Graded mental arithmetic as an active psychological challenge

Effects of green tea and roasted green tea on human responses

Our objective was to elucidate the effects of tea consumption on refreshment and stress reduction/recovery through examining the multiple associations among factors such as various physiological responses and task performance. Participants included 20 healthy young men who performed a mental arithmetic task while 11 physiological responses were measured. The experiments were conducted twice under different beverage consumption conditions on separate days. The mental arithmetic task was executed six times in 1 day; participants ingested hot water, green tea, or roasted green tea (hojicha) before each task. Several subjective assessments: subjective fatigue, stress, mental workload, and flow were evaluated after each task. The R-R intervals, heart rate variability spectral components, the Poincaré plot indices (SD1 and SD2) and plethysmogram amplitude tended to decrease during task periods compared to resting periods. Tissue blood volume/flow (TBV, TBF) and near-infrared spectroscopy responses (NIRS) were lower in the tea condition than in the hot water condition. By scrutinizing various indicators, we found that aromatic stimulation of Japanese tea beverages has the potential to induce positive effects, enhance mental task performance, promote refreshment, and alleviate feelings of fatigue. These positive effects were observed even in small quantities and within a short duration, mirroring responses observed in daily consumption.

Heart rate reactivity mediates the relationship between trait gratitude and acute myocardial infarction

OBJECTIVE

This study examines the relationship between trait gratitude and acute myocardial infarction. A burgeoning body of literature suggests that gratitude can play a role in regulating individual's cardiovascular responses to stress which in turn, may reduce the incidence of cardiovascular disease such as acute myocardial infarction. However, to date no research has examined these effects.

METHOD

This study used the Mid-Life in the United States dataset (MIDUS; N = 1031) to assess these relationships. Participants completed a standardised cardiovascular stress-testing laboratory protocol and were assessed at a second time-point; on average 6.7 years later.

RESULTS

Results from logistic parallel mediation models suggest that trait gratitude was found to be significantly associated with reduced risk of acute myocardial infarction through the mechanism of increased heart rate reactivity, β = -0.098, 95%CI [- 0.331, - 0.010]. However, neither systolic nor diastolic blood pressure reactivity mediated this relationship.

CONCLUSIONS

These findings suggest that gratitude may be associated with certain aspects of physical health. Specifically, our study reveals a potential link between gratitude and cardiovascular reactivity, which could be a mechanism through which trait gratitude contributes to reductions in the risk of myocardial infarction. As such, this study highlights the potential utility of positive psychological factors, such as gratitude, in promoting cardiovascular health.

Quantifying Cognitive Workload Using a Non-Contact Magnetocardiography (MCG) Wearable Sensor

Quantifying cognitive workload, i.e., the level of mental effort put forth by an individual in response to a cognitive task, is relevant for healthcare, training and gaming applications. However, there is currently no technology available that can readily and reliably quantify the cognitive workload of an individual in a real-world environment at a seamless way and affordable price. In this work, we overcome these limitations and demonstrate the feasibility of a magnetocardiography (MCG) sensor to reliably classify high vs. low cognitive workload while being non-contact, fully passive and low-cost, with the potential to have a wearable form factor. The operating principle relies on measuring the naturally emanated magnetic fields from the heart and subsequently analyzing the heart rate variability (HRV) matrix in three time-domain parameters: standard deviation of RR intervals (SDRR); root mean square of successive differences between heartbeats (RMSSD); and mean values of adjacent R-peaks in the cardiac signals (MeanRR). A total of 13 participants were recruited, two of whom were excluded due to low signal quality. The results show that SDRR and RMSSD achieve a 100% success rate in classifying high vs. low cognitive workload, while MeanRR achieves a 91% success rate. Tests for the same individual yield an intra-subject classification accuracy of 100% for all three HRV parameters. Future studies should leverage machine learning and advanced digital signal processing to achieve automated classification of cognitive workload and reliable operation in a natural environment.

State level income inequality affects cardiovascular stress responses: Evidence from the Midlife in the United States (MIDUS) study

RATIONALE

The slow and insidious effects of income inequality on health means that their effects can be difficult to reveal, taking many years to become apparent. These effects can also be experienced differently according to subjective status and ethnicity making the relation between income inequality and health difficult to understand. Cardiovascular reactions to acute stress are indicative of future health outcomes.

OBJECTIVE

To examine whether short to medium term income inequality affected cardiovascular responses to acute stress whilst accounting for ethnic groups and subjective status.

METHOD

Participants state of residence was available for 1155 people who participated in the MIDUS biomarker data project. This detail was used to merge the relevant US state level inequality data 1, 5, 10 and 15 years prior to the MIDUS biomarker data project which assessed cardiovascular responses to acute stress.

RESULTS

Our analysis demonstrated an association between inequality 5, 10 and 15 year prior and cardiovascular reactions to acute stress. Subjective community status and Black and minority ethnic group membership interacted to affect the association between inequality and cardiovascular reactions.

CONCLUSIONS

In states where income inequality was high, less healthy cardiovascular responses were evident. However lower subjective community status and Black and Ethnic minority group members interacted with income inequality such that their impact was variable contingent on state level inequality. These findings extend the literature on income inequality and health and particularly highlights a psychophysiology pathway linking income inequality and health.

