Heart rate variability during acute psychosocial stress: A randomized cross-over trial of verbal and non-verbal laboratory stressors

When virtual reality becomes psychoneuroendocrine reality: A stress(or) review

This review article was awarded the Dirk Hellhammer award from ISPNE in 2023. It explores the dynamic relationship between stressors and stress from a historical view as well as a vision towards the future of stress research via virtual reality (VR). We introduce the concept of a "syncytium," a permeable boundary that blurs the distinction between stress and stressor, in order to understand why the field of stress biology continues to inadequately measure stress alone as a proxy for the force of external stressors. Using Virtual Reality (VR) as an illustrative example to explicate the black box of stressors, we examine the distinction between 'immersion' and 'presence' as analogous terms for stressor and stress, respectively. We argue that the conventional psychological approaches to stress measurement and appraisal theory unfortunately fall short in quantifying the force of the stressor, leading to reverse causality fallacies. Further, the concept of affordances is introduced as an ecological or holistic tool to measure and design a stressor's force, bridging the gap between the external environment and an individual's physiological response to stress. Affordances also serve to ameliorate shortcomings in stress appraisal by integrating ecological interdependencies. By combining VR and psychobiological measures, this paper aims to unravel the complexity of the stressor-stress syncytium, highlighting the necessity of assessing both the internal and external facets to gain a holistic understanding of stress physiology and shift away from reverse causality reasoning. We find that the utility of VR extends beyond presence to include affordance-based measures of immersion, which can effectively model stressor force. Future research should prioritize the development of tools that can measure both immersion and presence, thereby providing a more comprehensive understanding of how external stressors interact with individual psychological states.

Integrative neuro-cardiovascular dynamics in response to test anxiety: A brain-heart axis study

Test anxiety (TA), a recognized form of social anxiety, is the most prominent cause of anxiety among students and, if left unmanaged, can escalate to psychiatric disorders. TA profoundly impacts both central and autonomic nervous systems, presenting as a dual manifestation of cognitive and autonomic components. While limited studies have explored the physiological underpinnings of TA, none have directly investigated the intricate interplay between the CNS and ANS in this context. In this study, we introduce a non-invasive, integrated neuro-cardiovascular approach to comprehensively characterize the physiological responses of 27 healthy subjects subjected to test anxiety induced via a simulated exam scenario. Our experimental findings highlight that an isolated analysis of electroencephalographic and heart rate variability data fails to capture the intricate information provided by a brain-heart axis assessment, which incorporates an analysis of the dynamic interaction between the brain and heart. With respect to resting state, the simulated examination induced a decrease in the neural control onto heartbeat dynamics at all frequencies, while the studying condition induced a decrease in the ascending heart-to-brain interplay at EEG oscillations up to 12Hz. This underscores the significance of adopting a multisystem perspective in understanding the complex and especially functional directional mechanisms underlying test anxiety.

Slow Breathing Reduces Biomarkers of Stress in Response to a Virtual Reality Active Shooter Training Drill

Tactical occupations regularly encounter life-threatening situations while on duty. Although these occupations are often trained to utilize slow breathing (SB) during intense stress, there is no evidence supporting the effects on markers of stress in response to a virtual reality active shooter training drill (VR-ASD). The purpose of the study was to determine the impact of acute SB on biomarkers of stress in response to a VR-ASD. Seventy-nine (n = 79) subjects performed either slow breathing method 1 (SB1), slow breathing method 2 (SB2), or normal breathing (control) for five minutes, both pre- and post-VR-ASD. Saliva samples were analyzed for stress markers, including α-amylase (sAA) and secretory immunoglobulin-A (SIgA). Both methods of SB resulted in significantly lower sAA concentrations at 5 (p < 0.001) and 30 min post-VR-ASD (SB1: p = 0.008; SB2: p < 0.001) compared to the control. In the control condition, the sAA concentrations were significantly elevated 5 min post-VR-ASD (p < 0.001) but did not change across time in SB1 or SB2 (p > 0.05). Thus, both SB1 and SB2 reduced the sAA response and resulted in lower concentrations post-VR-ASD. This study was pre-registered as a clinical trial ("Impact of Breathing Interventions on Stress Markers"; NCT05825846).

Heart Rate Variability for Evaluating Psychological Stress Changes in Healthy Adults: A Scoping Review

The utility of heart rate variability (HRV) for characterizing psychological stress is primarily impacted by methodological considerations such as study populations, experienced versus induced stress, and method of stress assessment. Here, we review studies on the associations between HRV and psychological stress, examining the nature of stress, ways stress was assessed, and HRV metrics used. The review was performed according to the PRISMA guidelines on select databases. Studies that examined the HRV-stress relationship via repeated measurements and validated psychometric instruments were included (n = 15). Participant numbers and ages ranged between 10 and 403 subjects and 18 and 60 years, respectively. Both experimental (n = 9) and real-life stress (n = 6) have been explored. While RMSSD was the most reported HRV metric (n = 10) significantly associated with stress, other metrics, including LF/HF (n = 7) and HF power (n = 6) were also reported. Various linear and nonlinear HRV metrics have been utilized, with nonlinear metrics used less often. The most frequently used psychometric instrument was the State-Trait Anxiety Inventory (n = 10), though various other instruments have been reported. In conclusion, HRV is a valid measure of the psychological stress response. Standard stress induction and assessment protocols combined with validated HRV measures in different domains will improve the validity of findings.

Physiological and Psychological Response to Acute Mental Stress in Female Patients Affected by Chronic Pulmonary Arterial Hypertension: An Explorative Controlled Pilot Trial

Little is known about physiological and psychological responses to mental stress in stable patients affected by pulmonary arterial hypertension (PAH). The current explorative controlled pilot study was conducted to investigate whether heart rate (HR) and perceived stress would differ during standardized mental stress testing in PAH patients compared to healthy subjects. Correlation analysis between HR, perceived stress, participants’ psychological status and performance on the mental stress task was also performed. The study included 13 female PAH patients (average age: 44.38 ± 10.88 years; average education: 14 ± 3.07 years; mean duration of illness: 9.15 ± 5.37 years) and 13 female controls similar in age (mean age: 47.85 ± 6.36 years) and education (15.92 ± 1.55 years). Participants performed a standardized 9 min mental stress test (computer based, adaptive math task). HR and perceived stress during the task were compared to resting baseline and correlated with psychological state and task performance. Both HR and perceived stress significantly increased during mental stress in a similar way in both groups. A significant correlation was found between HR and perceived stress. Our data show that moderate mental stress has a comparable effect on HR and perceived stress increase in stable PAH patients and control subjects.

