Secretory immunoglobulin A reactions to prolonged mental arithmetic stress: inter-session and intra-session reliability

Examining the association between habitual emotion regulation strategies and cardiovascular stress reactivity across three studies

Poor emotion regulation is associated with cardiovascular disease risk, with altered cardiovascular responses to psychological stress a possible underlying mechanism. However, prior research has predominantly focused on instructed (laboratory-based) emotion regulation; there is limited conclusive research on the relationship between every-day (habitual) emotion regulation and cardiovascular responses to active psychological stress. As such, this study aimed to examine the associations between two common habitual emotion regulation strategies-cognitive reappraisal and expressive suppression-and cardiovascular stress responses across three independent laboratory studies, each involving a different active acute psychological stress task. Participants (Study 1: N = 239, 64.9 % female; Study 2: N = 289, 51.9 % female, Study 3: N = 169, 50.9 % female) underwent cardiovascular monitoring during a 10-min baseline and subsequent stress task (Study 1: mental arithmetic task; Study 2: speech task; Study 3: Multisource Interference/Stroop tasks). Participants also completed the Emotion Regulation Questionnaire and ratings of perceived task stressfulness. Cardiovascular reactivity (stress mean - baseline mean) was calculated for systolic/diastolic blood pressure and heart rate for each study. Across all three studies, regression analyses demonstrated no statistically significant linear associations between habitual emotion regulation and cardiovascular reactivity (ps ≥ .10) or self-reported perceived stress (ps ≥ .06), both before and after controlling for demographic covariates. This investigation furthers our understanding of how habitual emotion regulation strategies may-or may not-impact cardiovascular stress responses, thus providing valuable insights into the complex relationship between emotion regulation and long-term cardiovascular health.

Emotion regulation tendencies and cardiovascular responses to repeated acute psychological stress

Poor emotion regulation has been associated with cardiovascular disease (CVD) through maladaptive cardiovascular responses to psychological stress. However, there has been scant research examining the relationship between emotion regulation and habituation of cardiovascular responses to recurrent stress, which may be more directly applicable to the experience of stress in everyday life. The aims of the current study were to examine the associations between emotion regulation tendencies and cardiovascular stress reactivity, as well as habituation of cardiovascular reactivity across repeated stressors. A sample of 453 participants (mean (SD) age = 19.5 (1.3) years; 62 % women) completed a repeated stress paradigm, which consisted of two 10-minute baselines and two identical 4-minute stress tasks, separated by a 10-minute recovery period. Heart rate (HR) was measured continuously; systolic/diastolic blood pressures (SBP/DBP) were measured every 2 min. At the end of the visit, participants completed the Emotion Regulation Questionnaire (ERQ) and Difficulties in Emotion Regulation Scale (DERS). Results indicate that impulse control difficulties when distressed (a DERS subscale) were significantly associated with blunted SBP, DBP, and HR reactivity to both stressors, as well as impaired HR habituation across the stressors. None of the ERQ subscales (cognitive reappraisal, expressive suppression) were found to be associated with cardiovascular stress reactivity or habituation. The outcomes of this study demonstrate a potential underlying physiological pathway through which impulse control difficulties when distressed may contribute to CVD risk. This study also reveals the importance of extending traditional cardiovascular stress reactivity protocols to include multiple exposures of the same stress task.

Cluster analysis reveals distinct patterns of childhood adversity, behavioral disengagement, and depression that predict blunted heart rate reactivity to acute psychological stress

BACKGROUND

There is considerable evidence documenting associations between early life adversity, behavioral disengagement, and depression with blunted cardiovascular reactivity to acute psychological stress. However, while often examined as independent predictors, it is also likely that a combination of these factors uniquely relate to cardiovascular reactivity.

PURPOSE

The present study employed multivariate cluster analysis to examine if distinct combinations of these outcomes relate to cardiovascular stress reactivity.

METHODS

Participants (N = 467) were predominantly female (60.6%) with a mean age of 19.30 years (SD = 0.82). Measures of early life adversity, behavioral disengagement, and depression were completed; in addition, participants had their blood pressure and heart rate monitored throughout a standardized stress testing session. Cardiovascular reactivity was calculated as the difference between mean stress and mean baseline cardiovascular values.

RESULTS

Analyses revealed two clusters with distinct patterns of exposure to early life adversity, levels of behavioral disengagement and depression, uniquely related to cardiovascular reactivity. In unadjusted models, Cluster 1 that was characterized by greater exposure to early life adversity, higher levels of behavioral disengagement and depression, was associated with lower systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) reactivity. Cluster 2 was characterized by reactivity values similar to the sample means. In fully adjusted models, Cluster 1 predicted heart rate reactivity to stress.

CONCLUSIONS

The present study identifies a behavioral cluster that is characteristic of a blunted heart rate reactivity profile, significantly extending the research in this area.

