Effect of lecturing to 200 students on heart rate variability and alpha-amylase activity

Assessing restorative effects of soundscapes in VR through EEG and HRV

This study aimed to extend the application of soundscape analysis by utilizing electroencephalogram (EEG) analysis as a physiological evaluation tool to determine the actual restorative impact on individual environmental perceptions and psycho-physiological responses stemming from various soundscape experiences. Initially, we constructed three distinct virtual reality (VR) environments: waterfront, urban, and green areas, each accompanied by three content variations. A total of 60 subjects participated in the study. Data were gathered through a survey assessing individual characteristics, psychological restorative responses, and soundscape perceptions. Additionally, quantitative physiological responses such as heart rate variability (HRV) and EEG, were measured. Subsequently, subjects were categorized into restoration and non-restoration groups based on HRV responses using cluster analysis. The analysis revealed positive HRV changes indicative of reduced stress levels. In EEG analysis, differences were observed in network connectivity rather than power spectral density. As a result of connectivity analysis, global efficiency increased overall in the restoration group, and differences in nodal efficiency occurred in a total of eight brain regions, enabling soundscape experience to efficiently process cognitive functions in the cerebrum, thereby having a positive effect on neural communication. This study is significant as it represents the first examination of soundscape restorative responses in terms of brain wave connectivity, underscoring the feasibility of employing physiological evaluations, including brain wave analysis, in the study of soundscapes.

mHealth interventions to reduce stress in healthcare workers (fitcor): study protocol for a randomized controlled trial

BACKGROUND

Causes and consequences of chronic stress levels in the context of healthcare work are well examined. Nevertheless, the implementation and evaluation of high-quality interventions to reduce stress of healthcare workers is still missing. Internet and app-based interventions are a promising venue for providing interventions for stress reduction to a population that is otherwise difficult to reach due to shift work and time constraints in general. To do so, we developed the internet and app-based intervention (fitcor), a digital coaching of individual stress coping for health care workers.

METHODS

We applied the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) statement as a guideline for the present protocol. A randomized controlled trial will be conducted. There are five different intervention groups and one waiting control group. To achieve the sample sizes required by power analysis (G*Power) (β-error 80%; effect size 0.25), the sample sizes of the respective scenarios will be at best as follows: 336 care workers from hospitals, 192 administrative health personnel, 145 care workers from stationary elderly care homes, and 145 care workers from ambulatory care providers in Germany. Participants will randomly be assigned to one of five different intervention groups. A crossover design with a waiting control group is planned. Interventions will be accompanied by three measurement points, first a baseline measure, second a post-intervention measure directly after completion of the intervention, and a follow-up measure 6 weeks after completion of the intervention. At all three measurement points, perceived team conflict, work-related experience patterns, personality, satisfaction with internet-based training, and back pain will be assessed using questionnaires, as well as heart rate variability, sleep quality, and daily movement will be recorded using an advanced sensor.

DISCUSSION

Workers in the health care sector increasingly face high job demands and stress levels. Traditional health interventions fail to reach the respective population due to organizational constraints. Implementation of digital health interventions has been found to improve stress coping behavior; however, the evidence in health care settings has not been established. To the best of our knowledge, fitcor is the first internet and app-based intervention to reduce stress among nursing and administrative health care personnel.

TRIAL REGISTRATION

The trial was registered at DRKS.de on 12 July 2021, registration number: DRKS00024605.

Efficacy of Individualized Sensory-Based mHealth Interventions to Improve Distress Coping in Healthcare Professionals: A Multi-Arm Parallel-Group Randomized Controlled Trial

Detrimental effects of chronic stress on healthcare professionals have been well-established, but the implementation and evaluation of effective interventions aimed at improving distress coping remains inadequate. Individualized mHealth interventions incorporating sensor feedback have been proposed as a promising approach. This study aimed to investigate the impact of individualized, sensor-based mHealth interventions focusing on stress and physical activity on distress coping in healthcare professionals. The study utilized a multi-arm, parallel group randomized controlled trial design, comparing five intervention groups (three variations of web-based training and two variations of an app training) that represented varying levels of individualization to a control group. Both self-reported questionnaire data (collected using Limesurvey) as well as electrocardiography and accelerometry-based sensory data (collected using Mesana Sensor) were assessed at baseline and post-intervention (after eight weeks). Of the 995 eligible participants, 170 (26%) completed the post-intervention measurement (Group 1: N = 21; Group 2: N = 23; Group 3: N = 7; Group 4: N = 34; Group 5: N = 16; Control Group: N = 69). MANOVA results indicated small to moderate time-by-group interaction effects for physical activity-related outcomes, including moderate to vigorous physical activity (F(1,5) = 5.8, p = ≤0.001, η2p = 0.057) and inactivity disruption (F(1,5) = 11.2, p = <0.001, η2p = 0.100), in the app-based intervention groups, but not for step counts and inactivity. No changes were observed in stress-related heart rate variability parameters over time. Despite a high dropout rate and a complex study design, the individualized interventions showed initial positive effects on physical activity. However, no significant changes in stress-related outcomes were observed, suggesting that the intervention duration was insufficient to induce physiological adaptations that would result in improved distress coping.

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.

