Sympathoadrenal stress reactivity is a predictor of future blood pressure: an 18-year follow-up study

Automated office blood pressure measurement with the assistance of an instructional video in patients with hypertension

OBJECTIVES

Automated office blood pressure (AOBP) measurement often requires assistance. Accompanied by an instructional video, AOBP measurement could be performed independently by patients.

DESIGN AND METHODS

Seventy-five patients with hypertension were enrolled. AOBP was measured three times at 1-min intervals after 5 min of rest by an automated BP measurement device with the assistance of an animated instructional video. The video was designed originally to instruct patients on the way to measure BP appropriately. Perceived stress was evaluated using a questionnaire after the AOBP measurement. Office BP was measured three times using the same device. Home BP measurement was performed on 5 consecutive days.

RESULTS

The mean age of the patients was 74.5 ± 10.6 years, and 96% were taking antihypertensive drugs. Mean AOBP, office BP and home BP measurements were 135.2 ± 17.2/81.3 ± 11.1, 139.3 ± 16.3/78.6 ± 10.9 and 129.2 ± 16.7/72.7 ± 8.9 mmHg, respectively. Regarding SBP, the mean AOBP was significantly lower than office BP ( P  = 0.005) and higher than home BP ( P  = 0.004). The differences in SBP and DBP between AOBP and home BP measurements were significantly related to patients' perceived stress when performing AOBP measurements ( r  = 0.289; P  = 0.013 and r  = 0.328; P  = 0.004). In a multivariate analysis, patients' perceived stress was a significant predictor of the difference between AOBP and home BP ( P  = 0.013), even after adjusting for age, sex, BMI and mean of AOBP and home BP.

CONCLUSION

AOBP values measured with the assistance of an instructional video were between conventional office and home BP measurements. Perceived stress during AOBP measurement was related to the difference in AOBP from home BP.

A Systematic Review of Intervention Trials Utilizing Biomarkers Among Informal Caregivers of People with Alzheimer's Disease & Related Dementias

Informal caregivers of people with Alzheimer's Disease and Related Dementias (ADRD) experience unique stressors, reduced quality of life, and report poorer health, compared to non-caregivers. Throughout the last thirty years, researchers have developed and tested various psychosocial interventions and their ability to improve caregiver health. Due to an exclusive focus on self-report methods, however, no existing systematic literature reviews specifically examine intervention studies employing biomarkers; this systematic review aims to address this gap in the literature. In each database (PubMed and Web of Science, respectively), a title search was conducted with the following keywords: "alzheimer*" OR "dementia" AND "caregiv*" AND "intervention", followed by a second search using identical keywords except "intervention" was replaced with "program." Study or intervention protocol articles, exclusively qualitative studies, cultural applicability papers, dissemination studies, descriptive articles or program reports, acceptability/feasibility studies, studies utilizing formal caregiving samples, commentaries, review papers, and meta-analyses, erratums/corrections, measure development articles, factor analyses, and case reports were excluded from the final pool of studies. In this systematic review, the findings of 14 studies are summarized, and are organized based on specific types of biomarkers: neuroendocrine, immune, and autonomic physiological. Overall, the review yielded mixed results, which may, in part, be due to differences in the types of interventions tested, as well as differing biomarker measurement, methodology, and analysis. More biobehavioral intervention trials are needed among ADRD caregivers. Including biological parameters as pre- and post-measures can shed insight into the extent to which interventions may help caregivers heal from the stress of caregiving.

Physiological reactivity to acute mental stress in essential hypertension-a systematic review

Objective

Exaggerated physiological reactions to acute mental stress (AMS) are associated with hypertension (development) and have been proposed to play an important role in mediating the cardiovascular disease risk with hypertension. A variety of studies compared physiological reactivity to AMS between essential hypertensive (HT) and normotensive (NT) individuals. However, a systematic review of studies across stress-reactive physiological systems including intermediate biological risk factors for cardiovascular diseases is lacking.

Methods

We conducted a systematic literature search (PubMed) for original articles and short reports, published in English language in peer-reviewed journals in November and December 2022. We targeted studies comparing the reactivity between essential HT and NT to AMS in terms of cognitive tasks, public speaking tasks, or the combination of both, in at least one of the predefined stress-reactive physiological systems.

Results

We included a total of 58 publications. The majority of studies investigated physiological reactivity to mental stressors of mild or moderate intensity. Whereas HT seem to exhibit increased reactivity in response to mild or moderate AMS only under certain conditions (i.e., in response to mild mental stressors with specific characteristics, in an early hyperkinetic stage of HT, or with respect to certain stress systems), increased physiological reactivity in HT as compared to NT to AMS of strong intensity was observed across all investigated stress-reactive physiological systems.

Conclusion

Overall, this systematic review supports the proposed and expected generalized physiological hyperreactivity to AMS with essential hypertension, in particular to strong mental stress. Moreover, we discuss potential underlying mechanisms and highlight open questions for future research of importance for the comprehensive understanding of the observed hyperreactivity to AMS in essential hypertension.

Patterns of Respiration Rate Reactivity in Response to a Cognitive Stressor Associate With Self-Reported Mental Health Outcomes

Many studies have examined physiological responses to acute stress in healthy and clinical populations. Some have documented exaggerated physiological stress reactivity in response to acute stress, while others have reported blunted physiological stress reactivity. Although the literature is conflicted, the relationship between abnormal physiological stress reactivity and negative outcomes is well-established. However, past research has neglected a critical aspect of physiological stress response - respiration - and it is unclear whether differences in respiration rate responses to acute stress are related to health outcomes. This secondary cross-sectional analysis explored differences in outcomes between three subgroups: blunted, moderate, and exaggerated respiration rate reactivity to an acute stress task. In a sample of at least mildly-stressed older adults (n = 55), we found that perceived stress (b = -7.63; p = .004) and depression (b = -9.13; p = .007) were significantly lower in the moderate reactivity group compared to the high reactivity group, and that self-reported mindfulness (b = 10.96; p = .008) was significantly lower in the moderate reactivity group as compared to the low reactivity group. Across outcomes, participants in the moderate range of physiological reactivity showed less negative and more positive psychological attributes and better health outcomes, while the blunted subgroup demonstrated more negative and less positive psychological attributes and worse health outcomes overall, when compared to the exaggerated and moderate groups. This study extends the literature by adding respiration to markers of acute physiological stress reactivity and demonstrating the effects of blunted respiration reactivity on negative psychological attributes and health outcomes.

Sex Difference in Clinical and Management Outcomes in Patients With Takotsubo Syndrome: A Systematic Review and Meta-Analysis

Takotsubo syndrome (TTS) is being increasingly recognized globally with a female sex predilection. However, sex-related differences in clinical outcomes are yet to be identified. Therefore, we aim to investigate the sex differences in clinical outcomes in patients with TTS. We included cohort studies retrieved from the Web of Science, SCOPUS, EMBASE, PubMed, and Cochrane until September 14, 2022. The risk ratio (RR) for dichotomous outcomes with the corresponding 95% confidence interval (CI) was used. The study protocol was registered in PROSPERO with ID: CRD42022363349. Thirteen retrospective cohort studies, with a total of 104,410 patients were included. Men had a higher risk of in-hospital mortality (RR: 2.42 with 95% CI [1.53, 3.83], P = 0.0002), long-term mortality (RR: 1.59 with 95% CI [1.40, 1.80], P = 0.00001), cardiogenic shock (RR: 1.65 with 95% CI [1.52, 1.79], P = 0.00001), arrhythmia (RR: 1.70 with 95% CI [1.56, 1.86], P = 0.00001), and acute kidney injury (RR: 1.71 with 95% CI [1.50, 1.96]. P = 0.00001), as compared with women. However, no significant difference was observed in stroke (RR: 1.22 with 95% CI [0.78, 1.89], P = 0.39), left ventricular thrombus (RR: 0.96 with 95% CI [0.40, 2.33], P = 0.93), and TTS recurrence (RR: 1.11 with 95% CI [0.68, 1.82], P = 0.67) between men and women. Despite women having a higher incidence of TTS, men have higher morbidity and mortality rates. Hence, further studies are necessary to identify the pathophysiological factors of this sex difference in clinical outcomes, including hormonal and psychological variables.