Adverse childhood experiences, sex, and cardiovascular habituation to repeated stress

Adverse childhood experiences (ACEs) are robustly associated with later cardiovascular disease. Alterations in cardiovascular responses to stress may be an underlying mechanism. The present study examined whether ACEs predicted habituation of cardiovascular responses across two acute laboratory stress tasks, and whether this differed between men and women. During a single laboratory visit, 453 healthy young adults completed two identical stress-inducing protocols, each involving a 10-minute baseline and 4-minute acute psychological stress task. Heart rate (HR) and systolic/diastolic blood pressure (S/DBP) were recorded throughout. Participants also completed the Adverse Childhood Experiences scale. Cardiovascular responses habituated from the first to second stress task on average across the entire sample. However, women-but not men-with higher self-reported ACEs displayed less habituation of HR and DBP, but not SBP, across the stress tasks. Results suggest that ACEs may alter the body's ability to adaptively respond to stress exposures in adulthood, specifically in women.

Detection of cognitive impairment by choice auditory reaction time (ART) and visual reaction time (VRT) s during acute mental stress in young hypertensives: A case control study

BACKGROUND

Acute stress is known to be associated with both negative and positive influences on cognitive performance. Hypertension is one of the risk factors for lowered cognitive performance. Mental stress testing is easier to administer and can be regulated by the investigator. Mental arithmetic, using serial subtraction, is the most widely used method to administer stress. Reaction time (RT) is widely used to assess cognitive domains like attention, execution, and psychomotor speed. Researchers have shown that choice reaction times are delayed in hypertension. It is not known whether acute mental stress improves or deteriorates attention, execution, and psychomotor speed in hypertension. We hypothesized in the present study that acute mental stress deteriorates cognitive function in hypertensives without overt cerebro-vascular disease or other vascular risk factors.

METHODS

After getting medical ethical clearance from our institution, this case-control study was carried out over eight months (January 2017 to September 2017). 60 subjects between the age group of 35 to 55 years were included in the study. They were divided into 2 groups. Group 1 consisted of 30 diagnosed cases of hypertension with at least two years of duration. Group 2 consisted of 30 sex and age-matched controls. MMSE was performed to assess the cognitive function in these groups. Simple (S) and choice (C) auditory reaction time (ART) and visual reaction time (VRT) were measured at rest and acute mental stress in these groups to assess cognitive function. The predictive value of VRTC resting and VRTC during acute mental stress among hypertensives for cognitive dysfunction was calculated by using the receiver operating characteristic (ROC) curve.

RESULTS

There was a significant difference between ART and VRT, both simple and choice in hypertensive and non-hypertensive subjects, and these reaction times further increased during mental stress. (P<0.001). VCRT can be a predictor of cognitive dysfunction in hypertensives and during acute mental stress.

CONCLUSION

A significant difference in cognitive functions in hypertensive and non-hypertensive subjects exists, and this further deteriorates with acute mental stress.

Heart Rate Reactivity to Acute Psychological Stress Predicts Higher Levels of Posttraumatic Stress Disorder Symptoms During the COVID-19 Pandemic

OBJECTIVE

Increased autonomic arousal is a proposed risk factor for posttraumatic stress disorder (PTSD). Few studies have prospectively examined the association between physiological responses to acute psychological stress before a traumatic event and later PTSD symptoms. The present prospective study examined whether cardiovascular responses to an acute psychological stress task before the COVID-19 global pandemic predicted PTSD symptoms related to the ongoing pandemic.

METHODS

Participants (n = 120) were a subsample of an ongoing research study. Phase 1 consisted of a 10-minute baseline and 4-minute acute psychological stress task with blood pressure and heart rate recorded throughout. Phase 2 was initiated 2 weeks after the COVID-19 pandemic declaration. Participants completed the Impact of Event Scale-Revised (IES-R) with respect to the ongoing pandemic. Hierarchical linear regression analyses were used to examine whether cardiovascular stress reactivity predicted COVID-19 PTSD symptoms.

RESULTS

Heart rate reactivity significantly predicted IES intrusion (β = -0.208, t = -2.28, p = .025, ΔR2 = 0.041, confidence interval = -0.021 to -0.001) and IES hyperarousal (β = -0.224, t = -2.54, p = .012, ΔR2 = 0.047, confidence interval = -0.22 to - 0.003), but not IES avoidance (p = .077). These results remained statistically significant after adjustment for sex, socioeconomic status, baseline cardiovascular activity, neuroticism, race, ethnicity, body mass index, and adverse childhood experiences. There were no statistically significant associations between blood pressure and any of the Impact of Event Scale-Revised subscales (p values > .12).

CONCLUSIONS

Diminished heart rate responses (i.e., lower physiological arousal) to acute psychological stress before the COVID-19 pandemic significantly predicted reported PTSD symptoms during the crisis.

Toward Emotion Recognition From Physiological Signals in the Wild: Approaching the Methodological Issues in Real-Life Data Collection

Emotion, mood, and stress recognition (EMSR) has been studied in laboratory settings for decades. In particular, physiological signals are widely used to detect and classify affective states in lab conditions. However, physiological reactions to emotional stimuli have been found to differ in laboratory and natural settings. Thanks to recent technological progress (e.g., in wearables) the creation of EMSR systems for a large number of consumers during their everyday activities is increasingly possible. Therefore, datasets created in the wild are needed to insure the validity and the exploitability of EMSR models for real-life applications. In this paper, we initially present common techniques used in laboratory settings to induce emotions for the purpose of physiological dataset creation. Next, advantages and challenges of data collection in the wild are discussed. To assess the applicability of existing datasets to real-life applications, we propose a set of categories to guide and compare at a glance different methodologies used by researchers to collect such data. For this purpose, we also introduce a visual tool called Graphical Assessment of Real-life Application-Focused Emotional Dataset (GARAFED). In the last part of the paper, we apply the proposed tool to compare existing physiological datasets for EMSR in the wild and to show possible improvements and future directions of research. We wish for this paper and GARAFED to be used as guidelines for researchers and developers who aim at collecting affect-related data for real-life EMSR-based applications.