Experimental Study on the Evaluation and Influencing Factors on Individual's Emergency Escape Capability in Subway Fire

Studying an individual’s emergency escape capability and its influencing factors is of great practical significance for evacuation and escape in subway emergencies. Taking Zhengzhou Zijing Mountain Subway station as the prototype, and using VR technology, a virtual subway fire escape scene was built. Combined with the total escape time, the total contact time with fire, and the total contact time with smoke, it proposed a calculation formula on emergency escape capability. A total of 34 participants with equal gender distribution were recruited to carry out the virtual subway fire escape experiment, and participants’ physiological data (heart rate variability, skin conductance) were real-time recorded by ErgoLAB V3.0 throughout the whole experiment. The emergency escape capability of each participant was evaluated quantitatively, and the related influencing factors were analyzed. The results show that for the age ranges (19–22 years old) in the experiment, the emergency escape capability of women is significantly lower than that of men (p < 0.05); although there is no significance in emergency escape capability in DISC personality types (p > 0.05), the mean emergency escape capability of people with influence personality type is the worst, and that of people with compliance type is the best; during virtual fire escape vs. baseline, Mean_SC and Mean_HR both increased very significantly (all p < 0.01), and participants were under stress during their virtual fire escape. There is a significant negative correlation between emergency escape capability and LF_increase_rate (p < 0.05), and a remarkably significant negative correlation between emergency escape capability and LF/HF_increase_rate (p < 0.01); the greater the increase rate of LF or LF/HF, the smaller the emergency escape capability, with excessive stress probably not being conducive to emergency escape. There is a very significant negative correlation between an individual’s emergency escape capability and the degree of familiarity with the Zijing Mountain subway station (p < 0.01). The findings provide references and suggestions on the emergency management and emergency evacuation for government and subway departments.

Is the Association Between Education and Sympathovagal Balance Mediated by Chronic Stressors?

Background

This study investigated whether raised chronic stress in low education groups contributes to education differences in cardiovascular disease by altering sympathovagal balance.

Methods

This study included cross-sectional data of 10,202 participants from the multi-ethnic, population-based HELIUS-study. Sympathovagal balance was measured by baroreflex sensitivity (BRS), the standard deviation of the inter-beat interval (SDNN) and the root mean square of successive differences between normal heartbeats (RMSSD). The associations between chronic stressors (work, home, psychiatric, financial, negative life events, lack of job control and perceived discrimination) in a variety of domains and BRS, SDNN and RMSSD were assessed using linear regression, adjusted for age, ethnicity, waist-to-hip ratio and pack-years smoked. Mediation analysis was used to assess the contribution of chronic stress to the association between education and sympathovagal balance.

Results

Modest but significant associations were observed between financial stress and BRS and SDNN in women, but not in RMSSD nor for any outcome measure in men. Women with the highest category of financial stress had 0.55% lower BRS (ms/mmHg; β = -0.055; CI = -0.098, -0.011) and 0.61% lower SDNN (ms; β = -0.061; CI = -0.099, -0.024) than those in the lowest category. Financial stress in women contributed 7.1% to the association between education and BRS, and 13.8% to the association between education and SDNN.

Conclusion

No evidence was found for the hypothesized pathway in which sympathovagal balance is altered by chronic stress, except for a small contribution of financial stress in women.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12529-021-10027-9.

The relationship between affective flexibility, spontaneous emotion regulation and the response to induced stress

Effective emotion regulation contributes to adapting well to challenging situations. One of the proposed cognitive mechanisms underlying emotion regulation is cognitive flexibility in processing of affective material (i.e. affective flexibility). We investigated (n = 118) effects of affective flexibility on the response to a stressor and on spontaneous use of 'adaptive' and 'maladaptive' emotion regulation strategies. Additionally, we examined how emotion regulation influences stress reactivity and recovery. Affective flexibility was measured with a task-switching paradigm in which participants shift attention between affective and non-affective aspects of emotional material. We investigated changes in emotion and heart rate variability to a stress induction. Affective flexibility did not influence the response to stress, but less efficient shifting of attention towards affective aspects of negative information, and more efficient shifting of attention towards non-affective aspects of positive information were related to more use of maladaptive strategies. Emotion regulation strategy use had limited influence on the perceived and actual physiological response to a stress induction, but especially more use of adaptive regulation strategies reduced negative emotional reactivity. Our findings suggest that individual differences in affective flexibility have limited influence on the (acute) response to a stressful event and recovery afterwards, but do influence spontaneous use of emotion regulation strategies.

Phasic heart rate variability and the association with cognitive performance: A cross-sectional study in a healthy population setting

Introduction

Sympathovagal balance measured by heart rate variability is a core component of psychophysiological research. Through the close link of physiological and psychological aspects, often a reduced heart rate variability is associated with impaired cognitive function. A better understanding of the associations between cognitive and cardiovascular dysfunctions is necessary to prevent the manifestation of diseases. Therefore, this study investigated phasic heart rate variability using rest, anticipatory, stress, and recovery periods and the association with high and low cognitive performance in a generally healthy population setting.

Methods

114 healthy individuals (40 males, 74 females) aged 20 to 70 participated in the cross-sectional study. The heart rate variability based on standard deviation of NN intervals (SDNN), and the root means square of successive differences (RMSSD), low frequency (LF), high frequency (HF) and LF/HF ratio and its association with high and low cognitive performance measured by the California Verbal Learning Task II were examined.

Results

The results of this study indicate that the paradigm was successful in producing stress and showed a significant association between phasic heart rate variability (SDNN) and verbal episodic memory performance, irrespective of age and sex.

Discussion

The results of this study suggest that a reduced heart rate variability is associated with reduced cognitive function regardless of age and sex and seem to be an early indicator of sympathovagal disbalance.

Conclusion

This leads to the conclusion that differences between high and low cognitive performance might show differences in heart rate variability at an early stage, where no diseases are yet manifest.

Nicotine supplementation enhances simulated game performance of archery athletes

Background

Nicotine is beneficial to mood, arousal and cognition in humans. Due to the importance of cognitive functioning for archery athletes, we investigated the effects of nicotine supplementation on the cognitive abilities, heart rate variability (HRV), and sport performance of professional archers.

