Long-term cortisol secretion in attention deficit hyperactivity disorder: roles of sex, comorbidity, and symptom presentation.

Low activity of the hypothalamic-pituitary-adrenal axis (HPAA) has been found in children with attention deficit hyperactivity disorder (ADHD). The condition may be related to the reduced attention regulation capacity and/or to comorbid oppositional defiant or conduct disorder (ODD/CD). Sex differences are probable but not sufficiently studied. We analyzed the HPAA activity and sympathetic nervous system reactivity (SR) in children with ADHD while accounting for ADHD symptom presentation, comorbidity, and sex differences. The sample comprised 205 children, 98 (61 boys, 37 girls) with ADHD and 107 (48 boys, 59 girls) healthy controls. DSM-5 phenotypic symptom presentation and comorbid ODD/CD were assessed using clinical interviews. Hair cortisol concentration (HCC) was used to assess the long-term, cumulative activity of the HPAA. SR was assessed via skin conductance response (SCR). For control purposes, comorbid internalizing symptoms and indicators of adverse childhood experiences (ACE) were assessed. Children were medication naive. Boys presenting with predominantly inattentive symptoms (ADHD-I) showed lower HCC than healthy boys. Girls presenting with combined symptoms (ADHD-C) showed higher HCC than did healthy girls (p's < 0.05, sex-by-group interaction, F (2,194) = 4.09, p = 0.018). Boys with ADHD plus ODD/CD showed a blunted SR (p < 0.001, sex-by-group interaction, F (2,172) = 3.08, p = 0.048). Adjustment for ACE indicators led to non-significant differences in HCC but did not affect differences in SR. HCC constitutes an easily assessable, reliable, and valid marker of phenotypic ADHD-related features (i.e. symptom presentation and comorbidity). It indicates more homogenous subgroups of ADHD and might point to specifically involved pathophysiological processes.

Homeostatic Regulation of Energetic Arousal During Acute Social Isolation: Evidence From the Lab and the Field.

Recent evidence suggests that social contact is a basic need governed by a social homeostatic system. Little is known, however, about how conditions of altered social homeostasis affect human psychology and physiology. Here, we investigated the effects of 8 hr of social isolation on psychological and physiological variables and compared this with 8 hr of food deprivation in a lab experiment (N = 30 adult women). Social isolation led to lowered self-reported energetic arousal and heightened fatigue, comparable with food deprivation. To test whether these findings would extend to a real-life setting, we conducted a preregistered field study during a COVID-19 lockdown (N = 87 adults; 47 women). The drop in energetic arousal after social isolation observed in the lab replicated in the field study for participants who lived alone or reported high sociability, suggesting that lowered energy could be part of a homeostatic response to the lack of social contact.

Diurnal dynamics of stress and mood during COVID-19 lockdown: a large multinational ecological momentary assessment study.

The COVID-19 pandemic resulted in severe disruption to people's lives as governments imposed national 'lockdowns'. Several large surveys have underlined the detrimental short- and long-term mental health consequences resulting from this disruption, but survey findings are only informative of individuals' retrospectively reported psychological states. Furthermore, knowledge on psychobiological responses to lockdown restrictions is scarce. We used smartphone-based real-time assessments in 731 participants for 7 days and investigated how individuals' self-reported stress and mood fluctuated diurnally during lockdown in spring 2020. We found that age, gender, financial security, depressive symptoms and trait loneliness modulated the diurnal dynamics of participants' momentary stress and mood. For example, younger and less financially secure individuals showed an attenuated decline in stress as the day progressed, and similarly, more lonely individuals showed a diminished increase in calmness throughout the day. Hair collected from a subsample (n = 140) indicated a decrease in cortisol concentrations following lockdown, but these changes were not related to any of the assessed person-related characteristics. Our findings provide novel insights into the psychobiological impact of lockdown and have implications for how, when and which individuals might benefit most from interventions during psychologically demanding periods.

Alpha-2 Adrenoreceptor Antagonist Yohimbine Potentiates Consolidation of Conditioned Fear.

