What do arithmetic stress tests measure? Protocol variations and cardiovascular responses

ECG and EEG based detection and multilevel classification of stress using machine learning for specified genders: A preliminary study

Mental health, especially stress, plays a crucial role in the quality of life. During different phases (luteal and follicular phases) of the menstrual cycle, women may exhibit different responses to stress from men. This, therefore, may have an impact on the stress detection and classification accuracy of machine learning models if genders are not taken into account. However, this has never been investigated before. In addition, only a handful of stress detection devices are scientifically validated. To this end, this work proposes stress detection and multilevel stress classification models for unspecified and specified genders through ECG and EEG signals. Models for stress detection are achieved through developing and evaluating multiple individual classifiers. On the other hand, the stacking technique is employed to obtain models for multilevel stress classification. ECG and EEG features extracted from 40 subjects (21 females and 19 males) were used to train and validate the models. In the low&high combined stress conditions, RBF-SVM and kNN yielded the highest average classification accuracy for females (79.81%) and males (73.77%), respectively. Combining ECG and EEG, the average classification accuracy increased to at least 87.58% (male, high stress) and up to 92.70% (female, high stress). For multilevel stress classification from ECG and EEG, the accuracy for females was 62.60% and for males was 71.57%. This study shows that the difference in genders influences the classification performance for both the detection and multilevel classification of stress. The developed models can be used for both personal (through ECG) and clinical (through ECG and EEG) stress monitoring, with and without taking genders into account.

Comparison between the Effects of Acute Physical and Psychosocial Stress on Feedback-Based Learning

Stress modulates feedback-based learning, a process that has been implicated in declining mental function in aging and mental disorders. While acute physical and psychosocial stressors have been used interchangeably in studies on feedback-based learning, the two types of stressors involve distinct physiological and psychological processes. Whether the two types of stressors differentially influence feedback processing remains unclear. The present study compared the effects of physical and psychosocial stressors on feedback-based learning. Ninety-six subjects (Mage = 19.11 years; 50 female) completed either a cold pressor task (CPT) or mental arithmetic task (MAT), as the physical or psychosocial stressor, while electrocardiography and blood pressure were measured to assess cardiovascular stress reactivity (CVR). Self-ratings on the emotional valence of the stressors were also obtained. A probabilistic learning task was given prior to and after the stressors. Accuracy in selecting positive (Go accuracy) and avoiding negative stimuli (No-go accuracy) were recorded as learning outcomes. Repeated measures ANOVA and multiple regressions were used to compare the effects of two stressors and examine the effects of CVR and valence on the learning outcomes. The results showed that although the effects of CPT and MAT on feedback processing were not different, CVR and valence influenced Go and No-go accuracy, respectively. The results suggest that stress-modulated feedback-based learning involves multiple pathways and underscore the link between CVR and reward sensitivity. The findings have clinical implications and may contribute to a better understanding of human behavioral systems.

Perfectionistic self-presentation, coping, and affective response during laboratory performance

BACKGROUND AND OBJECTIVES

The impact of trait perfectionism on coping and affective response has been well-documented in laboratory performances, and yet little is known about the role played by perfectionistic self-presentation in performances beyond the effects of trait perfectionism.

DESIGN

We aimed to address this knowledge gap by examining the relationships between perfectionistic self-presentation, maladaptive emotion-focused coping, and affective response to laboratory problem-solving tasks.

METHODS

A group of 130 undergraduates attempted challenging, time-limited arithmetic and anagram tasks. Upon task completion, participants' scores were announced along with their mistakes. Additionally, participants completed measures assessing their positive and negative affect before and after lab performance, as well as coping strategies utilized during performance.

RESULTS

Participants with elevated perfectionistic self-presentation experienced greater levels of negative affect and maladaptive emotion-focused coping. Moreover, nondisclosure of imperfection emerged as a significant predictor of lowered positive affect from pre- to post-performance after controlling for self-oriented perfectionism and socially prescribed perfectionism. Path analysis indicated that both nondisplay of imperfection and nondisclosure of imperfection exerted an indirect effect on post-performance negative affect via maladaptive emotion-focused coping.

CONCLUSIONS

Our findings highlight the unique contribution of perfectionistic self-presentation beyond trait perfectionism in performance settings and suggest a need for future research.