Methods

Eleven college archers were recruited and given 2 mg of nicotine supplementation (NIC group) and placebo (PLA group) in a crossover design.

Results

The results showed that at 30 min after the intake of nicotine gum, the “correct rejection” time in the NIC group was significantly lower than that of the PLA group (7.29 ± 0.87 vs. 8.23 ± 0.98 msec, p < 0.05). In addition, the NIC group completed the grooved pegboard test in a shorter time than the PLA group (48.76 ± 3.18 vs. 53.41 ± 4.05 s, p < 0.05), whereas motor reaction times were not different between the two groups. Saliva α-amylase activity was significantly lower after nicotine supplementation (p < 0.01) but increased immediately after the archery test in the NIC group (p < 0.05). In addition, nicotine supplementation significantly decreased HRV and increased the archery score (290.58 ± 10.09 vs. 298.05 ± 8.56, p < 0.01).

Conclusions

Nicotine enhances the performance of archery athletes by increasing cognitive function and stimulating the sympathetic adrenergic system.

Effect of Virtual Reality on Stress Reduction and Change of Physiological Parameters Including Heart Rate Variability in People With High Stress: An Open Randomized Crossover Trial

Introduction: Although, attempts to apply virtual reality (VR) in mental healthcare are rapidly increasing, it is still unclear whether VR relaxation can reduce stress more than conventional biofeedback. Methods: Participants consisted of 83 healthy adult volunteers with high stress, which was defined as a score of 20 or more on the Perceived Stress Scale-10 (PSS-10). This study used an open, randomized, crossover design with baseline, stress, and relaxation phases. During the stress phase, participants experienced an intentionally generated shaking VR and serial-7 subtraction. For the relaxation phase, participants underwent a randomly assigned relaxation session on day 1 among VR relaxation and biofeedack, and the other type of relaxation session was applied on day 2. We compared the State-Trait Anxiety Inventory-X1 (STAI-X1), STAI-X2, the Numeric Rating Scale (NRS), and physiological parameters including heart rate variability (HRV) indexes in the stress and relaxation phases. Results: A total of 74 participants were included in the analyses. The median age of participants was 39 years, STAI-X1 was 47.27 (SD = 9.92), and NRS was 55.51 (SD = 24.48) at baseline. VR and biofeedback significantly decreased STAI-X1 and NRS from the stress phase to the relaxation phase, while the difference of effect between VR and biofeedback was not significant. However, there was a significant difference in electromyography, LF/HF ratio, LF total, and NN50 between VR relaxation and biofeedback. Conclusion: VR relaxation was effective in reducing subjectively reported stress in individuals with high stress.

Positive and Negative Post Performance-Related Thoughts Predict Daily Cortisol Output in University Music Students

Psychophysiological research on music performance has focused on musicians' short-term affective, cognitive, and physiological responses. Much less attention has been devoted to the investigation of musicians' psychophysiological activity beyond the performance situation. Musicians report having both positive and negative performance-related thoughts (e.g., "My concert was good" and "I made a lot of mistakes") for days following performances. The potential physiological implications of this post-performance cognitive processing are largely unknown. Salivary cortisol (sC) and salivary alpha-amylase (sAA) are markers of the activity of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathoadrenal medullary (SAM) system, respectively. The goal of the present study was to investigate whether self-reported positive and negative post performance-related thoughts predict the daily sC output and the daily sAA activity at the between- and within-person levels during a 2-day period following a solo music performance. Seventy-two university music students collected saliva samples six times per day and reported their positive and negative performance-related thoughts for 2 days after a solo performance. We tested between-person and within-person components of positive and negative post performance-related thoughts as predictors of the diurnal area under the curve with respect to ground (AUCg) for sC and sAA while adjusting for relevant person-level and day-level variables. Negative post performance-related thoughts were positively associated with sC AUCg both at the between- and within-person levels, whereas positive post performance-related thoughts were negatively associated with sC AUCg at the between-person level. Post performance-related thoughts did not significantly predict sAA AUCg. These findings provide evidence for a relationship between affectively valenced cognitive processing of a recent music performance and the activity of the HPA axis. Although the directionality of this relationship remains to be established more conclusively, the study makes a significant contribution to the literature on the prolonged psychophysiological effects of music performance situations and more broadly of social-evaluative stressors. Integrating the topic of post-performance cognitive processing and its optimal management into performance training programs would likely have positive effects on music students.

Teachers' ambulatory heart rate variability as an outcome and moderating variable in the job demands-resources model

Background and Objectives: According to the job demands-resources (JD-R) model, strain reactions are based on the level of job demands and moderating resources. The present study aims to contribute to psychophysiological research by integrating vagally mediated heart rate variability (HRV) into the JD-R framework. Design and Methods: Using a sample of school teachers, we conducted an ambulatory assessment study to investigate HRV as (1) a state outcome measure of job demands and resources and (2) a trait moderator in the relationship between job demands and emotional exhaustion. In total, 101 participants wore an electrocardiogram device on two school days and rated their level of job demands (emotional demands and time pressure), job resources (control and support), and exhaustion six times a day. Based on 669 measurements, multilevel models of the 5-minute state HRV measure and emotional exhaustion were built. Results: The results supported the health-impairing effects of job demands on emotional exhaustion but not state HRV. There was no evidence of the moderating effects of job resources. Notably, the 48-hour trait HRV measure significantly buffered the effect of emotional demands on exhaustion. Conclusions: These findings highlight the stress-buffering potential of trait HRV as theoretical research extension and practical intervention goal.