PTSD symptom clusters and cardiovascular responses to stress: Reactivity and recovery

OBJECTIVE

Posttraumatic stress disorder (PTSD) symptoms are associated with high blood pressure (BP) and decreased heart rate variability (HRV) at rest and in response to acute stress. Unique contributions of PTSD symptom clusters to cardiovascular responses to stress are rarely investigated. This study tested whether PTSD-related arousal/reactivity drives relationships of higher PTSD symptoms with higher BP and lower HRV during rest, reactivity (stressor-induced change from baseline), and recovery.

METHODS

Using a cross-sectional observational design, we enrolled 84 trauma-exposed community adults (83% female; 68% White; Mage = 35) who endorsed at least one core PTSD symptom. Participants completed a physical exam, self-reports of trauma history and PTSD symptoms, and BP and HRV frequency domain measurements during rest, stressor (mental arithmetic task), and recovery.

RESULTS

Arousal/reactivity was not associated with BP or HRV reactivity but associated with a higher low (LF) to high (HF) frequency (HF) ratio (LF/HF) during recovery reflecting sympathetic predominance. During the stressor, more avoidance and intrusion were associated with increased diastolic blood pressure (DBP) from baseline; more avoidance was associated with parasympathetic predominance (lower LF/HF); and more negative cognitions/mood was associated with decreased systolic blood pressure (SBP), DBP, and LF from baseline. During recovery, more intrusion and negative cognitions/mood were associated with increased SBP from baseline; less negative cognitions/mood was associated with sympathetic predominance (higher LF/HF).

CONCLUSIONS

PTSD symptom clusters demonstrated differential relationships with SBP, DBP, and HRV during reactivity and recovery. Findings may inform targeted PTSD symptom reduction interventions for disrupting links between PTSD and CVD risk.

Workplace Culture and Biomarkers of Health Risk

Workplace culture has been studied for impact on health risk; however, connections with robust biologic markers of health remain to be established. We examined associations between the work environment and urinary levels of catecholamines and their metabolites as biomarkers of sympathetic nervous system activity, indicative of stress. We recruited participants (n = 219; 2018-2019) from a cardiovascular risk cohort to investigate workplace culture, well-being, and stress. Participants completed seven questionnaires. Urine samples were used to measure catecholamines and their metabolites by LC/MS/MS. Pearson correlation and linear regression models were used after adjusting for demographics and creatinine. Participants reporting higher well-being had lower urinary levels of dopamine, serotonin, and 3-methoxytyramine. Participants reporting a more engaged and more positive workplace had lower levels of dopamine and 3-methoxytyramine. Reported workplace isolation was correlated with higher levels of dopamine and 3-methoxytyramine. Given correlations between catecholamines, we used 3-methoxytyramine for linear regression. In fully adjusted models, in environments with a more positive culture, levels of 3-methoxytyramine remained lower (β = -0.065 ± 0.025, p = 0.01) and indicated a positive association between workplace isolation and 3-methoxytyramine (β = 0.064 ± 0.030, p = 0.04). These findings are consistent with an important relationship between workplace environment and sympathetic nervous system activity.

The Omnipresence of Autonomic Modulation in Health and Disease

The Autonomic Nervous System (ANS) is a critical part of the homeostatic machinery with both central and peripheral components. However, little is known about the integration of these components and their joint role in the maintenance of health and in allostatic derailments leading to somatic and/or neuropsychiatric (co)morbidity. Based on a comprehensive literature search on the ANS neuroanatomy we dissect the complex integration of the ANS: (1) First we summarize Stress and Homeostatic Equilibrium - elucidating the responsivity of the ANS to stressors; (2) Second we describe the overall process of how the ANS is involved in Adaptation and Maladaptation to Stress; (3) In the third section the ANS is hierarchically partitioned into the peripheral/spinal, brainstem, subcortical and cortical components of the nervous system. We utilize this anatomical basis to define a model of autonomic integration. (4) Finally, we deploy the model to describe human ANS involvement in (a) Hypofunctional and (b) Hyperfunctional states providing examples in the healthy state and in clinical conditions.

Effect of six months pranayama training on stress-induced salivary cortisol response among adolescents-Randomized controlled study

BACKGROUND

A combination of yoga practices has been documented to reduce stress and stress-induced cortisol levels. The objective of the current study is to examine the effects of six months of a single pranayama practice (Bhramari [Bhr. P]) on reducing salivary cortisol response to the cold pressor test (CPT) among adolescents.

METHODS

Twenty-six healthy adolescents between the ages of 11 and 19 were randomly assigned to either yoga group (n-13) or control group (n-13). Yoga group participants were trained to do Bhr. P for 45 min, thrice a week for six months. All participants underwent CPT at baseline and at end of six months. Saliva samples were collected at baseline (t0), at 20 min (t1), 40 min (t2), and 60 min after the CPT (t3).

RESULTS

Contradictory to our hypothesis, participants in the yoga group exhibited a higher salivary cortisol response to the CPT at t1 (p = 0.04) when compared to the control group. However, the t3 salivary cortisol levels showed a statistically significant reduction (p = 0.03) in yoga group when compared to the control group. A significant interaction with time (F (1, 88) = 316.5, p = .001, ηp²:0.91) and between the group × time (F (3, 88) = 2.83, p = 0.04, ηp²:0.8) was found after the intervention.

CONCLUSIONS

An increase in the cortisol responsiveness observed in the study is an indication of the adaptive capability achieved through regular yoga training, evidenced by an initial rise in cortisol followed by a rapid fall below baseline after 60 min. Further research is required to conclusively determine the changes in cortisol levels over time in response to stress in long-term yoga practitioners.

Stress coping strategies and stress reactivity in adolescents with overweight/obesity

This study explored the associations between the frequency and effectiveness of habitual stress coping strategies on physiological and psychological stress responses to an acute laboratory stressor in adolescents with overweight/obesity (51 adolescents; 47% female; ages 14-19 years). Coping strategies were assessed using the Schoolager's Coping Strategies Inventory. Acute physiological stress responses were measured as salivary cortisol and α-amylase output during the Trier Social Stress Test and during a control condition. Acute psychological stress was measured using a Likert-type scale, and systolic blood pressure (SBP) and heart rate were measured at baseline. Results revealed that higher coping effectiveness was associated with lower log-based α-amylase during the stress (β = -0.025, p = 0.018) and control (β = -0.030, p = 0.005) conditions, but not with cortisol across either condition (all ps > 0.05). SBP moderated the association between coping effectiveness and α-amylase during the stress condition, with higher coping effectiveness associated with lower α-amylase only among individuals with lower SBP (β = 0.002, p = 0.027). Coping frequency was not associated with cortisol responses, neither was habitual stress coping strategies associated with psychological stress (all ps > 0.05). These findings provide preliminary evidence that effective use of stress coping strategies may provide a dampening effect on sympathetic activity in an at-risk adolescent population.

Neurobiological Pathways Linking Acute Mental Stress to Impairments in Executive Function in Individuals with Coronary Artery Disease

BACKGROUND

Individuals with coronary artery disease (CAD) have worse executive function compared to the general population but the mechanisms are unknown.

OBJECTIVE

To investigate the role of acute mental stress (MS) on the executive function of patients with CAD.

METHODS

Participants with stable CAD underwent acute MS testing with simultaneous peripheral vascular function measurements and brain imaging using high resolution-positron emission tomography. Digital pulse wave amplitude was continuously measured using peripheral artery tonometry (PAT, Itamar Inc). Stress/rest PAT ratio (sPAT) of pulse wave amplitude during MS/baseline was calculated as a measure of microvascular constriction during MS. Plasma levels of catecholamine and interleukin-6 were assessed at baseline and after MS. Executive function was assessed both at baseline and at 2 years follow-up using the Trail Making Test parts A and B.

RESULTS

We studied 389 individuals with brain data available for 148 participants. Of this population follow-up cognitive assessments were performed in 226 individuals (121 with brain imaging). After multivariable adjustment for baseline demographics, risk factors, and medication use, a lower sPAT, indicating greater vasoconstriction, a higher inferior frontal lobe activation with MS, and increases in norepinephrine and IL-6 levels with MS were all independently associated with greater time to complete Trail B test.-38.4pt.