A Review of Biophysiological and Biochemical Indicators of Stress for Connected and Preventive Healthcare

Stress is a known contributor to several life-threatening medical conditions and a risk factor for triggering acute cardiovascular events, as well as a root cause of several social problems. The burden of stress is increasing globally and, with that, is the interest in developing effective stress-monitoring solutions for preventive and connected health, particularly with the help of wearable sensing technologies. The recent development of miniaturized and flexible biosensors has enabled the development of connected wearable solutions to monitor stress and intervene in time to prevent the progression of stress-induced medical conditions. This paper presents a review of the literature on different physiological and chemical indicators of stress, which are commonly used for quantitative assessment of stress, and the associated sensing technologies.

The Need for a Neutral Speaking Period in Psychosocial Stress Testing

Abstract. Tasks such as the Trier Social Stress Test, narrative recall, and some cognitive challenges require participants to speak in order to measure acute physiological responses to induced stress. Typically, the physiological measures during the stressed state are compared to a silent baseline period. This does not differentiate between stress that is induced by emotion and stress due to the physical act of vocalization. We modified a psychosocial stress task for 41 participants to add a period of neutral speaking. We hypothesized that there would be significant differences in physiological measures between the silent baseline and neutral speaking periods, and that these differences would explain a substantial proportion of the stress response traditionally attributed to emotion. Blood pressure, skin conductance level, respiration rate, salivary alpha-amylase, and high frequency heart rate variability showed significant changes during the neutral speaking period compared to a silent baseline, demonstrating the need for this control. Of the magnitude of physiological response which would have typically been attributed to emotion, 36–77% was due to vocalization alone. In stress-inducing tasks that require speaking, care should be taken in study design to account for the physiological impact of speech.

Introduction of Application of Gini Coefficient to Heart Rate Variability Spectrum for Mental Stress Evaluation

Background

The Gini coefficient is a statistical tool generally used by economists to quantify income inequality. However, it can be applied to any kind of data with unequal distribution, including heart rate variability (HRV).

Objectives

To assess the application of the Gini coefficient to measure inequality in power spectral density of RR intervals, and to use this application as a psychophysiological indicator of mental stress.

Methods

Thirteen healthy subjects (19 ± 1.5 years) participated in this study, and their RR intervals were obtained by electrocardiogram during rest (five minutes) and during mental stress (arithmetic challenge; five minutes). These RR intervals were used to obtain the estimates of power spectral densities (PSD). The limits for the PSD bands were defined from 0.15 to 0.40 Hz for high frequency band (HF), from 0.04 to 0.15 Hz for low frequency band (LF), from 0.04 to 0.085 Hz for first low frequency sub-band (LF1) and from 0.085 to 0.15 Hz for second low frequency sub-band (LF2). The spectral Gini coefficient (SpG) was proposed to measure the inequality in the power distribution of the RR intervals in each of above-mentioned HRV bands. SpG from each band was compared with its respective traditional index of HRV during the conditions of rest and mental stress. All the differences were considered statistically significant for p < 0.05.

Results

There was a significant decrease in HF power (p = 0.046), as well as significant increases in heart rate (p = 0.004), LF power (p = 0.033), LF2 power (p = 0.019) and LF/HF (p = 0.002) during mental stress. There was also a significant increase in SpG(LF) (p = 0.009) and SpG(LF2) (p = 0.033) during mental stress. Coefficient of variation showed SpG has more homogeneity compared to the traditional index of HRV during mental stress.

Conclusions

This pilot study suggested that spectral inequality of Heart Rate Variability analyzed using the Gini coefficient seems to be an independent and homogeneous psychophysiological indicator of mental stress. Also, HR, LF/HF, SpG(LF) of HRV are possibly important, reliable and valid indicators of mental stress.

Design and Implementation of an Ultra-Low Resource Electrodermal Activity Sensor for Wearable Applications ‡

While modern low-power microcontrollers are a cornerstone of wearable physiological sensors, their limited on-chip storage typically makes peripheral storage devices a requirement for long-term physiological sensing—significantly increasing both size and power consumption. Here, a wearable biosensor system capable of long-term recording of physiological signals using a single, 64 kB microcontroller to minimize sensor size and improve energy performance is described. Electrodermal (EDA) signals were sampled and compressed using a multiresolution wavelet transformation to achieve long-term storage within the limited memory of a 16-bit microcontroller. The distortion of the compressed signal and errors in extracting common EDA features is evaluated across 253 independent EDA signals acquired from human volunteers. At a compression ratio (CR) of 23.3×, the root mean square error (RMSErr) is below 0.016 μS and the percent root-mean-square difference (PRD) is below 1%. Tonic EDA features are preserved at a CR = 23.3× while phasic EDA features are more prone to reconstruction errors at CRs > 8.8×. This compression method is shown to be competitive with other compressive sensing-based approaches for EDA measurement while enabling on-board access to raw EDA data and efficient signal reconstructions. The system and compression method provided improves the functionality of low-resource microcontrollers by limiting the need for external memory devices and wireless connectivity to advance the miniaturization of wearable biosensors for mobile applications.