Cardiorespiratory Fitness Predicts Greater Vagal Autonomic Activity in Drug Users Under Stress

While drug use has been shown to impair cardiac autonomic regulation, exercise might overcome some of the damage. Herein, we describe how individuals with substance use disorder (SUD) have their heart rate variability (HRV) and drug-related behaviors negatively affected in response to a stressor. However, we show how cardiorespiratory fitness may attenuate those impairments in autonomic control. Fifteen individuals with SUD were matched with 15 non-SUD individuals by age, weight, height, and fitness level, and had their HRV responses under stress induced by the Cold Pressor Test (CPT). The SUD group had lower mean of R-R intervals before and after the CPT when compared with the non-SUD group. In addition, in individuals with SUD, higher cardiorespiratory fitness level predicted greater vagal activity before, during, and after CPT. Moreover, for individuals with SUD, days of abstinence predicted greater mean of R-R intervals during recovery from the CPT. Finally, years of drug use negatively predicted mean of R-R intervals during recovery. Thus, our results suggest that chronic drug use impairs cardiac autonomic regulation at rest and after a physical stress. However, cardiorespiratory fitness might attenuate these impairments by increasing vagal autonomic activity.

Effects of sex and menstrual cycle phase on cardiac response and alpha- amylase levels in psychosocial stress

The impact of sex and the menstrual cycle phase on the autonomic response to psychosocial stress remains controversial. This study explored autonomic nervous system activity through salivary alpha-amylase, heart rate, and heart rate variability responses to the Trier Social Stress Test (TSST) in healthy young people. The sample was composed of 25 men, 26 women in the luteal phase, and 25 women in the follicular phase, from 18 to 25 years of age. Participants were exposed to the TSST or a control condition. The results indicate that women in their follicular phase showed a blunted alpha-amylase response to stress compared to men and women in the luteal phase. In addition, men showed higher sympatho-vagal activity in the stress condition compared to the two groups of women. These results confirm that sex and the menstrual cycle phase are potential modulators of autonomic nervous system reactivity to psychosocial stress.

Positive verbal feedback about task performance is related with adaptive physiological responses: An experimental study of the effort-reward imbalance stress model

Effort-reward imbalance in the workplace has been related with poor mental and physical health and a variety of negative organisational outcomes including increased rates of absenteeism, presentism, and job turnover, but the model has rarely been assessed using experimental designs. Female participants (N = 90) were randomly assigned to positive verbal feedback and no verbal feedback conditions. Within a simulated office environment, all participants were under time-pressure to successfully complete computer-based tasks in order to gain remuneration. Positive verbal feedback about task performance was provided to improve the aspect of 'esteem reward' (while keeping effort constant) using a mixed within-between subjects design. Psychological, behavioural (task performance), and physiological (heart rate variability, salivary alpha amylase) measures assessed the impact of the positive verbal feedback. Participants receiving the esteem manipulation did not self-report increased rewards, but performed moderately better on the task, and had more adaptive physiological reactivity in the high reward versus the standard condition. Similar to recent research our findings highlight the importance of concurrent assessments of both self-reports and physiological measures of stress, and suggest that positive verbal feedback about work performance can elicit adaptive physiological responses and may also positively influence task efficacy.

Effect of Seminar on Compassion on student self-compassion, mindfulness and well-being: A randomized controlled trial

OBJECTIVE

Mindfulness-based interventions have been shown to have psychological benefits in college students. We explored the effects of an academic Seminar on Compassion on student psychological health.

PARTICIPANTS

Forty-one participants (14 male, 27 female, mean age 19.8 ± 1.4 years) were assessed pre- and post- spring semesters 2013 and 2014.

METHODS

Students were randomized to the Seminar on Compassion or a wait-list control group. Participants completed self-report measures on anxiety, depression, perceived stress, self-compassion, compassion and mindfulness. Salivary alpha-amylase was also assessed.

RESULTS

At baseline, self-compassion and mindfulness were negatively correlated with depression, anxiety, and perceived stress. There were significant changes between the intervention and control group from Time 1 to Time 2 in mindfulness, self-compassion, compassion, and salivary alpha-amylase; however, there were no significant changes in depression, anxiety, and perceived stress.

CONCLUSIONS

The course was effective in increasing mindfulness, self-compassion and compassion, and decreasing a salivary marker of stress.

Prolonged performance-related neuroendocrine activation and perseverative cognition in low- and high-anxious university music students

Music performances are social-evaluative situations that can elicit marked short-term neuroendocrine activation and anxious thoughts especially in musicians suffering from music performance anxiety (MPA). The temporal patterns of neuroendocrine activity and concert-related worry and rumination (perseverative cognition, PC) days before and after a concert in low- and high-anxious musicians are unknown. The first goal of the present study was to investigate the prolonged effects of a solo music performance and the effects of trait MPA on salivary cortisol (sC), alpha-amylase (sAA), and concert-related PC. The second goal was to investigate whether concert-related PC is associated with neuroendocrine activity and mediates the effects of measurement day and trait MPA on neuroendocrine responses. Seventy-two university music students collected saliva samples and reported their PC for seven consecutive days. On the fifth day, they performed solo. Measurement day and trait MPA were tested as main predictors of the diurnal area under the curve with respect to ground (sC AUCg, sAA AUCg), awakening responses, and PC. SC AUCg, sAA AUCg, and concert-related PC were highest on concert day. SC AUCg decreased only partially on post-concert days. SAA AUCg remained elevated on the first post-concert day among students with moderate to very high trait MPA. Throughout the assessment period, trait MPA was associated with smaller sC AUCg and higher concert-related PC. Concert-related PC showed significant positive associations with sC AUCg and sAA AUCg but did not mediate the effects of measurement day and trait MPA on these measures. These findings suggest that solo music performances have prolonged neuroendocrine effects and that trait MPA is an important factor having specific effects on university music students' hypothalamic-pituitary-adrenal axis, autonomic nervous system, and cognitive activity.