Possibility of using salivary ultra-weak chemiluminescence as a biomarker for feelings of anxiety in hospital settings

The aim of this study was to assess whether a particular value of noninvasive salivary ultra-weak chemiluminescence (UCL) could be used as a biomarker of psychological stress. Our study covered two groups. Group 1 comprised six healthy volunteers who stayed in a hospital for one night and group 2 comprised 15 patients with lung cancer and 24 patients with respiratory diseases other than lung cancer who were in hospital for an extended stay. First, we evaluated the UCL of saliva from six healthy volunteers before and after one night in hospital. Immunoglobulin A (IgA) concentrations were also measured. The integrated intensity value of UCL was correlated with the IgA concentration (correlation coefficient 0.90). Second, in the case of a long hospital stay, we found that the maximum salivary UCL intensities were higher in patients with lung cancer than in those with respiratory diseases other than lung cancer or in 28 healthy controls. Copyright © 2016 John Wiley & Sons, Ltd.

Bifidobacterium bifidum R0071 results in a greater proportion of healthy days and a lower percentage of academically stressed students reporting a day of cold/flu: a randomised, double-blind, placebo-controlled study

Acute psychological stress is positively associated with a cold/flu. The present randomised, double-blind, placebo-controlled study examined the effect of three potentially probiotic bacteria on the proportion of healthy days over a 6-week period in academically stressed undergraduate students (n 581) who received Lactobacillus helveticus R0052, Bifidobacterium longum ssp. infantis R0033, Bifidobacterium bifidum R0071 or placebo. On each day, participants recorded the intensity (scale: 0 = not experiencing to 3 = very intense) for nine cold/flu symptoms, and a sum of symptom intensity >6 was designated as a day of cold/flu. B. bifidum resulted in a greater proportion of healthy days than placebo (P≤ 0·05). The percentage of participants reporting ≥ 1 d of cold/flu during the 6-week intervention period was significantly lower with B. bifidum than with placebo (P< 0·05). There were no effects of B. infantis or L. helveticus compared with placebo on either outcome. A predictive model accounted for influential characteristics and their interactions on daily reporting of cold/flu episodes. The proportion of participants reporting a cold on any given day was lower at weeks 2 and 3 with B. bifidum and B. infantis than with placebo for the average level of stress and the most commonly reported number of hours of sleep. Daily intake of bifidobacteria provides benefit related to cold/flu outcomes during acute stress.

Activation of antioxidant defenses in whole saliva by psychosocial stress is more manifested in young women than in young men

Psychosocial stress has been long known to have deleterious effects on health. Nevertheless, an exposure to moderate stressors enhances resilience and promotes health benefits. Male and female organisms differ in many aspects of health and disease. The aim of this study was to investigate antioxidant activity and oxidative damage in saliva in a psychosocial stress paradigm in men and women. Here, we show that an acute stressor of moderate strength augments antioxidant activity and decreases oxidative damage in whole saliva of young people. An examination stress caused a significant increase of catalase activity, accompanied by a decrease of levels of oxidized proteins. Levels of thiobarbituric acid-reacting substances did not increase at stress, indicating that lipid peroxidation was not activated. The stress-induced alterations were more manifested in young women compared to young men. Thus, antioxidant protective mechanisms are more activated by a moderate stressor in young women than in young men.

Underlying inflammation has no impact on the oxidative stress response to acute mental stress

INTRODUCTION

Mental stress is considered to be a trigger for acute myocardial infarction (MI), with inflammation thought to provide a mechanism. Inflammation is reciprocally linked to oxidative stress, which has also been implicated in MI. The purpose of this study was to assess the effects of experimentally-induced inflammation on the oxidative stress response to mental stress in healthy participants.

METHODS

Healthy males undertook one of two inflammatory stimuli: typhoid vaccination (Vaccination paradigm, N=17) or eccentric exercise (Eccentric exercise paradigm, N=17). All participants completed a mental arithmetic stress task twice (within-subject design): 6h after the inflammatory stimulus, and during a control non-inflammation condition. Blood samples were taken before, immediately and 30min after the stress task. Plasma was assessed for interleukin-6 (IL-6), protein carbonyls (PC), lipid hydroperoxides (LOOH), total antioxidant capacity (TAC) and nitric oxide metabolites (NOx).

RESULTS

Vaccination paradigm: IL-6, PC and NOx were significantly higher in the vaccination condition, relative to the control condition (p<.05). PC, TAC, LOOH and NOx were unchanged in response to mental stress in both the vaccination and control conditions. Eccentric Exercise paradigm: IL-6 and TAC were significantly higher in the eccentric exercise condition (p<.05), relative to the control condition. PC, TAC and NOx were unchanged in response to mental stress in both the eccentric exercise and control conditions.

CONCLUSIONS

Two different inflammatory paradigms were successful in increasing selective plasma markers of inflammation and oxidative stress prior to a mental stress task. However, experimentally induced transient inflammation had no impact on mental stress-induced changes in plasma LOOH, PC, TAC or NOx in young healthy participants.

