PubMed Health⌕ Search

Biomedical subjects

Julian F Thayer

Publications and source records attributed to Julian F Thayer.

At least 19 recordsLinked to original sources
PubMed2006

The role of vagal function in the risk for cardiovascular disease and mortality.

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide. The understanding of the risk factors for CVD may yield important insights into the prevention, etiology, course, and treatment of this major public health concern. We review the evidence for the role of vagal function in the risk for cardiovascular disease and mortality. Using a broad range of indicators of vagal function including resting heart rate, heart rate recovery, heart rate variability, and baroreflex sensitivity we show that decreased vagal function is associated with an increased risk for morbidity and mortality. These effects are independent of traditional risk factors. Moreover, we show that decreased vagal function is associated with both traditional and emerging risk factors as well as modifiable and non-modifiable risk factors. Most importantly, we provide evidence to support the notion that decreased vagal function precedes the development of a number of risk factors and that modification of risk profiles in the direction of lower risk is associated with increased vagal function. We close with a brief overview of the neural concomitants of vagal function and suggest that a model of neurovisceral integration may provide a unifying framework within which to investigate the impact of risk factors, including psychosocial factors, on cardiovascular disease.

Acetylcholine↗
PubMed2006

Daily worry is related to low heart rate variability during waking and the subsequent nocturnal sleep period.

Stress and anxiety are risk factors for cardiovascular (CV) disease. Worry might be a mediator of their risks by prolonging their cognitive representation and concomitant CV activity. We hypothesized that daily stressors and worry, and trait anxiety and trait worry would be associated with high heart rate (HR) and low heart rate variability (HRV) during waking and the subsequent nocturnal sleep period, and that worry would mediate the effects of daily stressors. Low HRV and high HR are physiological risk factors for CV disease. Using an hourly diary, stressors, worry frequency and duration, and biobehavioral variables were measured during one day in 52 healthy subjects. During this time and the subsequent nocturnal sleep period, ambulatory ECG was measured. Stressors, worry and traits were related to higher HR and lower HRV during waking, and the effects of stressors and worry were extended into the sleeping period. Worry duration mediated the effects of stressors. The results were largely independent of biobehavioral variables including sleep quality. The results support the notion that worry, by prolonging CV activity, is a mediator of the CV risks of stress. They also imply a role for unconscious cognitive representation of stress.

Adolescent↗
PubMed2006

Anxiety and respiratory variability.

Associations of inter- and intra-individual differences in anxiety and fear with within subject variability in breathing parameters were explored. Timing and volume components of respiration and FETCO(2) were measured non-intrusively before and during anxious and fearful imagery in 98 young women. Trait anxiety was associated with less variability in several breathing parameters during baseline preceding imagery. Significant decreases in the variability of expiratory time and inspiratory drive were also observed during anxious imagery. During fearful imagery, however, the variability of FETCO(2) increased compared to baseline. Results on anxiety are largely in agreement with models that posit that healthy systems are characterized by variability and flexibility. The paradoxical findings for fearful imagery enhance the importance of a distinction between fearful and anxious affects.

Adaptation, Physiological↗
PubMed2006

Tryptophan depletion affects heart rate variability and impulsivity in remitted depressed patients with a history of suicidal ideation.

BACKGROUND: Depression is a major risk factor for cardiovascular disease. An important risk factor for cardiovascular disease, low heart rate variability, often has been found in depressed patients and has been associated with impulsivity. The present study investigated whether experimental lowering of serotonin would decrease heart rate variability and increase impulsivity in remitted depressed patients, in particular in those patients with disturbed impulse control. METHODS: Nineteen patients in remission from depression received high-dose and low-dose acute tryptophan depletion in a randomized, counterbalanced, double-blind crossover design. Heart rate variability and impulsivity were assessed during each acute tryptophan depletion session and during a baseline session. Suicidal ideation during past depression was used as an index for individual differences in impulse control. RESULTS: High-dose acute tryptophan depletion led to a larger increase in depressive symptoms than did low-dose acute tryptophan depletion. High-dose acute tryptophan depletion decreased heart rate variability and increased impulsivity and anxiety, but only in patients with a history of suicidal ideation. Symptom effects of high-dose acute tryptophan depletion correlated with low heart rate variability at baseline. CONCLUSIONS: Depressed patients who have problems with controlling impulsivity might be more at risk for developing cardiovascular disease, possibly related to increased vulnerability to impaired 5-hydroxytryptamine function.