Sex effects in the interaction of acute stress and pain perception

ABSTRACT

A reciprocity between the stress and the pain system is recognized; however, the manner by which sex affects this reciprocity is unclear. Understanding the interactions of stress, pain, and sex may shed light on the apparent women's vulnerability to chronic pain, which often coexists with increased distress, and to affective disorders, which often coexist with chronic pain. The study's aim was to examine the effect of acute, validated, psychosocial stress on pain perception and modulation of women and men in a controlled manner. Participants were 82 women and 66 men. Heat-pain threshold, heat-pain tolerance, and pain modulation by temporal summation of pain (TSP), and pain adaptation were measured before and after exposure to the Montreal Imaging Stress Task (MIST) or to a sham task. The stress response was verified by perceived ratings of stress and anxiety, autonomic variables, and salivary cortisol. A significant stress response was obtained by the MIST among both sexes; however, women displayed a greater increase in perceived distress, and men displayed a greater increase in cortisol. Among women, TSP decreased and pain adaptation increased following the MIST, responses that were predicted by perceived distress levels. Among men, TSP increased following the MIST but was not predicted by the stress variables. In conclusion, acute stress manipulation seems to differentially affect both stress and pain responses of women and men: women exhibited stress-induced antinociception and men exhibited stress-induced pronociception. Higher perceived stress levels among women may trigger a temporary increase in pain inhibition mechanisms to serve evolutionary purposes.

Third Trimester Fetuses Demonstrate Priming, a Form of Implicit Memory, In Utero

Research examinations of changes in fetal heart rate (HR) to operationalize fetal memory suggests that human memory capacities emerge in utero. However, there is little evidence for a form of implicit memory or priming. The present aim was to determine if priming is evident in utero. Fetal HR, maternal HR and maternal respiratory rate (RR) were examined in 105 women during the third trimester of pregnancy. Women experienced two counterbalanced laboratory tasks, the Stroop task and the paced breathing task, and their cardiorespiratory activity functioned as a stimulus for fetuses. Repeated measures ANOVAs revealed maternal HR increased during the Stroop task but only when the Stroop task was presented first (89.64 bpm to 92.39 bpm) (p = 0.04). Maternal RR increased during the Stroop task, regardless of task order (17.72 bpm to 21.11 bpm; 18.50 bpm to 22.60 bpm) (p < 0.01). Fetal HR increased during the paced breathing task, but only when it followed maternal exposure to the Stroop task (141.13 bpm to 143.97 bpm) (p < 0.01). Fetuses registered maternal HR and RR reactivity to the Stroop task, which influenced their response during maternal engagement with a related task, suggesting priming. Further study of fetal memory may suggest another pathway by which prenatal exposures impact future development.

Alignment Between Heart Rate Variability From Fitness Trackers and Perceived Stress: Perspectives From a Large-Scale In Situ Longitudinal Study of Information Workers

BACKGROUND

Stress can have adverse effects on health and well-being. Informed by laboratory findings that heart rate variability (HRV) decreases in response to an induced stress response, recent efforts to monitor perceived stress in the wild have focused on HRV measured using wearable devices. However, it is not clear that the well-established association between perceived stress and HRV replicates in naturalistic settings without explicit stress inductions and research-grade sensors.

OBJECTIVE

This study aims to quantify the strength of the associations between HRV and perceived daily stress using wearable devices in real-world settings.

METHODS

In the main study, 657 participants wore a fitness tracker and completed 14,695 ecological momentary assessments (EMAs) assessing perceived stress, anxiety, positive affect, and negative affect across 8 weeks. In the follow-up study, approximately a year later, 49.8% (327/657) of the same participants wore the same fitness tracker and completed 1373 EMAs assessing perceived stress at the most stressful time of the day over a 1-week period. We used mixed-effects generalized linear models to predict EMA responses from HRV features calculated over varying time windows from 5 minutes to 24 hours.

RESULTS

Across all time windows, the models explained an average of 1% (SD 0.5%; marginal R2) of the variance. Models using HRV features computed from an 8 AM to 6 PM time window (namely work hours) outperformed other time windows using HRV features calculated closer to the survey response time but still explained a small amount (2.2%) of the variance. HRV features that were associated with perceived stress were the low frequency to high frequency ratio, very low frequency power, triangular index, and SD of the averages of normal-to-normal intervals. In addition, we found that although HRV was also predictive of other related measures, namely, anxiety, negative affect, and positive affect, it was a significant predictor of stress after controlling for these other constructs. In the follow-up study, calculating HRV when participants reported their most stressful time of the day was less predictive and provided a worse fit (R2=0.022) than the work hours time window (R2=0.032).

CONCLUSIONS

A significant but small relationship between perceived stress and HRV was found. Thus, although HRV is associated with perceived stress in laboratory settings, the strength of that association diminishes in real-life settings. HRV might be more reflective of perceived stress in the presence of specific and isolated stressors and research-grade sensing. Relying on wearable-derived HRV alone might not be sufficient to detect stress in naturalistic settings and should not be considered a proxy for perceived stress but rather a component of a complex phenomenon.

Insights on Modelling Physiological, Appraisal, and Affective Indicators of Stress using Audio Features

Stress is a major threat to well-being that manifests in a variety of physiological and mental symptoms. Utilising speech samples collected while the subject is undergoing an induced stress episode has recently shown promising results for the automatic characterisation of individual stress responses. In this work, we introduce new findings that shed light onto whether speech signals are suited to model physiological biomarkers, as obtained via cortisol measurements, or self-assessed appraisal and affect measurements. Our results show that different indicators impact acoustic features in a diverse way, but that their complimentary information can nevertheless be effectively harnessed by a multi-tasking architecture to improve prediction performance for all of them.