Vaccine-induced inflammation attenuates the vascular responses to mental stress

Inflammation is associated with poorer vascular function, with evidence to suggest that inflammation can also impair the vascular responses to mental stress. This study examined the effects of vaccine-induced inflammation on vascular responses to mental stress in healthy participants. Eighteen male participants completed two stress sessions: an inflammation condition having received a typhoid vaccination and a control (non-inflamed) condition. Tumor necrosis factor-alpha and interleukin-6 (p's<.001) increased following vaccination, confirming modest increases in inflammation. Mental stress increased blood flow, blood pressure, heart rate, and cardiac output in both conditions (all p's<.001), but the blood flow response to stress was attenuated having received the vaccination compared to the control condition (p's<.05). These results further implicate the interaction between inflammation and the vasculature as a mechanism through which stress may trigger myocardial infarction.

The effect of acute mental stress on limb vasodilation is unrelated to total peripheral resistance

Mental stress can trigger myocardial infarction, with poor vascular responses to stress implicated as a pathway. Vascular stress reactivity can be assessed by different methods, such as total peripheral resistance (TPR) and forearm blood flow (FBF). Little is known about how these vascular assessments are linked. This was examined in two separate studies. Healthy men (Study 1: N = 29, Study 2: N = 23) completed rest and mental arithmetic (Study 1: 8 min, Study 2: 16 min). In both studies, heart rate, mean arterial pressure, and FBF increased in response to stress. In Study 1, no changes in TPR were seen, but Study 2 found stress-induced increases in TPR. FBF was not linked to TPR at any time (all ps > .05). It appears that limb vasculature and TPR responses to stress do not give the same information about impairments of the vasculature. These findings are relevant to the interpretation of prior research findings and the design of future studies on stress and vascular responses.

Eccentric-exercise induced inflammation attenuates the vascular responses to mental stress

Mental stress has been identified as a trigger of myocardial infarction (MI), with inflammation and vascular responses to mental stress independently implicated as contributing factors. This study examined whether inflammation moderates the vascular responses to mental stress. Eighteen healthy male participants completed a stress task under two counter balanced conditions. In the exercise condition, a morning bout of eccentric exercise (12×5 repetitions of unilateral eccentric knee extension at 120% intensity of concentric one repetition maximum) was used to increase levels of inflammatory-responsive cytokines during an afternoon stress session scheduled 6h later. In the control condition, participants sat and relaxed for 45min, 6h prior to the afternoon stress session. Forearm blood flow, calf blood flow (measured in the leg which completed the exercise task), blood pressure, heart rate and cardiac output were assessed at rest and in response to mental stress. As expected, interleukin-6 was higher (p=.02) 6h post exercise, i.e., at the start of the stress session, as compared to the no-exercise control condition. Mental stress increased forearm blood flow, calf blood flow, blood pressure, heart rate, and cardiac output in both conditions (p's<.001). Stress-induced calf blood flow was attenuated in the exercise condition compared to the control condition (p<.05) which was not the case for forearm blood flow. This study found that the inflammatory response to eccentric exercise attenuated the vascular responses to mental stress locally at the site of eccentric exercise-induced inflammation. The observed impairment in vascular responses to stress associated with increased levels of inflammation suggests a mechanism through which inflammation might increase the risk for MI.

DETECTION OF HUMAN STRESS USING SHORT-TERM ECG AND HRV SIGNALS

This paper introduces a method for resolving the problem of human stress detection through short-term (less than 5 min) electrocardiogram (ECG) and heart rate variability (HRV) signals. The explored methodology helps to improve the stress detection rate and reliability through multiple evidences originated in same sensor. In this work, stress-inducing protocol, data acquisition, preprocessing, feature extraction and classification are the major steps involved to detect the stress. In total, 60 subjects (30 males and 30 females) participated in the Stroop color word-based stress-inducing task and ECG signal was acquired simultaneously. The wavelet denoising algorithm was applied to remove high frequency, baseline wander and power line noises. Discrete wavelet transform (DWT)-based heart rate (HR) detection algorithm is used for deriving HRV signal from the preprocessed ECG signal. The ectopic beat removal method is employed to eliminate the ectopic beat and noise peaks in the HRV signal. In order to detect the stress, the issue of uneven sampling with the HRV signal has been successfully rectified using the Lomb-Scargle periodogram (LSP). The application of LSP in short-term HRV signals (32 s), uneven sampling issue, and power spectral information issue has been rectified and the trustworthiness of the short-term HRV signal has been proved by hypothesis as well as experimental results. Theoretical analysis suggested that a minimum 25 s of online or offline ECG data is required to analyze the autonomous nervous system (ANS) activity related to stress. In addition to the HRV signal, ECG-based stress assessment has been proposed to detect the stress through optimum features using fast Fourier transform (FFT). Various features extracted from the ECG and HRV signal have been classified into normal and stress using PNN and kNN classifiers with different smoothing factor and k values. The experimental results indicate that the proposed methodology for short-term ECG and HRV signal can achieve the overall average classification accuracy of 91.66% and 94.66% in the subject-independent mode.

