Dissociation of temporal dynamics of heart rate and blood pressure responses elicited by conditioned fear but not acoustic startle

Fear-inducing stimuli were hypothesized to elicit fast heart rate (HR) responses but slow mean arterial blood pressure (MAP) responses and thus were studied in auditory fear conditioning and acoustic startle at high temporal resolution in freely moving mice and rats. Fear-induced instantaneous acceleration of HR reaching maximum physiological values and subsequent recovery to baseline were observed. The MAP response consisted of an immediate, mild, and transient increase followed by a sluggish, profound elevation and slow recovery. HR and MAP responses served as reliable indicators of conditioned fear in mice with dissociated temporal dynamics. Unconditioned auditory stimuli, including acoustic startle stimuli, elicited only fast, mild, and transient MAP and HR elevations in mice and rats, reflecting arousal and attention under these experimental conditions.     

Effect of aging on heart rate and blood pressure variabilities in healthy men and women

OBJECT: To clarify the effect of aging and gender on heart rate and blood pressure variability in healthy men and women. SUBJECT AND METHODS: One hundred ninety four healthy subjects aged from 20 to 70(97 men and 97 women) were examined. Heart beat and blood pressure during 5 minutes in the supine and standing positions were measured under a respiration rate of 15/min. Blood pressure and heart were measured with Finapres and Biotop, respectively. Data entry and spectral analysis were carried out by the Fast Fourier Transform(FFT) method with BIMUTAS-II, after correcting 256 data with Hanning window function and resampling at 200 Hz. RESULT AND DISCUSSION: High frequency power(HF: 0.15-0.50 Hz) of heart rate variability decreased with age in both men and women, Low frequency power (LF: 0.05-0.15 Hz) of systolic blood pressure(SBP) variability in the standing posture decreased with age in men. The HF of SBP variability in the standing posture was decreased with age in both men and women. These findings suggest that aging and gender affected heart rate and blood pressure variability.     

The effect of type and dose of oestrogen on the blood pressure of post-menopausal women

Evidence from two groups of post-menopausal women who were randomly allocated to be treated with either conjugated equine oestrogens or piperazine oestrone sulphate demonstrates that the two oestrogens produce markedly different effects on blood pressure. The conjugated equine oestrogens appear to produce no significant change in either systolic or diastolic blood pressure whereas piperazine oestrone sulphate produced a significant fall in both systolic and diastolic blood pressure. This finding is discussed in relationship to the known causes for a change in cardiovascular response to oestrogen and several hypotheses are put forward.     

Metabolic clearance rate of oestrone sulphate in post-menopausal women

The feasibility of using constant infusions of unlabelled oestrone sulphate (E₁S) for the purposes of calculating its metabolic clearance rate (MCR_E1S) and its conversion ratios to oestrone (E₁) and oestradiol (E₂) in post-menopausal women was exploited in this study.

The results obtained by the infusion of unlabelled E₁S were similar to those obtained by the infusion of labelled steroid.

The MCR_E1S values seen in our group of post-menopausal women fell within the range previously reported for fertile women.

The contribution of E₁S to circulating E₁ averaged 18% (range 14–24%), indicating that the E₁S-E₁ equilibrium should be taken into account during studies on oestrogen balance in post-menopausal women.     

Ambulatory blood pressure and heart rate in relation to hot flash experience among women of menopausal age

OBJECTIVE: The purpose of this study was to evaluate whether ambulatory blood pressure and heart rate varied with hot flash experience among women of menopausal age. SUBJECTS AND METHODS: A total of 1149 ambulatory blood pressure and heart rate measurements from 20 women aged 44-55 were examined. Women were categorized by hot flash experience as (1) having had hot flashes during the study period (Symptomatic during Study; n = 5; 302 measurements), (2) having a past history of hot flashes, but no hot flashes during the study period (Historically Symptomatic; n = 7; 385 measurements), and (3) never having had a hot flash (Asymptomatic; n = 8; 462 measurements). Using repeated measures, nested ANOVA models that also adjusted for posture, the variation in blood pressure and heart rate associated with hot flash experience over the whole day and by location of measurement (microenvironment) was evaluated. RESULTS: The results show that, overall, systolic pressure did not differ among the hot flash experience groups although the Symptomatic during Study group had higher pressures at work than the other two groups (p<0.01), and tended to have higher pressures during sleep (p<0.08). The sleep diastolic pressure of the Asymptomatic group was significantly lower than that of the women who had hot flashes on the study day (p<0.01), but women who had a past history of hot flashes had slightly lower diastolic pressure (p<0.01) than those in the other two groups overall. Heart rates of the Asymptomatic group, however, were significantly lower (4-6 b.p.m.; p<0.001) in each microenvironment and over the whole day than both groups who had hot flash experience. CONCLUSIONS: These data suggest first that there may be a relationship between the experience of hot flashes and accelerated heart rate, and second that women who do not experience hot flashes may have lower sleep blood pressures than women who do.     