Cardiovascular and affective responses to social stress in adolescents with internalizing and externalizing problems

Behavioral responses to stress and challenge are based in emotional and physiological arousal reactions. Adolescents with maladaptive or problematic behavior patterns, such as internalizing or externalizing problems, are likely to show atypical emotional and physiological reactions to stress. Relations between problems and reactions to stress were examined in a sample of 55 young adolescents with normal to clinical levels of internalizing and externalizing problems. Youth had their self-reported emotional states, heart rate, and blood pressure levels measured before and after engaging in two socially challenging, evaluative manipulations. Internalizing problems were associated with less positive affect but greater anxiety and cardiovascular arousal, whereas externalizing problems predicted greater hostility and positive affect but less cardiovascular arousal. The necessity of recognizing and incorporating comorbid characteristics and multiple response systems into studies of the links between problems and reactivity is emphasized in the discussion.

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

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

The role of immersion and narrative in mediated presence: the virtual hospital experience

The "mediated sense of presence" is a technology-induced illusion of being present in one (simulated) place when one is actually present in another (physical) place. Typically experienced in virtual worlds, mediated presence is generated by different technological, cognitive, and emotional factors. The aim of this study was to test how to optimise the virtual experience by manipulating some of these factors. Specifically, we tested if an immersive technology and/or a meaningful narrative context influence the users' sense of presence, providing a more compelling experience than a non-immersive and non-contextualized virtual space. Eighty-four students, randomly divided into four groups, were asked to find a blood container inside a virtual hospital in an immersive or non-immersive condition and with or without an emotionally related narrative. Two presence questionnaires and heart-rate variations were used to measure the effects of the four conditions on the users' sense of presence. Results showed a significant effect of narrative, F(8, 73) = 30.346, p < 0.001, and level of immersion, F (8, 73) = 10.913, p < 0.001, and a significant interaction between narrative and immersion, F(8, 73) = 2.062, p = 0.05, both on the presence questionnaires and on the heart-rate variations. Moreover, considering the factors immersion (I) and narrative (N) together, we found that the I-N condition generated the highest level of presence. We argue that both immersion and narrative are important in creating an effective virtual reality experience because they contribute differently to increasing the sense of presence. Immersion increases the place illusion, while the narrative contributes to generating an emotional response and strengthening the subjects' sense of inner presence.

Physiological stress reactivity in human pregnancy—a review

Prenatal maternal stress has been found to have long-lasting effects on the behavioral and physiological development of the offspring. These programming effects on the fetus would be physiologically mediated through heightened and/or abnormal activity of the maternal sympathetic-adrenal-medullary system (SAM) and especially of her hypothalamic-pituitary-adrenocortical axis (HPA-axis). The abnormalities in maternal physiology could be present in her basal functioning, but also in her physiological reactivity to stressors, which constitutes the topic of this paper. This article reviews studies that have used laboratory challenges to study physiological stress reactivity in pregnant women. It concentrates on stress tests designed to produce pain or discomfort, or cognitive and psychological stress, and that assess changes in blood pressure, heart rate and/or cortisol as reactivity measures. The general conclusion is that physiological stress reactivity appears to be dampened during pregnancy. Nonetheless, the physiological responses to laboratory challenges are clearly present and display enough inter-individual variability to enable the study of links between responsivity patterns, psychosocial variables, fetal behavior, pregnancy outcome and offspring development. This paper also looks into the methodological limitations present in the reviewed studies. Options for sound design of stress test protocols are discussed and recommendations for future studies are presented. These methodological points are general and can therefore also be of use for researchers studying human stress reactivity in other populations and ages.