Influence of chewing force on salivary stress markers as indicator of mental stress

The aim of this study was to investigate the influence of chewing force on salivary stress markers (alpha-amylase activity, salivary cortisol level and secretory immunoglobulin A secretion rate) as indicators of mental stress. Participants comprised 20 healthy men. The first set of saliva specimens (S1) was collected at immediately after a 20-min rest to evaluate stress markers. As stress loading, the participants were required to perform arithmetic calculations for 20 min, after which the second set of saliva specimens (S2) was collected. Each participant was then required to chew a piece of tasteless gum for 10 min, after which the third set of saliva specimens (S3) was collected. After a 20-min rest, the fourth set of saliva specimens (S4) was collected. Weak, habitual and strong chewing forces were assigned. Change rates of stress markers between S2 and S3, and S2 and S4 were calculated. A significant difference was observed in the change rate of cortisol levels between S2 and S3. Cortisol level decreased more under strong chewing than under weak chewing. No significant differences were observed in the change rate of amylase activity or s-IgA secretion rate among the three chewing forces. The results suggest that differences in chewing force influence the salivary cortisol level of the three stress markers, and that a strong chewing force induces a greater reduction in mental stress than a weak one.

Effects of mental workload on long-latency auditory-evoked-potential, salivary cortisol, and immunoglobulin A

This paper researches on the effects of mental workload on long-latency auditory-evoked-potential (AEP), salivary cortisol, and immunoglobulin A (IgA). 20 Healthy subjects (11 males and 9 females) participated in the experiment voluntarily. The mental task consisted of two parts: arithmetic task and reading comprehension task. The Latencies of N1, P2, N2, P3, and mismatch negativity (MMN) all increased significantly after the mental tasks were adopted at all of the three recording sites: Cz, Fz, and Pz (p<0.05). In this experiment, changes of salivary cortisol and s-IgA levels due to mental tasks were not significant. With the introduction of mental tasks, more processing resources are allocated to the primary task (mental task), and decreased processing resources available for the secondary task (auditory task), which is reflected on the increases in the latencies of probe-evoked AEP components.

Child care setting affects salivary cortisol and antibody secretion in young children

Elevated afternoon levels of cortisol have been found repeatedly in children during child care. However, it is unclear whether these elevations have any consequences. Because physiologic stress systems and the immune system are functionally linked, we examined the relationship between salivary cortisol concentration and antibody secretion across the day at home and in child care, and their relationships with parent-reported illnesses. Salivary antibody provides a critical line of defense against pathogens entering via the mouth, but little is known about its diurnal rhythm in young children or the effect of different environmental contexts. Saliva samples were taken at approximately 10:30 a.m., 3:30 p.m. and 8:00 p.m. on two child care and two home days in a sample of 65 3-5-year-old children attending very high quality, full time child care centers. Results indicated that (1) a rising cortisol profile at child care, driven by higher afternoon levels, predicted lower antibody levels on the subsequent weekend, (2) higher cortisol on weekend days was related to greater parent-reported illness, and (3) a declining daily pattern in sIgA was evident on weekend and child care days for older preschoolers, but only on weekend days for younger preschoolers. The results suggest that elevated cortisol in children during child care may be related to both lowered antibody levels and greater illness frequency.

Altered human neutrophil function in response to acute psychological stress

OBJECTIVE

To examine the effects of an acute laboratory psychological stress task on neutrophil function, specifically phagocytosis of Escherichia coli and stimulated superoxide production in human neutrophils. There is mounting evidence that acute stress is associated with short-term increases in a number of immune indices.

METHODS

Participants were 40 (n = 20 females) university students (mean age, 25.9 ± 4.56 years). Blood samples to determine neutrophil function by flow cytometry were taken at the end of resting baseline, during an acute stress task, and during recovery. The stress task was a 10-minute time-pressured mental arithmetic challenge with social evaluation.

RESULTS

There was an acute increase in phagocytic ability, p = .047, η(2)p = 0.076, and a reduction of superoxide production, p = .026, η(2)p = 0.101, associated with the stress task relative to baseline.

CONCLUSION

These findings suggest that neutrophil bactericidal function may be sensitive to mental challenge tasks that provoke acute psychological stress. Further research is needed to replicate the observed psychological stress-induced changes in neutrophil function.

Use of saliva for assessment of stress and its effect on the immune system prior to gross anatomy practical examinations

The objective of this study was to determine the longitudinal effects of a series of stressful gross anatomy tests on the immune system. Thirty-six freshman occupational therapy students completed a written stress evaluation survey, and saliva samples were obtained at baseline and prior to each of three timed-practical gross anatomy tests. Cortisol, secretory IgA (sIgA), and IL-12 concentrations were measured within the salivary samples by enzyme-linked immunosorbent assay. The total scores from the stress surveys were used as markers for environmental stress. Data were compiled for each student at baseline and prior to each examination and were compared by repeated-measures MANOVA and Pearson's correlation test. Following normalization for protein concentration and flow rate, the concentrations of IL-2, IL-6, IL-12, and sIgA progressively increased from baseline to the third test. Cortisol concentrations, following normalization for flow rate, were highest prior to the first test and became significantly reduced prior to second and third test. Prior to second and third test, salivary concentrations of IL-6, IL-2, IL-12, and sIgA were significantly correlated (P < 0.05). In contrast, prior to third test, there was a negative correlation between salivary concentrations of cortisol and IL-12 (P < 0.05). Progressive increases in salivary sIgA, IL-6, IL-2, and IL-12 concentrations from the first to the third test coincident to decreased salivary cortisol suggest that the initial examination stressors precede significant effects on the immune system. These data suggest that there may be latent effects of examination stress on the immune system and that saliva can be used to predict these effects.