Mental Stress Assessment Using Ultra Short Term HRV Analysis Based on Non-Linear Method

Mental stress is on the rise as one of the major health problems in modern society. It is important to detect and manage mental stress to prevent various diseases caused by stress and to maintain a healthy life. The purpose of this paper is to present new heart rate variability (HRV) features based on empirical mode decomposition and to detect acute mental stress through short-term HRV (5 min) and ultra-short-term HRV (under 5 min) analysis. HRV signals were acquired from 74 young police officers using acute stressors, including the Trier Social Stress Test and horror movie viewing, and a total of 26 features, including the proposed IMF energy features and general HRV features, were extracted. A support vector machine (SVM) classification model is used to classify the stress and non-stress states through leave-one-subject-out cross-validation. The classification accuracies of short-term HRV and ultra-short-term HRV analysis are 86.5% and 90.5%, respectively. In the results of ultra-short-term HRV analysis using various time lengths, we suggest the optimal duration to detect mental stress, which can be applied to wearable devices or healthcare systems.

Nurse evaluation of stress levels during CPR training with heart rate variability using smartwatches according to their personality: A prospective, observational study

Background

Cardiopulmonary resuscitation (CPR) is a very critical phenomenon, and to prepare for it, most nurses undertake simulation training, during which learners’ stress levels should be managed. This study aims to evaluate nurses’ stress levels during CPR simulation training using heart rate variability (HRV) measured with a smartwatch and to determine the correlation between individual personality traits and stress levels.

Methods

This prospective observational study was conducted from July 2020 to December 2021. For nurses participating in advanced life support training with more than six months of clinical experience, their stress levels while performing as a CPR team leader were measured. Regarding stress levels, heart rate data measured with a smartwatch were processed using Kubios HRV Standard software to generate HRV parameters. The personality of participants was evaluated using the Big Five personality test. The degree of stress according to personality was determined using HRV parameters. Consequently, the correlation between personality and stress according to the clinical experience of cardiac arrest was analyzed.

Results

Of the 132 participants, 91.7% were female, and the median age of the sample was 27 years. Agreeable personality had the highest score (32.84±3.83). LF power (r = 0.18, p = 0.04) and HF power (r = 0.20, p = 0.02) showed a significant positive correlation with the agreeableness trait. In subgroup analysis according to the cardiac arrest experience, the agreeableness trait had a positive correlation with a standard deviation of NN intervals (r = 0.24, p = 0.01), root-mean-square of successive differences (r = 0.23, p = 0.02), LF Power (r = 0.26, p = 0.01), and HF power (r = 0.23, p = 0.02), but a negative correlation with mean HR (r = -0.22, p = 0.03).

Conclusion

The clinical experience in cardiac arrest and agreeableness were related to acute stress during training. In the future, it is necessary to apply a scenario of a level suitable for individual personality and experience, and evaluate the level and achievement of students.

Physiological Responses to Narrative Anger Recall and Correlates to Anger, Forgiveness, and Rumination

Abstract. Narrative recall, or describing an event from one’s past, is a common method to study anger in the laboratory. However, most research using this method has not included a neutral speaking control, and therefore the physiological response attributable to emotion versus the act of speech is unknown. We evaluated heart rate, blood pressure, skin conductance level, heart rate variability, and salivary alpha-amylase during silent baseline, neutral speaking, anger recall, and recovery periods, and correlated these measures with trait anger, forgiveness, and rumination ( n = 104). Only systolic blood pressure and skin conductance levels were elevated in the anger recall period above the values in the neutral speaking period, showing the need for this important control. Alpha-amylase was inversely correlated to forgiveness, particularly in females. A neutral speaking control is critical for anger recall protocols because the physiological responses are mostly due to speaking, not anger. Salivary alpha-amylase may be a promising autonomic marker in studies of forgiveness and anger.

Association between distinct coping styles and heart rate variability changes to an acute psychosocial stress task

Modern life comprises a myriad of stressful situations, ranging from life-threatening ones to others not so deadly, all of which activate a physiologic stress response. Engaging in healthy ways to cope can prevent us from wearing out our physiological systems. Heart rate variability (HRV) is often used as an index of emotion regulation response. Hence, our goal is to investigate whether the habitual use of coping strategies is related to a distinct pattern of HRV changes when the individual is exposed to a moderate psychosocial stressor. In this study, 60 female participants performed a psychosocial stress task-oral speech preparation-while ECG signals were collected during the whole experimental procedure. Heart rate (HR), HRV parameters (SDNN, RMSSD, LF, HF) and coping strategies (Brief COPE) were registered. Participants were divided into two groups (low and high groups) as a function of their scores on the maladaptive and adaptive coping strategies of the Brief COPE. As expected, the task alone induced increases in heart rate and reductions in HRV parameters. Additionally, the analyses revealed a different pattern of HRV (SDNN, RMSSD, LF and HF) changes in response to the stressor, with participants using less maladaptive strategies being able to maintain the HRV at baseline levels when confronting the stressor, while those using more maladaptive strategies reducing HRV during the task. These results show a different pattern of HRV changes as a function of the coping style, suggesting a possible autonomic advantage, namely, the maintenance of HRV, in individuals who use maladaptive coping strategies less frequently.

An Evaluation of Speech-Based Recognition of Emotional and Physiological Markers of Stress

Life in modern societies is fast-paced and full of stress-inducing demands. The development of stress monitoring methods is a growing area of research due to the personal and economic advantages that timely detection provides. Studies have shown that speech-based features can be utilised to robustly predict several physiological markers of stress, including emotional state, continuous heart rate, and the stress hormone, cortisol. In this contribution, we extend previous works by the authors, utilising three German language corpora including more than 100 subjects undergoing a Trier Social Stress Test protocol. We present cross-corpus and transfer learning results which explore the efficacy of the speech signal to predict three physiological markers of stress—sequentially measured saliva-based cortisol, continuous heart rate as beats per minute (BPM), and continuous respiration. For this, we extract several features from audio as well as video and apply various machine learning architectures, including a temporal context-based Long Short-Term Memory Recurrent Neural Network (LSTM-RNN). For the task of predicting cortisol levels from speech, deep learning improves on results obtained by conventional support vector regression—yielding a Spearman correlation coefficient (ρ) of 0.770 and 0.698 for cortisol measurements taken 10 and 20 min after the stress period for the two corpora applicable—showing that audio features alone are sufficient for predicting cortisol, with audiovisual fusion to an extent improving such results. We also obtain a Root Mean Square Error (RMSE) of 38 and 22 BPM for continuous heart rate prediction on the two corpora where this information is available, and a normalised RMSE (NRMSE) of 0.120 for respiration prediction (−10: 10). Both of these continuous physiological signals show to be highly effective markers of stress (based on cortisol grouping analysis), both when available as ground truth and when predicted using speech. This contribution opens up new avenues for future exploration of these signals as proxies for stress in naturalistic settings.