The joint effect of noise exposure and job complexity on distress and injury risk among men and women: the cardiovascular occupational risk factors determination in Israel study

We sought to explore the possibility that exposure to noise at work might interact with job complexity and gender to affect the incidence of occupational injury among industrial employees. In this study, we examined 4084 men and 1643 women from 21 industrial plants while controlling for a number of potent confounding variables, among them active safety hazards. Logistic regression results showed that the predictor variables interacted and that the highest injury risk (odds ratio = 2.72) was observed in women in high noise and high job complexity, compared with the referents scoring low on these predictors. The comparable injury risk in men was only 1.3. Parallel results were observed for three noise stress indicators: workload, noise annoyance and postwork irritability. We conclude that the joint exposure to noise and high job complexity is disruptive, resulting in higher distress and occupational injury risk, particularly among women.

Cardiovascular reactivity and adaptation to recurrent psychological stress: Replication and extension

We analyzed the effects of evaluative observation and baseline duration on cardiovascular reactivity and adaptation to recurrent psychological stress. Cardiovascular reactivity to mental arithmetic stress was assessed in college men and women (N=224) during two pretest tasks, a test task, and a posttest task. Participants were assigned randomly in a 2 x 2 design to manipulations of baseline duration before the test task (4 min vs. 12 min) and evaluative observation during the test task (observed vs. control). Repeated exposure to stress attenuated cardiac but not vascular reactivity. Evaluative observation disrupted cardiac adaptation, resulting in a resurgence of beta-adrenergic cardiac reactivity during the test task. Cardiac adaptation resumed fully during the posttest task. Baseline duration had no effect on reactivity. The results replicate and extend previous work, and support the dual process theory of habituation and sensitization.

Defensiveness and 3-year blood pressure levels among young adults: the mediating effect of stress-reactivity

Stress-reactivity has long been proposed to act as a possible mechanism linking psychological factors and increases in blood pressure (BP). This study used results from an intensive cardiovascular investigation to examine the mediating role of reactivity in the relationship between defensiveness and 3-year ambulatory BP levels. A total of 125 male and female participants (M = 29.1 years) completed a protocol including laboratory reactivity testing, 8- to 12-hr ambulatory BP monitoring, and standardized response style instruments. Further, participants returned 3 years later for an identical second test protocol. Results indicated that high- and low-defensiveness participants did not differ on Year 1 BP, but the high-defensiveness group showed higher BP during the reactivity tasks and on Year 3 ambulatory measures. Statistical mediation testing supported reactivity levels as an intervening mechanism between defensiveness and 3-year BP levels.

Vascular maternal reactivity and neonatal size in normal pregnancy

OBJECTIVE

The purpose of the present study was to determine the associations of cold pressor test (CPT) cardiovascular reactivity with gestational age at birth and neonatal size in normotensive pregnant women.

METHODS

Seventy (70) healthy pregnant women were enrolled. The CPT consisted of introducing the patients' hands in cold water (4 degrees C) for 3 min. An automatic oscillometric device was used to record blood pressure (BP) every minute for the following 5 min. Perinatal results were correlated with CPT findings.

RESULTS

Vascular reactivity assessed by CPT was higher in pregnant hypertensive women and in women with a hypertensive family history. Mean BP increases caused by CPT showed a significant negative correlation for gestational age (r = -0.58, p < 0.001) and cephalic perimeter (r = -0.57, p = 0.03). Diastolic BP increases caused by CPT were negatively correlated with newborn weight (r = -0.78, p < 0.001). Predictable newborn weight, gestational age, and cephalic perimeter were 4046 (47 x diastolic BP increase), 40.2 (0.07 x mean BP increase), and 35.8 (0.09 x mean BP increase), respectively.

CONCLUSIONS

Results show that every mm Hg diastolic BP increase in response to CPT was correlated with a 47-g decrease in the newborn normal weight. Furthermore, every mean mm Hg BP increase in response to CPT was associated with a 0.07-week decrease in the newborn normal gestational age and a 0.09-cm decrease in the normal cephalic perimeter at birth.

Physiologic responses to cognitive challenge during pregnancy: effects of task and repeat testing

