Hemodynamic response patterns: responder type differences in reactivity and recovery

We examined whether responder type groups reflecting patterns of hemodynamic reactivity might also differ in recovery responses. Cardiac output (CO), total peripheral resistance (TPR), systolic and diastolic blood pressure, heart rate, and Heather index were assessed at rest and during speech and cold pressor tasks in young adults. Participants (n = 152) were classified as myocardial, vascular, or mixed-mild responders based on CO and TPR responses to speech presentation. Vascular responders exhibited slower CO and TPR speech recovery than the myocardial and/or mixed-mild groups. Responder type differences in reactivity showed limited task-generalizability. The sustained vascular response pattern of the vascular group is consistent with that seen in hypertension. In light of associations of heightened TPR with markers of disease risk, this suggests potentially negative health implications for vascular responders.     

Comparison of cardiac versus vascular reactors and ethnic groups in plasma epinephrine and norepinephrine responses to stress

This study examined differences in plasma epinephrine (EPI) and norepinephrine (NOREPI) responses to stressors in 67 healthy African-American and Caucasian American men and women of the ages 18 to 49. Subjects were divided into three groups: (a) those who showed high blood pressure (BPI responses to stress associated with consistently high cardiac output (CO) increases with no substantial increases in total peripheral resistance (TPR), labeled cardiac reactors: (b) those with equally high BP increases associated with consistently higher TPR increases and lesser CO increases. labeled vascular reactors; (c) those who showed mixed hemodynamic responses or were low BP reactors. Ethnic and gender group differences in EPI and NOREPI responses were also examined. Cardiac reactors, vascular reactors and mixed + low reactors did not differ in EPI or NOREPI levels at baseline. During stressors, cardiac reactors showed greater increases in plasma EPI than vascular reactors or others during math, reaction time, and passive and active speech tasks: they also showed a weak trend toward greater NOREPI increases during these challenges as well. No differences were seen during the cold pressor: this stressor evoked the least change in EPI of all tasks, whereas the active speech elicited the greatest increases in both EPI and NOREPI of all tasks. Vascular reactors did not differ from mixed + low reactors in EPI or NOREPI reactivity, and men and women did not differ in EPI or NOREPI reactivity to any task. In contrast, Black subjects showed greater increases in NOREPI levels across all stressors compared to White subjects. These findings have implications for investigations of the role of sympathetic nervous system activity in the pathogenesis of hypertension in both African-American and Caucasian American populations.     

Shifting hemodynamics of blood pressure control during prolonged mental stress

The present study examined the hemodynamics underlying blood pressure elevations for evidence of a shift in the control of blood pressure during prolonged mental stress. Mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR) were measured at rest, during a 28-min mental arithmetic stress task, and during recovery, in 30 young healthy men and women. The stress task elicited a sustained increase in MAP: CO rose during the first half of the task but returned to baseline levels during the last quarter of the task, whereas TPR increased as the task progressed. When participants' hemodynamic reactions were classified as cardiac, vascular, or neither, there were more cardiac reactors early relative to late in the task, whereas there were more vascular reactors late relative to early. Thus, the sustained pressor response was initially supported mainly by cardiac mechanisms but subsequently by predominantly vascular mechanisms.     

Establishing the validity of a novel passive stress task

Laboratory tasks used to elicit a cardiovascular stress response in the laboratory can involve either active or passive coping. However, in previous work, passive stress tasks often incorporate a distinct physical stress element, such as the handgrip or cold pressor task, meaning observed changes in cardiovascular parameters may be the result of the physical element of the stressor rather than truly reflecting psychological stress. The present study aimed to establish the validity of a psychological passive stressor; one more analogous to active tasks than those previously employed in laboratory studies. Twenty-six young, healthy adults completed a speech task in the laboratory following a resting baseline period. Twelve months later, they were invited back to the laboratory and watched the video recording of their speech. Analyses confirmed that while both tasks elicited significant SBP and DBP change (all ps < .001), only the active task was associated with HR and CO reactivity (both ps < .001), while only the passive task was associated with TPR reactivity (p = .028). Furthermore, the passive stressor was associated with a mixed hemodynamic profile, whereas the active stressor was associated with a clear myocardial profile. This study confirms that watching a video recording of oneself complete a speech task is associated with a more vascular response profile, a response associated with passive coping contexts.     

Cardiovascular reactivity and adaptation to recurrent psychological stress: effects of prior task exposure.

