better understand possible multidirectional interactions between depressive symptoms, sleep quality and stress response. Although a significant amount of research has been done studying the effect of sleep quality and depression on stress response, they provided mixed results and showed large methodological differences. We extend previous research by testing three hypotheses: (a) Poor sleep leads to increased stress responses; (b) Higher levels of depressive symptoms lead to increased stress responses; and (c) The effect of minimal levels of depressive symptoms on stress reactivity is greater for individuals with poor sleep. Method: In 46 participants (69,60% female; 18–29 years), we assessed sleep quality using the Pittsburgh Sleep Quality Index (and depressive symptoms using the Hospital Anxiety and Depression Scale (HADS). The Trier Social Stress Test (TSST), a psychosocial stress task, was used to induce moderate stress in a controlled environment in order to assess stress reaction. Results: Participants with poorer sleep quality did not have elevated salivary cortisol response after being exposed to a social stressor compared to participants with better sleep quality. Also, no proof was found for (minimal) depressive symptoms being a predictor of salivary cortisol response to psychosocial stress. The results further indicated that individuals with poor sleep quality did not experience a greater effect of (minimal) depressive symptoms on stress reactivity. Conclusion: No support was found for a role of sleep quality and depressive symptoms in cortisol stress response. Future research should take person- and situation-specific characteristics into account when analyzing cortisol responses to psychological stress.Show less
The aim of the study was to examine the effects of maternal stress, oxytocin and cortisol in breast milk, and frequency of breastfeeding on infant temperamental traits (Fear Aversion, Negative...Show moreThe aim of the study was to examine the effects of maternal stress, oxytocin and cortisol in breast milk, and frequency of breastfeeding on infant temperamental traits (Fear Aversion, Negative Affectivity, Orienting/Regulation, Extraversion/Surgency). In the cross-sectional study, Polish mothers and their 4 months old infants (N-163) were tested in two different meetings. The mothers filled out EPDS, RLCQ, IBQ-R and a survey concerning their breastfeeding pattern. Furthermore, breast milk samples were collected to assess oxytocin, cortisol and energy levels in milk. The findings does not support the prediction that maternal stress influences infants’ temperamental traits. The results of the study indicated that oxytocin in mother’s milk was significantly associated with negative affectivity. However, no significant association was found between temperamental traits and cortisol. Moreover, nursing frequency was also significantly related to higher negative affectivity, however, the relationship is in the opposite direction of what is expected.Show less
The purpose of this study is to assess whether infant attachment of early adopted children is related to their cortisol secretion at the age of fourteen. In addition, it is examined whether...Show moreThe purpose of this study is to assess whether infant attachment of early adopted children is related to their cortisol secretion at the age of fourteen. In addition, it is examined whether temperament at the age of fourteen influences this relationship. The 88 participants (37 boys and 51 girls) are examined through the following measurements: At the age of twelve months attachment is measured by the Strange Situation Procedure; at the age of fourteen years cortisol levels during the day are measured by taking saliva and temperament is measured by the Dutch Temperament Questionnaire. The first hypothesis concerned attachment and cortisol levels in general, namely that there is a connection between attachment and the height and slope of the cortisol diurnal curves. Furthermore, we expected insecurely attached children to have lower and flatter cortisol diurnal curves as compared to securely attached children and disorganized attached children to have lower and flatter cortisol diurnal curves as compared to organized attached children. The last hypothesis stated that the relation between attachment and cortisol secretion is different for children with different forms of temperament. All hypotheses had to be rejected according to the results and we conclude that early attachment is not related to cortisol secretion at the age of fourteen. Also, we conclude that temperament does not influence this relationship. A possible explanation for the results could be that there were only 88 participants included in this study. A too small sample size may cause that little differences are less likely to become evident. Another explanation may be that we have to deal with a particular sample, which includes adopted children and their adoptive parents. Off course, it is also possible that the results are indeed a reflection of the reality.Show less