Physiological responses to stress during pregnancy are believed to influence birth outcomes. Researchers have studied pregnant women in laboratory stressor paradigms to investigate these associations, yet normative data on cardiovascular and respiratory responses to laboratory challenge during pregnancy are not yet established. To begin to establish such normative data, this study examined the effects of task and repeat stressor exposure on reactivity in third-trimester pregnant women. Thirty-one healthy pregnant women (mean age=27 years; range 18-36) between the 33rd and 39th week of pregnancy, were instrumented for continuous electrocardiography, blood pressure (BP), and respiration data. Subjects rested quietly for a 5-min baseline and then performed both a mental arithmetic stressor and a Stroop color-word-matching task, each 5 min in length and each followed by a 5-min recovery period. The order of the tasks was counterbalanced. After each 5-min period, subjects rated the period on a 10-point stress scale. Averaged across task type and challenge period, systolic and diastolic BP and respiration rate increased significantly in response to cognitive challenge, but heart rate (HR) did not. When data were examined for task and period effects, the following results emerged: the Stroop task elicited significantly greater systolic BP and HR reactivity than the arithmetic task, yet subjects rated the arithmetic task as more stressful. Averaged across task type, subjects showed greater systolic BP reactivity during the second challenge period compared to the first. Finally, women's BP tended to drift upward and did not return to baseline during the first recovery period. These findings indicate that averaging data across tasks and periods can obscure the time course of response patterns that may be important in the study of associations between maternal stress and perinatal development, as well as in other research on reactivity to repeat stress exposure.

Secretory immunoglobulin A and cardiovascular activity during mental arithmetic: effects of task difficulty and task order

Secretory immunoglobulin A (sIgA) in saliva and cardiovascular activity were measured at rest and during mental arithmetic. Task difficulty was manipulated by presenting easy, hard, and impossible versions of the mental arithmetic task in counterbalanced order, while task novelty was operationalised as order of presentation (i.e. first, second, third). Mental arithmetic elicited significant increases in sIgA concentration and sIgA secretion rate, as well as significant cardiovascular effects. Performance decreased and rated difficulty increased with increasing task difficulty. However, sIgA and cardiovascular activity, with the exception of diastolic blood pressure, were insensitive to variations in task difficulty. In contrast, sIgA concentration and a broad range of cardiovascular variables were influenced by task novelty, with more pronounced activity characterising the task version presented first, irrespective of its level of difficulty. Task novelty would seem to be a more important determinant of sIgA and cardiovascular activity than task difficulty.

To eat or not to eat: affective and physiological mechanisms in the stress-eating relationship

The current study aggregated methods from the cardiovascular reactivity and dietary restraint paradigms in an attempt to advance our understanding of stress-induced eating behavior. Seventy-seven female subjects completed a protocol consisting of distinct baseline, stress-induction, and recovery phases during which we monitored blood pressure, heart rate, and self-reported affect. Food was inconspicuously made available to participants during the recovery phase. Our results replicated the restraint x affect level interaction observed in the restraint literature, while showing that physiological measures could further explain distressed eating behavior. Physiological arousal was found reliably to predict reduced food consumption, but only among unrestrained eaters. Analysis of the recovery data showed that food consumption was associated with impaired physiological recovery rates for restrained but not for unrestrained participants. We believe that our results help to reconcile findings in the stress, eating, and dietary restraint fields and offer support for recently developed theories of stress-induced overeating.

Heart period variability and respiratory changes associated with physical and mental load: non-linear analysis

In the investigation of heart rate and heart rate variability, the discrimination between mental workload, physical activity and respiration is known to be methodologically difficult. At most, heart rate variability measures are more likely to be coarse-grained measures with variability confounded by heart rate. Moreover, the spectral analysis of heart rate variability shows broad-band frequency characteristics, pointing towards non-stationarity or non-linearity. From this it is suggested to focus on non-linear dynamic analyses that are variance-insensitive. The experimental section of the paper focuses on the estimation of two non-linear measures for both heartbeat dynamics and respiration, the correlation dimension indicating complexity and the Lyapunov exponents indicating predictability. The results indicate that the complexity of heart dynamics is related to the type of task and that the predictability of heart dynamics is related to the amount of load.

Cardiovascular reactivity to video game predicts subsequent blood pressure increases in young men: The CARDIA study

OBJECTIVE

This study was undertaken to determine the relationship between heightened reactivity of blood pressure (BP) during stress and 5-year changes in blood pressure and hypertensive status, using the CARDIA study.

METHOD

A total of 3364 participants (910 white men, 909 white women, 678 black men, and 867 black women), initially 20 to 32 years old and normotensive, were included. Cardiovascular reactivity to psychological stressors (video game and star-tracing tasks for 3 minutes, cold pressor test for 1 minute) was measured in 1987-1988. We then examined reactivity as a predictor of significant BP change (> or = 8 mm Hg, thought to represent a clinically significant increase) over the next 5 years. Logistic regression models were used to control for potential covariates. Significant BP change and the development of hypertension (BP greater than 140/90 or taking medication for hypertension) over the 5-year follow-up were examined in separate analyses.