BACKGROUND: Hyperconsolidation of aversive associations and poor extinction learning have been hypothesized to be crucial in the acquisition of pathological fear. Previous animal and human research points to the potential role of the catecholaminergic system, particularly noradrenaline and dopamine, in acquiring emotional memories. Here, we investigated in a between-participants design with 3 groups whether the noradrenergic alpha-2 adrenoreceptor antagonist yohimbine and the dopaminergic D2-receptor antagonist sulpiride modulate long-term fear conditioning and extinction in humans. METHODS: Fifty-five healthy male students were recruited. The final sample consisted of n = 51 participants who were explicitly aware of the contingencies between conditioned stimuli (CS) and unconditioned stimuli after fear acquisition. The participants were then randomly assigned to 1 of the 3 groups and received either yohimbine (10 mg, n = 17), sulpiride (200 mg, n = 16), or placebo (n = 18) between fear acquisition and extinction. Recall of conditioned (non-extinguished CS+ vs CS-) and extinguished fear (extinguished CS+ vs CS-) was assessed 1 day later, and a 64-channel electroencephalogram was recorded. RESULTS: The yohimbine group showed increased salivary alpha-amylase activity, confirming a successful manipulation of central noradrenergic release. Elevated fear-conditioned bradycardia and larger differential amplitudes of the N170 and late positive potential components in the event-related brain potential indicated that yohimbine treatment (compared with a placebo and sulpiride) enhanced fear recall during day 2. CONCLUSIONS: These results suggest that yohimbine potentiates cardiac and central electrophysiological signatures of fear memory consolidation. They thereby elucidate the key role of noradrenaline in strengthening the consolidation of conditioned fear associations, which may be a key mechanism in the etiology of fear-related disorders.

Increased hair cortisol in mothers of children with ADHD symptoms and psychosocial adversity background.

Parents of children with attention deficit hyperactivity disorder (ADHD) have shown high perceived parenting stress. Hence, physiological adjustment processes, involving the hypothalamic-pituitary-adrenal axis, seem possible. We hypothesized that (1) ADHD symptoms of the child predict an increase of maternal hair cortisol concentration (HCC), and (2) presence of psychosocial adversity amplifies the prediction. We analyzed a preschool-aged sample using a longitudinal design (T1, at the children's age of 4 years; T2, 12 months later). 128 mothers and their children participated in the study. To determine HCC of the previous 3 months, the first scalp-near 3 cm hair segment was used. ADHD symptoms of the child were measured using teacher- and parent-report questionnaires and a clinical interview with the mother. The T1 teacher-reported ADHD symptoms score of the child was significantly positively associated with the mother`s T1 and T2 HCC score. In families with high psychosocial adversity, the prediction of an increase in maternal HCC by the teacher-reported ADHD symptoms of child was significantly stronger than in low-adversity families. In presence of psychosocial family adversity, ADHD symptoms of the child predicted an increase in the mother's HCC. As a continuously high cortisol level implicates health risks and might in turn affect parenting resources, the identifying of caregivers at risk through biological markers of stress could be helpful for planning targeted interventions. As our study is the first on this issue, cross-validation is needed.

Salivary Cortisol and Alpha-Amylase in Posttraumatic Stress Disorder and Their Potential Role in the Evaluation of Cognitive Behavioral Treatment Outcomes.

Alterations in HPA-axis and autonomic nervous system activity have been associated with posttraumatic stress disorder (PTSD) development and maintenance and are potentially associated with trauma-focused cognitive behavioral therapy (TF-CBT) outcomes. We examined the role of salivary cortisol (sCort) and alpha-amylase (sAA) in PTSD and TF-CBT outcomes in German Armed Forces service members (N = 100). Participants categorized as PTSD patients (n = 39), previously deployed healthy controls (n = 33), and nondeployed healthy controls (n = 28) provided diurnal profiles of sCort and sAA; PTSD patients provided samples before, immediately after, and 3 months after an internet-based TF-CBT intervention. No group differences emerged regarding total daily sCort and sAA output or daily slopes, ps = .224-.897, fs = 0.05-0.24. Participants with PTSD demonstrated a significantly attenuated sCort awakening response compared to deployed, p = .021, d = 0.59, but not nondeployed controls, p = .918, d = 0.08. Moreover, a significantly steeper sAA awakening response emerged in PTSD patients, p = .034, d = 0.67, and deployed controls, p = .014, d = 0.80, compared to nondeployed controls. From pretreatment to posttreatment (n = 21) and posttreatment to follow-up (n = 14), stable sCort, ps = .282-.628, fs = 0.34-0.49, and sAA concentrations, ps = .068-.758, fs = 0.24-1.13 paralleled a nonsignificant treatment effect. Both PTSD and trauma exposure were associated with alterations in awakening responses, but further investigation is needed to determine whether the observed correspondence remains when PTSD symptoms significantly decline.