Pre-sleep social media use does not strongly disturb sleep: a sleep laboratory study in healthy young participants

OBJECTIVE

Sleep is critical for our mental health and optimal cognitive functioning. Social media use is increasingly common and suspected to disturb sleep due to increasing bedtime arousal. However, most studies rely on self-reported sleep.

METHODS

We tested the effects of 30 min social media use on arousal and subsequent sleep in the sleep laboratory in 32 healthy young volunteers. Effects of blue-light were excluded in this study. We compared it to 30 min progressive muscle relaxation (PMR) and neutral sleep in a within-subject design.

RESULTS

Thirty minutes of social media use immediately before sleep did not significantly increase arousal and did neither disturb objective nor subjective sleep. After social media use, participants only spent less time in sleep stage N2. In contrast, PMR had the expected positive effects on pre-sleep arousal level indicated by reduced heart rate. In addition, PMR improved sleep efficiency, reduced sleep onset latency, and shortened the time to reach slow-wave sleep compared to a neutral night. Oscillatory power in the slow-wave activity and spindle bands remained unaffected.

CONCLUSION

Social media use before sleep (controlling for effects of blue-light) had little effect on bedtime arousal and sleep quality than what was previously expected. The most notable effect appears to be the additional time spent engaging in social media use at bedtime, potentially keeping people from going to sleep. As wake up-time is mostly determined externally, due to school or working hours, limiting personal media use at bedtime-and especially in bed-is recommended to get sufficient hours of sleep.

Assessing stress variations in children during the strange situation procedure: comparison of three widely used respiratory sinus arrhythmia estimation methods

Objective.The respiratory sinus arrhythmia (RSA) is a well-known marker of vagal activity that can be exploited to measure stress changes. RSA is usually estimated from heart rate variability (HRV). This study aims to compare the RSA obtained with three widely adopted methods showing their strengths and potential pitfalls.Approach.The three methods are tested on 69 healthy preschoolers undergoing a stressful protocol, the strange situation procedure (SSP). We compare the RSA estimated by the Porges method, the univariate autoregressive (AR) spectral analysis of the HRV signal, and the bivariate AR spectral analysis of HRV and respirogram signals. We examine RSA differences detected across the SSP episodes and correlation between the estimates provided by each method.Main results.The Porges and the bivariate AR approaches both detected significant differences (i.e. stress variations) in the RSA measured across the SSP. However, the latter method showed higher sensitivity to stress changes induced by the procedure, with the mean RSA variation between baseline and first separation from the mother (the most stressful condition) being significantly different among methods: Porges, -17.5%; univariate AR, -18.3%; bivariate AR, -23.7%. Moreover, the performances of the Porges algorithm were found strictly dependent on the applied preprocessing.Significance.Our findings confirm the bivariate AR analysis of the HRV and respiratory signals as a robust stress assessment tool that does not require any population-specific preprocessing of the signals and warn about using RSA estimates that neglect breath information in more natural experiments, such as those involving children, in which respiratory frequency changes are extremely likely.

Evaluating cannabidiol (CBD) expectancy effects on acute stress and anxiety in healthy adults: a randomized crossover study

RATIONALE

Cannabidiol (CBD) has been reported to attenuate stress and anxiety, but little is known about the extent to which such effects result from pharmacological versus expectancy factors.

OBJECTIVES

We evaluated whether CBD expectancy alone could influence stress, anxiety, and mood, and the extent to which beliefs regarding CBD effects predicted these responses.

METHODS

In this randomized crossover study, 43 health adults (23 women) attended two experimental laboratory sessions, where they self-administered CBD-free hempseed oil sublingually. During one session, they were (incorrectly) informed that the oil contained CBD and in the other session, that the oil was CBD-free. Following administration, participants engaged in the Maastricht Acute Stress Test (MAST). Heart rate variability (HRV) was assessed continuously, and subjective state was assessed at baseline, 90-min following oil administration, immediately following the MAST, and after a 10-min recovery period.

RESULTS

The CBD expectancy condition was associated with increased sedation as well as with changes in HRV that were consistent with heightened anticipatory stress regulation. Overall, there were no systematic changes in subjective stress, or anxiety, according to expectancy condition. However, participants who endorsed strong a priori beliefs that CBD has anxiolytic properties reported significantly diminished anxiety in the CBD expectancy condition.

CONCLUSIONS

CBD expectancy alone impacted several subjective and physiological responses. Additionally, expectancy-related factors were implicated in anxiolytic effects of CBD for those who believed it was helpful for such purposes, emphasizing the need to measure and control for CBD-related expectancies in clinical research that involves the administration of CBD.

Short-Term Fasting and Ingestion of Caloric Drinks Affect Heartbeat-Evoked Potentials and Autonomic Nervous System Activity in Males

Central nervous systems receive and process information from the internal and external environment to maintain homeostasis. This includes interoceptive awareness of the organism’s nutritional state. Whenever food supply is required, feelings of hunger initiate the search for and the consumption of appropriate amounts of nutrients. How this is physiologically regulated in humans has been subjected to research into interoceptive awareness of body states during fasting and food consumption. However, there is no research on the distinct effects of carbohydrate or protein intake on interoception. Therefore, we aimed to investigate the impact of fasting and consumption of standardized carbohydrate and protein shakes on interoception in a repeated-measures cross-over design in a sample of 37 healthy, normal weight males. As a physiological correlate of interoception, we measured heartbeat-evoked potentials (HEPs), which are suggested to reflect the cortical representation of cardiac signals, during eight-minutes resting state EEG-recordings. After a 16-hour fasting period, the HEP amplitudes were lower over right central and parietal electrodes and increased after ingestion of the nutritional shake. Exploratory analyses indicated that the difference between fasting and satiety was more prominent at carbohydrate compared protein testing days. Correlation analyses with heart rate variability (HRV) suggested that high cardiac sympathetic activity is related to lower HEP amplitudes. Furthermore, cardiac sympathetic activity and stress indices decreased from before to after the intervention, whereas HRV increased. Together, this study shows for the first time that fasting and the intake of a nutritional shake affects cardiac measures of autonomic nervous system functioning and the neural correlates of cardiac interoception. These findings could be relevant for diets and psychosomatic disorders, including eating disorders.