Stress and Heart Rate Variability: A Meta-Analysis and Review of the Literature

OBJECTIVE

Physical or mental imbalance caused by harmful stimuli can induce stress to maintain homeostasis. During chronic stress, the sympathetic nervous system is hyperactivated, causing physical, psychological, and behavioral abnormalities. At present, there is no accepted standard for stress evaluation. This review aimed to survey studies providing a rationale for selecting heart rate variability (HRV) as a psychological stress indicator.

METHODS

Term searches in the Web of Science^®, National Library of Medicine (PubMed), and Google Scholar databases yielded 37 publications meeting our criteria. The inclusion criteria were involvement of human participants, HRV as an objective psychological stress measure, and measured HRV reactivity.

RESULTS

In most studies, HRV variables changed in response to stress induced by various methods. The most frequently reported factor associated with variation in HRV variables was low parasympathetic activity, which is characterized by a decrease in the high-frequency band and an increase in the low-frequency band. Neuroimaging studies suggested that HRV may be linked to cortical regions (e.g., the ventromedial prefrontal cortex) that are involved in stressful situation appraisal.

CONCLUSION

In conclusion, the current neurobiological evidence suggests that HRV is impacted by stress and supports its use for the objective assessment of psychological health and stress.

An experimental examination of the effort-reward imbalance model of occupational stress: Increased financial reward is related to reduced stress physiology

Effort-reward imbalance in the workplace is linked to a variety of negative health and organisational outcomes, but it has rarely been assessed experimentally. We manipulated reward (while keeping effort constant) in a within-subjects design with female participants (N=60) who were randomly assigned to high and standard reward conditions within a simulated office environment. Self-report, behavioural (task performance), and physiological (heart rate variability, salivary alpha amylase) measures assessed the impact of increased financial reward. Participants reported increased perceptions of reward, performed moderately better on the task, and were less physiologically reactive in the high reward versus the standard condition. These findings highlight the importance of assessing both subjective self-reports of stress together with objective physiological measures of stress, and suggest that increasing monetary rewards has the potential to decrease stress physiological reactivity, and in turn, reduce the risk of ill-health in employees, and may also positively influence task efficacy.

Salivary cortisol and α-amylase: subclinical indicators of stress as cardiometabolic risk

Currently, the potential for cardiovascular (CV) stress-induced risk is primarily based on the theoretical (obvious) side effects of stress on the CV system. Salivary cortisol and α-amylase, produced respectively by the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic-adrenomedullary (SAM) system during stress response, are still not included in the routine evaluation of CV risk and require additional and definitive validation. Therefore, this article overviews studies published between 2010 and 2015, in which salivary cortisol and α-amylase were measured as stress biomarkers to examine their associations with CV/CMR (cardiometabolic risk) clinical and subclinical indicators. A comprehensive search of PubMed, Web of Science and Scopus electronic databases was performed, and 54 key articles related to the use of salivary cortisol and α-amylase as subclinical indicators of stress and CV/CMR factors, including studies that emphasized methodological biases that could influence the accuracy of study outcomes, were ultimately identified. Overall, the biological impact of stress measured by salivary cortisol and α-amylase was associated with CV/CMR factors. Results supported the use of salivary cortisol and α-amylase as potential diagnostic tools for detecting stress-induced cardiac diseases and especially to describe the mechanisms by which stress potentially contributes to the pathogenesis and outcomes of CV diseases.

Classifying Stress From Heart Rate Variability Using Salivary Biomarkers as Reference

An accurate and noninvasive stress assessment from human physiology is a strenuous task. In this paper, a pattern recognition system to learn complex correlates between heart rate variability (HRV) features and salivary stress biomarkers is proposed. Using the Trier social stress test, heart rate and salivary measurements were obtained from volunteers under varying levels of stress induction. Measurements of salivary alpha-amylase and cortisol were used as objective measures of stress, and were correlated with the HRV features using fuzzy ARTMAP (FAM). In improving the predictive ability of the ARTMAPs, techniques, such as genetic algorithms for parameter optimization and voting ensembles, were employed. The ensemble of FAMs can be used for predicting stress responses of salivary alpha-amylase or cortisol using heart rate measurements as the input. Using alpha-amylase as the stress indicator, the ensemble was able to classify stress from heart rate features with 75% accuracy, and 80% accuracy when cortisol was used.

An exploratory study of the relationship between psychosocial hazard and ambulatory physiological response in higher education employees

Purpose

As exposure to psychosocial hazard at work represents a substantial risk factor for employee health in many modern occupations, being able to accurately assess how employees cope with their working environment is crucial. The workplace is generally accepted as being a dynamic environment, therefore, consideration should be given to the interaction between employees and the acute environmental characteristics of their workplace. The purpose of this paper is to investigate the effects of both acute demand and chronic work-related psychosocial hazard upon employees through ambulatory assessment of heart rate variability and blood pressure.

Design/methodology/approach

A within-subjects repeated measures design was used to investigate the relationship between exposure to work-related psychosocial hazard and ambulatory heart rate variability and blood pressure in a cohort of higher education employees. Additionally the effect of acute variation in perceived work-related demand was investigated.

Findings

Two dimensions of the Management Standards were found to demonstrate an association with heart rate variability; more hazardous levels of “demand” and “relationships” were associated with decreased standard deviation of the normal-to-normal interval. Significant changes in blood pressure and indices of heart rate variability were observed with increased acute demand.

Originality/value

This is the first attempt to combine the Health and Safety Management Standards Indicator Tool with physiological assessment of employees. The results provide evidence of associations between scores on the indicator tool and ambulatory heart rate variability as well as demonstrating that variation in acute perceived work-related demand is associated with alterations to autonomic and cardiovascular function. This has implications not only for employee health and workplace design but also for future studies employing ambulatory physiological monitoring.