Fingernail cortisol - State of research and future directions.

The extraction of cortisol from fingernails represents a recent advancement in the retrospective, long-term assessment of hypothalamic-pituitaryadrenal (HPA) axis activity: Fingernail cortisol has the potential to overcome some of the major disadvantages of established HPA axis markers. However, the introduction of any novel methodology also raises certain caveats. This review provides a comprehensive summary of the current state of research on fingernail cortisol. It identifies a number of strengths of his novel methodology (e.g., its high feasibility), while also pointing out open questions which currently challenge the interpretability of fingernail findings, in particular regarding the time period of cortisol secretion reflected in fingernail samples, as well as regarding potential determinants or confounders of fingernail cortisol (e.g. sociodemographic, lifestyle, or health characteristics). Clarification of these issues in the context of further methodological studies is necessary to validate the use of fingernail cortisol as a retrospective marker of HPA axis activity.

HOME vs. LAB hair samples for the determination of long-term steroid concentrations: a comparison between hair samples collected by laypersons and trained research staff.

Hair segment analysis is a valuable tool for the assessment of cumulative long-term steroid secretion. Preliminary findings suggest comparable cortisol concentrations in hair collected by instructed laypersons and research staff. However, it remains unclear whether hair sample quality and hair steroids other than cortisol are affected by level of experience (laypersons vs. research staff), home collection circumstances (instructions, familiarity to participant, performance confidence), and characteristics of the layperson (conscientiousness). Sixty participants (23.6 ± 3.9 years; 43 females) provided hair samples twice: first collected by laypersons (HOME) according to provided instructions (written vs. written/video-based instructions) and second by trained research staff (LAB) on the same day or the day after the HOME collection. Hair steroid concentrations (cortisol, cortisone, DHEA, progesterone) were determined using LC-MS/MS. Hair sample quality was evaluated using nine predefined criteria. Laypersons completed questionnaires for the assessment of potential factors of hair outcome measures (hair steroid concentrations, hair sample quality). Hair steroids from HOME and LAB samples were positively correlated (rs between 0.76 and 0.89) and did not significantly differ, with the exception of cortisone. The quality of hair samples was significantly higher for LAB than for HOME samples. Neither HOME collection circumstances nor layperson-related characteristics had an impact on hair outcome measures. However, a low self-reported performance confidence predicted a high absolute difference between HOME and LAB DHEA. In summary, our findings suggest higher quality of hair samples collected by trained research staff compared to instructed laypersons. However, these differences might be negligible, considering the high correlation between HOME and LAB hair steroid concentrations, with the characteristics of the layperson or collection circumstances having a minor impact on hair steroids and hair sample quality. These findings provide further support for the notion that well-instructed laypersons can be enabled to collect hair samples.

The impact of preschool child and maternal attention-deficit/hyperactivity disorder (ADHD) symptoms on mothers' perceived chronic stress and hair cortisol.

Providing care for a child with attention-deficit/hyperactivity disorder (ADHD) is associated with parenting stress. Moreover, adults with elevated ADHD symptoms report increased perceived stress. Despite this, it has rarely been examined whether and how child and maternal ADHD symptoms may affect maternal perceived stress and the stress-sensitive hypothalamic-pituitary-adrenal axis. This study therefore investigated the possible impact of child and maternal ADHD symptoms on mothers' perceived chronic stress and hair cortisol concentration (HCC), while simultaneously considering the effects of child oppositional defiant/conduct disorder (ODD/CD) and maternal depressive symptomatology. In total, 124 mothers (35.96 ± 5.21 years) of preschool children were included. Maternal perceived stress, ADHD and depressive symptoms were assessed using self-report measures. Child ADHD symptoms were assessed using an interview and questionnaires completed by mothers and teachers. Additionally, mothers provided information about their children's ODD/CD symptoms. Hair samples were taken from mothers to assess HCC. Child and maternal ADHD, child ODD/CD, and maternal depressive symptoms accounted for 50% of the variance in perceived chronic stress (F(4, 119) = 30.24; p < 0.01), with only maternal ADHD (ß = 0.52, p < 0.01) and depressive symptoms (ß = 0.49, p < 0.01) being uniquely significant. Maternal ADHD symptoms did not moderate the relationship between child ADHD symptoms and maternal perceived chronic stress (b = - 0.01; SE b = 0.17; t(5, 118) = - 0.05; p = 0.96). Mother's age became the only significant predictor of maternal HCC (ß = 0.29; p < 0.01). Based on these findings, practitioners are advised to be aware of and take into account possible maternal ADHD and depressive symptomatology and perceived chronic stress when treating children diagnosed with ADHD.