The effects of prior task exposure on cardiovascular reactivity to stress were examined in two experiments by randomly assigning participants to repeated exposure groups that performed mental arithmetic pretest and test tasks versus delayed exposure groups that performed only the test task after prolonged rest. Impedance cardiographic and blood pressure measures were recorded continuously from 60 undergraduate men in Experiment 1 and 112 undergraduate men and women in Experiment 2. Task repetition attenuated cardiovascular reactivity and improved task performance in repeated exposure groups (p < .001), suggesting an integrated process of behavioral adaptation. During the test task, delayed exposure groups showed greater cardiac reactivity (p < .01), but not vascular reactivity, than repeated exposure groups. Thus, cardiac reactivity varied as a specific function of prior task exposure, whereas vascular reactivity varied as a general function of time.     

Hostility, emotional expression, and hemodynamic responses to laboratory stressors: Reactivity attenuating effects of a tendency to express emotion interpersonally

The present study examined the interactive effects of hostility and a predisposition towards emotional expression or suppression in interpersonal situations. We also attempted to partially replicate findings from a recent investigation which provided evidence of lower myocardial and greater vascular responses in high-hostile relative to low-hostile individuals. Undergraduate students (n = 99) participated in a protocol consisting of rest periods, speech preparation and presentation, a social-evaluative mental arithmetic task, and a stress interview. After classifying participants into high/low hostility by high/low interpersonal emotional expression groups using median-splits, high-hostile individuals showed lower HR and SBP responses to speech preparation and reported greater threat appraisal and negative affect than low-hostile participants. High-hostile interpersonal expressors and male interpersonal expressors displayed lower DBP and TPR reactivity, respectively, than high-hostile or male suppressors. High-hostile expressors also reported lower levels of positive affect than high-hostile suppressors, and expressors reported lower threat appraisals than suppressors, irrespective of hostility. Findings are discussed in terms of an absence of conflict or ambivalence over interpersonal emotional expression for high-hostile expressors and are suggestive of potential health benefits of expressing emotion interpersonally for at-risk groups.     

Cardiovascular reactivity and adaptation to recurrent psychological stress: the moderating effects of evaluative observation

The impact of evaluative observation on cardiovascular reactivity and adaptation to recurrent psychological stress was evaluated in 162 undergraduate men and women. All participants performed three mental arithmetic tasks with or without evaluative observation. Impedance cardiographic, blood pressure, task performance, and stress appraisal measures were recorded for each task. Evaluative observation moderated the effects of task repetition on cardiac reactivity but not vascular reactivity. The introduction of evaluative observation disrupted cardiac adaptation, resulting in a resurgence of beta-adrenergic cardiac reactivity (p < .005), whereas the removal of evaluative observation promoted cardiac adaptation. Evaluative observation also increased stress appraisals and slowed task performance. The results support the dual process theory of habituation, rather than stimulus comparator theory, but only partially support cognitive appraisal theory.     

Gender differences in blood pressure control during a variety of behavioral stressors

This study assessed gender differences in hemodynamic response patterns to behavioral stressors. In addition, the extent to which gender differences in cardiovascular reactivity were a function of the type of challenge was determined by employing tasks relying on stereotypically male areas of competence and a task relying on stereotypically female areas of competence. Sixteen female and 15 male graduate, medical or dental students were exposed to two speech tasks and two math tasks. While there were no significant differences in blood pressure reactivity between the genders, females exhibited significantly greater cardiac output increases across all tasks than males, while males tended to respond with greater increases in total peripheral resistance compared with females. Furthermore, during two of the tasks, significantly more females were classified as myocardial hyperreactors (based on increases in cardiac output), while significantly more males were vascular hyperreactors (based on increases in total peripheral resistance). A post hoc analysis also indicated an apparent association between oral contraceptive use and higher cardiovascular reactivity among the females tested. This association may have been a consequence of the decision to test all women during days 10 to 14 of the menstrual cycle when reactivity in women not using oral contraceptives may be suppressed.     

Sex differences in cardiovascular reactivity to physical appearance and performance challenges

We examined sex differences in cardiovascular reactivity to a novel body image speech task and to three performance-oriented challenges: serial subtraction, handgrip, and mirror tracing tasks. Forty-nine men and 64 women completed the four tasks while heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure were measured. The speech was perceived as requiring more emotionality and empathy for success, whereas the performance tasks were perceived as requiring greater competitiveness. As predicted, women showed greater heart rate reactivity to the body image speech, but men showed greater blood pressure reactivity to the subtraction, grip, and mirror tracing tasks. Results underscore the importance of contextual factors in influencing sex differences in stress responses; women may be more physiologically vulnerable to challenges in the domain of physical appearance, whereas men may react to competitive, performance-oriented challenges.     