Trier Social Stress Test Elevates Blood Pressure, Heart Rate, and Anxiety, But a Singing Test or Unsolvable Anagrams Only Elevates Heart Rate, among Healthy Young Adults

The Trier Social Stress Test (TSST) is a psychosocial stressor that effectively stimulates the stress response but is labor and time intensive. Although other psychological stressors are often used experimentally, none are known to comparably elevate stress. Two stressors that may potentially elevate stress are a singing task (ST) and unsolvable anagrams, but there are not enough data to support their effectiveness. In the current experiment, 53 undergraduate males and females (mean age = 21.9 years) were brought into the laboratory, and baseline blood pressure, heart rate, self-rated anxiety, and salivary cortisol were recorded. Then, participants were randomly assigned to one of three stress conditions: TSST (n = 24), ST (n = 14), or an unsolvable anagram task (n = 15). Stress measures were taken again after the stressor and during recovery. The TSST significantly elevated systolic blood pressure, diastolic blood pressure, heart rate, and self-rated anxiety from pre-stress levels, replicating its stress-inducing properties. However, the ST and unsolvable anagrams only elevated heart rate, indicating that these methods are not as able to stimulate physiological or psychological stress. Overall, results indicate that out of these three laboratory stressors, the TSST clearly engages the stress response over the ST or unsolvable anagrams.

Catching the audience in a job interview: Effects of emotion regulation strategies on subjective, physiological, and behavioural responses

In the emotion regulation process more than one strategy is often used, though studies continue to rely on the manipulation of one strategy alone. This study compares the effects of Combined Cognitive Reappraisal (CCR: acceptance and reappraise via perspective-taking) and suppression using the Trier Social Stress Test (TSST). One hundred participants were randomly assigned to one of the two groups and subjective, physiological, and behavioural data were recorded. Continuous electrocardiography was recorded to measure heart rate variability (HRV) and stress levels. Affective ratings were provided before and after the TSST. Behavioural expressions were videotaped and analysed independently. Trait social anxiety/fear, age and gender entered as covariates. Although no group differences were found on affective ratings, the CCR group presented less physiological stress, higher HRV, their speech was better perceived, displayed more affiliative smile and hand gestures. Results suggested that CCR is more appropriate than suppression for managing social stress situations.

Virtual Reality Customized 360-Degree Experiences for Stress Relief

The latest studies in virtual reality (VR) have evidenced the potential of this technology to reproduce environments from multiple domains in an immersive way. For instance, in stress relief research, VR has been presented as a portable and inexpensive alternative to chromotherapy rooms, which require an adapted space and are expensive. In this work, we propose a portable and versatile alternative to the traditional chromotherapy color-loop treatment through four different 360-degree virtual experiences. A group of 23 healthy participants (mean age 22.65 ± 5.48) were conducted through a single-session experience divided into four phases while their electroencephalography (EEG) was recorded. First, they were stressed via the Montreal imaging stress task (MIST), and then relaxed using our VR proposal. We applied the Wilcoxon test to evaluate the relaxation effect in terms of the EEG relative gamma and self-perceived stress surveys. The results that we obtained validate the effectiveness of our 360-degree proposal to significantly reduce stress (p-value = 0.0001). Furthermore, the participants deemed our proposal comfortable and immersive (score above 3.5 out of 5). These results suggest that 360-degree VR experiences can mitigate stress, reduce costs, and bring stress relief assistance closer to the general public, like in workplaces or homes.

Effects of Saffron Extract Supplementation on Mood, Well-Being, and Response to a Psychosocial Stressor in Healthy Adults: A Randomized, Double-Blind, Parallel Group, Clinical Trial

Anxiety, stress, and low mood are closely related and may contribute to depressive symptoms. Among non-pharmacological solutions to improve subclinical mood symptoms and resilience to stress, natural products such as saffron—identified as promising following preliminary beneficial effects in major depressive disorder—represent a relevant strategy. This study aimed to assess the efficacy of 8 weeks' supplementation with 30 mg standardized saffron extract on emotional well-being in healthy adults with subclinical feelings of low mood and anxiety and/or stress and evaluate the acute effect of saffron in response to a lab-based psychosocial stressor. The study adopted a double-blind, randomized, parallel groups design in which 56 healthy male and female individuals (18–54 years) received either a saffron extract or a placebo for 8 weeks. Chronic effects of saffron on subjective anxiety, stress, and depressive feelings were assessed using a questionnaire battery [including Profile of Mood State-2, (POMS)] and acute effects in response to a lab-based psychosocial stressor were measured through psychological and physiological parameters. Urinary crocetin levels were quantified. Participants who received the saffron extract reported reduced depression scores and improved social relationships at the end of the study. Urinary crocetin levels increased significantly with saffron supplementation and were correlated with change in depression scores. The typical stress-induced decrease in heart rate variability (HRV) during exposure to the stressor was attenuated following acute saffron intake. Saffron extract appears to improve subclinical depressive symptoms in healthy individuals and may contribute to increased resilience against the development of stress-related psychiatric disorders.

Clinical trials number: NCT03639831.

Ecology of cooperation: The influence of fasting and satiety on interpersonal trust

The willingness to cooperate in social interaction often depends on factors such as trustworthiness, reciprocity, and gender, but perhaps also on situational factors such as satiety. Here, we examined Trust Game performance before (fasting condition) and after ingestion of a high-caloric drink (satiety condition) of 37 psychologically healthy male subjects who played the game against individuals of both sexes differing in facial attractiveness. Participants invested significantly fewer money units (MUs) in the fasting condition compared to the satiated condition. Female opposing players received more MUs than males and attractive players more than less attractive ones. Time to arrive at a decision was shorter in the satiated condition than in the fasting condition. These findings indicate that satiety affects social cooperation and suggests that physical needs are prioritized over social cooperation.