The association of the 5-HTTLPR polymorphism and the response to different stressors in healthy males.

The experience of stress is related to individual wellbeing and vulnerability to psychopathology. Therefore, understanding the determinants of individual differences in stress reactivity is of great concern from a clinical perspective. The functional promotor polymorphism of the serotonin transporter gene (5-HTTLPR/rs25531) is such a factor, which has been linked to the acute stress response as well as the adverse effect of life stressors. In the present study, we compared the impact of two different stress induction protocols (Maastricht Acute Stress Test and ScanSTRESS) and the respective control conditions on affective ratings, salivary cortisol levels and cognitive performance. To this end, 156 healthy young males were tested and genotyped for the 5-HTTLPR/rs25531 polymorphism. While combined physiological and psychological stress in the MAST led to a greater cortisol increase compared to control conditions as well as the psychosocial ScanSTRESS, subjective stress ratings were highest in the ScanSTRESS condition. Stress induction in general affected working memory capacity but not response inhibition. Subjective stress was also influenced by 5-HTTLPR/rs25531 genotype with the high expression group showing lower stress ratings than lower expression groups. In line with previous research, we identified the low expression variant of the serotonin transporter gene as a risk factor for increased stress reactivity. While some dimensions of the human stress response may be stressor specific, cognitive outcomes such as working memory performance are influenced by stress in general. Different pathways of stress processing and possible underlying mechanisms are discussed.

The Effects of Sensory Enrichment After a Laboratory Stressor on Human Skin Barrier Recovery in a Randomized Trial.

OBJECTIVE: Environmental enrichment (EE) can reduce stress, alter immunity, and speed wound healing in animals. However, it is not known whether these effects translate to humans. This study aimed to investigate whether sensory EE could improve wound healing after a stressor in humans. METHODS: A total of 105 participants underwent a tape-stripping procedure and were then stressed using a laboratory stress paradigm. After this, they were randomized to interact for 30 minutes with one of two possible sensory EE interventions (music as auditory enrichment or a Paro robot as multisensory enrichment) or to a control condition. Skin barrier recovery was measured using transepidermal water loss at baseline, after the stressor, and after the intervention. Stress was measured using self-report, heart rate, blood pressure, and salivary stress-related biological measures. Enjoyment during the intervention was measured by self-report as a possible mediator. RESULTS: The Paro condition had significantly improved skin barrier recovery (mean [M] = 44%, standard error [SE] = 1.92) compared with the control condition (M = 37% SE = 2.01, F(2,88) = 3.25, p = .043), both with and without controlling for covariates. The music condition did not significantly differ from the other conditions (M = 42%, SE = 1.95, p values > .05). Both objective and subjective stress measures did not significantly differ between conditions. Mediational analysis showed that enjoyment levels during the intervention period significantly mediated the relationship between condition and skin barrier recovery (z = 2.00, p = .046). CONCLUSIONS: Paro, or other companion robots, may be an effective form of enrichment to improve skin barrier recovery in humans after a laboratory stressor, and this effect may be due to enjoyment. Further research with patient groups is required to investigate whether Paro can help heal clinical wounds. TRIAL REGISTRATION: ACTRN12618000953235, registered at https://anzctr.org.au.

Associations between Health Behaviors and Factors on Markers of Healthy Psychological and Physiological Functioning: a Daily Diary Study.