Hemoconcentration during a prolonged stress task: associations with hemodynamic reactivity and microvascular permeability

This study explored the association between stress-induced hemoconcentration and plasma colloid osmotic pressure, hemodynamic reactivity, and microvascular permeability during a protracted stress task in 26 healthy, young participants. Microvascular permeability was measured during rest using venous congestion plethysmography in a subsample of 13 participants. The task increased hematocrit, colloid osmotic pressure, blood pressure, and heart rate and decreased R-wave to pulse interval. Resting microvascular permeability was not correlated with hemoconcentration. Colloid osmotic pressure and diastolic blood pressure were associated with stress-induced hemoconcentration throughout the task. The association with systolic blood pressure as well as heart rate, however, was more evident during the initial 8min of the task than throughout the total task duration. These findings suggest that factors associated with hemoconcentration vary with task duration.

Immunochromatographic assay using gold nanoparticles for measuring salivary secretory IgA in dogs as a stress marker

The concentration of salivary secretory immunoglobulin A (sIgA) is a well-known stress marker for humans. The concentration of salivary sIgA in dogs has also been reported as a useful stress marker. In addition, salivary sIgA in dogs has been used to determine the adaptive ability of dogs for further training. There are conventional procedures based on enzyme-linked immunosorbent assay (ELISA) for measuring salivary sIgA in dogs. However, ELISA requires long assay time, complicated operations and is costly. In the present study, we developed an immunochromatographic assay for measuring salivary sIgA in dogs using a dilution buffer containing a non-ionic surfactant. We determined 2500-fold dilution as the optimum condition for dog saliva using a phosphate buffer (50 mM, pH 7.2) containing non-ionic surfactant (3 wt% Tween 20). The results obtained from the saliva samples of three dogs using immunochromatographic assay were compared with those obtained from ELISA. It was found that the immunochromatographic assay is applicable to judge the change in salivary sIgA in each dog. The immunochromatographic assay for salivary sIgA in dogs is a promising tool, which should soon become commercially available for predicting a dog's psychological condition and estimating adaptive ability for training as guide or police dogs.

Caregiving is associated with low secretion rates of immunoglobulin A in saliva

Although the chronic stress of caring for a sick/disabled relative has been associated with poorer immunity using a range of outcomes, its impact on secretory immunoglobulin A (S-IgA) in saliva has yet to be examined. Three hypotheses were tested in analyses of data from a large community sample: first, caregivers would have lower S-IgA secretion rates than non-caregivers; second, the impact of caregiving on S-IgA would be particularly apparent in older participants; third, for caregivers, caregiving burden would be negatively associated with S-IgA. The sample comprised three distinct age cohorts, one young (N=623), one middle aged (N=639), and the other elderly (N=582). Participants were classified as caregivers if they regularly cared for somebody other than routine childcare. Caregiving strain was measured and a caregiving burden index was then derived as the composite of the number of people being cared for, the type of care provided, and the residential status of the person being cared for. From 2-min saliva samples, S-IgA secretion rate was measured. There was a significant caregiver status by age cohort interaction; caregivers in the eldest cohort had lower S-IgA secretion rates than their non-caregiving counterparts. Caregiving strain and burden and S-IgA were related, such that caregivers who experienced greater strain and burden had lower S-IgA secretion rates. These findings resonate with those from other studies using different immune outcomes. Considered together, it is clear that that the chronic stress of caregiving has widespread effects on immunity.

Short-term meditation training improves attention and self-regulation

Recent studies suggest that months to years of intensive and systematic meditation training can improve attention. However, the lengthy training required has made it difficult to use random assignment of participants to conditions to confirm these findings. This article shows that a group randomly assigned to 5 days of meditation practice with the integrative body-mind training method shows significantly better attention and control of stress than a similarly chosen control group given relaxation training. The training method comes from traditional Chinese medicine and incorporates aspects of other meditation and mindfulness training. Compared with the control group, the experimental group of 40 undergraduate Chinese students given 5 days of 20-min integrative training showed greater improvement in conflict scores on the Attention Network Test, lower anxiety, depression, anger, and fatigue, and higher vigor on the Profile of Mood States scale, a significant decrease in stress-related cortisol, and an increase in immunoreactivity. These results provide a convenient method for studying the influence of meditation training by using experimental and control methods similar to those used to test drugs or other interventions.

The Influence of 10min of the Johrei healing method on laboratory stress

OBJECTIVE

Johrei has been shown to decrease exam stress responses but its immediate effects have not been assessed.

DESIGN

In a randomised, blinded, counter-balanced design, 33 medical students were asked to calculate mental arithmetic in the Paced Auditory Serial Addition Task (PASAT), which served as an acute stressor prior to two conditions, 10 min of Johrei or a control resting condition involving 10 min without Johrei in a cross-over trial; after each, saliva was collected and mood tested.

SETTING

University EEG laboratory.

INTERVENTION

Johrei, a non-touch healing method.