CONCLUSION

In response to acute MS, greater peripheral vasoconstriction, higher inferior frontal lobe brain activation, and increases in the levels of norepinephrine and IL-6 are associated with worse executive function.

Heightened Stress Reactivity in Response to an Attachment Related Stressor in Patients With Medically Treated Primary Hypertension

Background: A heightened stress reactivity to mental stress tasks has been shown in hypertensive patients and might contribute to a higher disease risk. We investigated this hyperreactivity with regard to an attachment related stressor that focuses on emotions instead of performance and we examined whether this effect can also be found in patients on antihypertensive drugs. Materials and Methods: Fifty patients with primary hypertension, treated with at least one antihypertensive drug, were compared with 25 healthy individuals. After 10 min of rest, they participated in an attachment-related interview (Adult Attachment Projective picture system, AAP) and were exposed to an attachment-related stressor (Separation Recall, SR), a short-time stressor which activates attachment-related emotions and thoughts by talking 5 min about a personal experience of loneliness. Blood samples to measure adrenocorticotrope hormone (ACTH), cortisol, norepinephrine, epinephrine, and dopamine were taken. Blood pressure, heart rate and arterial stiffness were measured at rest, after AAP, after SR and 10 min after recovery. Standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive differences (RMSSD) were calculated. Parameters were compared using Mann Whitney U-test and linear mixed-effects regression models controlling for age and body mass index (BMI) after logarithmic transformation if appropriate. Results: Healthy test persons were younger and had lower BMI than patients. Comparing the two groups there were no significant differences in blood pressure and heart rate at rest. Both stressors provoked a significant response in almost all parameters. Results of the post-estimation of contrasts from linear mixed-effects regression models showed a steeper rise in systolic BP and arterial stiffness as well as a more pronounced decline in SDNN in hypertensive patients than in healthy controls. Levels of cortisol rose earlier and higher in hypertensive patients than in healthy controls. Conclusion: Vascular, autonomic, and hypothalamic pituitary adrenal axis response is heightened in medicated subjects with hypertension in response to attachment-focused stressors compared to healthy subjects. We conclude that the remaining hyper-reactivity even with sufficient antihypertensive medication still poses a substantial risk for affected patients. New ways to diminish this risk should be developed.

Temperature-adjusted hypertension prevalence and control rate: a series of cross-sectional studies in Guangdong Province, China

BACKGROUND

Previous studies have shown negative relationships between ambient temperature and blood pressure (BP). However, few studies estimated temperature-adjusted hypertension prevalence and control rate in different population.

OBJECTIVE

To estimate the effects of temperature on BP, and further calculate temperature-adjusted hypertension prevalence and control rate.

METHODS

Meteorological and BP data in Guangdong Province from 2004 to 2015 were collected. There were 31 351 participants aged 18 years and over. Based on 2018 European society Arterial Hypertension Guidelines, participants were divided into normotensive patients (n = 23 046), known hypertensive patients (n = 2807), and newly detected hypertensive patients (n = 5498). We first used generalized additive model to establish the nonlinear relationship between daily mean temperature and BP, and then calculated the linear effects of temperature on BP among populations with different hypertension status. Finally, we calculated the temperature-adjusted hypertension prevalence and control rate.

RESULTS

Generally, there is an inverse relationship between temperature and BP. For a 1 °C increase in temperature, the decreased SBPs for normotensive patients, newly detected hypertensive patients, and known hypertensive patients were 0.37 [95% confidence interval (CI): -0.40, -0.33] mmHg, 0.21 (95% CI: -0.32, -0.10) mmHg and 0.81 (95% CI: -1.02, -0.59) mmHg, while reduced DBPs were 0.19 (95% CI: -0.21, -0.16) mmHg, 0.01 (95% CI: -0.06,0.08) mmHg, and 0.44 (95% CI: -0.56, -0.32) mmHg, respectively. At 5, 10, 15, 20, and 25 °C, the hypertension prevalence rates were 32.5, 29.7, 27.7, 26.0, and 25.0%, respectively, and the control rates were 12.0, 17.5, 23.5, 30.1, and 37.1%, respectively.

CONCLUSION

Low temperature increased BP for all populations, especially for known hypertensive patients, which makes hypertension prevalence increase and control rate decrease if temperature reduce. Our findings suggest that temperature should be considered in hypertension clinic management and epidemiological survey.

Individual sensitivity of cold pressor, environmental meteorological factors associated with blood pressure and its fluctuation

Previous studies have examined the associations of meteorological factors with blood pressure; however, these associations have not fully elucidated, especially lacking of evidence from cohort study, little information about the associations of cold pressor sensitivity with blood pressure and its fluctuation. The objective of this study was to investigate the outdoor and indoor temperature, barometric pressure, humidity, and cold pressor sensitivity with blood pressure and its fluctuation. Forty-eight healthy subjects were recruited, and response of blood pressure to cold exposure was measured with cold pressor test (CPT). Then, all the subjects were followed up, and blood pressure was measured every half a month in a period of consecutive 12 months. Multiple panel analysis with random-effects generalized least squares (GLS) regression was used to analyze the effect of the outdoor and indoor temperature, barometric pressure, humidity, and response to cold pressor exposure on blood pressure. Outdoor and indoor temperature and humidity were found to be independently associated with blood pressure (all the P values < 0.05). The response to cold exposure positively associated with blood pressure and its fluctuation (P < 0.05). The subjects with higher cold pressor sensitivity had about 4.7 mmHg higher maximum difference of SBP in 1 year than the subjects with lower sensitivity. Outdoor and indoor temperature, humidity, and response to cold exposure are associated with blood pressure and its fluctuation. These findings provided extending evidence on blood pressure management in clinic and preventive practice.

Associations between geographical environment and systolic pulmonary arterial pressure of Chinese adults: impact analysis and predictive modeling

Since systolic pulmonary arterial pressure (SPAP) is an important diagnostic indicator for various cardiovascular diseases, it is of great significance to determine scientific SPAP reference value in clinical application. However, the SPAP reference values currently have not been applied under a unified standard, and its formulation does not consider the impacts from geographical environment which has proved to be closely associated with SPAP. This study aims to quantify the impacts of geographical factors on SPAP and formulate scientific SPAP reference values, thereby providing support for more accurate diagnosis. Measured SPAP values of 4550 healthy adults were collected from 88 cities across China, and 11 geographical factors were selected. Four geographical factors with significant impacts on SPAP were determined via correlation analysis, including two positive factors (altitude, soil organic matter) and two negative ones (longitude, annual average temperature). Then partial least-squares regression analysis (PLSR) and trend surface analysis were applied to establish predictive models. Through model test using both collected and simulated SPAP data of control points, the PLSR model was determined to have better prediction accuracy and was selected as optimal model to calculate the SPAP reference values of 2322 cities in China. The predictive results ranged from 22.09 to 31.77 mmHg. Finally, hotspot analysis and kriging interpolation method were applied to explore the spatial distribution of SPAP reference values. The result of spatial analysis shows that SPAP reference values of Chinese adults decreased gradually from the West to East in China. This study indicated the significant impacts of geographical environment on SPAP and established predictive model for determining SPAP reference values, which is expected to help enhance clinical diagnostic accuracy.

Is the Brain an Early or Late Component of Essential Hypertension?

The brain's relationship to essential hypertension is primarily understood to be that of an end-organ, damaged late in life by stroke or dementia. Emerging evidence, however, shows that heightened blood pressure (BP) early in life and prior to traditionally defined hypertension, relates to altered brain structure, cerebrovascular function, and cognitive processing. Deficits in cognitive function, cerebral blood flow responsivity, volumes of brain areas, and white matter integrity all relate to increased but prehypertensive levels of BP. Such relationships may be observed as early as childhood. In this review, we consider the basis of these relationships by examining the emergence of putative causative factors for hypertension that would impact or involve brain function/structure, e.g., sympathetic nervous system activation and related endocrine and inflammatory activation. Currently, however, available evidence is not sufficient to fully explain the specific pattern of brain deficits related to heightened BP. Despite this uncertainty, the evidence reviewed suggests the value that early intervention may have, not only for reducing BP, but also for maintaining brain function.