Effects of elevation change on mental stress in high-voltage transmission tower construction workers

High-voltage transmission tower construction is a high-risk operation due to the construction site locations, extreme climatic factors, elevated working surfaces, and narrow working space. To comprehensively enhance our understanding of the psychophysiological phenomena of workers in extremely high tower constructions, we carried out a series of field experiments to test and compare three working surface heights in terms of frequency-domain heart rate variability (HRV) measurements. Twelve experienced male workers participated in this experiment. The dependent variables, namely, heart rate (HR), normalized low-frequency power (nLF), normalized high-frequency power (nHF), and LF-to-HF power ratio (LF/HF), were measured with the Polar RS800CX heart rate monitor. The experimental results indicated that the task workload was similar between working surface heights. Tower construction workers perceived an increased level of mental stress as working surface height increased.

Left-handers look before they leap: handedness influences reactivity to novel Tower of Hanoi tasks

A sample of 203 task naïve left- and right-handed participants were asked to complete a combination of the 3- and 4-disk Towers of Hanoi (ToH), manipulating novelty and complexity. Self-reported state anxiety and latency to respond (initiation time) were recorded before each ToH. Novelty had a major effect on initiation time, particularly for left-handers. Left-handers had a longer latency to start and this was significantly longer on the first trial. Irrespective of hand-preference, initiation time reduced on the second trial, however, this was greatest for left-handers. Condition of task did not systematically influence initiation time for right handers, but did for left-handers. State anxiety was influenced by task novelty and complexity in a more complicated way. During the first trial, there was a significant handedness × number of disks interaction with left-handers having significantly higher state anxiety levels before the 3-disk ToH. This suggests that the initial reaction to this task for left-handers was not simply due to perceived difficulty. On their second trial, participants completing a novel ToH had higher state anxiety scores than those completing a repeated version. Overall, left-handers had a larger reduction in their state anxiety across trials. Relating to this, the expected strong positive correlation between state and trait anxiety was absent for left-handed females in their first tower presentation, but appeared on their second. This was driven by low trait anxiety individuals showing a higher state anxiety response in the first (novel) trial, supporting the idea that left-handed females respond to novelty in a way that is not directly a consequence of their trait anxiety. A possible explanation may be stereotype threat influencing the behavior of left-handed females.

An experimental study of the job demand-control model with measures of heart rate variability and salivary alpha-amylase: Evidence of increased stress responses to increased break autonomy

We assessed in an experimental design whether the stress response towards a work task was moderated by the autonomy to choose a break during the assigned time to complete the task. This setting is defined in accordance with the theoretical framework of the job-demand-control (JDC) model of work related stress. The findings from naturalistic investigations of a stress-buffering effect of autonomy (or 'buffer hypothesis') are equivocal and the experimental evidence is limited, especially with relation to physiological indices of stress. Our objective was to investigate if increased autonomy in a particular domain (break time control) was related with adaptive physiology using objective physiological markers of stress; heart rate variability (HRV) and salivary alpha amylase (sAA). We used a within-subject design and the 60 female participants were randomly assigned to an autonomy (free timing of break) and standard conditions (fixed timing of break) of a word processing task in a simulated office environment in a random order. Participants reported increased perceptions of autonomy, no difference in demand and performed worse in the task in the break-time autonomy versus the standard condition. The results revealed support for the manipulation of increased autonomy, but in the opposing direction. Increased autonomy was related with dysregulated physiological reactivity, synonymous with typical increased stress responses. Potentially, our findings may indicate that autonomy is not necessary a resource but could become an additional stressor when it adds additional complexity while the amount of work (demands) remains unchanged. Further, our findings underscore the need to collect objective physiological evidence of stress to supplement self-reported information. Self-report biases may partially explain the inconsistent findings with the buffer hypothesis.

Global stress response during a social stress test: impact of alexithymia and its subfactors

OBJECTIVES

Alexithymia is a personality trait characterized by difficulties in identifying, describing and communicating one's own emotions. Recent studies have associated specific effects of this trait and its subfactors with hypothalamo-pituitary-adrenal (HPA) axis markers during stress. The aim of this study was to analyze the association between alexithymia and its subfactors with HPA and sympatho-adrenal medullar (SAM) activity. Stress was induced experimentally using a public-speaking paradigm. Salivary cortisol, alpha-amylase (AA), chromogranin A (CgA) and heart rate (HR) were collected during the defined periods of baseline, stress, and recovery in 19 males and 24 female healthy university students.

RESULTS

Subjects reacted to the stressor with a significant cortisol and SAM response. Subjects scoring high on alexithymia reacted significantly more intensely than low scorers in basal anticipatory as well as peak cortisol and area under the curve. Regression analyses revealed that the increased HPA activity was related to only one alexithymia subfactor, the difficulty in differentiating feelings and distinguishing them from bodily sensations and emotion arousal.

CONCLUSION

Alexithymia and its subfactors were specifically related to cortisol responses. This research should be replicated with more subjects and should take into account more parameters reflecting sympathetic and/or parasympathetic activation, as well as HPA axis. Factors such as coping strategies and the perception of the situation as a challenge have also to be explored.