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

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

Cardiovascular patterns associated with appetitive and defensive activation during affective picture viewing

In this study we assessed blood pressure (BP), heart rate (HR), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) in response to 13 picture series in 37 participants in order to investigate their hemodynamic response associated with activation of the appetitive and defensive motivational systems underlying emotional experience. BP and SV, but not TPR, increased with increasing self‐rated arousal, whereas HR decelerated more in response to negative than positive and neutral pictures. These findings suggest that modulation of the cardiovascular response to pictures is primarily myocardial. The observed response pattern is consistent with a configuration of cardiac sympathetic–parasympathetic coactivation. The relationships between self‐rated arousal, BP, and SV were mainly exhibited by men, suggesting that increases in the sympathetic inotropic effect to the heart with self‐rated arousal may be larger in men than in women.     

Myocardial and Peripheral Vascular Responses to Behavioral Challenges and Their Stability in Black and White Americans

The purpose of this study was to assess the short term stability of myocardial and peripheral vascular responses to behavioral challenges, and to compare the response patterns of Black and White men. Blood pressure and heart rate, as well as stroke volume, cardiac output, total peripheral resistance, and systolic time interval measures derived from the impedance cardiogram were obtained in 12 Black and 12 White men. These measures were taken prior to and during an evaluative speech stressor, a mirror star tracing task, and a forehead cold pressor test presented during two laboratory sessions scheduled two weeks apart. In general, total peripheral resistance and impedance-derived baseline measures showed acceptable reproducibility (G greater than .85). With a few exceptions, adequate reliability was also demonstrated for change (delta) scores. All tasks raised blood pressure responses above resting levels. Blacks demonstrated significantly greater increases in total peripheral resistance responses across tasks. Whites but not Blacks also revealed increases above baseline in cardiac output and contractility as estimated by the Heather Index. These findings are consistent with the view that Blacks show greater vascular responsiveness than Whites across a variety of tasks, but reveal less myocardial responsiveness.     

Coping mechanisms, perception of health and cardiovascular dysfunction in Africans.

The purpose of this study was to compare active and passive coping strategies of Africans with perception of own health and cardiovascular data. The subjects included 236 apparently healthy Africans (men=109; women=127). The COPE questionnaire was adapted, translated and validated for Africans. Scores on reliable sub-scales were used to classify men and women into more active coping (AC) and more passive coping (PC) subgroups. The General Health Questionnaire measured subjective perception of health. Blood pressure was recorded before and during application of the handgrip test, using the Finapres, a continuous non-invasive blood pressure monitor. Plasma renin activity (PRA) values, measured with radio immuno assay, were compared to blood pressure variables. Analyses of co-variance, adjusted for resting values and age, indicated that PC men responded with a larger increase in total peripheral resistance (TPR) (p=0.006), larger decrease in stroke volume (p=0.07), smaller increase in cardiac output (p=0.09) and larger increases in PRA resting (p=0.04) and reactivity (p< or =0.05) values. PC subjects reported a more negative perception of health than AC subjects. Young PC women presented greater hypertension prevalence rates (p< or =0.01) than AC women. In conclusion, all AC and PC subjects reacted with increased vascular reactivity on the handgrip test. PC men presented enhanced vascular reactivity, PRA and perception of poorer health values.     

The influence of forgiveness and apology on cardiovascular reactivity and recovery in response to mental stress

To investigate the relation between forgiveness and apology as they relate to cardiovascular reactivity and recovery, 29 men and 50 women were exposed to an interpersonal transgression (i.e., verbal harassment) while performing a serial subtraction task. Participants were categorized into high and low forgiveness groups based on scores on the forgiving personality scale. Following the task, approximately half of the participants received an apology from the experimenter for his/her comments during the task. Although no group differences in cardiovascular reactivity were observed during the serial subtraction task, persons high in forgiveness displayed more rapid diastolic and mean arterial blood pressure recovery than persons low in forgiveness. In response to the apology, participants displayed greater high frequency heart rate variability recovery compared to those who did not receive an apology. A significant apology × sex interaction was observed for diastolic blood pressure and mean arterial blood pressure. Women who received an apology exhibited faster recovery from the transgression than women who did not receive an apology. In contrast, men who received an apology exhibited delayed recovery from the transgression compared to men who did not receive an apology. These results indicate that there are potentially healthful benefits to forgiveness and apology, but the relation is influenced by situation and by sex.     