Greater Daily Psychosocial Stress Exposure is Associated With Increased Norepinephrine-Induced Vasoconstriction in Young Adults

Background Epidemiological data suggest a link between psychological stress and increased cardiovascular disease risk; however, the underlying mechanisms remain incompletely understood. The purpose of this investigation was to directly examine the influence of daily psychosocial stress on microvascular adrenergic vasoconstrictor responsiveness in healthy adults. We hypothesized increased daily psychosocial stress would be positively related to increased norepinephrine-induced vasoconstriction. Methods and Results Eighteen healthy adults (19-36 years; 10 women) completed a daily psychosocial experiences telephone interview for 8 consecutive evenings in order to document their exposure and emotional responsiveness to common stressors (eg, arguments, work stress) over the preceding 24 hrs. On the last interview day, red cell flux (laser Doppler flowmetry) was measured during graded intradermal microdialysis perfusion of norepinephrine (10^-12 to 10^-2 mol/L) and expressed as a percentage of baseline vascular conductance. Exogenous norepinephrine elicited progressive and robust vasoconstriction in all individuals (maximal vasoconstriction: 71±4%_base; cumulative vasoconstriction [area under the curve]: 118±102 arbitrary units). Participants experienced a stressor on 51±5% of days and a total of 5.2±0.9 stressors over the 8-day time frame. Increased daily frequency of stressor exposure was positively related to both maximal (R²=0.26; P=0.03) and cumulative (R²=0.31; P=0.02) vasoconstrictor responsiveness. Likewise, the total number of stressors was associated with increased maximal (R²=0.40; P<0.01) and cumulative (R²=0.27; P=0.03) norepinephrine-induced vasoconstriction. Neither stressor severity nor stress-related emotions were related to vasoconstrictor responsiveness. Conclusions Collectively, these data suggest that daily psychosocial stressor exposure by itself is sufficient to adversely influence microvascular vasoconstrictor function, regardless of the perceived severity or emotional consequences of the stressor exposure.

Psychological stress reactivity and future health and disease outcomes: A systematic review of prospective evidence

BACKGROUND

Acute psychological stress activates the sympatho-adrenal medullary (SAM) system and hypothalamo-pituitary adrenal (HPA) axis. The relevance of this stress reactivity to long-term health and disease outcomes is of great importance. We examined prospective studies in apparently healthy adults to test the hypothesis that the magnitude of the response to acute psychological stress in healthy adults is related to future health and disease outcomes.

METHODS

We searched Medline Complete, PsycINFO, CINAHL Complete and Embase up to 15 Aug 2019. Included studies were peer-reviewed, English-language, prospective studies in apparently healthy adults. The exposure was acute psychological stress reactivity (SAM system or HPA axis) at baseline. The outcome was any health or disease outcome at follow-up after ≥1 year.

RESULTS

We identified 1719 papers through database searching and 1 additional paper through other sources. Forty-seven papers met our criteria including 32,866 participants (range 30-4100) with 1-23 years of follow-up. Overall, one third (32 %; 83/263) of all reported findings were significant and two thirds (68 %; 180/263) were null. With regard to the significant findings, both exaggerated (i.e. high) and blunted (i.e. low) stress reactivity of both the SAM system and the HPA axis at baseline were related to health and disease outcomes at follow-up. Exaggerated stress reactivity at baseline predicted an increase in risk factors for cardiovascular disease and decreased telomere length at follow-up. In contrast, blunted stress reactivity predicted future increased adiposity and obesity, more depression, anxiety and PTSD symptoms, greater illness frequency, musculoskeletal pain and regulatory T-Cell percentage, poorer cognitive ability, poorer self-reported health and physical disability and lower bone mass.

CONCLUSION

Exaggerated and blunted SAM system and HPA axis stress reactivity predicted distinct physical and mental health and disease outcomes over time. Results from prospective studies consistently indicate stress reactivity as a predictor for future health and disease outcomes. Dysregulation of stress reactivity may represent a mechanism by which psychological stress contributes to the development of future health and disease outcomes.

The effect of an exam period as a stress situation on baroreflex sensitivity among healthy university students

Purpose: Authors investigated the effect of a university exam period on blood pressure (BP) and baroreflex-sensitivity (BRS) among healthy students.Materials and methods: Fifty-three healthy normotensive university students participated in the test. BP values and BRS were recorded once during a 14-week long semester and once during a 6-week long exam period with a Finometer device. The time-domain spontaneous BRS in lying position and after standing up was calculated with Nevrokard software. Students were divided into optimal, normal, high-normal and hypertension (HT) groups by BP values.Results: All the BRS values calculated in the exam period were significantly lower compared to the semester period in the same positions. In supine position: (semester vs. exam) up-BRS was 21.9 ± 13.2 ms/mmHg vs. 18.5 ± 11.9 ms/mmHg (p = .013), down-BRS was 22.3 ± 9.3 ms/mmHg vs. 18.4 ± 8.2 ms/mmHg (p = .019). After standing up: (semester vs. exam) up-BRS was 9.3 ± 3.3 ms/mmHg vs. 7.6 ± 3.1 ms/mmHg (p = .02), down-BRS was 9.5 ± 3.6 ms/mmHg vs. 7.0 ± 2.8 ms/mmHg (p < .0001). The number of students decreased in optimal BP group and increased in normal and HT groups in the exam period.Conclusions: A 6-week long exam period had enough stress effect to change cardiovascular parameters towards a higher risk even in healthy young people.

Potential Therapeutic Use of Neurosteroids for Hypertension

The sympathetic nervous system (SNS) contribution to long-term setting of blood pressure (BP) and hence hypertension has been a continuing controversy over many decades. However, the contribution of increased sympathetic vasomotor tone to the heart, kidney, and blood vessels has been suggested as a major influence on the development of high BP which affects 30-40% of the population. This is relevant to hypertension associated with chronic stress, being overweight or obese as well to chronic kidney disease. Treatments that have attempted to block the peripheral aspects of the SNS contribution have included surgery to cut the sympathetic nerves as well as agents to block α- and β-adrenoceptors. Other treatments, such as centrally acting drugs like clonidine, rilmenidine, or moxonidine, activate receptors within the ventrolateral medulla to reduce the vasomotor tone overall but have side effects that limit their use. None of these treatments target the cause of the enhanced sympathetic tone. Recently we have identified an antihypertensive action of the neurosteroid allopregnanolone in a mouse model of neurogenic hypertension. Allopregnanolone is known to facilitate high-affinity extra-synaptic γ-aminobutyric acid A receptors (GABA_AR) through allosteric modulation and transcriptional upregulation. The antihypertensive effect was specific for increased expression of δ subunits in the amygdala and hypothalamus. This focused review examines the possibility that neurosteroids may be a novel therapeutic approach to address the neurogenic contribution to hypertension. We discuss the causes and prevalence of neurogenic hypertension, current therapeutic approaches, and the applicability of using neurosteroids as antihypertensive therapy.

Peripheral Vasoconstriction During Mental Stress and Adverse Cardiovascular Outcomes in Patients With Coronary Artery Disease

RATIONALE

Excessive vasoconstriction in response to mental stress may be a potential mechanism by which acute psychological stress leads to adverse cardiac events.

OBJECTIVES

We investigated whether excessive digital vasoconstriction during acute mental stress predicts adverse cardiovascular outcomes among patients with coronary artery disease.

METHODS AND RESULTS

Five hundred forty-nine patients with stable coronary artery disease (age 63±9, 76% male, 29% black) underwent mental stress testing with a standardized public speaking stressor and followed prospectively for cardiovascular end points. Digital pulse wave amplitude was continuously measured using peripheral artery tonometry (PAT, Itamar Inc). Stress/rest PAT ratio (sPAT) of pulse wave amplitude during mental stress/baseline was calculated and dichotomized by the median value into low and high sPAT ratio groups. Upon 3-year follow-up, Fine and Gray's subdistribution hazard ratios were used to examine the association between sPAT ratio and the composite end point of cardiovascular death, myocardial infarction, revascularization, and hospitalization for heart failure. The median sPAT ratio was 0.68 (interquartile range, 0.48-0.88), indicating 32% vasoconstriction with mental stress. Men were more likely to have low sPAT ratio than women (odds ratio, 1.79; P=0.007) while those on β-blockers were less likely to have low sPAT ratio (odds ratio, 0.52; P=0.003). After adjusting for demographic and cardiovascular risk factors, medications, and rate-pressure product change during mental stress, those with low sPAT ratio were at significantly higher risk of adverse outcomes (subdistribution hazard ratio, 1.77 [95% CI, 1.12-2.80]).