RESULTS

Increased systolic blood pressure (SBP) reactivity to the video game was associated with a significant 5-year SBP increase among the entire cohort, independent of resting SBP (p < .0001). Subsequent analyses showed that this relationship held for men but not for women. Reactivity to the star-tracing task or the cold pressor test did not predict significant BP change. Among black men only, new hypertensives (N = 36) had greater diastolic blood pressure (DBP) reactivity to the video game (p = .01).

CONCLUSIONS

Although BP reactivity to all physical and mental stressors used in this study did not consistently predict 5-year change in BP in this young cohort, the results indicate that reactivity to a video game stressor predicts 5-year change in BP and early hypertension among young adult men. These findings are consistent with other studies showing the usefulness of stressors producing a primarily beta-adrenergic response in predicting BP change and hypertension. The results may be limited by the shortened initial rest and recovery periods used in the CARDIA protocol.

Cardiovascular recovery from stress and hypertension risk factors: a meta-analytic review

Recent research has suggested that cardiovascular recovery from stress can play a potential role in hypertension pathogenesis. Sixty-nine studies were included in a meta-analytic review to evaluate the effect of various hypertension risk factors (e.g., race, lack of exercise) on cardiovascular recovery from stress. Small mean effect sizes were observed for studies examining hypertension status and race as risk factors associated with delayed diastolic blood pressure recovery. Lack of fitness was also associated with delayed heart rate recovery. These results revealed that, for the specified risk factors and cardiovascular variables, high-risk individuals exhibited delayed cardiovascular recovery as compared with low-risk individuals. Further, the relationships between hypertension status, race, and cardiovascular recovery were typically associated with the use of "active" laboratory stressors. The relationship between lack of fitness and cardiovascular recovery was also associated with the use of "active" and exercise laboratory stressors.

Cardiovascular responses during effortful active coping and acute experience of anger in women

This study addresses the question of whether effortful active coping and anger provocation add in their effects on cardiovascular responses. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) responses of 64 female students were collected during an active versus nonactive coping task with and without provocation. After a baseline period, women did mental arithmetic (active coping) or read numbers aloud (nonactive coping). Half of each group was then additionally provoked. Ratings of the emotional states (Positive and Negative Affect Scale) indicate that provocation led to an increase in anger, but not in fear or negative or positive affect. Effortful active coping and provocation elevated cardiovascular activity. Although active coping enhanced all cardiovascular variables, provocation particularly affected HR and DBP. The effects of active coping and provocation on HR and DBP but not on SBP were additive and probably were produced by different physiological mechanisms.

Alexithymia, defensiveness and cardiovascular reactivity to stress

This article attempts to further our understanding of alexithymia by testing two conceptual questions about the construct: (a) Is alexithymia characterized by reduced autonomic activity? and (b) Can it be clearly distinguished from defensiveness? Eighty healthy university students completed a battery of personality scales including the Toronto Alexithymia Scale, measures of self-deception and impression management, depression, and anger-in. They also participated in three lab stress tasks: isometric handgrip; mental arithmetic; and a negative affect provocation task. Blood pressure and heart rate were monitored throughout the lab procedure. Analyses were conducted with tercile groups of low, medium, and high alexithymia scorers. The "high alexithymia" tercile showed smaller heart rate responses to the stress tasks and more anger-in behavior. Blood pressure responses did not differentiate the low/ medium/high alexithymia subgroups. Alexithymia scores were unrelated to defensiveness, that is, there was no relationship between alexithymia and impression management or self-deception, and alexithymia was unrelated to depression. We conclude that students defined as "high alexithymia" on the Toronto Alexithymia Scale are not self-deceptive nor do they try to leave a particular impression; they tend to be somewhat hypoaroused autonomically, and they report as many psychological distress symptoms as do subjects with lower TAS scores.

Spouse-pair risk factors and cardiovascular reactivity

Epidemiological research has identified increased risk for coronary heart disease in Type A men married to well-educated women. The present study examined mechanisms that may explain the increased risk associated with this specific spouse-pair combination. Cardiovascular and self-report responses to an individual, standardized laboratory stress task and a dyadic, interactive affect provocation task were assessed in Type A or B men married to women of either low ( < or = 13 years) or high ( > 13 years) educational levels. Type A men with highly educated spouses (i.e., the highest risk group) also reported the greatest anger-out tendency, high trait anger, and low anger control scores. These men further exhibited elevated diastolic blood pressure at baseline and greater diastolic reactivity specific to the dyadic task than did the men in the lower risk groups. These findings, based on a laboratory study of spousal interactions, support the epidemiological high-risk designation of the Type A man with a highly educated spouse and confirm earlier conceptions that Type A research benefits more from a social interaction approach rather than from an individual trait perspective.