Perceived control and reactivity to acute stressors: Variations by age, race and facets of control

Greater perceived control is associated with better health and well-being outcomes, possibly through more adaptive stress processes. Yet little research has examined whether facets of perceived control (personal mastery and perceived constraints) predict psychological and physiological stress reactivity. The present study evaluated the associations of personal mastery and perceived constraints with changes in subjective stress and cortisol in response to acute laboratory stressors, with age and race as potential moderators. In the Midlife in the United States Refresher Study (N = 633 adults aged 25-75), participants completed a baseline perceived control measure and were subsequently recruited to participate in the laboratory stress protocol. The protocol consisted of completing two mental stress tasks (mental arithmetic and Stroop) as well as providing saliva samples and subjective stress ratings. Race moderated the association between perceived constraints and subjective stress reactivity, such that higher constraints predicted greater subjective stress responses in White participants, but no association was observed in Black participants. Higher personal mastery and perceived constraints each predicted greater increases in cortisol in response to the stress tasks (AUC_i ) among younger but not older adults. These findings suggest that older adults were buffered against the association between facets of control and cortisol stress reactivity. Discussion on potential racial differences in the link between constraints and stress reactivity are elaborated further, as well as considerations for future work to distinguish between facets of control and examine age and racial differences.

Early Life Adversity and Blunted Cardiovascular Reactivity to Acute Psychological Stress: The Role of Current Depressive Symptoms

OBJECTIVE

The pathways underlying the early life adversity and cardiovascular reactivity association remain unclear. The current study examined the role of current depressive symptoms on this relationship.

METHODS

Mediation analyses were conducted using data from 639 participants drawn from the Midlife Development in the United States 2 Biomarker Project. Responses were derived from the Childhood Trauma Questionnaire and Center for Epidemiologic Studies Depression Scale. Participants had their systolic and diastolic blood pressure (SBP, DBP) and heart rate monitored throughout a standardized stress testing protocol.

RESULTS

The association between early life adversity and reactivity was mediated by current depressive symptoms; all adversity factors were linked to higher levels of current depressive symptoms, which, in turn, were associated with lower cardiovascular reactivity. For emotional abuse, this was noted for SBP (β = -0.06 [95% confidence interval {CI}, -0.13 to -0.01]) and DBP (β = -0.04 [-0.07 to -0.01]), physical abuse (SBP: β = -0.05 [-0.11 to -0.01]; DBP: β = -0.03 [-0.06 to -0.01]), sexual abuse (SBP: β = -0.04 [-0.09 to -0.01]; DBP: β = -0.02 [-0.05 to -0.01]), emotional neglect (SBP: β = -0.04 [-0.09 to -0.01]; DBP: β = -0.02 [-0.05 to -0.01]), physical neglect (SBP: β = -0.09 [-0.17 to -0.02]; DBP: β = -0.05 [-0.09 to -0.02]), and total Childhood Trauma Questionnaire score (SBP: β = -0.02 [-0.03 to -0.00]; DBP: β = -0.01 [-0.02 to -0.00]).

CONCLUSIONS

The present findings extend research and demonstrate that depression is an underlying mechanism linking early life adversity and blunted cardiovascular reactivity.

Integrative Science Approach to Resilience: The Notre Dame Study of Health & Well-being (NDHWB)

Although many studies have unequivocally demonstrated the promise of understanding resilience to adversity and characterizing the consequences if stress is unabated, needed are dynamic theories and methods to enhance the rigor and interpretation of these assessments. From a dynamic systems perspective, the focus is not whether an individual possesses some fixed ability or unchangeable trait, but rather to understand the flexibility and responsiveness of stress regulation systems to daily hassles and adverse life events. A renewed interest in individual variability allows researchers to see trajectories of change over both short- and long-time scales to understand the developmental course. As a result, it is possible to answer questions, such as, how does the dysregulation in emotion caused by stress, to both within and between daily affect processes, relate to longitudinal trajectories (over time-scales of years) of dysfunction and disease? The overarching goal of the Notre Dame Study of Health & Well-being is to detail the types and qualities of contextual influences, in conjunction with dynamic psychobiological systems, to assess the precursors, concomitant influences and consequences of stress and resilience in the face of adversity on cognitive, health and well-being outcomes.

Social support, social participation, and cardiovascular reactivity to stress in the Midlife in the United States (MIDUS) study

This study tested two hypotheses of associations between dimensions of social connectedness and cardiovascular reactivity to acute stress: (1) high social support predicts diminished cardiovascular responses to stress (i.e., the stress-buffering model of social support), and (2) diminished cardiovascular responses predict lower social participation, a form of motivated behaviour. Participants (N = 606) in the main Midlife in the United States study completed measures of social support and social participation and underwent psychophysiological stress testing. In unadjusted analyses, social support was positively, rather than inversely, associated with reactivity. Results withstood adjustment for several control variables, but not for depressive symptoms, which was associated with diminished reactivity. Further, diminished reactivity was associated with lower social participation, but not in fully adjusted models. No robust evidence was observed for either the stress-buffering model, or for an association between diminished reactivity and lower social participation. The implications for our understanding of links between social connectedness and cardiovascular reactivity are discussed.

Personality, cardiovascular, and cortisol reactions to acute psychological stress in the Midlife in the United States (MIDUS) study

Recent research has suggested that diminished, as well as elevated reactivity to acute psychological stress is maladaptive. These differences in stress reactions have been hypothesized to relate to the Big Five personality traits, which are said to be biologically-based and stable across adulthood; however, findings have been inconclusive. This study sought to replicate the findings of the largest study conducted to date (Bibbey et al., 2013), with a sample of participants from the Midlife in the United States Study (MIDUS), aged between 35 and 84 years (M = 56.33, SD = 10.87). Participants (N = 817) undertook a standardized, laboratory-based procedure during which their cardiovascular and neuroendocrine reactivity to acute stress was measured. In contrast to Bibbey et al. (2013), associations between neuroticism and blunted reactivity did not withstand adjustment for confounding variables. Further, following adjustment for multiple tests, no significant positive association between agreeableness and HR reactivity was observed. Methodological differences between the studies, which may account in part for the contrasting findings, are discussed. Further conceptual replication research is needed to clarify associations between the Big Five personality traits and stress reactivity, across the lifespan.