CONCLUSIONS

Greater peripheral vasoconstriction with mental stress, denoted by a low sPAT ratio, is associated with a higher risk of adverse cardiovascular outcomes in patients with coronary artery disease.

Effects of Social Exclusion on Cardiovascular and Affective Reactivity to a Socially Evaluative Stressor

PURPOSE

Socially disconnected individuals have worse health than those who feel socially connected. The mechanisms through which social disconnection influences physiological and psychological outcomes warrant study. The current study tested whether experimental manipulations of social exclusion, relative to inclusion, influenced subsequent cardiovascular (CV) and affective reactivity to socially evaluative stress.

METHODS

Young adults (N = 81) were assigned through block randomization to experience either social exclusion or inclusion, using a standardized computer-based task (Cyberball). Immediately after exposure to Cyberball, participants either underwent a socially evaluative stressor or an active control task, based on block randomization. Physiological activity (systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR)) and state anxiety were assessed throughout the experiment.

RESULTS

Excluded participants evidenced a significant increase in cardiovascular and affective responses to a socially evaluative stressor. Included participants who underwent the stressor evidenced similar increases in anxiety, but systolic blood pressure, diastolic blood pressure, and heart rate did not change significantly in response to the stressor.

CONCLUSIONS

Results contribute to the understanding of physiological consequences of social exclusion. Further investigation is needed to test whether social inclusion can buffer CV stress reactivity, which would carry implications for how positive social factors may protect against the harmful effects of stress.

Altered baroreflex sensitivity in young women with a family history of hypertension

A positive family history of hypertension (+FH) is a risk factor for the future development of hypertension. Hypertension is associated with reductions in baroreflex sensitivity (BRS). Therefore, we hypothesized that young women with a +FH [ n = 12, 22 ± 1 yr, body mass index (BMI) 21 ± 1 kg/m², mean arterial pressure (MAP) 79 ± 1 mmHg] would have lower BRS compared with young women without a family history of hypertension (-FH) ( n = 13, 22 ± 1 yr, BMI 21 ± 1 kg/m², MAP 77 ± 2 mmHg, all P > 0.05 between groups). Continuous measurements of muscle sympathetic nerve activity, blood pressure, and electrocardiogram derived R-R interval were recorded at rest and during a Valsalva maneuver. Both cardiovagal BRS and vascular sympathetic BRS were assessed. Resting cardiovagal BRS was reduced in the +FH women (all sequences: -FH 32.3 ± 3.7 vs. +FH 20.2 ± 2.9 ms/mmHg, P = 0.02). Cardiovagal BRS during phase IV (-FH 16.5 ± 2.7 vs. +FH 7.6 ± 1.3 ms/mmHg, P < 0.01) but not phase II (-FH 5.5 ± 0.9 vs. +FH 5.0 ± 0.8 ms/mmHg, P = 0.67) of the Valsalva maneuver was also lower in the +FH women. Vascular sympathetic BRS at rest (-FH -2.38 ± 0.7 vs. +FH -2.33 ± 0.3 bursts· min^-1·mmHg^-1, P = 0.58) and during the Valsalva (-FH -0.74 ± 0.23 vs. +FH -0.66 ± 0.18 bursts·15 s^-1·mmHg^-1, P = 0.79) were not different between groups. These data suggest that healthy young women with a positive family history of hypertension have reduced cardiovagal BRS. This may be one mechanism contributing to the increased incidence of hypertension in this population later in life. NEW & NOTEWORTHY Having a family history of hypertension increases the risk of developing future hypertension. Reductions in baroreflex function have been demonstrated in hypertension and are an important marker for future cardiovascular disease. We show that young women with a family history of hypertension have lower cardiovagal baroreflex sensitivity. This alteration in autonomic function may be one mechanism contributing to the future incidence of hypertension in this patient population.

Benzodiazepine Consumption Is Associated With Lower Blood Pressure in Ambulatory Blood Pressure Monitoring (ABPM): Retrospective Analysis of 4938 ABPMs

BACKGROUND

The effect of chronic benzodiazepine use on blood pressure has not been documented. We aimed to evaluate whether regular benzodiazepine use can be associated to the results of ambulatory blood pressure monitoring (ABPM).

METHODS

A retrospective analysis of the ABPM database between 2009 and 2015 was performed. The study groups were divided according to benzodiazepine treatment at least 3 months before ABPM. Generalized estimating equation (GEE) model analysis was conducted to estimate the association between benzodiazepine treatment and ABPM test measurements. Multivariable COX regression survival analysis model for mortality and cardiovascular (CV) events was performed.

RESULTS

A total of 4,938 ABPM studies were included in final analysis, 670 ABPMs of benzodiazepine-treated patients, and 4,268 of untreated patients. The benzodiazepine-treated group was significantly older, with a predominance of female patients, comprised more diabetic patients and consumed more antihypertensive medications. Adjustment for age, gender, diabetes mellitus, and number of antihypertensive medications, showed an association between benzodiazepine treatment and significantly lower ABPM measurements. When the analysis was split into those ≥60 years old and the other <60 years old, regular benzodiazepine consumption was associated with lower ABPM measurements only among ≥60 years old. Multivariable Cox regression survival analysis showed that regular benzodiazepine consumption was not associated with increased mortality or CV events (mean follow-up period of 42.4 ± 19.8 and 42.1 ± 20.0 months, respectively).

CONCLUSIONS

Long-term use of benzodiazepines by ≥60 years old was independently associated with lower diastolic and systolic blood pressure in all parameters of ABPM, but not among younger patients.

High-intensity handgrip training lowers blood pressure and increases heart rate complexity among postmenopausal women: a pilot study

OBJECTIVE

Handgrip exercise is an emerging strategy for resting blood pressure (BP) reduction requiring minimal time and exercise effort. However, the research literature is currently limited to handgrip protocol designs predominantly prescribing sustained grip contractions, with little assessment of alternative options. Furthermore, our understanding of the utility of handgrip exercise would be strengthened by an evaluation of the physiological mechanisms driving BP reductions and an assessment of the interindividual response variability. As such, this research was designed to perform an initial evaluation of the pragmatic effectiveness of a novel at-home, high-intensity, unilateral (nondominant) handgrip exercise training program in reducing resting BP, while simultaneously exploring mediators of BP change including a neurocardiac index of autonomic nervous control [heart rate (HR) variability], measures of arterial stiffness (radial augmentation index and carotid-radial pulse wave velocity), and cardiovascular reactivity to psychophysiological stressors.

METHODS

Postmenopausal women were recruited to complete 8 weeks of handgrip exercise training. Aforementioned measures of resting BP and mediators of BP change were acquired at the midway point and end of training.

RESULTS

All participants (n=17) completed training with high self-reported adherence (96.9%) and improvement in grip strength (2.7±2.4kg, P<0.05). Handgrip training reduced resting systolic BP (-5.1±7.7 mmHg, P<0.05) and improved HR complexity (sample entropy: 0.24±0.31, P<0.05), without significant changes to resting diastolic BP, HR, or arterial stiffness (all P>0.05).

CONCLUSION

This pilot study successfully shows the potential utility of high-intensity intermittent handgrip exercise for improvements in cardiovascular health among postmenopausal women, with additional research required to further explore the underlying physiological mechanisms driving such improvements.