Diurnal patterns of salivary alpha-amylase and cortisol secretion in female adolescent tennis players after 16 weeks of training

We examined the effects of 16 weeks of training on diurnal pattern of salivary alpha-amylase (sAA), cortisol, and the ratio of sAA over cortisol (AOC) in 12 national adolescent female tennis players. Stress and recovery were also evaluated using the Recovery-Stress-Questionnaire for Athletes-RESTQ-Sport. Data were collected after a 2-week rest (January, W0), and 4 months after W0 (W16). Subjects collected five saliva samples throughout a day. While all participants displayed the previously shown decrease after awakening in adolescents at W0, they showed a rise in the alpha-amylase awakening response and a higher alpha-amylase activity output (p<0.01) at W16 compared to W0. For the daily rhythm of cortisol we found subjects having a low overall output of salivary cortisol (p<0.01) and a blunted response to awakening at W16. Furthermore, an increase in the ratio AOC at W16, and a negative correlation between this ratio and Sport-specific recovery score. Our findings offer support for the hypothesis that increase of training load during the study period induced asymmetry activation between the two stress systems, in relation to psychological alterations and performance decrease. These results provide encouragement to continue exploring the impact of training program using a psychobiological approach among young athletes in order to prevent fatigue and preserve the health of these athletes.

Gum chewing modulates heart rate variability under noise stress

OBJECTIVE

Gum chewing may relieve stress, although this hypothesis has not been proven. Heart-rate variability (HRV) is commonly used to measure stress levels. However, it is not known if gum chewing modulates HRV under acute stress. The aim of this study was to investigate the effects of gum chewing on HRV under acute stress.

MATERIALS AND METHODS

A cross-over study involving 47 non-smoking healthy subjects, aged 22-27 years, was carried out. The subjects received a stress procedure with gum chewing (GS group) and without gum chewing (S group). Additionally, the other 20 subjects were allocated to the gum chewing without stress group (G group). The GS and S groups were exposed to noise for 5 min (75 dBA) as stress. Before and after stress exposure/gum chewing, participants completed the state portion of the State-Trait Anxiety Inventory (STAI-s) and a single Stress Visual Analogue Scale (VAS) measurement. HRV measurement was performed before and during stress/gum chewing for 5 min.

RESULTS

After the stress procedure, VAS score significantly increased in the GS and S groups. During the stress procedure, the GS group showed a significantly lower level of high frequency (HF) and higher levels of low frequency (LF) and LF/HF than the S group. However, there were no significant differences in the scores of the state portion of the State-Trait Anxiety Inventory (STAI-s) and VAS between the two stress groups.

CONCLUSIONS

These findings suggest that gum chewing modulates HRV, but may not relieve acute stress caused by noise.

Saliva as a diagnostic fluid. Literature review

There is a growing interest in diagnosis based on the analysis of saliva. This is a simple, non-invasive method of obtaining oral samples which is safe for both the health worker and the patient, not to mention allowing for simple and cost-efficient storage. The majority of studies use general saliva samples in their entirety, complex fluids containing both local and systemic sources and whose composition corresponds to that of the blood. General saliva contains a considerable amount of desquamated epithelial cells, microorganisms and remnants of food and drink; it is essential to cleanse and refine the saliva samples to remove any external elements. Immediate processing of the sample is recommended in order to avoid decomposition, where this is not possible, the sample may be stored at -80ºC. Salivary analysis – much the same as blood analysis – aims to identify diverse medication or indications of certain diseases while providing a relatively simple tool for both early diagnosis and monitoring various irregularities. The practicalities of salivary analysis have been studied in fields such as: viral and bacterial infections, autoimmune diseases (like Sjögren’s syndrome and cɶliac disease), endocrinopathies (such as Cushing’s syndrome), oncology (early diagnosis of breast, lung and stomach carcinoma and oral squamous cell carcinoma), stress assessment, medication detection and forensic science among others. It is hoped that salivary analysis, with the help of current technological advances, will be valued much more highly in the near future. There still remain contradictory results with respect to analytic markers, which is why further studies into wider-ranging samples are fundamental to prove its viability.

Key words:Saliva, biomarkers, early diagnosis.

Normative references of heart rate variability and salivary alpha-amylase in a healthy young male population

Background

This study aimed to present normative reference values of heart rate variability and salivary alpha-amylase in a healthy young male population with a particular focus on their distribution and reproducibility.

Methods

The short-term heart rate variability of 417 young healthy Japanese men was studied. Furthermore, salivary alpha-amylase was measured in 430 men. The average age of the subjects were 21.9 years with standard deviation of 1.6 years. Interindividual variations in heart rate variability indices and salivary alpha-amylase levels were plotted as histograms. Data are presented as the mean, median, standard deviation, coefficient of variation, skewness, kurtosis, and fifth and 95th percentiles of each physiological index.

Results

Mean recorded values were heart period 945.85 ms, log-transformed high frequency component 9.84 ln-ms², log-transformed low frequency component 10.42 ln-ms², log-transformed low frequency to high frequency ratio 0.58 ln-ratio, standard deviation of beat-to-beat interval 27.17 ms and root mean square of successive difference 37.49 ms. The mean value of raw salivary alpha-amylase was 17.48 U/mL, square root salivary alpha-amylase 3.96 sqrt[U/mL] and log-transformed salivary alpha-amylase 2.65 ln[U/mL]. Log-transformed heart rate variability indices exhibited almost symmetrical distributions; however, time-domain indices of heart rate variability (standard deviation of beat-to-beat interval and root mean square of successive difference) exhibited right-skewed (positive skewness) distributions. A considerable right-skewed distribution was observed for raw salivary alpha-amylase. Logarithmic transformation improved the distribution of salivary alpha-amylase, although square root transformation was insufficient. The day-to-day reproducibility of these indices was assessed using intraclass correlation coefficients. Intraclass correlation coefficients of most heart rate variability and salivary indices were approximately 0.5 to 0.6. Intraclass correlation coefficients of raw salivary markers were approximately 0.6, which was similar to those of heart rate variability; however, log transformation of the salivary markers did not considerably improve their reproducibility. Correlations between sympathetic indicators of heart rate variability and salivary alpha-amylase were not observed.

Conclusion

Because the sample population examined in this study involved limited age and gender variations, the present results were independent of these factors and were indicative of pure interindividual variation.