Influence of acute fluid loading on stress-induced hemoconcentration and cardiovascular reactivity

The goal of this study was to assess the possible attenuating effects of oral fluid loading on hematological and hemodynamic factors during acute psychological stress in two separate experiments: Experiment 1 assessed the effects of hypotonic fluid loading (water) and Experiment 2 assessed the effects of isotonic fluid loading (Gatorade). Twenty-eight participants were recruited for Experiment 1, and 28 participants were recruited for Experiment 2. Participants for each experiment completed two test sessions, once in a hypo-hydrated condition (following 12-h fast) and once in a fluid loaded condition (hypotonic or isotonic fluid). During each session, hematocrit (Hct), hemoglobin (Hgb), calculated plasma volume (CPV), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), cardiac output (CO), stroke volume (SV), and total peripheral resistance (TPR) were assessed during a 10-min resting baseline period, 6-min mental arithmetic (MA) task, and a 16-min recovery period. Results for Experiment 1 revealed that the fluid load condition Hct, Hgb, and HR levels were significantly lower in comparison to the hypo-hydration condition, and that Hct, Hgb, and CPV reactivity was greater during the fluid load condition. Results for Experiment 2 revealed that Hct, Hgb, and TPR were lower and CPV, SBP, SV, and CO were higher during the fluid load condition compared to the hypo-hydration condition and that HR, CO, and TPR reactivity was greater during the fluid load condition. Finally, analytic comparisons between the two fluid types revealed that SV and CO levels were significantly greater at baseline and during MA when isotonic fluid was ingested compared to hypotonic fluid ingestion.     

Hemodynamic profile of stress-induced anticipation and recovery.

Systolic and diastolic blood pressure, heart rate, stroke volume, cardiac output, and total peripheral resistance were measured in 100 healthy men and women with the aim of investigating hemodynamic profile during anticipation of, and recovery from, exposure to active and passive laboratory stressors. A 5-min anticipatory period preceded two tasks, both of which lasted 2.5 min. The tasks were mental arithmetic ('beta-adrenergic' stress) and the cold pressor test ('alpha-adrenergic' stress). Each task was followed by a 5-min recovery period. Blood pressure and heart rate were measured with a FinaPres 2300e, and stroke volume, cardiac output, and total peripheral resistance were computed from these parameters. Salivary cortisol was measured in relation to both tasks, and participants completed tests of state and trait anxiety, locus of control, and hostility. As expected, mental arithmetic and the cold pressor test elicited myocardial and vascular patterns of reactivity, respectively. However, contrary to expectations, anticipatory and recovery hemodynamic profile involved essentially vascular responding for both stressors. Salivary cortisol increased in response to both tasks but only weakly correlated with hemodynamic changes. None of the subjective measurements was a strong predictor of physiological reactivity. The findings suggest that stress-induced anticipatory and recovery reactivity may be generally vascular rather than myocardial. This could have important implications in light of suggestions that anticipatory and recovery responses may be better predictors of subsequent cardiovascular disease than direct stress-induced reactivity.     

The influence of social support on cardiovascular responses during stressor anticipation and active coping

This study investigated effects of different types of social support on cardiovascular reactivity during anticipation of, performance of and recovery from an evaluative speaking task. Thirty male and 30 female students were assigned to one of three social conditions: alone, mental activation of supportive ties, actual support transactions. Cardiovascular effects of social support were found to differ over task conditions and they were not unidirectional. During passive stressor anticipation, support conditions attenuated SBP reactivity, in particular mental activation of supportive ties. During active speech performance gender-specific support effects were observed. The alone condition elicited higher SBP reactivity in men compared to women, support conditions enhanced SBP reactivity in women and attenuated SBP reactivity in men resulting in comparable cardiovascular activation across gender groups. Drawing from research on active coping and energization gender-specific cardiovascular activation was attributed to differences in effort expenditure.     

Neural correlates of response inhibition for behavioral regulation in humans assessed by functional magnetic resonance imaging

We evaluated the influence of smoking and gender on diurnal variations of heart rate reactivity during performance of two vigilance tasks (auditory and visual) and a working memory task. Heart rate was measured hourly (08:00-21:00 h) at rest and during performance tasks in 20 smokers (ten men, ten women) and 20 non-smokers (ten men, ten women). Smoking and gender influenced reactivity only at certain times, especially at the earliest and latest hours and during the post-lunch period. Smokers displayed major post-lunch interference and a pattern of lowered stress in the second half of the day. Women showed greater reactivity at the first daily recording, although their levels later became similar to the men's and were even lower. The statement that women are myocardial hyperreactors must be further investigated, as it seems women may take longer than men to adapt to a task.     

Gender differences in cardiovascular and natural killer cell reactivity to acute stress following a hassling task

To determine the influence of increased ambient stress load on subsequent cardiovascular and natural killer (NK) cell reactivity to acute stress, 30 men and women were exposed to a 5-min mental arithmetic (MA) stressor. Half the participants experienced a bureaucratic hassle designed to increase ambient stress load prior to the MA task, and the other half experienced the MA task without this pretreatment. Hassle group x gender effects suggested that hassled men had greater heart rate increases to the MA task than did hassled women, and hassled men had greater NK reactivity to the MA task than did any other group.