Aerobic Interval Training and Cardiometabolic Health in Patients with Type 2 Diabetes: A Meta-Analysis

Vigorous to maximal aerobic interval training (INT) has received remarkable interest in improving cardiometabolic outcomes for type 2 diabetes patients recently, yet with inconsistent findings. This meta-analysis was aimed to quantify its effectiveness in type 2 diabetes. Randomized controlled trials (RCTs) were identified by searches of 3 databases to October 2017, which evaluated the effects of INT with a minimal training duration of 8 weeks vs. moderate-intensity continuous training (MICT) or non-exercise training (NET) among type 2 diabetes patients on outcomes including cardiorespiratory fitness, glycemic control, body composition, blood pressure, and lipid profiles. Weighted mean differences with 95% confidence intervals (CIs) were calculated with the random-effects model. Nine datasets from 7 RCTs with 189 patients were included. Compared with MICT, INT improved maximal oxygen consumption (VO_2max) by 2.60 ml/kg/min (95% CI: 1.32 to 3.88 ml/kg/min, P <0.001) and decreased hemoglobin A1c (HbA1c) by 0.26% (95% CI: −0.46% to −0.07%, P = 0.008). These outcomes for INT were also significant vs. energy expenditure-matched MICT, with VO_2max increased by 2.18 ml/kg/min (P = 0.04) and HbA1c decreased by 0.28% (P = 0.01). Yet their magnitudes of changes were larger compared with NET, with VO_2max increased by 6.38 ml/kg/min (P <0.001) and HbA1c reduced by 0.83% (P = 0.004). Systolic blood pressure could be lowered by INT compared with energy expenditure-matched MICT or NET (both P <0.05), but other cardiometabolic markers and body composition were not significantly altered in general. In conclusion, despite a limited number of studies, INT improves cardiometabolic health especially for VO_2max and HbA1c among patients with type 2 diabetes, and might be considered an alternative to MICT. Yet the optimal training protocols still require to be established.

Vascular hyperreactivity in black Cameroonian hypertensive and normotensive patients: a comparative study

Introduction

Vascular hyperreactivity is a risk factor and a factor predicting hypertension (high blood pressure). Unlike other continents where several studies were carried out, it has rarely been studied in black Africa in general and in Cameroon in particular.

Methods

Vascular reactivity was measured by the cold test. Vascular hyperreactivity was defined as an increase in blood pressure > 20 mmHg for systolic and/or > 15 mmHg for diastolic. Khi², Man-Withney, Wilcoxon's signed ranks and logistic regression tests were used for statistical analysis.

Results

A total of 31 hypertensive and 31 normotensive patients matched by age and sex participated in this study. Vascular hyperreactivity was present in 77.4% hypertensive patients and 51.6% normotensive patients. There was a significant association between vascular hyperreactivity and hypertension [OR = 3.2 (1.07 - 9.63), p = 0.034]. The median arterial pressure was higher in responders compared to non-responders in the normotensive group. Age > 45 years, female sex, obesity and family history of hypertension appeared to be associated with vascular hyperreactivity, but only in normotensive patients.

Conclusion

Vascular hyperreactivity appears to be a risk factor for high blood pressure in black Cameroonians. It appeared to be associated with low blood pressure, age, sex, obesity and family history of hypertension but this was only in the normotensive.

Positive allosteric modulation of GABAA receptors attenuates high blood pressure in Schlager hypertensive mice

OBJECTIVE

Blood pressure high Schlager (BPH/2J) mice have neurogenic hypertension associated with differences in hypothalamic GABAA receptors compared with their normotensive counterparts (BPN/3J). Allopregnanolone is an endogenous neurosteroid reduced in chronic stress, and when administered, decreases anxiety by positive allosteric modulation of GABAA receptors.

METHODS

To determine if allopregnanolone could be a viable therapeutic for neurogenic hypertension, male BPH/2J (n = 6-7) and BPN/3J (n = 8-9) mice were equipped with radiotelemetry probes to compare cardiovascular variables before and after implantation of subcutaneous minipumps delivering allopregnanolone (5 mg/kg per day), or its vehicle, for a period of 2 weeks. In addition to baseline recordings, the response to stress and ganglionic blockade with pentolinium was recorded, before and 7-14 days after minipump implantation. Following treatment, brains were processed for c-Fos immunohistochemistry and quantitative real-time polymerase chain reaction.

RESULTS

Administration of allopregnanolone selectively reduced mean arterial pressure (-8.0 ± 2.7 mmHg; P = 0.02) and the depressor response to pentolinium (-15.3 ± 3.2 mmHg; P = 0.001) in BPH/2J mice, with minimal effects observed in BPN/3J mice. Following allopregnanolone treatment, the diminished expression of GABAA δ, α4 and β2 subunits in the hypothalamus (-1.6 to 4.8-fold; Pstrain < 0.05) was abolished. Furthermore, in BPH/2J mice, allopregnanolone treatment reduced the pressor response to dirty cage switch stress (-26.7 ± 4.5%; P < 0.001) and abolished the elevated c-Fos expression in pre-sympathetic nuclei.

CONCLUSION

The selective antihypertensive and stress inhibitory effects of allopregnanolone in BPH/2J mice suggest that allosteric modulation of GABAA receptors, in amygdalo-hypothalamic pathways, may contribute to the development of hypertension in this model and may offer a potential new therapeutic avenue.

Reducing effect of aerobic exercise on blood pressure of essential hypertensive patients: A meta-analysis

BACKGROUND

The comprehensive meta-analysis aimed to explore the reductive effect of aerobic exercise on blood pressure of hypertensive patients.

METHODS

The related researches were selected from PubMed and Embase databases up to June 2016. Based on specific inclusive criteria, the eligible studies were selected, and the heterogeneities in their results were estimated by χ-based Q-test and I statistics. Quantitative meta-analysis was assessed by R 3.12 software, and results were presented by standardized mean difference (SMD) and their 95% confidence intervals (CIs). Outcome indicators were systolic blood pressure (SBP) and diastolic blood pressure (DBP). The publication biases were estimated by Egger test. Besides, the "leave one out" method was used for sensitivity evaluations.

RESULTS

As a result, a total of 13 papers with 802 samples were included. Based on the meta-analysis results, there were no significant differences in SBP and DBP between aerobic and control groups before exercise (SMD = 0.15, 95%CI: -0.16-0.46; SMD = 0.16, 95% CI: -0.23-0.55). However, significant reductions were obviously in aerobic group after aerobics, compared with control (SMD = -0.79, 95% CI: -1.29 to -0.28; SMD = -0.63, 95% CI: -1.14 to -0.12). A significant publication bias was detected in SBP (t = -2.2314, P = 0.04549) but not in DBP (t = -1.4962, P = 0.1604). Additionally, the DBP result would be altered after the exclusion of 2 individual papers.

CONCLUSION

Aerobic exercise may be a potential nonpharmacological treatment for blood pressure improvement in essential hypertensive patients.

Basal autonomic activity, stress reactivity, and increases in metabolic syndrome components over time

CONTEXT

Basal autonomic nervous system (ANS) functioning has been linked to the metabolic syndrome (MetS), but the role of ANS reactivity in response to stress remains unclear.

OBJECTIVE

To examine cross-sectionally and longitudinally to what extent ANS basal level and stress reactivity are related to MetS.

DESIGN

2-year and 6-year data from a prospective cohort: the Netherlands Study of Depression and Anxiety.

SETTING

Participants were recruited from the general community, primary care, and mental health care organizations.

PARTICIPANTS

1922 respondents (mean age=43.7years).

MAIN OUTCOME MEASURES

Indicators of ANS functioning were heart rate (HR), respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP). ANS stress reactivity was measured during a cognitively challenging stressor and a personal-emotional stressor. MetS components included triglycerides, high-density lipoprotein cholesterol, blood pressure, glucose and waist circumference.

RESULTS

Cross-sectional analyses indicated that higher basal HR, lower basal values of RSA and PEP, and higher RSA reactivity during cognitive challenge were related to less favorable values of almost all individual MetS components. Longitudinal analyses showed that higher basal HR and shorter basal PEP predicted 4-year increase in many MetS abnormalities. Higher RSA stress reactivity during cognitive challenge predicted 4-year increase in number of MetS components.

CONCLUSION

Higher basal sympathetic, lower basal parasympathetic activity, and increased parasympathetic withdrawal during stress are associated with multiple MetS components, and higher basal sympathetic activity predicts an increase in metabolic abnormalities over time. These findings support a role for ANS dysregulation in the risk for MetS and, consequently, the development of cardiovascular disease.

Do Cardiovascular Responses to Active and Passive Coping Tasks predict Future Blood Pressure over a 10-Month Later?