Vulnerability to stress: Personality facet of vulnerability is associated with cardiovascular adaptation to recurring stress

It is increasingly suggested that personality traits are critical to understanding patterns of cardiovascular stress adaptation. However, studies have focused on higher-order traits with no research having examined underlying facet effects to repeated stress. The examination of facets provides a more granular examination, which has the potential to identify specific personality components that are relevant within the context of psychophysiological stress adaptation. This study objective was to determine if the underlying facets which encapsulate the dimension of emotional stability, are associated with cardiovascular adaptation to recurring stress. Continuous cardiovascular monitoring and psychometric measures were collated from 79 healthy young male and female adults, across a protocol of recurring active stress tasks. Multiple regression analysis revealed that the facet of vulnerability was associated with systolic and diastolic blood pressure adaptation across the protocol. More specifically, vulnerability was negatively associated with adaptation to recurring stress, such that those highest in vulnerability displayed a sensitization to the recurring stressor. No significant effects emerged for any other facet. Importantly, this research adds to the existing literature examining stress adaptation and has implications for future research on the relevance of examining facet effects. This study is the first to implicate the personality facet of vulnerability which encapsulates an individual's tendency to feel unable to cope with stress and becoming hopeless when faced with emergency situations, in the context of cardiovascular stress adaptation. Taken together, this study suggests that the facet of vulnerability is a critical component to consider in the context of cardiovascular stress adaptation.

Individual Differences in the Association Between Subjective Stress and Heart Rate Are Related to Psychological and Physical Well-Being

The physiological response to stress is intertwined with, but distinct from, the subjective feeling of stress, although both systems must work in concert to enable adaptive responses. We investigated 1,065 participants from the Midlife in the United States 2 study who completed a self-report battery and a stress-induction procedure while physiological and self-report measures of stress were recorded. Individual differences in the association between heart rate and self-reported stress were analyzed in relation to measures that reflect psychological well-being (self-report measures of well-being, anxiety, depression), denial coping, and physical well-being (proinflammatory biomarkers interleukin-6 and C-reactive protein). The within-participants association between heart rate and self-reported stress was significantly related to higher psychological well-being, fewer depressive symptoms, lower trait anxiety, less use of denial coping, and lower levels of proinflammatory biomarkers. Our results highlight the importance of studying individual differences in coherence between physiological measures and subjective mental states in relation to well-being.

An Investigation of the Effects of Changes in the Indoor Ambient Temperature on Arousal Level, Thermal Comfort, and Physiological Indices

Thermal factors not only affect the thermal comfort sensation of occupants, but also affect their arousal level, productivity, and health. Therefore, it is necessary to control thermal factors appropriately. In this study, we aim to design a thermal environment that improves both the arousal level and thermal comfort of the occupants. To this end, we investigated the relationships between the physiological indices, subjective evaluation values, and task performance under several conditions of changes in the indoor ambient temperature. In particular, we asked subjects to perform a mathematical task and subjective evaluation related to their thermal comfort sensation and drowsiness levels. Simultaneously, we measured their physiological parameters, such as skin temperature, respiration rate, electroencephalography, and electrocardiography, continuously. We investigated the relationship between the comfort sensation and drowsiness level of occupants, and the physiological indices. From the results, it was confirmed that changes in the indoor ambient temperature can improve both the thermal comfort and the arousal levels of occupants. Moreover, we proposed the evaluation indices of the thermal comfort and the drowsiness level of occupants using physiological indices.

Openness to experience and stress responsivity: An examination of cardiovascular and underlying hemodynamic trajectories within an acute stress exposure

The personality trait openness to experience has been implicated in health, and in particular cardiovascular wellbeing. In a sample of 62 healthy young female adults, the role of openness in cardiovascular responsivity during a stress exposure was examined. Traditionally, methodologies have averaged a stress exposure into a single reading. This may be limited in that it does not consider patterns of cardiovascular adaptation within a stress exposure. Continuous cardiovascular data were reduced to mean 10 second readings, with phases determined through examinations of shifts in responsivity between each 10 second pairing. Analyses revealed a significant linear interaction for openness across the entire exposure for systolic blood pressure, and cardiac output. A significant between-subjects effect for heart rate also emerged. Contrary to their lower counterparts, those highest in openness exhibited an increasingly myocardial hemodynamic response profile throughout the exposure. Comparisons of responsivity suggests adaptive stress response trajectories for those highest in openness. This study also provides evidence that an attenuation of myocardial responsivity may underpin blunted responsivity. This study provides a potential mechanism in reported openness-health associations.

Openness to experience and adapting to change: Cardiovascular stress habituation to change in acute stress exposure

Underlying psychophysiological mechanisms of effect linking openness to experience to health outcomes, and particularly cardiovascular well-being, are unknown. This study examined the role of openness in the context of cardiovascular responsivity to acute psychological stress. Continuous cardiovascular response data were collected for 74 healthy young female adults across an experimental protocol, including differing counterbalanced acute stressors. Openness was measured via self-report questionnaire. Analysis of covariance revealed openness was associated with systolic blood pressure (SBP; p = .016), and diastolic blood pressure (DBP; p = .036) responsivity across the protocol. Openness was also associated with heart rate (HR) responding to the initial stress exposure (p = .044). Examination of cardiovascular adaptation revealed that higher openness was associated with significant SBP (p = .001), DBP (p = .009), and HR (p = .002) habituation in response to the second differing acute stress exposure. Taken together, the findings suggest persons higher in openness are characterized by an adaptive cardiovascular stress response profile within the context of changing acute stress exposures. This study is also the first to demonstrate individual differences in cardiovascular adaptation across a protocol consisting of differing stress exposures. More broadly, this research also suggests that future research may benefit from conceptualizing an adaptive fitness of openness within the context of change. In summary, the present study provides evidence that higher openness stimulates short-term stress responsivity, while ensuring cardiovascular habituation to change in stress across time.