MAIN OUTCOME MEASURES

Profile of mood states (POMS-Bi); state anxiety (STAI); salivary variables: cortisol, DHEA, IgA.

RESULTS

Mood scores on 5/6 of the POMS-Bi subscales were slightly but significantly more positive in the Johrei condition. State anxiety was similarly decreased. IgA levels were unchanged but cortisol levels were found to be slightly but non-significantly lower after Johrei than after the control condition and DHEA levels slightly but non-significantly raised, with a negative correlation between cortisol and DHEA levels.

CONCLUSIONS

This study gives some indication that Johrei can reduce negative mood and increase positive mood states after the acute effects of a laboratory stressor in comparison to a resting control condition.

Time course and mechanisms of hemoconcentration in response to mental stress

Hemoconcentration with mental stress exposure may be involved in the triggering of acute cardiovascular events. In the present study, hematocrit was measured repeatedly at baseline, during a 4 min mental stress task and during 20 min of recovery. Blood was sampled every 1-2 min throughout. Blood pressure, heart rate and R-wave to pulse interval, a measure of cardiac contractility, were measured with the same periodicity. The stress task elicited a 1.3% increase in hematocrit, which was sustained with full return to baseline level occurring only after 16 min of recovery. Between-subject correlations between hematocrit and hemodynamic activity were low. Aggregate within-subject coefficients were more impressive; the temporal profile of hematocrit correlated significantly with all hemodynamic variables. Similar within-subject analyses indicated that whereas cardiac contractility was correlated with hematocrit both during stress-related increase and subsequent recovery, blood pressure was related to hematocrit only during the increase. This suggests that stress-induced hemoconcentration may driven by different mechanisms than those which underlie its recovery.

Stressful life events are associated with low secretion rates of immunoglobulin A in saliva in the middle aged and elderly

Whether chronic stress experience is related to downregulation of secretory immunoglobulin A (S-IgA) was tested in two substantial cohorts, one middle aged (N = 640) and another elderly (N = 582), comprising similar numbers of men (N = 556) and women (N = 666) and manual (N = 606) and non-manual (N = 602) workers. Participants indicated from a list of major stressful life events, up to six, they had experienced in the past 2 years. They also rated how disruptive and stressful the events were, at the time and now, as well as their perceived seriousness; the products of these impact values and event frequency were adopted as measures of stress load. From unstimulated 2-min saliva samples, saliva volume and S-IgA concentration were measured, and S-IgA secretion rate determined as their product. There was a negative association between the stress load measures and the S-IgA secretion rate, still evident following adjustment for such variables as smoking and saliva volume. The associations also withstood adjustment for sex, cohort, and household occupational status. Although these associations are small in terms of the amount of variance explained, they nonetheless suggest that chronic stress experience either decreases IgA production by the local plasma cells or reduces the efficiency with which S-IgA is transported from the glandular interstitium into saliva. Given the importance of S-IgA in immune defence at mucosal surfaces and the frequency with which infections are initiated at these surfaces, S-IgA downregulation could be a means by which chronic stress increases susceptibility to upper respiratory tract infection.

Effects of competition, exercise, and mental stress on secretory immunity

It has been suggested that the psychological stress associated with competitive sports events may help to explain the increased susceptibility to respiratory infections due to reductions in secretory immunity. In the current study, we investigated the influence of competitive exercise and psychological stress on secretory immunoglobulin A (s-IgA). Salivary s-IgA and heart rate were measured in 62 healthy young recreationally active men at rest and, in a between-subjects design, following one of four 8-min tasks: mental arithmetic, cycling at workloads of 60 to 180 W (mean = 146 W), mental arithmetic while cycling, or competitive cycling. Mental arithmetic was associated with significant increases in s-IgA concentration (mean = 49 microg.min(-1)) and s-IgA secretion rate (mean = 25 microg.ml(-1)) compared with rest, while mental arithmetic combined with exercise was associated with a significant increase in s-IgA concentration only (mean = 124 microg.min(-1)). In contrast, competitive exercise and exercise alone did not influence s-IgA concentration or secretion rate. Heart rate increased modestly to mental arithmetic (mean = 7 beats.min(-1)) and substantially, and similarly, to the three exercise tasks (mean = 56(62 beats.min(-1)). The hypothesis that the psychological stress of competitive exercise contributes to increased susceptibility to infection via reductions in s-IgA requires further investigation.

Symptomatic effects of exposure to diluted air sampled from a swine confinement atmosphere on healthy human subjects

Aerial emissions from a swine house at North Carolina State University's field laboratory were diluted to a level that could occur at varying distances downwind from a confined animal feeding operation (CAFO) both within and beyond the property line, and these emissions were delivered to an environmental exposure chamber. The study design consisted of two 1-hr sessions, one in which 48 healthy human adult volunteers were exposed to diluted swine air and another in which they were exposed to clean air (control). Objective measures of blood pressure, temperature, heart rate, respiratory rate, lung function, nasal inflammation, secretory immunity, mood, attention, and memory were correlated with objective measures of air quality. Ratings of perceived (self-reported) health symptoms were also obtained. The mean levels of airborne constituents in the swine air condition were hydrogen sulfide (24 ppb), ammonia (817 ppb), total suspended particulates (0.0241 mg/m3), endotoxin (7.40 endotoxin units/m3), and odor (57 times above odor threshold). No statistical differences on objective measures of physical symptoms, mood, or attention resulted from the 1-hr exposure to swine emissions in the environmental chamber when compared with clean air for healthy human volunteers. However, subjects were 4.1 (p = 0.001) times more likely to report headaches, 6.1 (p = 0.004) times more likely to report eye irritation, and 7.8 (p = 0.014) times more likely to report nausea in the swine air (experimental) condition than in the control condition. These results indicate that short-term exposure in an environmental chamber to malodorous emissions from a swine house at levels expected downwind can induce clinically important symptoms in healthy human volunteers.