The study examined whether cardiovascular responses to active or passive coping tasks and single or multiple tasks predicted changes in resting blood pressure (BP) over a ten-month period. Heart rate (HR), BP, cardiac output (CO), and total peripheral resistance (TPR) were measured at rest, and during mental stress tests (mental arithmetic, speech, and cold pressor tasks). A total of 104 eligible participants participated in the initial study, and 77 (74.04%) normotensive adult participants’ resting BP were re-evaluated at ten-month follow-up. Regression analyses indicated that after adjustment for baseline BP, initial age, gender, body mass index, family history of cardiovascular disease, and current cigarette smoking, heighted systolic blood pressure (SBP) and HR responses to an active coping task (mental arithmetic) were associated with increased future SBP (ΔR2 = .060, ΔR2 = .045, respectively). Further, aggregated SBP responsivity (over the three tasks) to the predictor models resulted in significant, but smaller increases in ΔR2 accounting for .040 of the variance of follow-up SBP. These findings suggest that cardiovascular responses to active coping tasks predict future SBP. Further, compared with single tasks, the findings revealed that SBP responses to three tasks were less predictive compared to an individual task (i.e., mental arithmetic). Of importance, hemodynamic reactivity (namely CO and TPR) did not predict future BP suggesting that more general psychophysiological processes (e.g., inflammation, platelet aggregation) may be implicated, or that BP, but not hemodynamic reactivity may be a marker of hypertension.

Leptin relates to prolonged cardiovascular recovery after acute stress in Africans: The SABPA study

BACKGROUND AND AIMS

Heightened cardiovascular reactivity and delayed recovery to stress are associated with an increased risk of cardiovascular disease. Africans, who are more prone to develop hypertension, show greater cardiovascular reactivity to stress. However, causal factors underlying individual and ethnic differences in stress reactivity and recovery remain largely unexplored. Leptin, which is known for its sympatho-activating effects, is higher in Africans compared to Caucasians for any given body mass index. We compared how cardiovascular reactivity and recovery relate to leptin in African (n = 200) and Caucasian (n = 209) teachers.

METHODS AND RESULTS

We measured leptin in serum and cardiovascular baseline and reactivity continuously with the Finometer device during the cold pressor test for 1 min, and recovery at intervals of 1, 3 and 5 min. Africans had higher body mass index, leptin and blood pressure (all P < 0.001). After full adjustment in multiple regression analyses, associations were seen mainly at the 5 min recovery interval. In Africans, cardiac output reactivity (β = -0.335; P = 0.0018) and arterial compliance- (β = -0.241; P = 0.048) associated negatively and total peripheral resistance- (β = 0.227; P = 0.047) positively with leptin. In Caucasians, diastolic blood pressure correlated positively with leptin (β = 0.200; P = 0.015).

CONCLUSION

In Africans, higher circulating leptin levels associated with prolonged cardiovascular recovery after exposure to stress which could explain their increased vulnerability to hypertension development.

Blood Pressure Reactivity to the Cold Pressor Test Predicts Hypertension Among Chinese Adults: The GenSalt Study

BACKGROUND

Blood pressure (BP) hyper-reactivity to the cold pressor test (CPT) has been suggested as a predictor of hypertension. We examined whether BP reactivity to the CPT was associated with hypertension incidence among the Genetic Epidemiology Network of Salt Sensitivity (GenSalt) study participants from China.

METHODS

A total of 1,961 GenSalt study participants without any antihypertensive treatment completed the CPT at the baseline examination. Hypertension status was assessed at baseline (2003-2005) and 2 follow-up visits (2008-2009 and 2011-2012).

RESULTS

After adjustment for multiple covariates, both systolic BP (SBP) and diastolic BP reactivity to the CPT were significantly associated with hypertension incidence. For example, the multivariable adjusted odds ratios (ORs, 95% CI) of developing hypertension were 0.92 (0.66, 1.29), 1.42 (1.03, 1.97), and 1.45 (1.05, 2.00) for participants with maximum SBP responses of 6.7-12.0, 12.1-19.2, and ≥19.3mm Hg, respectively, compared to those with responses of <6.7mm Hg (P for trend = 0.006). Likewise, the multivariable-adjusted ORs (95% CI) of hypertension were 1.12 (0.79, 1.57), 1.62 (1.15, 2.29), and 1.82 (1.30, 2.55) for participants with the area under the curve of SBP responses of 3.0-16.0, 16.1-29.9, and ≥ 30.0mm Hg·min, respectively, compared to those with responses of < 3.0mm Hg·min (P for trend = 0.0001). The associations between BP reactivity variables and the risk of hypertension were not different among subgroups of sex, age, and baseline BP levels.

CONCLUSIONS

BP hyperreactivity to the cold stimulus may predict the risk of hypertension among Chinese adults.

Sympathoneural and adrenomedullary responses to mental stress

This concept-based review provides historical perspectives and updates about sympathetic noradrenergic and sympathetic adrenergic responses to mental stress. The topic of this review has incited perennial debate, because of disagreements over definitions, controversial inferences, and limited availability of relevant measurement tools. The discussion begins appropriately with Cannon's "homeostasis" and his pioneering work in the area. This is followed by mental stress as a scientific idea and the relatively new notions of allostasis and allostatic load. Experimental models of mental stress in rodents and humans are discussed, with particular attention to ethical constraints in humans. Sections follow on sympathoneural responses to mental stress, reactivity of catecholamine systems, clinical pathophysiologic states, and the cardiovascular reactivity hypothesis. Future advancement of the field will require integrative approaches and coordinated efforts between physiologists and psychologists on this interdisciplinary topic.

Polyphenol-rich juices reduce blood pressure measures in a randomised controlled trial in high normal and hypertensive volunteers

Intake of fruits and berries may lower blood pressure (BP), most probably due to the high content of polyphenols. In the present study, we tested whether consumption of two polyphenol-rich juices could lower BP. In a randomised, double-blinded, placebo-controlled trial of 12 weeks, 134 healthy individuals, aged 50–70 years, with high normal range BP (130/85–139/89 mmHg, seventy-two subjects) or stage 1-2 hypertension (140/90–179/109 mmHg, sixty-two subjects), were included. They consumed 500 ml/d of one of either (1) a commercially available polyphenol-rich juice based on red grapes, cherries, chokeberries and bilberries; (2) a juice similar to (1) but enriched with polyphenol-rich extracts from blackcurrant press-residue or (3) a placebo juice (polyphenol contents 245·5, 305·2 and 76 mg/100 g, respectively). Resting BP was measured three times, with a 1 min interval, at baseline and after 6 and 12 weeks of intervention. Systolic BP significantly reduced over time (6 and 12 weeks, respectively) in the pooled juice group compared with the placebo group in the first of the three measurements, both for the whole study group (6·9 and 3·4 mmHg; P= 0·01) and even more pronounced in the hypertensive subjects when analysed separately (7·3 and 6·8 mmHg; P= 0·04). The variation in the BP measurements was significantly reduced in the pooled juice group compared with the placebo group (1·4 and 1·7 mmHg; P= 0·03). In conclusion, the present findings suggest that polyphenol-rich berry juice may contribute to a BP- and BP variability lowering effect, being more pronounced in hypertensive than in normotensive subjects.

Anxiety in the "age of hypertension"

In the USA, hypertension affects one in three adults, and anxiety disorders are the most commonly diagnosed mental health disorders. Both hypertension and anxiety have been studied extensively. Yet, a full understanding of anxiety's relationship to hypertension has been elusive. In this review, we discuss the spectrum of anxiety disorders. In addition, we consider the evidence for acute and long-term effects of anxiety on blood pressure. We review the effect on blood pressure of several "real-world" stressors, such as natural disasters. In addition, we review the effect of anxiety treatments on blood pressure. We explain the American Heart Association's recent recommendations regarding meditation and other relaxation methods in the management of hypertension. We conclude that novel research methods are needed in order to better elucidate many aspects of how anxiety relates to hypertension.

A blunted sympathetic and accentuated parasympathetic response to postural change in subjects with depressive disorders

BACKGROUND

In recent years, the bi-directional relationship between depression and ANS dysfunction has received considerable attention, but findings remain inconclusive. In this study, we aimed to examine the spectral HRV response to postural change in subjects with depressive disorders and in healthy controls, in order to gain insight into the characteristics of autonomic nervous system (ANS) response to postural change in subjects with depressive disorders.

METHODS

We compared HRV response to postural change between subjects with depressive disorders and healthy controls aged 20-37 years. Depression severity was assessed by the self-reported Beck Depression Inventory-II (BDI-II). Spectral HRV was analyzed at two moments: 10 min seated rest and 10 min at standing position, with spontaneous breathing.