BACKGROUND: Cross-sectional and experimental knowledge highlight the contribution of various health-promoting behaviors, such as physical activity, regular sleep, and healthy nutrition to mental and physical health. Beyond these well-studied lifestyle behaviors, music listening and perceived respect in social interactions are just recently proposed everyday life experiences, which may act as health-promoting factors. PURPOSE: This study tested the simultaneous contribution of several health-promoting behaviors and factors and examined listening to music and positive social interaction by means of perceived respect as new potentially preventive and health-promoting behaviors and factors using an ambulatory assessment design. METHODS: Seventy-seven young healthy adults (38 women, 23.9 ± 4.5 years) completed surveys on their psychological state (i.e., mood, stress, and fatigue) five times a day for four consecutive days. A saliva sample was collected with each data entry to explore the physiological stress markers salivary cortisol, alpha-amylase, and flow rate as further outcome variables. As predictors, perceived respect, self-reported physical activity, the sleep's restfulness, daily coffee, alcohol, vegetable/fruit consumption, and music listening behavior were recorded. RESULTS: Overall, restful sleep, mean daily perceived respect, and listening to music were most clearly associated with more positive psychological states, that is, better mood and lower fatigue and perceived stress. Associations with daily alcohol, coffee, and vegetable/fruit consumption appeared rather minor. While perceived respect scores were associated with lower daily cortisol output, coffee consumption was positively related to daily cortisol and alpha-amylase. Self-reported physical activity was unrelated to either outcome measure. CONCLUSIONS: These findings provide important insights regarding potential resources of health (i.e., music and respect), their covariation, and which psycho-physiological mechanisms may underlie the links between health factors and well-being. Findings also have implications for the development of interventions aiming to increase resilience and foster health. Here, strategies for improving sleep quality, the use of music, and approaches that emphasize mutual respect and appreciation appear useful additions.

Hair cortisol concentration in mothers and their children: roles of maternal sensitivity and child symptoms of attention-deficit/hyperactivity disorder.

Associations between mothers' and children's cortisol secretion parameters are well established. According to the bio-behavioral synchrony model, these associations reflect influences of the mother-child relationship, the child's social adjustment, and might also reflect shared genetic dispositions. From the bio-behavioral synchrony model, we predicted a stronger mother-child hair cortisol concentration (HCC) link in mothers showing highly adequate (compared to those showing less adequate) parenting behaviors and in children showing low (compared to those showing high) ADHD symptoms. From a genetic perspective, no such moderator effects, or a stronger mother-child HCC link in children with high ADHD symptoms, can be expected. The study sample consisted of 111 4-5-year-old children (64 of whom screened positive for increased ADHD symptoms) and their mothers. ADHD symptoms were assessed by a clinical interview and parent and teacher questionnaires. Maternal sensitive/responsive parenting behavior was assessed by an at-home behavior observation procedure. In mothers and children, HCC in the most proximal 3-cm scalp hair segment was analyzed using luminescence immunoassay. Overall HCCs of mothers and their children correlated significantly. Maternal sensitivity/responsiveness and child ADHD symptoms proved to be significant moderator variables of this association: High maternal sensitivity/responsiveness and low ADHD symptoms of the child were associated with a stronger mother-child link in HCC. The findings are in line with the bio-behavioral synchrony model in the mother-child relationship, and are less compatible with a genetic perspective. The results might hint at environmental events influencing the development of stress axis functioning in subgroups of preschoolers with high ADHD symptoms.

Hair and salivary cortisol in a cohort of women with chronic fatigue syndrome.

Hypocortisolism has been found in CFS patients in blood, urine, and saliva. It is unclear if hypocortisolism can also be demonstrated using long-term cortisol measurements, such as cortisol in hair. In addition, the interaction between the HPA axis and the immune system, both expected to play an important role in CFS, is unclear. The objective of the current study was to compare hair and salivary cortisol concentrations in a cohort of female CFS patients to those in healthy controls, and to test the effect of an interleukin-1 receptor antagonist (anakinra) on the HPA axis. Salivary cortisol concentrations of 107 CFS patients were compared to 59 healthy controls, with CFS patients showing a decreased cortisol awakening response (4.2 nmol/L ±â€¯5.4 vs 6.1 nmol/L ±â€¯6.3, p = 0.036). Total cortisol output during the day did not differ significantly in saliva, but there was a trend to lower hair cortisol in a subset of 46 patients compared to 46 controls (3.8 pg/mg ±â€¯2.1 vs 4.3 pg/mg ±â€¯1.8, p = 0.062). After four weeks of treatment with either daily anakinra (100 mg/day) or placebo, there was a slight decrease of hair cortisol concentrations in the anakinra group compared to an increase in the placebo group (p = 0.022). This study confirms the altered dynamics of the HPA axis in a group of CFS patients, and for the first time shows that this might also be present for long-term cortisol measures.