Job strain and shift work influences on biomarkers and subclinical heart disease indicators: a pilot study

This pilot study is one of the first to examine the impact of job strain and shift work on both the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis using two salivary stress biomarkers and two subclinical heart disease indicators. This study also tested the feasibility of a rigorous biological sampling protocol in a busy workplace setting. Paramedics (n = 21) self-collected five salivary samples over 1 rest and 2 workdays. Samples were analyzed for α-amylase and cortisol diurnal slopes and daily production. Heart rate variability (HRV) was logged over 2 workdays with the Polar RS800 Heart Rate monitors. Endothelial functioning was measured using fingertip peripheral arterial tonometry. Job strain was ascertained using a paramedic-specific survey. The effects of job strain and shift work were examined by comparing paramedic types (dispatchers vs. ambulance attendants) and shift types (daytime vs. rotating day/night). Over 90% of all expected samples were collected and fell within expected normal ranges. Workday samples were significantly different from rest day samples. Dispatchers reported higher job strain than ambulance paramedics and exhibited reduced daily alpha-amylase production, elevated daily cortisol production, and reduced endothelial function. In comparison with daytime-only workers, rotating shift workers reported higher job strain, exhibited flatter α-amylase and cortisol diurnal slopes, reduced daily α-amylase production, elevated daily cortisol production, and reduced HRV and endothelial functioning. Despite non-statistically significant differences between group comparisons, the consistency of the overall trend in subjective and objective measures suggests that exposure to work stressors may lead to dysregulation in neuroendocrine activity and, over the long-term, to early signs of heart disease. Results suggest that further study is warranted in this population. Power calculations based on effect sizes in the shift type comparison suggest a study size of n = 250 may result in significant differences at p = 0.05. High compliance among paramedics to complete the intensive protocol suggests this study will be feasible in a larger population.

Nonlinear Heart Rate Variability features for real-life stress detection. Case study: students under stress due to university examination

Background

This study investigates the variations of Heart Rate Variability (HRV) due to a real-life stressor and proposes a classifier based on nonlinear features of HRV for automatic stress detection.

Methods

42 students volunteered to participate to the study about HRV and stress. For each student, two recordings were performed: one during an on-going university examination, assumed as a real-life stressor, and one after holidays. Nonlinear analysis of HRV was performed by using Poincaré Plot, Approximate Entropy, Correlation dimension, Detrended Fluctuation Analysis, Recurrence Plot. For statistical comparison, we adopted the Wilcoxon Signed Rank test and for development of a classifier we adopted the Linear Discriminant Analysis (LDA).

Results

Almost all HRV features measuring heart rate complexity were significantly decreased in the stress session. LDA generated a simple classifier based on the two Poincaré Plot parameters and Approximate Entropy, which enables stress detection with a total classification accuracy, a sensitivity and a specificity rate of 90%, 86%, and 95% respectively.

Conclusions

The results of the current study suggest that nonlinear HRV analysis using short term ECG recording could be effective in automatically detecting real-life stress condition, such as a university examination.

Heart rate variability and pre-competitive anxiety in BMX discipline

Altered neural mechanisms implying autonomic functioning have been described related to anxiety. Pre-competitive stress may be considered as an anxiety-state associated with disorders (i.e. somatic and cognitive alterations, and self-confidence worsening) that severely impair sport performance, conditioning short-lasting strength-related disciplines like BMX. From the psychological perspective, coaches use questionnaires like CSAI-2R to identify these alterations. However, with the emergence of psycho-physiological and non-linear approaches, recent studies suggest that HRV analysis provides a non-invasive tool to assess them. Hence, our purpose was to analyze how BMX competition affects subjective perception of anxiety, and if this emotional alteration is reflected in HR dynamics, analyzed both linear and nonlinearly, exploring the evolution of this relationship in a 2-day competition. Eleven male athletes from the BMX Spanish National Team were assessed from baseline HRV the morning of a training session (rT) and on two successive days of competition (rC1 and rC2), repeating HRV recording with CSAI-2R 20 min prior to training (aT) and competition (pre-competitive: aC1 and aC2). Repeated measures MANOVA showed significant vagal slow-down responses in aC1 and aC2 comparing not only with aT, but also comparing with rT, rC1 and rC2, coinciding with significant greater scores for the somatic and cognitive anxiety (SA and CA) in aC1 and aC2 versus aT. Pearson analysis showed a large and positive correlation between α1 and SA in C1, and close to it between SampEn and CA in aC2; both were confirmed by Bland-Altman chart analysis. Our results confirm that HRV analysis provide a complementary tool to assess competitive pressure.

Lecturing to 200 students and its effects on cytokine concentration and salivary markers of adrenal activation

Stress not only activates the SAM system and the hypothalamic-pituitary-adrenal axes, but also the immune system. The aims of this study are to assess the physiological variations in saliva (cytokines, cortisol and alpha-amylase) and perceived stress in professors when they had to lecture to 200 students. A total of eight unstimulated saliva samples were collected from nine professors: four on a working day that included the lecture and four controls on a working day without a lecture. The professors also rated subjective stress on a seven-point scale 5 min before the lecture, immediately after the lecture and at the same times on the control day. The lecture elicited substantial increases in subjective stress ratings, with the values on the lecture day significantly higher than those on the control day. Lecturing resulted in significant increases in Tumor Necrosis Factor (TNF)-α, Interleukin (IL)-2 and IL-4 concentrations, but did not affect the IL-10 values. These changes appeared to be concomitant with changes in the concentrations of the stress markers, alpha-amylase and cortisol. The mechanisms by which psychosocial stress can induce cytokine changes and modify the activity of salivary alpha-amylase are not entirely understood, and further research is thus warranted.