Adult↗
PubMed2006

The perseverative cognition hypothesis: a review of worry, prolonged stress-related physiological activation, and health.

Perseverative cognition, as manifested in worry and rumination, is a common response to stress, but biopsychological models of stress and health have largely ignored it. These models have generally focused on physiological activation that occurs during stress and have insufficiently addressed effects that occur in anticipation of, or following, stressful events. We argue that perseverative cognition moderates the health consequences of stressors because it can prolong stress-related affective and physiological activation, both in advance of and following stressors. We review evidence that worry, rumination, and anticipatory stress are associated with enhanced cardiovascular, endocrinological, immunological, and neurovisceral activity. The findings yield preliminary support for our hypothesis, suggesting that perseverative cognition might act directly on somatic disease via enhance activation via the cardiovascular, immune, endocrine, and neurovisceral systems.

Anxiety↗
PubMed2006

A Norwegian adaptation of the Penn State Worry Questionnaire: factor structure, reliability, validity and norms.

A Norwegian version of the Penn State Worry Questionnaire (PSWQ) was administered to 304 undergraduate students together with the Beck Depression Inventory (BDI), the State-Trait Anxiety Inventory (STAI) and the Maudsley Obsessive Compulsive Inventory (MOCI). The PSWQ was also administered to a community sample comprising 879 subjects, together with the Beck Anxiety Inventory (BAI), the Beck Depression Inventory II (BDI II) and the White Bear Suppression Inventory (WBSI). Structural equation modeling showed that a three-factor solution of the PSWQ gave the best goodness of fit. The Norwegian version of the PSWQ demonstrated adequate psychometric properties in terms of reliability and validity in both samples. Females scored higher than males on PSWQ.

Adult↗
PubMed2006

Beyond heart rate variability: vagal regulation of allostatic systems.

The autonomic nervous system (ANS) plays a role in a wide range of somatic and mental diseases. Whereas the role of the ANS in the regulation of the cardiovascular system seems evident, its role in the regulation of other systems associated with allostasis is less clear. Using a model of neurovisceral integration we describe how the ANS and parasympathetic tone in particular may be associated with the regulation of allostatic systems associated with glucose regulation, hypothalamic-pituitary-adrenal (HPA) axis function, and inflammatory processes. Decreased vagal function and heart rate variability (HRV) were shown to be associated with increased fasting glucose and hemoglobin A1c levels, increased overnight urinary cortisol, and increased proinflammatory cytokines and acute-phase proteins. All of these factors have been associated with increased allostatic load and poor health. Thus, vagal activity appears to play an inhibitory function in the regulation of allostatic systems. The prefrontal cortex and the amygdala are important central nervous system structures linked to the regulation of these allostatic systems via the vagus nerve. Finally, the identification of this neurovisceral regulatory system may help to illuminate the pathway via which psychosocial factors may influence health and disease.

Autonomic Nervous System↗
PubMed2006

Comparison of arterial compliance indices derived via beat-to-beat blood pressure waveforms: aging and ethnicity.