Cognitive and psychophysiological correlates of positive, negative, and disorganized symptoms in the schizophrenia spectrum

This study examined the cross-sectional and prospective relationships between cognitive and psychophysiological variables and positive, negative, and disorganized symptoms in 40 outpatients with diagnoses of schizophrenia or schizoaffective disorder. The results indicated that disorganized symptoms were related to deficits in auditory and visuomotor attentional processing, increased skin conductance orienting response, and lower stress reactivity. Negative symptoms were related to reduced resting heart rate, increased stress reactivity, and deficits in visuomotor processing. Prospective findings indicated that both the cognitive and heart-rate variables might be trait-related aspects of the negative symptoms, while the skin conductance, but not the cognitive, variables might be trait-related aspects of the disorganized symptoms. Positive symptoms were not related to any of the cognitive or psychophysiological variables.

Transient loss of serum protective activity following short-term stress: a possible biochemical link between stress and atherosclerosis

Very low density lipoproteins (VLDL) are toxic to aortic endothelial cells in vitro, and toxicity preventing activity (TxPA) inhibits this toxic effect of VLDL. Stress, an established arteriosclerosis risk factor, was examined for its effect on TxPA and on the ability of serum to protect endothelial cells from in vitro injury by VLDL. A standardized mirror tracing task with noise was administered to four healthy subjects. Blood samples were obtained at 0, 30, (stressor) 35, 50 and 80 min. Cortisol and non-esterified fatty acids increased during the stress period. TxPA significantly decreased following the stressor and had recovered by 80 min. When the ratio of non-TxPA/TxPA rose above 2, serum was no longer able to protect the cells from VLDL injury. If endothelial cells in vivo respond similarly to the endothelial cells in culture, the effect of stress on atherosclerosis may be mediated through these transient decreases in TxPA.

Behavioral and psychophysiological predictors of self-monitored 19 month blood pressure change in normotensives

Selected demographic, behavioral and psychophysiological variables (sex of the subject, exercise, coffee and cigarette consumption, baroreceptor stimulation-dependent pain dampening, initial blood pressure, body mass index, daily stress rating, reactivity to mental stress as measured by change in stress rating and heart rate and blood pressure from resting to mental arithmetic conditions) were entered into a stepwise multiple-regression equation to predict changes of oscillometrically self-measured tonic blood pressure in 80 normotensives over a 19 month period. The prediction equation (r = 0.55) associated increases in diastolic blood pressure with baseline diastolic blood pressure, more baroreceptor stimulation-dependent pain inhibition, and less heart rate change during mental arithmetic. There were no significant predictors of systolic changes, and no sex differences. Results are discussed in terms of the learned model of hypertension.

Effects of vocalization on cardiovascular and electrodermal responses during mental arithmetic

This study assessed the contribution of vocalization to autonomic responses during mental arithmetic. Specifically this study compared the autonomic responses of subjects during aloud and silent phases of repeated mental arithmetic tasks. The results were consistent for both tasks. As expected, heart rate and skin conductance responses were elevated during the aloud phases. Preejection period and cardiac output reactions, however, were greater during the silent phases. Furthermore, stroke volume declined during the aloud phases, but was maintained near resting levels during the silent phases. There were no phase effects for systolic pressure, diastolic pressure, or total peripheral resistance. The pattern of autonomic responses between aloud and silent phases of mental arithmetic suggest that the relationship between vocalization and autonomic response is not unidirectional but varies depending on the physiological parameter under investigation.

Speaking from the heart: cardiovascular components of stress rating changes and the relative reactivity of physiological and psychological variables

The first part of the experiment compared the relative reactivity of various cardiovascular measurements and self-reported assessment of mental arithmetic, an active coping stress task. It was found that the self-reported stress rating was more responsive (student's t = 9.4) than the physiological measurements. Among the cardiovascular indices, heart rate was the most responsive (student's t = 6.5), followed by the interval between R-wave and the maximal systolic pressure (student's t = 5.0). The second part of the study used a multiple regression to examine the cardiovascular components of change in stress rating following mental arithmetic. Both resting (psychophysiological "trait" variables) and change under stress (psychophysiological "state" variables) were used to predict change in stress rating. Stress rating increase were associated with greater maximal systolic pressure rate of rise (finger dP/dt) at baseline and less heart rate increase during mental arithmetic, yielding a multiple r of 0.67. The dual autonomic nature of active coping stress response is discussed. The shortcomings of using a correlate of a correlate are noted.