Sleep Duration and Quality in Relation to Autonomic Nervous System Measures: The Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

Short sleep duration and poor sleep quality are associated with adverse cardiovascular outcomes. Potential pathophysiological mechanisms include sleep-associated alterations in the autonomic nervous system. The objective of this study was to examine the associations of shorter sleep duration and poorer sleep quality with markers of autonomic tone: heart rate (HR), high-frequency HR variability (HF-HRV) and salivary amylase.

METHODS

Cross-sectional analysis of data from actigraphy-based measures of sleep duration and efficiency and responses to a challenge protocol obtained from 527 adult participants in the Multi-Ethnic Study of Atherosclerosis.

RESULTS

Participants who slept fewer than 6 h per night (compared to those who slept 7 h or more per night) had higher baseline HR (fully adjusted model 0.05 log beats/min, 95% confidence interval [CI] 0.01, 0.09) and greater HR orthostatic reactivity (fully adjusted model 0.02 log beats/min, 95% CI 0.002, 0.023). Participants who slept 6 to less than 7 h/night (compared to those who slept 7 h or more per night) had lower baseline HF-HRV (fully adjusted model -0.31 log msec², 95% CI -0.60, -0.14). Participants with low sleep efficiency had lower baseline HF-HRV than those with higher sleep efficiency (fully adjusted model -0.59 log msec², 95% CI -1.03, -0.15). Participants with low sleep efficiency had higher baseline levels of amylase than those with higher sleep efficiency (fully adjusted model 0.45 log U/mL, 95% CI 0.04, 0.86).

CONCLUSIONS

Short sleep duration, low sleep efficiency, and insomnia combined with short sleep duration were associated with markers of autonomic tone that indicate lower levels of cardiac parasympathetic (vagal) tone and/or higher levels of sympathetic tone.

Vagal Recovery From Cognitive Challenge Moderates Age-Related Deficits in Executive Functioning

Decline in executive functioning (EF) is a hallmark of cognitive aging. We have previously reported that faster vagal recovery from cognitive challenge is associated with better EF. This study examined the association between vagal recovery from cognitive challenge and age-related differences in EF among 817 participants in the Midlife in the U.S. study (aged 35-86). Cardiac vagal control was measured as high-frequency heart rate variability. Vagal recovery moderated the association between age and EF (β = .811, p = .004). Secondary analyses revealed that older participants (aged 65-86) with faster vagal recovery had superior EF compared to their peers who had slower vagal recovery. In contrast, among younger (aged 35-54) and middle-aged (aged 55-64) participants, vagal recovery was not associated with EF. We conclude that faster vagal recovery from cognitive challenge is associated with reduced deficits in EF among older, but not younger individuals.

The Association between Neuroticism and Heart Rate Variability Is Not Fully Explained by Cardiovascular Disease and Depression

Neuroticism is associated with cardiovascular disease, autonomic reactivity, and depression. Here we address the extent to which neuroticism accounts for the excess heart disease risk associated with depression and test whether cardiac autonomic tone plays a role as mediator. Subjects were derived from a nationally representative sample (n = 1,255: mean age 54.5, SD = 11.5). Higher neuroticism was associated with reduced heart rate variability equally under rest and stress. The baseline structural equation model revealed significant paths from neuroticism to heart rate variability, cardiovascular disease and depression, and between depression and cardiovascular disease, controlling for age, sex, height, weight, and BMI. Dropping both the neuroticism to heart rate variability, and neuroticism to heart disease paths significantly reduced the model fit (p < .001 in each case). We conclude that neuroticism has independent associations with both autonomic reactivity and cardiovascular disease, over and above its associations with depression and other related variables.

Type D personality is associated with a sensitized cardiovascular response to recurrent stress in men

The present study sought to examine the role of gender and Type D personality on cardiovascular reactivity to stress, by examining patterns of cardiovascular adaptation to recurrent laboratory-based stress. Cardiovascular data were collected from 76 students who, following an initial 10-min baseline period, underwent two cognitive stress tasks. Type D personality was assessed using the 16-item Type D scale. Adaptation of cardiovascular response to recurrent stress was examined by scrutinizing the changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) across the procedure. Female participants and non-Type D males showed cardiovascular habituation to recurrent stress. For Type D males, however, cardiovascular sensitization was evident. The results implicate Type D personality in maladaptive cardiovascular responses, particularly in men, highlighting a possible direct mechanism of psychosomatic cardiovascular pathogenesis.

The association of cardiac vagal control and executive functioning--findings from the MIDUS study

Cardiac vagal control (CVC), an index of parasympathetic contribution to cardiac regulation, has been linked to enhanced executive functioning (EF). However, findings to date have been based on small or unique samples. Additionally, previous studies assessed the CVC-EF link only during rest or recovery period from a cognitive challenge, but not during both states. In the present study, data on 817 socioeconomically diverse participants were obtained from the Midlife Development in the United States (MIDUS) study. As part of this study, participants completed cognitive tests, including EF, along with laboratory-based measures of CVC during rest and following recovery from a cognitive challenge. Regression analyses adjusting for respiratory rate revealed no effect of CVC at rest or during recovery on a global index of EF. However, exploratory post-hoc analyses of the components of the global EF index revealed a significant association between faster vagal recovery and better attention-switching and response inhibition abilities, as indexed by faster reaction time to the mixed SGST. This association remained significant after controlling for demographic, clinical (BMI, diseases and medications altering cardiac autonomic functioning, etc.), and health behavior covariates (Beta = .148, p = .010). Our findings suggest that future studies may need to investigate the links of CVC to specific EF abilities, rather than global measures of EF. Additionally, our results highlight the importance of assessing CVC during both rest and recovery from a cognitive challenge. The authors discuss the putative neurobiological underpinning of this link, as well as suggestions for future basic and clinical research.