Reduced arterial compliance has been implicated as a risk factor for future cardiovascular events in hypertensive patients. Recently, several non-invasive techniques have been used to access arterial compliance. However, comparisons of these techniques with older individuals and African-Americans have not been done. In the present study, beat-to-beat blood pressure was examined in 75 males and females (n = 24 old Caucasian; n = 24 young Caucasian; n = 27 African-Americans) who were part of the Baltimore Longitudinal Study of Aging (BLSA). Resting beat-to-beat blood pressure (5 minutes) was assessed using the PORTAPRES Ambulatory Blood Pressure Device. Results indicated that the three-element windkessel and the stroke volume-pulse pressure ratio measures of arterial compliance provide comparable estimates. Specifically, arterial compliance is reduced in the oldest individuals in our sample with young and African-Americans showing higher compliance. These results indicate that the simpler stroke volume-pulse pressure ratio provides reliable estimates of arterial compliance in both older adults and African-Americans. This technique is an excellent means to assess arterial compliance and is a useful measure to determine risk for adverse cardiovascular events.

Aged↗
PubMed2005

Alcohol use, urinary cortisol, and heart rate variability in apparently healthy men: Evidence for impaired inhibitory control of the HPA axis in heavy drinkers.

Alcoholism and heavy drinking are associated with a number of physiological, behavioral, affective, and cognitive problems. One such problem involves dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, with alcoholics showing higher basal cortisol levels and reduced inhibitory feedback control. In addition, alcohol consumption is associated with decreased heart rate variability (HRV). In the present study we examined the relationships among alcohol consumption, cortisol excretion, and HRV in 542 apparently healthy men. Men in the top tertile of self-reported alcohol consumption had higher cortisol levels and lower HRV compared to men in the lower two tertiles of alcohol consumption. In addition, the inverse relationship between cortisol and HRV was greatly attenuated in the heavy drinking group even after accounting for a number of potential confounding factors. These results support prior research on the HPA axis dysregulation in alcoholics and suggest impaired inhibitory control of the HPA axis in heavy drinkers. The findings are consistent with the neurovisceral integration model, which links central and peripheral processes, and may provide a comprehensive framework for the future investigation of the complex mix of physiological, behavioral, affective, and cognitive factors which comprise the heavy drinking phenotype.

Adolescent↗
PubMed2005

Ethnic differences and heritability of heart rate variability in African- and European American youth.

This study investigated whether heart rate variability (HRV) in young African-Americans differed from that in young European Americans. It further examined the genetic and/or environmental sources of HRV variance and to what extent they depend on ethnicity or gender in young twins. Subjects were available from 1 data set including 166 subjects (mean age 16 +/- 2 years; 63 African-Americans) and another including 219 twins (11 singletons [4 African-Americans] and 104 pairs [42 African-Americans]; mean age 15 +/- 2 years). HRV was measured over 256 RR intervals in a supine position. Two time-domain variables, the SD of normal RR intervals (SDNN) and the root-mean-square of successive differences (RMSSD) of normal RR intervals, and 3 frequency-domain variables, high-frequency (HF) power, low-frequency (LF) power, and the LF power/HF power ratio, were used. African-Americans had higher RMSSDs (p <0.01) and HF power (p = 0.047) and lower LF power/HF power ratios (p <0.01) than European Americans. These differences remained significant after adjusting for covariates. All HRV parameters were heritable; estimated heritability ranged from 32% to 71%. Model fitting showed no ethnic or gender differences for any measure. SDNN, RMSSD, and HF power were strongly correlated (r values >0.8). One factor explaining >90% of the variance for all 3 measures was identified. The heritability of this combined HRV score was 70%. In conclusion, this study suggests that ethnic differences in HRV already exist in youth, with African-Americans having greater HRV than European Americans. High heritability estimates for HRV measures were observed, and no differences in HRV heritability estimates were noted for ethnicity or gender.

Adolescent↗
PubMed2005

Nonlinear relations of blood pressure to cognitive function: the Baltimore Longitudinal Study of Aging.