Virtual Reality as a Portable Alternative to Chromotherapy Rooms for Stress Relief: A Preliminary Study

Chromotherapy rooms are comfortable spaces, used in places like special needs schools, where stimuli are carefully selected to cope with stress. However, these rooms are expensive and require a space that cannot be reutilized. In this article, we propose the use of virtual reality (VR) as an inexpensive and portable alternative to chromotherapy rooms for stress relief. We recreated a chromotherapy room stress relief program using a commercial head mounted display (HD). We assessed the stress level of two groups (test and control) through an EEG biomarker, the relative gamma, while they experienced a relaxation session. First, participants were stressed using the Montreal imaging stress task (MIST). Then, for relaxing, the control group utilized a chromotherapy room while the test group used virtual reality. We performed a hypothesis test to compare the self- perceived stress level at different stages of the experiment and it yielded no significant differences in reducing stress for both groups, during relaxing (p-value: 0.8379, α = 0.05) or any other block. Furthermore, according to participant surveys, the use of virtual reality was deemed immersive, comfortable and pleasant (3.9 out of 5). Our preliminary results validate our approach as an inexpensive and portable alternative to chromotherapy rooms for stress relief.

Exploring the Effects of a Brief Biofeedback Breathing Session Delivered Through the BioBase App in Facilitating Employee Stress Recovery: Randomized Experimental Study

Background

Recovery from stress is a predictive factor for cardiovascular health, and heart rate variability (HRV) is suggested to be an index of how well people physiologically recover from stress. Biofeedback and mindfulness interventions that include guided breathing have been shown to be effective in increasing HRV and facilitating stress recovery.

Objective

This study aims to assess the effectiveness of a brief app-based breathing intervention (BioBase) in enhancing physiological recovery among employees who were induced to cognitive and emotional stress.

Methods

In total, we recruited 75 full-time employees. Interbeat (RR) intervals were recorded continuously for 5 min at baseline and during cognitive and emotional stress induction. The session ended with a 5-min recovery period during which participants were randomly allocated into 3 conditions: app-based breathing (BioBase), mindfulness body scan, or control. Subjective tension was assessed at the end of each period.

Results

Subjective tension significantly increased following stress induction. HRV significantly decreased following the stress period. In the recovery phase, the root mean square of successive RR interval differences (P=.002), the percentage of successive RR intervals that differed by >50 ms (P=.008), and high frequency (P=.01) were significantly higher in the BioBase breathing condition than in the mindfulness body scan and the control groups.

Conclusions

Biofeedback breathing interventions digitally delivered through a commercially available app can be effective in facilitating stress recovery among employees. These findings contribute to the mobile health literature on the beneficial effects of brief app-based breathing interventions on employees’ cardiovascular health.

Photoplethysmographic Waveform Analysis for Autonomic Reactivity Assessment in Depression

OBJECTIVE

In the present study, a photoplethysmographic (PPG) waveform analysis for assessing differences in autonomic reactivity to mental stress between patients with Major Depressive Disorder (MDD) and healthy control (HC) subjects is presented.

METHODS

PPG recordings of 40 MDD and 40 HC subjects were acquired at basal conditions, during the execution of cognitive tasks, and at the post-task relaxation period. PPG pulses are decomposed into three waves (a main wave and two reflected waves) using a pulse decomposition analysis. Pulse waveform characteristics such as the time delay between the position of the main wave and reflected waves, the percentage of amplitude loss in the reflected waves, and the heart rate (HR) are calculated among others. The intra-subject difference of a feature value between two conditions is used as an index of autonomic reactivity.

RESULTS

Statistically significant individual differences from stress to recovery were found for HR and the percentage of amplitude loss in the second reflected wave ( A₁₃) in both HC and MDD group. However, autonomic reactivity indices related to  A₁₃ reached higher values in HC than in MDD subjects (Cohen's [Formula: see text]), implying that the stress response in depressed patients is reduced. A statistically significant ( ) negative correlation ( r=-0.5) between depression severity scores and A₁₃ was found.

CONCLUSION

A decreased autonomic reactivity is associated with higher degree of depression.

SIGNIFICANCE

Stress response quantification by dynamic changes in PPG waveform morphology can be an aid for the diagnosis and monitoring of depression.

Binary symbolic dynamics analysis to detect stress-associated changes of nonstationary heart rate variability

Psychological stress may have harmful physiological effects and result in deteriorating health. Acute psychological stress acts also on cardiac autonomic regulation and may lead to nonstationarities in the interbeat interval series. We address the requirement of stationary RR interval series to calculate frequency domain parameters of heart rate variability (HRV) and use binary symbolic dynamics derived from RR interval differences to overcome this obstacle. 24 healthy subjects (12 female, 20–35 years) completed the following procedure: waiting period, Trier Social Stress Test to induce acute psychological stress, recovery period. An electrocardiogram was recorded throughout the procedure and HRV parameters were calculated for nine 5-min periods. Nonstationarities in RR interval series were present in all periods. During acute stress the average RR interval and SDNN decreased compared to rest before and after the stress test. Neither low frequency oscillations (LF), high frequency oscillations (HF) nor LF/HF could unambiguously reflect changes during acute stress in comparison to rest. Pattern categories derived from binary symbolic dynamics clearly identified acute stress and accompanying alterations of cardiac autonomic regulation. Methods based on RR interval differences like binary symbolic dynamics should be preferred to overcome issues related to nonstationarities.

Parsing inter- and intra-individual variability in key nervous system mechanisms of stress responsivity and across functional domains

Exposure to stressful events is omnipresent in modern human life, yet people show considerable heterogeneity in the impact of stress exposure(s) on their functionality and overall health. Encounter with stressor(s) is counteracted by an intricate repertoire of nervous-system responses. This narrative review starts with a brief summary of the vast evidence that supports heart rate variability, cortisol secretion, and large-scale cortical network interactions as kay physiological, endocrinological, and neural mechanisms of stress responsivity, respectively. The second section highlights potential sources for inter-individual variability in these mechanisms, by focusing on biological, environmental, social, habitual, and psychological factors that may influence stress responsivity patterns and thus contribute to heterogeneity in the impact of stress exposure on functionality and health. The third section introduces intra-individually variability in stress responsivity across functional domains as a novel putative source for heterogeneity in the impact of stress exposure. Challenges and future directions are further discussed. Parsing inter- and intra-individual variability in nervous-system mechanisms of stress responsivity and across functional domains is critical towards potential clinical translation.