The interactive effect of change in perceived stress and trait anxiety on vagal recovery from cognitive challenge

The present study tested the hypothesis that the change in state negative affect (measured as perceived stress) after cognitive challenge moderates the relationship of trait anxiety and anger to vagal recovery from that challenge. Cardiac vagal control (assessed using heart rate variability) and respiratory rate were measured in a sample of 905 participants from the Midlife in the United States Study. Cognitive challenges consisted of computerized mental arithmetic and Stroop color-word matching tasks. Multiple regression analyses controlling for the effects of the demographic, lifestyle, and medical factors influencing cardiac vagal control showed a significant moderating effect of change in perceived stress on the relationship of trait anxiety to vagal recovery from cognitive challenges (Beta=.253, p=.013). After adjustment for respiratory rate, this effect became marginally significant (Beta=.177, p=.037). In contrast, for the relationship of trait anger to vagal recovery, this effect was not significant either before (Beta=.141, p=.257) or after (Beta=.186, p=.072) adjusting for respiratory rate. Secondary analyses revealed that among the individuals with higher levels of trait anxiety, greater reductions in perceived stress were associated with greater increases in cardiac vagal control after the challenge. In contrast, among the individuals with lower levels of trait anxiety, changes in perceived stress had no impact on vagal recovery. Therefore, change in perceived stress moderates the relationship of trait anxiety, but not trait anger, to vagal recovery from cognitive challenge.

Heart rate recovery after cognitive challenge is preserved with age

OBJECTIVE

To investigate the effect of age on heart rate recovery (HRR) from cognitive challenge.

BACKGROUND

Aging is an independent risk factor for the development of cardiovascular disease. HRR from exercise is an established predictor of cardiac morbidity and mortality, and evidence suggests that HRR from cognitive challenge is predictive of cardiac morbidity as well. Aging is associated with delayed HRR from exercise stress, but little is known about the effect of aging on HRR from psychological stress. We tested the hypothesis that age would be related to delayed HRR from psychological stress.

METHODS

HRR post exposure to cognitive challenge (mental arithmetic and Stroop) was investigated in a sample of 436 participants aged 35 to 84 years in MIDUS II, a national study of health and well-being. HRR was measured as 1) the amount of change from the stress level; 2) time to recover; and 3) the area under the curve. The analyses were controlled for medical comorbidities and medications that influence HR, such as body mass index, smoking, sex, menopausal status, and amount of physical activity/exercise.

RESULTS

There was no effect for age on HRR as evaluated by all three recovery assessment methods.

CONCLUSIONS

Contrary to expectation and in contrast to findings concerning HRR from exercise, HRR from cognitive challenge was preserved with age. These findings require further inquiry into differential mechanism(s) underlying HRR from psychological versus exercise stress, including any role for improved emotion regulation with greater age.

Anger, negative emotions, and cardiovascular reactivity during interpersonal conflict in women

OBJECTIVE

In order to evaluate the relationship between women's subjective emotional discomfort with anger and cardiovascular responses to stress, cardiovascular and affective responses were examined during two anger-provoking conditions: one in which anger would be in self-defense, and one in which anger would be in defense of a significant other.

METHODS

A total of 42 healthy, normotensive women aged 18-35 years recruited a close female friend to participate in the study with them, and were randomly assigned to one of two harassment conditions: (i) Self-Harass, where women were harassed while performing a math task; (ii) Friend-Harass, where women witnessed a close female friend being harassed while their friend performed a math task.

RESULTS

Self-Harass and Friend-Harass women reported feeling equally angry, annoyed, and irritated (all P's<.01) during their respective anger-provocation conditions. However, Self-Harass women reported experiencing significantly greater increases in feelings of depression and guilt during anger provocation (P's<.05) relative to Friend-Harass women. Interestingly, it was also the Self-Harass women who exhibited significantly greater elevations in heart rate (HR), cardiac output (CO), systolic blood pressure (SBP), forearm blood flow (FBF), and significant reductions in forearm vascular resistance (FVR; P's<.001) relative to Friend-Harass women during anger provocation.

CONCLUSIONS

Results suggest that women may experience other negative emotions (e.g., guilt, depression) when anger is in self-defense relative to when it is in defense of others, and that these emotions may play a more important role than anger in moderating cardiovascular reactivity (CVR) during interpersonal conflict.

Parental history of hypertension and hostility moderate cardiovascular responses to interpersonal conflict

A parental history of hypertension has been implicated in the development of hypertension, perhaps by virtue of an elevated cardiovascular response to stress. Similarly, hostility has been hypothesized to be linked to cardiovascular disease through cardiovascular hyperreactivity. The interaction of parental history and hostility in moderating cardiovascular response has been infrequently examined, though research suggests the two may be linked through familial factors. The present study examined the cardiovascular response of 98 healthy young adult males categorized as offspring of hypertensive subjects (PH+) or offspring of normotensive subjects (PH-) and as high or low hostile, based on Cook-Medley Hostility scores (HiHo vs. LoHo). Subjects were exposed to either an harassment or non-harassment stressor. Results indicated elevated cardiac output and forearm blood flow responses in PH+/HiHo subjects who were harassed as compared to any other harassed subject and all non-harassed individuals. This hemodynamic response pattern of elevated blood flow suggests a mechanism of hypertensive disease development.