Low hair cortisol concentration and emerging attention-deficit/hyperactivity symptoms in preschool age.

Previous research demonstrated hypoactivity of the HPA axis in children with attention-deficit/hyperactivity disorder (ADHD) or externalizing symptoms. We analyzed the predictive association between the long-term HPA axis activity and increasing symptoms of ADHD in the preschool period. The sample consisted of n = 125 4-year-old children and their families (including n = 64 children with elevated ADHD symptoms). ADHD symptoms were assessed by a structured clinical interview with the mother and by parent- and teacher-report questionnaires. The long-term HPA axis activity was assessed by the hair cortisol concentration (HCC) (over a 3-month period). After controlling for potential confounders, low HCC predicted an increase in ADHD symptoms between the age of 4 and 5 years. Exploration of gender effects revealed that cross-sectional and predictive associations were significant in boys but not in girls. Low HCC might thus be regarded as an early marker of a possibly gender-related developmental pathway to ADHD.

[The Role of Resilience Factors in Informal Caregivers of Dementia Patients - A Review on Selected Factors]. / Die Bedeutung von Resilienzfaktoren für pflegende Angehörige von Demenzpatienten ­ eine Übersicht zu ausgewählten Faktoren.

In the face of demographic change, the informal care of dementia patients is becoming increasingly important. However, due to dementia symptoms as well as persisting care demands, this subgroup of informal caregivers is confronted with a large number of stressors resulting in chronic stress and impaired physical and mental health in many caregivers. Based on the current research on resilience (i. e., maintaining or regaining health despite stress and adversities), there is increasing interest in identifying resilience factors that may serve as resources to cope with informal care and protect caregivers against health problems. The review discusses the role of resilience factors in the association between ongoing caregiving stress and health. In analyzing the current state of research on resilience factors for dementia caregivers, we focus on the factors self-efficacy, relationship quality, and social support.

Psychobiological impact of ethnic discrimination in Turkish immigrants living in Germany.

Perceived ethnic discrimination has a negative impact on health. One of the key mechanisms may be a dysregulation of stress-responsive systems. Our aims were to investigate whether (1) acute face-to-face ethnic discrimination induces a stress response, and (2) to compare long-term endocrine functioning between immigrants and nonimmigrants. 30 male Turkish immigrants living in Germany underwent an ethnic discrimination condition and a control condition in the laboratory. Perceived ethnic discrimination, stress, salivary alpha-amylase and cortisol were measured four times. Heart rate and electrodermal activity were measured continuously. In addition, hair samples were collected from immigrants and 25 male nonimmigrants to determine long-term cortisol concentrations. Immigrants showed increases in perceived ethnic discrimination, stress, heart rate, alpha-amylase and cortisol during the ethnic discrimination condition. Immigrants had significantly lower hair cortisol concentrations than nonimmigrants. These findings suggest that acute ethnic discrimination elicits a psychobiological stress response. Abnormalities in long-term endocrine functioning in ethnic minorities may set the stage for the development of stress-related illnesses. Lay summary The present study found that racial discrimination of Turkish immigrants induced both psychological and physiological stress responses in the laboratory. Immigrants showed lower hair cortisol concentrations than nonimmigrants, indicating a dysregulated biological stress system.

The role of week(end)-day and awakening time on cortisol and alpha-amylase awakening responses.