RESULTS

No significant differences existed in the resting spectral HRV indices between subjects with depressive disorders and controls, however, following postural change, the increasing level of LF and LF/HF was lower and the decreasing level of HF power was higher, in the individuals with depression than that in healthy subjects. The differences in the LF power, HF power and the LF/HF ratio between seated rest before standing up and after postural change were found negatively correlated with depression severity.

CONCLUSION

We found a blunted sympathetic and accentuated parasympathetic response to postural change in subjects with depressive disorder, suggesting that the autonomic impairment and early ANS dysfunction may exist among depressed individuals. These findings indicated that spectral analysis of HRV associated with postural change may be a more sensitive method than resting HRV analysis for detecting ANS dysfunction in depressive disorders.

LIMITATIONS

Further studies are needed to expand the sample size and to clarify the mechanisms responsible for the autonomic dysfunction observed in individuals with depressive disorders.

Personality traits modulate emotional and physiological responses to stress

An individual's susceptibility to psychological and physical disorders associated with chronic stress exposure, for example, cardiovascular and infectious disease, may also be predicted by their reactivity to acute stress. One factor associated with both stress resilience and health outcomes is personality. An understanding of how personality influences responses to acute stress may shed light upon individual differences in susceptibility to chronic stress-linked disease. This study examined the relationships between personality and acute responses to stress in 125 healthy adults, using hierarchical linear regression. We assessed personality traits using the Multidimensional Personality Questionnaire (MPQ-BF), and responses to acute stress (cortisol, heart rate, blood pressure, mood) using a standardized laboratory psychosocial stress task, the Trier Social Stress Test. Individuals with high Negative Emotionality exhibited greater emotional distress and lower blood pressure responses to the Trier Social Stress Test. Individuals with high agentic Positive Emotionality exhibited prolonged heart rate responses to stress, whereas those with high communal Positive Emotionality exhibited smaller cortisol and blood pressure responses. Separate personality traits differentially predicted emotional, cardiovascular, and cortisol responses to a psychosocial stressor in healthy volunteers. Future research investigating the association of personality with chronic stress-related disease may provide further clues to the relationship between acute stress reactivity and susceptibility to disease.

Sympathetic reactivity in young women with a family history of hypertension

Young adults with a family history of hypertension (+FH) have increased risk of developing hypertension. Furthermore, the blood pressure (BP) response to sympathoexcitatory stimuli in young adults can predict the future development of hypertension. Therefore, we hypothesized young women with a +FH would have exaggerated cardiovascular and sympathetic reactivity compared with young women without a family history of hypertension (-FH). Beat-by-beat mean arterial pressure (MAP) and muscle sympathetic nerve activity (MSNA) were measured in 14 women +FH (22 ± 1 yr, 21 ± 1 kg/m(2), MAP 80 ± 2 mmHg) and 15 women -FH (22 ± 1 yr, 22 ± 1 kg/m(2), MAP 78 ± 2 mmHg) during acute sympathoexcitatory maneuvers: cold pressor test, 2 min of isometric handgrip (HG) exercise at 30% of maximal voluntary contraction, and 3 min of postexercise ischemia (PEI; isolated activation of the skeletal muscle metaboreflex). During cold pressor test, the increase in BP was greater in women +FH (ΔMAP: +FH 16 ± 2 vs. -FH 11 ± 1 mmHg, P < 0.05), which was accompanied by an exaggerated increase in MSNA (ΔMSNA: +FH 17 ± 2 vs. -FH 8 ± 2 burst/min, P < 0.05). The increase in BP was greater in +FH during the last minute of HG (ΔMAP: +FH 23 ± 3 vs. -FH 12 ± 1 mmHg, P < 0.05) and during PEI (ΔMAP: +FH 17 ± 3 vs. -FH 9 ± 2 mmHg, P < 0.05). Similarly, the increase in MSNA was greater in +FH during both HG (ΔMSNA: +FH 12 ± 2 vs. -FH 6 ± 2 burst/min, P < 0.05) and PEI (ΔMSNA: +FH 16 ± 2 vs. -FH 4 ± 2 burst/min, P < 0.05). These data demonstrate that +FH women have greater BP and sympathetic reactivity compared with -FH women.

Sympathetic neural activity to the cardiovascular system: integrator of systemic physiology and interindividual characteristics

The sympathetic nervous system is a ubiquitous, integrating controller of myriad physiological functions. In the present article, we review the physiology of sympathetic neural control of cardiovascular function with a focus on integrative mechanisms in humans. Direct measurement of sympathetic neural activity (SNA) in humans can be accomplished using microneurography, most commonly performed in the peroneal (fibular) nerve. In humans, muscle SNA (MSNA) is composed of vasoconstrictor fibers; its best-recognized characteristic is its participation in transient, moment-to-moment control of arterial blood pressure via the arterial baroreflex. This property of MSNA contributes to its typical "bursting" pattern which is strongly linked to the cardiac cycle. Recent evidence suggests that sympathetic neural mechanisms and the baroreflex have important roles in the long term control of blood pressure as well. One of the striking characteristics of MSNA is its large interindividual variability. However, in young, normotensive humans, higher MSNA is not linked to higher blood pressure due to balancing influences of other cardiovascular variables. In men, an inverse relationship between MSNA and cardiac output is a major factor in this balance, whereas in women, beta-adrenergic vasodilation offsets the vasoconstrictor/pressor effects of higher MSNA. As people get older (and in people with hypertension) higher MSNA is more likely to be linked to higher blood pressure. Skin SNA (SSNA) can also be measured in humans, although interpretation of SSNA signals is complicated by multiple types of neurons involved (vasoconstrictor, vasodilator, sudomotor and pilomotor). In addition to blood pressure regulation, the sympathetic nervous system contributes to cardiovascular regulation during numerous other reflexes, including those involved in exercise, thermoregulation, chemoreflex regulation, and responses to mental stress.

An explorative study of metabolic responses to mental stress and yoga practices in yoga practitioners, non-yoga practitioners and individuals with metabolic syndrome

BACKGROUND

Stress places a metabolic burden on homeostasis and is linked to heightened sympathetic activity, increased energy expenditure and pathology. The yogic state is a hypometabolic state that corresponds with mind-body coherence and reduced stress. This study aimed to investigate metabolic responses to stress and different yoga practices in regular yoga practitioners (YP), non-yoga practitioners (NY) and metabolic syndrome patients (MS).

METHODS

YP (n = 16), NY (n = 15) and MS (n = 15) subjects underwent an experimental protocol that comprised of different 5-minute interventions including mental arithmetic stress test (MAST), alternate nostril breathing (ANB), Kapabhati breathing (KB) and meditation (Med) interspersed with 5 minutes of quiet resting (neutral condition (NC)). During the intervention periods continuous body weight adjusted oxygen consumption (VO2ml/min/kg) was measured using open circuit indirect calorimetry with a canopy hood.

RESULTS

This is the first study to report oxygen consumption (OC) in yoga practitioners during and after MAST and the first to report both within and between different populations. The results were analysed with SPSS 16 using 3X9 mixed factorial ANOVAs. The single between-subject factor was group (YP, NY and MS), the single within-subject factor was made up of the nine intervention phases (NC1, MAST, NC2, ANB, NC3, KB, NC4, Med, NC5). The results demonstrated that the regular YP group had significantly less OC and greater variability in their OC across all phases compared to the MS group (p = .003) and NY group (p = .01). All groups significantly raised their OC during the mental arithmetic stress, however the MS group had a significantly blunted post-stress recovery whereas the YP group rapidly recovered back to baseline levels with post stress recovery being greater than either the NY group or MS group.

CONCLUSIONS

Yoga practitioners have greater metabolic variability compared to non-yoga practitioners and metabolic syndrome patients with reduced oxygen requirements during resting conditions and more rapid post-stress recovery. OC in metabolic syndrome patients displays significantly blunted post-stress recovery demonstrating reduced metabolic resilience. Our results support the findings of previous randomised trials that suggest regular yoga practice may mitigate against the effects of metabolic syndrome.

CLINICAL TRIAL NUMBER

ACTRN12614001075673; Date of Registration: 07/10/2014.