Hostility, sodium consumption, and cardiovascular response to interpersonal stress

OBJECTIVE

Previous studies have reported poorer health behaviors in high vs. low hostile subjects. The role of stress in these observed differences has not been explored although interpersonal stress does increase cardiovascular response in high hostiles. Given evidence that stress may induce increased salt-intake, this study examined the role of hostility and interpersonal stress in increasing sodium consumption in addition to cardiovascular reactivity.

METHOD

Sixty-nine male undergraduates were categorized into high (HiHo) and low hostile (LoHo) groups based on Buss-Durkee Hostility Inventory scores. Subjects engaged in either a math task with harassment, math task without harassment, or a control/rest condition. Sodium intake was assessed posttask by having subjects ingest a sodium-free soup that was presented with a saltshaker without any comments. Cardiovascular measures were also recorded.

RESULTS

HiHo subjects consumed more salt than LoHo subjects irrespective of experimental condition. HiHo subjects who were harassed also exhibited greater cardiac output, systolic blood pressure, and forearm blood flow than did HiHo nonharassed, HiHo control, or LoHo subjects.

CONCLUSION

HiHo subjects exhibited increased salt-intake, although evidence for stress-induced salt-intake was not obtained. Nonetheless, the combination of salt and stress may contribute to the cardiovascular hyperreactivity and risk for cardiovascular disease in hostile individuals.

Dimensions of hostility and cardiovascular response to interpersonal stress

Emerging research suggests that hostility is a multidimensional construct with different dimensions conferring different cardiovascular disease risk. This study examined two dimensions of hostility, expressive and neurotic, and their hemodynamic response patterns upon exposure to interpersonal stress. Fifty-seven male undergraduates were categorized into high and low expressive hostility (HiEH, LoEH) and high and low neurotic hostility (HiNH, LoNH) groups based on their Buss-Durkee Hostility Inventory scores. Subjects engaged in a mathematical subtraction task, with half of the subjects harassed through anger-provoking statements. Separate analyses were conducted for the expressive and neurotic hostility groupings. For expressive hostility, results indicated that HiEH/harassed subjects exhibited greater systolic blood pressure, heart rate, and cardiac output responses than did HiEH/nonharassed subjects or LoEH subjects irrespective of harassment. Neurotic hostility analyses revealed elevated forearm blood flow in HiNH/harassed subjects as compared to HiNH/nonharassed subjects or LoNH subjects in either harassment condition. The hemodynamic response pattern of expressive hostiles is consistent with their risk for heart disease. The response pattern of neurotic hostiles may indicate risk for hypertension, though this remains to be established.

Parental history of hypertension and cardiovascular response to stress in black and white men

White offspring of hypertensives typically exhibit an elevated cardiovascular response to stress. Studies of Black offspring of hypertensives have been fewer, with inconsistent results. This may be due, in part. to incomplete characterizations of hemodynamic responses. This study examines cardiovascular reactivity in Black and White offspring of hypertensives with a particular focus on vascular resistance responses. A total of 62 healthy normotensive men, 41 with a parental history of hypertension (PH+: 21 Blacks, 20 Whites), and 21 without parental hypertension (PH-: 7 Blacks, 14 Whites) engaged in a series of laboratory tasks. Both Black and White PH+ participants exhibited elevated diastolic blood pressure (DBP) responses, but to different patterns of stressor tasks. Familial differences in total peripheral resistance response were also obtained for Black and White participants in a comparison across all tasks, but were particularly evident in tasks when PH+ participants had elevated DBP responses. These results suggest that a parental history of hypertension is an important moderator of cardiovascular, and in particular peripheral vascular, responses to stress in Black and White individuals.

Consistency of heart rate and sympathovagal reactivity across different autonomic contexts

Theories that psychophysiological reactivity constitutes a risk factor for coronary artery disease assume that reactivity is a consistent individual characteristic. We tested this assumption by measuring reactivity to three psychologically challenging tasks performed by 22 healthy subjects across different autonomic contexts produced by positional change. Dependent variables included heart rate (HR), low-frequency (LF; 0.04-0.15 Hz) and high-frequency (HF; 0.15-0.50 Hz) heart period variability, and the LF/HF ratio. HR (r = .44, p < .05) and LF/HF ratio (r = .48, p = .03) reactivity were modestly correlated across the different autonomic contexts, but HF and LF power reactivity were not. These findings suggest that HR reactivity to psychological challenge is a modestly consistent characteristic of individuals, despite differences in autonomic context. Although the same is true of cardiac sympathovagal balance, reactivity of HF and LF power were less consistent.

Coping styles, opioid blockade, and cardiovascular response to stress

We investigated the hypothesis that the effects of Monitoring and Blunting coping styles are mediated in part by endogenous opioids. Mean arterial pressure (MAP) and heart rate (HR) were measured in 39 males before, during, and after a mental arithmetic stressor. Each subject experienced the protocol once under opioid blockade (naltrexone) and once in a placebo condition, in counterbalanced order. Monitoring and Blunting were assessed using the Miller Behavioral Style Scale. High Blunting and high Monitoring were both associated with poorer MAP recovery under opioid blockade than in the placebo condition. Similar effects were noted for Blunting on the measure of HR. These results indicate that the coping styles of Monitoring and Blunting may be associated with enhanced opioid mediation of cardiovascular recovery from stress.