This investigation examined cross-sectional and longitudinal relations, both linear and nonlinear, of blood pressure (BP) and its interaction with demographic and lifestyle variables to a broad spectrum of cognitive functions. Eight hundred forty-seven participants (503 men and 344 women) from the Baltimore Longitudinal Study of Aging completed tests of verbal and nonverbal memory, attention, perceptuo-motor speed, executive functions, and confrontation naming, and clinical assessment of BP on 1 to 7 occasions over 11 years. Mixed-effects regression models, adjusted for age, education, gender, alcohol consumption, smoking status, depression scores, and use of antihypertensive medications, revealed nonlinear relations of systolic BP with longitudinal change on tests of nonverbal memory and confrontation naming; cognitive decline was apparent among older (80 years) individuals with higher systolic BP. Cross-sectional findings, across testing sessions, indicated moderated U- and J-shaped relations between BP and cognitive function. Both high and low diastolic BP were associated with poorer performance on tests of executive function and confrontation naming among less-educated persons; with tests of perceptuo-motor speed and confrontation naming among nonmedicated (antihypertensives) individuals; and with executive function among older individuals. Cross-sectional linear relations included higher systolic BP and poorer nonverbal memory in nondrinkers, and higher diastolic BP and poorer working memory among less-educated individuals. Results indicate that cross-sectional and longitudinal relations of BP to cognitive function are predominantly nonlinear and moderated by age, education, and antihypertensive medications. Careful monitoring and treatment of both high and low BP levels may be critical to the preservation of cognitive function.

Aged↗
PubMed2005

Expanding stress theory: prolonged activation and perseverative cognition.

Several theories of the stress-disease link have now incorporated prolonged activation. This article argues that these theories still lack an important element, that is, the cognitive nature of the mechanism that causes stress responses to be sustained. The perception of stress and the initial response to it do not automatically lead to prolonged activation. The active cognitive representations of stressors need to be prolonged in order to extend their physiological concomitants. We call this mediating process perseverative cognition, and it is manifested in phenomena such as worry, rumination, and anticipatory stress. We summarize evidence suggesting that these phenomena are indeed associated with physiological activation, including cardiovascular, endocrinological and immunological parameters. This evidence is still far from sufficient, due to the many methodological insufficiencies in the studies involved. Nevertheless, it makes clear that cognitive phenomena characterized by perseverative cognition may be likely candidates to mediate the effects of stress sources on somatic disease. We also argue that there is a dearth of evidence supporting the role of prolonged activation. There are a limited number of studies demonstrating prolonged activity related to stressors and emotional episodes, and their methodologies often do not allow unambiguous conclusions. Even more important, the crucial assumption that prolonged activation actually leads to pathogenic states and disease has received hardly any attention yet and therefore is still largely unsupported. There are only a few studies that showed that anticipatory responses and slow recovery from stress predicted disease states.

Cognition↗
PubMed2005

Psychosomatics and psychopathology: looking up and down from the brain.

The autonomic nervous system (ANS) plays a role in a wide range of somatic and mental diseases. Using a model of neurovisceral integration, this article describes how autonomic imbalance and decreased parasympathetic tone in particular may be the final common pathway linking negative affective states and conditions to ill health. The central nervous system (CNS) network that regulates autonomic balance (central autonomic network, CAN) is closely related and partially overlaps with networks serving executive, social, affective, attentional, and motivated behavior (anterior executive region, AER; and Damasio's [Damasio, A.R., 1998. Emotion in the perspective of an integrated nervous system. Brain Res. Rev. 26, 83-86.] 'emotion circuit'). A common reciprocal inhibitory cortico-subcortical neural circuit serves to regulate defensive behavior, including autonomic, emotional and cognitive features. This inhibitory cortico-subcortical circuit may structurally, as well as functionally, link psychological processes with health-related physiology. When the prefrontal cortex is taken 'offline' for whatever reason, parasympathetic inhibitory action is withdrawn and a relative sympathetic dominance associated with disinhibited defensive circuits is released, which can be pathogenic when sustained for long periods. This state is indicated by low heart rate variability (HRV), which is a marker for low parasympathetic activation and prefrontal hypoactivity. Consistent with this, HRV is associated with a range of psychological and somatic pathological conditions, including immune dysfunction. Finally, we discuss supportive evidence from recent studies of the reflexive startle blink, attention and working memory, which shows that low HRV predicts hypervigilance and inefficient allocation of attentional and cognitive resources.