Higher levels of Depressive Symptoms are Associated with Increased Resting-State Heart Rate Variability and Blunted Reactivity to a Laboratory Stress Task among Healthy Adults

Laboratory stress tasks induce strong changes in linear and non-linear indices of heart rate variability (HRV) among healthy adults, due to a task-induced parasympathetic withdrawal. Previous findings suggested that negative affectivity and its correlates (i.e., depressive symptoms, anxiety, hostility, type D personality, and situational stress) could profoundly affect autonomic activity. However, to date no studies considered these psychological dimensions simultaneously while trying to disentangle their acute effects on HRV during a laboratory stress task. A total of 65 healthy participants completed a battery of questionnaires and later underwent a psychosocial stress protocol, which involves a stressful and a non-stressful mental arithmetic task, with the latter serving as a control condition for the former. During the entire procedure, autonomic activity was recorded through a portable ECG device. We analysed longitudinal changes in HRV indices using Mixed Models, taking into account respiration rates and the associations between psychophysiological variables through bivariate Pearson's r (partial) correlation indices. We found significant changes in linear (e.g., HF power, RMSSD) and non-linear (e.g., Poincaré Plot and Correlation Dimension D2) HRV indices during the procedure, with the lowest point reached during the stressful mental arithmetic task. Interestingly, only depressive symptomatology was significantly and positively related to a higher resting-state HRV and to a blunted reactivity to the stress task, even after controlling for baseline values. Results suggest that healthy individuals with higher levels of depressive symptoms could experience atypical cardiovascular responses to stressful events: several speculative interpretations, considering autonomic, behavioral, and motivational dysregulations, are discussed.

Quantitative meta-analysis of heart rate variability finds reduced parasympathetic cardiac tone in women compared to men during laboratory-based social stress

Heart rate variability (HRV) is the inter-beat interval variation between consecutive heartbeats and an autonomic reflection of emotional regulatory abilities to flexibly respond to challenges, such as psychosocial stress. Whereas there are known sex differences in stress-induced hormonal and emotional responses, we identified a gap in our understanding of sex-specific autonomic cardiac control during stress. Thus, we assessed HRV prior to, during and after administration of a public speech task in healthy participants (n = 929) according to sex. Our meta-analysis found that during stress, women had lower HRV than men, with an overall Hedges' g of 0.29 (p < 0.0001) and 0.29 (p = 0.0003) for fixed and random effects models, respectively. We did not find significant heterogeneity or evidence of publication bias. Analyses of additional timepoints showed no baseline difference and marginally lower HRV in women during anticipation and recovery. Findings of the present meta-analysis confirm sex differences in stress-induced hyperarousal and form a justification for implementation of mechanistic studies evaluating gonadal hormones, their potent metabolites and pro-inflammatory cytokines as mediators of this relationship.

Influence of Slow-Paced Breathing on Inhibition After Physical Exertion

This research aims to investigate whether slow-paced breathing (SPB) improves adaptation to psychological stress, and specifically inhibition, when it is performed before or after physical exertion (PE). According to the resonance model, SPB is expected to increase cardiac vagal activity (CVA). Further, according to the neurovisceral integration model, CVA is positively linked to executive cognitive performance, and would thus play a role in the adaptation to psychological stress. We hypothesized that SPB, in comparison to a control condition, will induce a better adaptation to psychological stress, measured via better inhibitory performance. Two within-subject experiments were conducted with athletes: in the first experiment (N = 60) SPB (or control – neutral TV documentary) was realized before PE (“relax before PE”), and in the second experiment (N = 60) SPB (or the watching TV control) was realized after PE (“relax after PE”). PE consisted of 5 min Burpees, a physical exercise involving the whole body. In both experiments the adaptation to psychological stress was investigated with a Stroop task, a measure of inhibition, which followed PE. Perceived stress increased during PE (partial η² = 0.63) and during the Stroop task (partial η² = 0.08), and decreased during relaxation (partial η² = 0.15), however, no effect of condition was found. At the physiological level PE significantly increased HR, RF, and decreased CVA [operationalized in this research via the root mean square of successive differences (RMSSD)] in both experiments. Further, the number of errors in the incongruent category (Stroop interference accuracy) was found to be lower in the SPB condition in comparison to the control condition, however, these results were not mediated by RMSSD. Additionally, the Stroop interference [reaction times (RTs)] was found to be lower overall in “relax before PE,” however, no effect was found regarding SPB and Stroop interference (RTs). Overall, our results suggest that SPB realized before or after PE has a positive effect regarding adaptation to psychological stress and specifically inhibition, however, the underlying mechanisms require further investigation.

Investigating the Optimal Baseline Positioning to Maximize Cognitive Experimental Outcome

In emotional and cognitive research, the baseline is commonly used for standardization purposes in order to have a reference for the identification of the activation. Since no previous studies have investigated which moment of the experiment could be considered optimal for baseline evaluation, we designed an experimental protocol to analyze which time interval could be considered more effective in highlighting differences between the baseline state and the cognitive effort exhibited during tasks (specifically, reaction and working memory tasks). Several indexes were extracted from EEG signals during the visualization of the considered baseline stimuli and the execution of tasks. From our results, as regards to the considered Global Field Power (GFP) indexes (Attention and Memorization indexes), the last baseline stimulus seems to be the best one to highlight the difference in cognitive workload between the individual baseline condition and the two cognitive tasks. Instead, in terms of Engagement index (EI), the difference between Reaction Task (RT) and the individual baseline condition seems to be best highlighted by the relaxing video right after performed tasks. In conclusion, the best baseline position to maximize the differences in cognitive workload may vary among the considered indexes because of confounding effects and individual differences, but further analyses are required to validate this result.

Stress reactivity in healthy child offspring of parents with anxiety disorders

Several studies suggest that anxiety disorders (AD) involve dysregulation of the autonomic nervous system (ANS) and hypothalamic-pituitary (HPA) axis. However, it is unknown if alterations in these biological systems are premorbid markers of AD risk or a state-dependent feature of anxiety. This study examined ANS and HPA-axis response to a laboratory stressor in healthy child offspring of parents with (n = 55) and without (n = 98) a history of AD. High frequency heart rate variability (HF-HRV) was assessed during sitting and standing baseline conditions and during a speech task where participants remained standing. Salivary cortisol was measured at baseline and at 15, 30, 45 and 60 min post-speech. Subjective anxiety was assessed with a visual analogue scale. Children of parents with AD displayed reduced HRV and a blunted cortisol response to the speech task compared to children of non-anxious parents. No risk group effect was found for anxiety ratings. These preliminary data suggest that healthy children of anxious parents exhibit altered stress reactivity to an acute laboratory stressor. Further research is needed to confirm findings and identify mechanisms that may account for altered self-regulation processes to a stressor in children at familial risk for AD.