Postural stability of hemodynamic responses during mental challenge

Laboratory stress testing is typically conducted while subjects are seated, whereas real-life stressors may often be encountered while standing. The present study of 20 healthy young men evaluated blood pressure and underlying hemodynamic adjustments to a standardized mental arithmetic task performed twice while seated and twice while standing. Blood pressure increased during mental arithmetic in both postures, but the underlying hemodynamic determinants of the pressor responses were different for the two postures. Augmented cardiac output was responsible for increasing blood pressure during seated task performance, whereas increased vascular resistance was the mechanism for the pressor response to the task performed while standing. Blood pressure and hemodynamic responses were reproducible subject characteristics for a given posture; test-retest correlations were significant for all cardiovascular measures. However, seated blood pressures responses were not significantly correlated with standing blood pressure responses. In contrast, significant between-posture correlations were found for cardiac output and vascular resistance responses. This preliminary evidence of postural stability of the hemodynamic determinants of blood pressure responses during stress is consistent with growing evidence that hemodynamic response tendencies are robust characteristics of reactivity. Ambulatory monitoring of hemodynamic response patterns during real-life stress may reveal more idiosyncratic profiles of stress reactivity than are displayed by blood pressure responses alone.

Aerobic fitness and opioidergic inhibition of cardiovascular stress reactivity

The role of endogenous opioids in aerobic fitness-induced decrements in cardiovascular stress reactivity was examined by comparing the effects of opioid antagonism with naltrexone on responses to stress in young adults with high versus low levels of aerobic fitness. Two hundred forty subjects were given an activity questionnaire and males with the highest (Fit) and lowest (Nonfit) aerobic activity profiles were recruited for maximal oxygen consumption (VO2max) treadmill testing and psychological stress testing (final sample N = 28). Heart rate and blood pressures were measured during performance on a computer-controlled arithmetic task after pretreatment with either naltrexone (Trexan, DuPont) or a placebo. During placebo challenges, Fit subjects, compared with Nonfit, showed lower heart rate reactivity during stress and lower mean arterial blood pressures immediately before and during recovery from stress. Naltrexone eliminated these reactivity differences by increasing heart rate reactivity and raising mean arterial blood pressure in Fit subjects. These data suggest that aerobic fitness is associated with enhanced opioidergic inhibition of circulatory stress reactivity. Opioidergic modulatory effects on stress reactivity may comprise an important mechanism in fitness-associated risk reduction for cardiovascular disease.

Reactivity to written mental arithmetic: effects of exercise lay-off and habituation

The present study examined (i) the effects of exercise lay-off on heart rate (HR) and subjective response to mental stress in 24 individuals highly committed to exercise, and (ii) psychophysiological reactivity to a challenging written mental arithmetic with subjectively controlled difficulty level. Subjects were tested on two occasions one week apart. Exercise withdrawal did not influence psychophysiological stress response. Second exposure to the mental arithmetic resulted in significantly lower HR response, due to habituation; higher pretask resting HR, due to anticipation of performance; and later onset in HR recovery. No changes in task performance and subjective measures were observed from session one to session two, indicating that habituation is rather a physiological than behavioral phenomenon. While these findings do not strengthen the link between exercise and stress response, they demonstrate the significant mediatory roles of habituation and anticipation in laboratory studies employing a test-retest design.

Cardiovascular reactivity assessment: effects of choice of difficulty on laboratory task responses

This laboratory study of cardiovascular reactivity was designed to examine how a choice of difficulty element in a mental arithmetic task would affect cardiovascular responses. 20 healthy male subjects were tested on a computer-controlled mental arithmetic task, designed to standardize performance across subjects by keeping constant the proportion of correct responses. This was achieved by automatic adjustment of problem difficulty according to ongoing performance. Subjects were led to believe that they could take either a 'difficult' or an 'easy' version of the mental arithmetic task and were asked to make a choice; in fact, all subjects were given the same task. Subjects who chose the 'difficult' mental arithmetic task (N = 10) showed significantly greater increases in myocardial contractility, cardiac output and systolic blood pressure during task performance than those who chose 'easy' (N = 10). However, subjects who chose 'difficult' were presented with more difficult problems presumably due to their exerting greater levels of effort during the task. The differences in cardiovascular responses associated with choice of difficulty were absent during testing on four subsequent tasks which did not incorporate any choice options (reaction-time, speech, mirror trace, cold pressor). These findings are interpreted as being provocative, rather than in any way conclusive. Nevertheless, they are suggestive of the possibility that choice of difficulty in laboratory tasks may be one strategy for improving the ecological validity of laboratory reactivity assessment procedures.

Generalization of cardiovascular response: supportive evidence for the reactivity hypothesis

Cardiovascular responses were monitored while 36 subjects completed a battery of laboratory stressors comprising mental arithmetic, a reaction time task, a speech task, and the forehead cold pressor. Inter-task consistency was assessed for each of 6 physiological parameters for all task pairings. Considerable inter-task consistency for reactivity scores was seen among the psychological stressors for all variables. The question of such consistency between the cold pressor and the psychological tasks was then addressed. The pattern of consistency was not as clear-cut in this case. For systolic blood pressure and pre-ejection period, reactivity scores to the cold pressor did not correlate with those to any of the psychological tasks. In contrast, cardiac output and total peripheral resistance responses showed considerable consistency. The importance of determining the nature of the relationship between psychological and physical stressors is discussed.