Ambulatory blood pressure and heart rate in relation to hot flash experience among women of menopausal age

Objective: The purpose of this study was to evaluate whether ambulatory blood pressure and heart rate varied with hot flash experience among women of menopausal age.

Subjects and methods: A total of 1149 ambulatory blood pressure and heart rate measurements from 20 women aged 44–55 were examined. Women were categorized by hot flash experience as (1) having had hot flashes during the study period (Symptomatic during Study; n = 5; 302 measurements), (2) having a past history of hot flashes, but no hot flashes during the study period (Historically Symptomatic; n = 7; 385 measurements), and (3) never having had a hot flash (Asymptomatic; n = 8; 462 measurements). Using repeated measures, nested ANOVA models that also adjusted for posture, the variation in blood pressure and heart rate associated with hot flash experience over the whole day and by location of measurement (microenvironment) was evaluated.

Results: The results show that, overall, systolic pressure did not differ among the hot flash experience groups although the Symptomatic during Study group had higher pressures at work than the other two groups (?p<0.01), and tended to have higher pressures during sleep (?p<0.08). The sleep diastolic pressure of the Asymptomatic group was significantly lower than that of the women who had hot flashes on the study day (?p<0.01), but women who had a past history of hot flashes had slightly lower diastolic pressure (?p<0.01) than those in the other two groups overall. Heart rates of the Asymptomatic group, however, were significantly lower (4–6?b.p.m.; p<0.001) in each microenvironment and over the whole day than both groups who had hot flash experience.

Conclusions: These data suggest first that there may be a relationship between the experience of hot flashes and accelerated heart rate, and second that women who do not experience hot flashes may have lower sleep blood pressures than women who do.     

血压正常的2型糖尿病患者24h动态血压与血清胱抑素C相关性研究

目的:探讨血压正常的2型糖尿病(T2DM)患者24 h动态血压与血清胱抑素C(Cys C)的相关性。方法:入选符合纳入标准的T2DM患者82例,据血清Cys C水平将患者分为对照组(Cys C<1.25 mg/L,共42例)和高Cys C组(Cys C≥1.25 mg/L,共40例),所有患者均进行24 h动态血压监测(ABPM)。结果:高Cys C组患者在24 h收缩压(24hSBP)、白天收缩压(dSBP)、夜间收缩压(nSBP)、24 h平均脉压(24hmPP)、白天平均脉压(dmPP)、夜间平均脉压(nmPP)、夜间收缩压最低均值、起床前2 h收缩压均值及起床后2 h收缩压均值与对照组比较,差异均有统计学意义(P<0.05);而在24hDBP、dDBP、nDBP、夜间舒张压最低均值、起床前2 h舒张压均值及起床后2 h舒张压均值与对照组比较,差异均无统计学意义(P>0.05)。对Cys C作Pearson相关分析显示,Cys C与24hSBP、dSBP、nSBP、24hmPP、dmPP、nmPP、夜间收缩压最低均值、起床前2 h收缩压均值及起床后2 h收缩压均值呈正相关(P<0.05),但与24hDBP、dDBP、nDBP、夜间舒张压最低均值、起床前2 h舒张压均值及起床后2 h舒张压均值无相关(P>0.05)。结论:血压正常的T2DM患者中,其收缩压及平均脉压可能与DN有一定相关性。     

Effect of Qi-training on blood pressure, heart rate and respiration rate.

To examine the physiological effects of Korean traditional Qi-training, we investigated the changes in blood pressure, heart and respiratory rates before, during and after ChunDoSunBup (CDSB) Qi-training. Twelve normal healthy CDSB Qi-trainees (19-37 years old; trained for 1.3 +/- 0.2 years; 9 men and 3 women) volunteered to participate in this study. Heart rate, respiratory rate, systolic blood pressure and rate-pressure product were significantly decreased during Qi-training. From these results, we suggest that CDSB Qi-training has physiological effects that indicate stabilization of cardiovascular system.     

Reproducibility of blood pressure and heart rate reactivity: A meta-analysis

Reproducibilities of blood pressure and heart rule (HR) reactivity reported in studies assessing responses to the same laboratory stressors across occasions were reviewed with meta-analytic techniques. Changes in HR had the greatest reproducibility (r =.555), followed by systolic blood pressure (SBP) (.407) and diastolic blood pressure (DBF) (.348), Both SBP and HR response reproducibility was higher at shorter lest-retest intervals, whereas DBP values varied unsystematically with length of test-retest interval Older samples exhibited higher SBP and DBP reproducibility to stressors. SBP and DBP reproducibilities were better for tasks that did not make speech demands. The reliability of reactivity assessment was higher when based on three or more measurements, On the basis of able evidence, the drop in stress reproducibility, as test-retest interval increases, places limits on the viability of BP reactivity as a strong marker or risk factor for coronary heart disease.     