Awakening responses in salivary cortisol (CAR) and alpha-amylase (AAR) constitute proxies of morning activation patterns of the hypothalamic-pituitary-adrenal axis and autonomic nervous system, respectively. Previous studies suggest that the CAR is decreased at weekends and at late awakening. However, it is insufficiently studied (a) whether this also applies to the AAR and (b) whether week(end)-day and awakening time interact with each other. Using an ecological momentary assessment design, 48 healthy young adults (60% women) were investigated over a 7-d period (Study 1), and 27 chronic pain patients diagnosed with fibromyalgia syndrome were examined over a 14-d period (Study 2). For the assessment of the CAR and AAR, participants provided saliva samples each morning (upon awakening, 30 min after awakening). Preprogrammed electronic diary devices were used to track week(end)-day and exact time of saliva sampling (awakening time). In Study 1, CAR was unrelated to weekend, awakening time, or their interaction, whereas only early awakening time was positively associated with AAR. In Study 2, week-days as well as early awakening times on week-days predicted increased CAR. AARs were not predicted by week(end)-day, awakening times, or their interaction. These findings suggest that time-related factors may influence awakening responses, particularly the impact of week(end)-day on the CAR and the impact of awakening times on the AAR. Since week(end)-day and awakening times may negatively affect awakening responses, these potential confounding factors should be assessed and controlled for, particularly in studies assessing both CAR and AAR.

Physical activity buffers fatigue only under low chronic stress.

Fatigue is one of the most commonly reported complaints in the general population. As physical activity (PA) has been shown to have beneficial effects, we hypothesized that everyday life PA improves fatigue. Thirty-three healthy students (21 women, 22.8 ± 3.3 years, 21.7 ± 2.3 kg/m(2)) completed two ambulatory assessment periods. During five days at the beginning of the semester (control condition) and five days during final examination preparation (examination condition), participants repeatedly reported on general fatigue (awakening, 10 am, 2 pm, 6 pm and 9 pm) by means of an electronic diary, collected saliva samples for the assessment of cortisol and α-amylase immediately after providing information on fatigue and wore a triaxial accelerometer to continuously record PA. Self-perceived chronic stress was assessed as a moderator. Using hierarchical linear modeling, including PA, condition (control vs. examination), sex and chronic stress as predictors, PA level during the 15 min prior to data entry did not predict momentary fatigue level. Furthermore, there was no effect of condition. However, a significant cross-level interaction of perceived chronic stress with PA was observed. In fact, the (negative) relationship between PA and fatigue was stronger in those participants with less chronic stress. Neither cortisol nor α-amylase was significantly related to physical activity or fatigue. Our study showed an immediate short-term buffering effect of everyday life PA on general fatigue, but only when experiencing lower chronic stress. There seems to be no short-term benefit of PA in the face of higher chronic stress. These findings highlight the importance of considering chronic stress when evaluating the effectiveness of PA interventions in different target populations, in particular among chronically stressed and fatigued subjects.

Hair cortisol concentration and its association with acute stress responses and recovery in a sample of medical students in Germany.

INTRODUCTION: Experiencing acute and chronic stress can contribute to adverse health outcomes. Responses to acute stress differ between individuals (i.e., stress reactivity) and the experience of chronic stress has been discussed to be associated with acute stress responses and stress recovery. This study thus aims to investigate whether hair cortisol concentration (HCC), being an indicator for hypothalamus-pituitary-adrenal (HPA) axis activity over a prolonged period of time, is associated with acute stress responses and recovery in a sample of medical students. MATERIAL AND METHODS: From July 2020 to July 2021, medical students (n = 54) underwent a virtual-reality Trier Social Stress Test in which their blood pressure and heart rate variability (HRV) were measured, and hair samples were taken to determine HCC. Piecewise linear growth analyses were used to investigate whether HCC (categorized into low, medium and high levels) is associated with acute stress responses and recovery regarding blood pressure and HRV. RESULTS: Significant interaction effects in piecewise linear growth analyses showed that participants with higher levels of HCC had lower systolic and diastolic blood pressure responses compared to participants with medium levels of HCC. No significant interaction effects were observed for HRV responses or for recovery measures. CONCLUSIONS: The study suggests that higher levels of HCC are associated with a lower cardiovascular response in terms of blood pressure to an acute stressor in medical students. Therefore, long-term HPA-axis activity may contribute to different magnitudes of acute stress responses in the autonomic nervous system. As the shown lower blood pressure responses to acute stress in individuals with increased long-term HPA-axis activity may represent inadequate stress responses, these should be further studied in order to find out more about their interaction and potential subsequent disease risks.