Effects of expression and inhibition of negative emotions on health, mood states, and salivary secretory immunoglobulin A in Japanese mildly depressed undergraduates

Previous studies have indicated that expression of negative emotions facilitates mental and physical health and inhibition of negative emotions increases susceptibility to illness. This study was conducted to examine whether those findings can be expanded to populations with non-Western cultural backgrounds. Specifically, we explored effects of expression and inhibition of negative emotions on health, mood states, and mucosal immune function in mildly depressed Japanese individuals. 16 depressed and 16 nondepressed female undergraduates were required either to write about their unpleasant experiences and superficial topics or to suppress any emotional responses and thoughts about them. Secretory immunoglobulin A (s-IgA) in saliva and psychological indices were measured at an experimental session and at a follow-up 1 wk. later. Beneficial effects of expression of emotions on subjective health were indicated in the nondepressed group, whereas harmful effects of inhibition on subjective health were shown in the depressed group. Emotional expression by writing improved mood states both in the depressed and nondepressed groups but induced elevation of salivary s-IgA only in the depressed group.

Secretory immunoglobulin A reactivity to acute and cumulative acute multi-tasking stress: relationships between reactivity and perceived workload

The effects of an acute stressor upon secretory immunoglobulin A (S-IgA) were assessed using a task that requires participants to attend and respond to several stimuli simultaneously and is therefore analogous to a variety of working environments. In two studies, the task was administered for periods of 5 min to healthy samples of men and women at two sessions 24 h apart (n = 49) and three times in succession within one session (n = 20). Multi-tasking stress was, at all sessions, associated with increases in S-IgA secretion. Inter and intra-session reliability of pre and post-stress S-IgA measures was observed, although the reliability of stress reactivity data was reduced. Classification of participants as either high or low S-IgA reactors revealed differences in their perceptions of task workload. Low S-IgA reactors consistently perceived the task to be more demanding and frustrating than did those who demonstrated high S-IgA reactivity. We conclude that S-IgA reactivity to stressful situations depends not just upon the task, but also upon individual perceptions of the stressor.

Mental stress-induced hemoconcentration: Sex differences and mechanisms

Given the possible role of hemoconcentration in myocardial infarction and apparent sex differences in susceptibility, three studies examined sex differences in mental stress-induced hemoconcentration, and explored possible underlying mechanisms. Blood pressure, heart rate, and hematocrit were monitored at rest and in response to a mental stress task that was contrived to be increasingly provocative across the three studies. This was confirmed by self-report, performance, and cardiovascular reactivity data. The most convincing evidence for hemoconcentration effects and sex differences in hemoconcentration emerged from exposure to the more provocative of the stress tasks, with men also showing greater hemoconcentration than women. Blood pressure reactivity was a strong and consistent predictor of stress-induced hemoconcentration. These findings may help to explain sex differences in susceptibility to myocardial infarction.

Reductions in secretory immunoglobulin A to cold pressor stress are not influenced by timing of saliva sampling

Acute psychological stress has been shown to alter secretory immunity, principally secretory immunoglobulin A (S-IgA). Most acute stress tasks result in increases in S-IgA, but decreases have been reported in response to the cold pressor. However, the evidence is mixed, with increases and no changes in S-IgA in response to the cold pressor also being reported. It was hypothesised that differences in the timing of saliva sampling may provide an explanation for these discrepant results. Participants completed two 4-min cold pressor tasks, each preceded by a rest period in which baseline S-IgA was measured. In one condition, S-IgA was assessed during the final 2 min of the cold pressor; in the other, it was measured immediately after completion of the task. S-IgA decreased from baseline to task, regardless of timing of saliva sampling. It was concluded that differences in timing of sampling do not account for the mixed reports in the literature.

Increases in lipids and immune cells in response to exercise and mental stress in patients with suspected coronary artery disease: effects of adjustment for shifts in plasma volume

This study examined the role of shifts in plasma volume on lipid and immune reactions to stress. Lipid, immune, rheological, and cardiovascular reactions to exercise and mental stress in 51 patients with suspected coronary artery disease were determined. Blood pressure and heart rate were measured during and blood samples taken at the end of each rest and task. Lipids (total cholesterol, triglycerides, HDL, LDL) and immune cells (lymphocytes, monocytes, granulocytes) increased with exercise, whereas cholesterol, LDL, and lymphocytes increased with mental stress. Plasma volume decreased by 1 and 5% following mental and exercise stress, respectively. The task-induced increases in lipids were no longer statistically significant following adjustment for changes in plasma volume, whereas the increases in immune cell numbers survived such correction. This study provides evidence that, in coronary artery disease patients, exercise and mental stress-induced increases in lipids but not immune cells can be largely accounted for by shifts in plasma volume.