Moderating effects of the valence of social interaction on the dysfunctional consequences of perseverative cognition: an ecological study in major depression and social anxiety disorder

BACKGROUND AND OBJECTIVES

Major depression disorder (MDD) and social anxiety disorder (SAD) are characterized by the use of perseverative cognition (PC) as a dysfunctional coping strategy. We sought to investigate the dysfunctional physiological and psychological consequences of PC and how the valence of social interactions moderates such consequences in these psychopathological conditions.

DESIGN/METHODS

The study combined 24-hour heart rate variability (HRV) and ecological momentary assessments in 48 individuals with MDD, SAD, and sex-matched controls.

RESULTS

In all participants, PC was associated with mood worsening and reduced ability of the parasympathetic nervous system, mainly the vagus, to inhibit sympathetic arousal (i.e., reduced HRV). Individuals with SAD had the highest frequency of daily PC, while those with MDD reported that PC interfered more with their ongoing activities. In SAD, daily PC was associated with significantly lower HRV after negative social interactions. Individuals with MDD reported higher levels of sadness during PC irrespective of the valence of the preceding social interaction but higher levels of anxiety and efforts to inhibit PC following positive interactions.

CONCLUSIONS

Results highlight the need to account for important moderators like the valence of social interaction when looking at the physiological consequences of maladaptive emotion regulation strategies.

An Explanatory Model of Emotional Intelligence and Its Association with Stress, Burnout Syndrome, and Non-Verbal Communication in the University Teachers

The present study set out to define and contrast an explanatory model of perception of stress, the dimensions of burnout syndrome, emotional intelligence, and non-verbal communication in a sample of university teachers. A total of 1316 teachers from Spain, aged between 24 and 70 years (M = 45.64, SD = 10.33) and evenly distributed between both sexes, participated. The measurement instruments employed were the Perceived Stress Scale (PSS), the Maslach Burnout Inventory (MBI), the Trait Meta-Mood Scale (TMMS-24), and the Nonverbal Immediacy Scale (NIS) A structural equation model was produced that demonstrated adequate fit to the empirical data (130,259; df = 9; p < 0.001; CFI = 0.907; NIF = 0.914; IFI = 0.923; RMSEA = 0.077). Results revealed that stress relates positively with emotional exhaustion and negatively with personal fulfilment. Emotional exhaustion was associated directly with emotional attention and inversely with emotional clarity and emotional repair, with these being linked to personal fulfilment. Both emotional clarity and repair related positively with non-verbal communication. Conclusions from the present study are that emotional intelligence and body language are two relevant factors in the prevention of burnout syndrome, and as a result can help to ensure the mental wellbeing of university teachers.

Into the Wild: The Challenges of Physiological Stress Detection in Laboratory and Ambulatory Settings

Stress and mental health have become major concerns worldwide. Research has already extensively investigated physiological signals as quantitative and continuous markers of stress. In recent years, the focus of the field has shifted from the laboratory to the ambulatory environment. We provide an overview of physiological stress detection in laboratory settings with a focus on identifying physiological sensing priorities, including electrocardiogram, skin conductance, and electromyogram, and the most suitable machine learning techniques, of which the choice depends on the context of the application. Additionally, an overview is given of new challenges ahead to move toward the ambulant environment, including the influence of physical activity, lower signal quality due to motion artifacts, the lack of a stress reference, and the subject-dependent nature of the physiological stress response. Finally, several recommendations for future research are listed, focusing on large-scale, longitudinal trials across different population groups and just-in-time interventions to move toward disease prevention and interception.

Putting salient vocalizations in context: Adults' physiological arousal to emotive cues in domestic and external environments

Salient vocalizations are automatically processed and distinguished from emotionally irrelevant information. However, little is known of how contextual, gender and attentional variables interact to modulate physiological responses to salient emotive vocalizations. In this study, electrocardiogram (ECG) was utilized to investigate differences in peripheral nervous activity of men and women to infant cry (IC), infant laughter (IL) and adult cry (AC) in two different situational contexts: the domestic environment (DE) and the outside environment (OE). As the mental state of listeners can affect their response to vocalizations, a between-subject design was applied: one group was instructed to imagine being inside the scenes (Task 1: explicit task), and the other group was told to look at the scenes (Task 2: implicit task). Results revealed that females exhibited lower inter-beat interval (IBI) index in the OE condition, as compared to both males in OE and females in DE conditions, suggesting greater physiological arousal amongst females in response to vocalizations in an outside environment. Additionally, Task 1 revealed that males demonstrated higher Low Frequency/High Frequency (LFHF) index towards AC than IL. Task 2 showed the same association between these two sounds in females. The implicit task also elicited lower LFHF index in response to both IL and IC than control sound (CS), only amongst females. Findings highlight the important roles that contextual information and cognitive demand play in regulating physiological responses to salient emotive vocalizations. Integrated perspectives of physiological responses to emotive vocalizations that consider the influence of internal (adult mental states) and external (environment) contextual information will provide a better understanding of mechanisms underlying emotional processing of salient social cues.

Reducing Psychological Stress in Peripartum Women With Heart Rate Variability Biofeedback: A Systematic Review

Peripartum women are exposed to a variety of stressors that have adverse health consequences for the maternal-child dyad (e.g., impaired bonding). To combat these adverse health consequences, heart rate variability biofeedback (HRVBF) may be implemented by holistic nurses to aid peripartum women experiencing a high level of stress. A systematic review was completed using the guidelines established in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. To be included in the review, studies had to meet the following criteria: (a) published scientific articles, (b) studies published in English, (c) experimental, quasi-experimental, or case reports, (d) use of HRVBF as the main treatment, (e) use of psychological stress as a dependent variable, and (f) studies published until December 2017. The major findings of this review can be described as follows: (a) HRVBF and psychological stress in peripartum women are related concepts, (b) peripartum women who completed HRVBF report a reduction in stress compared with participants who did not receive HRVBF, and (c) there is currently no information on the effectiveness of HRVBF on psychological stress in the first and early second trimester of pregnancy. Overall, this systematic review of the literature provides objective evidence that HRVBF may be a potential beneficial adjuvant treatment for stress management in peripartum women.