Animals↗
PubMed2005

Understanding blood pressure variability: spectral indices as a function of gender and age.

Typically, blood pressure variability has been calculated by taking the simple mathematical standard deviations of a collection of discrete blood pressure (BP) measurements. Recently, spectral analytic techniques have been employed to examine beat-to-beat blood pressure variability and the underlying autonomic adjustments associated with the performance of various tasks. In the present study, beat-to-beat blood pressure was examined in 104 older African-Americans males and females who were part of the Healthy Aging in Nationally Diverse Longitudinal Samples (HANDLS) Study. Participants evaluated faces and sentences depicting emotional content and rested before (Baseline) and after (Recovery) the tasks. There were no significant gender effects in any analyses. In addition, there were no significant task effects. However, there was a trend for both low and high frequency systolic blood pressure variability to decrease linearly from baseline, through faces and sentences to recovery. Interestingly, both systolic and diastolic high frequency blood pressure variability was greater in older as compared to younger adults. Increased blood pressure variability has been associated with greater sheer stress and greater end organ damage. These results will explicate the effects of aging on cardiovascular disease risk. Overall, these data indicate that blood pressure variability derived via spectral analytic techniques is a useful tool for understanding cardiodynamics and may provide a more in-depth analysis of blood pressure response.

Age Factors↗
PubMed2004

Heart rate variability and its relation to prefrontal cognitive function: the effects of training and detraining.

The aim of the present study was to investigate the relationship between physical fitness, heart rate variability (HRV) and cognitive function in 37 male sailors from the Royal Norwegian Navy. All subjects participated in an 8-week training program, after which the subjects completed the initial cognitive testing (pretest). The subjects were assigned into a detrained group (DG) and a trained group (TG) based on their application for further duty. The DG withdrew from the training program for 4 weeks after which all subjects then completed the cognitive testing again (post-test). Physical fitness, measured as maximum oxygen consumption (VO2(max)), resting HRV, and cognitive function, measured using a continuous performance task (CPT) and a working memory test (WMT), were recorded during the pre-test and the post-test, and the data presented as the means and standard deviations. The results showed no between-group differences in VO2(max) or HRV at the pre-test. The DG showed a significant decrease in VO2(max) from the pre- to the post-test and a lower resting HRV than the TG on the post-test. Whereas there were no between-group differences on the CPT or WMT at the pre-test, the TG had faster reaction times and more true positive responses on tests of executive function at the post-test compared to the pre-test. The DG showed faster reaction times on non-executive tasks at the post-test compared to the pre-test. The results are discussed within a neurovisceral integration framework linking parasympathetic outflow to the heart to prefrontal neural functions.

Adolescent↗
PubMed2004

Alexithymia predicts attenuated autonomic reactivity, but prolonged recovery to anger recall in young women.

Alexithymia has been prospectively associated with all-cause mortality and with cardiovascular morbidity. Here, stress-induced autonomic reactivity and recovery were examined as potential pathways linking alexithymia to cardiovascular disease. The relation of alexithymia to blood pressure, heart rate, and other cardiovascular parameters derived from impedance cardiography (N = 80) and heart rate variability (N = 40) was evaluated during rest, an anger recall task and recovery in women (ages 18-30). During anger recall, alexithymia was associated with significantly attenuated heart rate and stroke index reactivity, greater low frequency power, and with marginally dampened blood pressure and high frequency power reactivity. Overall, this response pattern suggests blunted sympathetic activation and diminished vagal withdrawal. Alexithymia was also related to slower diastolic blood pressure and quicker preejection period recovery implying abbreviated sympathetic arousal and possibly greater vagal modulation. These results impart some evidence for the hypoarousal model of alexithymia during reactivity, but the hyperarousal model during recovery. Autonomic dysregulation during and following acute emotional stress is suggested as a possible physiological pathway connecting alexithymia to cardiovascular disease.

Adult↗