Postural effects on blood pressure reactivity: implications for studies of laboratory-field generalization

This study was designed as an in-laboratory evaluation of the significance of postural blood pressure (BP) adjustments in the investigation of laboratory-field generalization. Blood pressure responses were monitored while 20 subjects completed a mental arithmetic task in two postures, seated and standing. Baseline data were also collected in each posture. The standing challenge was regarded as a laboratory representation of real-world standing challenges. Reactivity scores for the seated stressor were calculated as seated task level minus seated baseline level. For the standing stressor, they were calculated in two ways; standing task level minus standing baseline, and standing task level minus seated baseline. It was hypothesized that the standing reactivity scores calculated from standing baselines (i.e. from the same-posture baselines) would be more highly correlated with seated reactivity than would the standing reactivity scores calculated using sitting baselines. This was not found to be the case for either SBP or DBP. Absolute task SBP levels were very similar in both postures, while they were significantly different for DBP, with standing task levels being higher. It was concluded that ignoring posture will not mask SBP reactivity associations between laboratory and field, but that it may do so for DBP, particularly in future studies as our overall understanding of laboratory-field generalization increases.

Cardiovascular and metabolic activity at rest and during psychological and physical challenge in normotensives and subjects with mildly elevated blood pressure

Heart rate, systolic and diastolic blood pressure, and respiratory and metabolic activity were recorded prior to and during mental arithmetic and a video game task in 20 young men with mildly elevated casual systolic blood pressures. Twenty-five unambiguously normotensive young men were tested under the same protocol. For pretask baseline physiological activity, group differences emerged for all cardiovascular and metabolic variables; thus the elevated blood pressure group displayed not only higher resting cardiovascular levels than normotensive subjects, but higher levels of metabolic activity too. With regard to change in physiological activity from rest to task, the group with mildly elevated blood pressure showed reliably larger increases in heart rate to the mental arithmetic task than the normotensive subjects. These effects, however, were not paralleled by group differences in metabolic activity increase. Physiological measures were also taken prior to and during graded dynamic exercise. The subsequent calculation of individual heart rate-oxygen consumption exercise regression lines allowed the comparison of actual and predicted heart rates during psychological challenge. The subjects with mildly elevated blood pressure displayed significantly greater discrepancies between actual and predicted heart rate values than normotensives during the psychological tasks in general and mental arithmetic in particular. Group differences in physiological activity during exercise largely reflected the pattern seen at rest. A possible exception here was systolic blood pressure. Not only were systolic blood pressure levels higher throughout the exercise phase for mildly elevated blood pressure subjects, but this group evidenced more of an increase from rest to exercise than the normotensives.

Cardiovascular responses to behavioral stressors: laboratory-field generalization and inter-task consistency

Blood pressure and heart rate responses were monitored while 30 medical, dental or graduate students completed four laboratory tasks. On a second day, subjects wore an ambulatory blood pressure monitor, and during this day they completed the real-world challenge of presenting their research in front of a small audience. Heart rate and blood pressures correlated significantly between all four laboratory tasks for both absolute levels and reactivity scores (calculated as task level minus pre-task baseline level). However, while heart rate and blood pressure absolute levels for each task correlated significantly with those attained during the real-world stressor, correlation coefficients obtained when similarly comparing reactivity scores were uniformly non-significant. Laboratory-field generalization was thus evident only for absolute values. Consideration was then given to the fact that the laboratory tasks were undertaken in a seated position, while subjects stood during the real-world task. Activity diaries completed by subjects during the time they wore the ambulatory monitor were examined to search for readings that could be regarded as standing baselines. Such values were obtained for 12 of the subjects. Real-world reactivity scores were recalculated using these standing baselines, and compared again with reactivity scores during the laboratory tasks. Marked increases in correlation coefficients were obtained for systolic and diastolic pressure, but not for heart rate.

Patterns of autonomic response during laboratory stressors

The present study was designed to include an index reflecting the influence of parasympathetic nervous system activity on the heart, respiratory sinus arrhythmia, in addition to measures reflecting primarily sympathetic nervous system activity. The inclusion of the parasympathetic index was considered important for two reasons:(a) Past studies have suggested different patterns of autonomic response to qualitatively different laboratory stressors but have had to infer parasympathetic influences more indirectly, and (b) there is evidence that borderline hypertensives may have reduced vagal tone at rest when compared to normotensives. This last point is important for the study of individual differences in cardiovascular reactivity because excessive responsiveness in young normotensives (beta-adrenergic reactors) has been suggested as a model for studying the precursors of some types of hypertension. Fifty-one male college students were given a reaction time task, a mental arithmetic task, a cold pressor task, and graded bicycle exercise. A variety of cardiovascular and respiratory measures were collected on each subject. Results indicated significant differences in levels of respiratory sinus arrhythmia during the three tasks and the rest period, giving additional evidence for parasympathetic differences (along with sympathetic differences) in these conditions. Additionally, high beta-adrenergic reactors did not differ in mean level of respiratory sinus arrhythmia from low reactors either at rest or during the task periods. These results are discussed in the context of previous research.

Individual differences in heart rate response during behavioral challenge

This program of experiments examined heart rate responses to mental arithmetic and a video game. Attention first focused on their metabolic relevance. Comparison with heart rate/oxygen consumption regression equations generated from isotonic exercise data revealed that the heart rate increases of certain individuals were considerably in excess of those necessitated by contemporary metabolic demand. Both temporal and intertask consistency of reaction were explored, and supportive evidence was obtained. The relationship between laboratory and real-world reactions was investigated, and preliminary evidence found suggesting that in-laboratory responses are indicative of responses to more naturalistic stressors. Finally, twin studies examining the genetic and environmental determinants of individual differences in heart rate change during the tasks revealed a substantial genetic component for these responses.

A comparative evaluation of heart rate reactivity during MATH and a standard mental arithmetic task

Heart rate was monitored while 20 young males completed MATH, a computer-operated mental arithmetic task specifically designed for use in experiments involving subjects of heterogeneous numerical ability, and a standard mental arithmetic task used in this laboratory on several occasions. Both tasks elicited sizeable increases in heart rate, and comparison of subjects' reactivity scores revealed significant inter-task consistency of reaction.