Laboratory reactivity models as predictors of ambulatory blood pressure and heart rate

We attempted to validate the usefulness of the laboratory reactivity paradigm by examining responses to three distinct lab tasks and an overall lab average as predictors for ambulatory blood pressure. Subjects were 126 university students. We assessed ambulatory blood pressure, heart rate and perceived distress during an 8-hr working day. In the lab, all subjects responded to three standardized 5-min tasks: isometric handgrip, mental arithmetic, and a structured discussion of a recent interpersonal conflict situation. The analyses used absolute task levels, change scores, a composite index of reactivity, and a mean value for all obtained lab measures. Task levels correlated significantly with means of the ambulatory cardiovascular indices; the scores ranged from 0.35 to 0.49 for SBP, from 0.45 to 0.58 for DBP, and from 0.57 to 0.65 for HR. Only the DBP change score associated with the discussion task correlated with the ambulatory mean. The correlations between lab task levels and ambulatory measures were strongest for the discussion task and the composite score; the task level for the math task was consistently the weakest predictor of ambulatory activity. When lab resting values were forced into a step-wise multiple regression as step one, only the response to the discussion added significantly (3% each for SBP and DBP) to the variance in ambulatory pressure that was not already explained by resting values. The overall lab mean for SBP was a better predictor of the ambulatory mean than was any combination of resting values and reactivity indices.

Applied use of cardiac and respiration measures: practical considerations and precautions

Cardiac and respiratory measures can be successfully applied to "real world" environments and these measures have certain advantages over both performance and subjective measures that are typically used to monitor operator state and workload. However, because of large differences between laboratory and "real world" environments one must utilize caution in directly applying laboratory data and theories to the day-to-day world environment. While most workers are highly over-trained in their jobs, laboratory subjects are often under-trained in the cognitive tasks that are used to study cognitive activity. It is possible that a substantial portion of experimental effects reported in laboratory studies is due to learning effects. In addition, relatively small changes in cardiac and respiration measures are reported to experimental manipulations in the laboratory while a much larger range of changes are reported in "real world" environments. These differences highlight questions about laboratory/real world similarities and the need to develop a database of actual work environment data. A third area of concern is the relative lack of control over the experimental situation that is the case with most applied research. The possible confounding of changes due to cognitive and physical activity levels is a major concern and strategies for overcoming these problems are suggested. The potential for valuable contributions by cardiac and respiratory measures to applied research make overcoming these difficulties worthwhile.

Family history of hypertension and cardiovascular changes during high and low affect provocation

The present study investigated whether subjects with a positive family history of hypertension would display differential responses in blood pressure and heart rate across different laboratory tasks. We also wanted to know whether subjects would display stable within-subject responses across different laboratory tasks. Twenty-three family history positive subjects and 23 with a negative family history participated in three tasks: 1) mental arithmetic, 2) a conversation about the weather (low affect task), and 3) a conversation about a recent upsetting, interpersonal event (high affect task). Positive family history was associated with elevated diastolic resting blood pressure and greater diastolic responsivity overall. For both groups, arithmetic was associated with the greatest heart rate changes, whereas the distressing conversation was accompanied by the greatest diastolic blood pressure response. Stability of cardiovascular activation across different tasks was present only for heart rate; it was weak for diastolic blood pressure, and completely absent for systolic blood pressure.

Converting enzyme inhibition and blood pressure reactivity to psychological stressors

There is considerable interest in blood pressure reactivity to psychological stressors. Because the sympathetic nervous system and the renin-angiotensin system are so responsive to stressors and are themselves the targets of many antihypertensive medications, many investigators have wondered if such medications decrease the blood pressure response to stressful stimuli. We studied 25 normotensive and 21 hypertensive men in a double-blind crossover study during which they received either placebo for 4 days or captopril (25 mg b.i.d.) for 4 days while they were hospitalized in a clinical research center. Patients were studied at resting baseline, while performing a mathematics task, and while reading out loud a disturbing newspaper article. Although captopril lowered the resting blood pressure levels, it had no effect on the amplitude of reactivity to stressors.