皮质下动脉硬化性脑病血压及心率变异性分析

目的和方法：采用动态检测技术观察３１例皮质下动脉硬化性脑病和对照组３１例健康人血压和心率的变异性。结果：患者均存在动态血压异常，其中平均收缩压、平均舒张压超过正常值者２７例（８７％），夜间基底血压异常升高２２例（７１％），血压异常波动２０例（６４％），昼夜节律逆转４例（１３％）。患者心率变异时域指标２４小时内全部正常心动周期的标准差、２４小时内５分钟节段平均正常心动周期的标准差、在一定时间内相邻两正常心动周期差值大于５０毫秒的个数所占的百分比均明显低于对照组，收缩压与心率无显著相关性。结论：提示血压波动及持续的夜间升压现象在该病中起着一定作用，而这种异常可能与患者植物神经系统功能失调有关     

The effects of rofecoxib on 24-h ambulatory blood pressure and heart rate monitoring in patients with hypertension and osteoarthritis

The aim of the study was to investigate the effects of the cylooxygenase (COX)-2 specific inhibitor rofecoxib, on blood pressure (BP) and heart rate (HR) in patients with well-controlled hypertension and osteoarthritis via 24-h ambulatory monitoring. Thirty patients with well controlled hypertension were included. Fifteen patients had osteoarthritis and were recommended by their rheumatologists to take rofecoxib 12.5 mg/day (rofecoxib group). The control group consisted of 15 patients who had hypertension but no clinical osteoarthritis and did not receive any anti-inflammatory drugs. Twenty-four-hour ambulatory monitoring of BP and HR were performed on the day before initiation of rofecoxib therapy and on days 3 and 14 of COX-2 therapy. The control group underwent 24-h monitoring three times at similar intervals. Antihypertensive medications were continued. On day 3 of rofecoxib therapy, mean HR for both daytime and nighttime were lower than those at baseline. On day 14, the changes in mean HR did not differ from baseline values. Similarly, diastolic BP (daytime and nighttime) on day 3 appeared to be lower than at baseline. However this difference was not observed on day 14, and mean daytime and nighttime diastolic BP returned to baseline values. There was no statistically significant difference in the mean arterial pressure or systolic BP recordings on days 3 or 14 than at baseline. Rofecoxib 12.5 mg/day did not significantly increase BP during 24-h ambulatory BP monitoring in patients with well-controlled hypertension and osteoarthritis.     

Periodic variations of blood pressure and heart rate in premature neonates

Laboratory of Experimental Brain Pathology and Department of Newborn and Premature Infants, Research Institute of Pediatrics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR M. Ya. Studenikin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 109, No. 3, pp. 217–219, March, 1990.     

Gender differences in the impact of daily sadness on 24‐h heart rate variability

Reduced heart rate variability (HRV) is proposed to mediate the relation between depressive symptoms and cardiovascular health problems. Yet, several studies have found that in women depression is associated with higher HRV levels, whereas in men depression is associated with lower HRV levels. So far, these studies have only examined gender differences in HRV levels using a single assessment. This study aimed to test the interactive effects of gender and sadness on ambulatory‐assessed HRV levels. A sample of 60 (41 women) employees participated in an ambulatory study. HRV levels (mean of successive differences; MSD) were continuously measured for 24 h. During the daytime, hourly assessments of sadness and other mood states were taken, while depressive symptoms were assessed with the Center for Epidemiologic Studies Depression scale (CES‐D). Gender differences were observed when examining the impact of average daily sadness on MSD. In women, but not in men, the total amount of sadness experienced during the day was associated with higher circadian MSD levels. These findings suggest that researchers need to take gender differences into account when examining the relation between sadness, HRV, and cardiovascular problems.     

Changes in blood pressure,heart rate and blood constituents during heat exposure in men with elevated blood pressure

Summary Although the vascular volume response of hypertensive men during exercise has been rather well characterized, the effect of resting heat exposure in this patient population has not been examined. This was done in the present report in seven men with high blood pressure (BP) (i. e., diastolic pressure>12 kPa (90 mmHg) upon initial interview) and 5 normotensive control subjects. 50 min after each subject had consumed an amount of water equal to 1% of his body weight, he reclined on a cot. 10 min later the subject was carried into an environmental chamber equilibrated at Tdb=45 C, Twb=28 C. Free-flowing venous blood samples were obtained from a cubital vein, and BP and heart rate were measured, before the heat exposure and at 15 min intervals during the experiment. Within 30 min systolic, diastolic and mean BP of the high BP subjects had decreased to normal levels; no BP changes were detected in normotensive subjects. Accompanying this depressor response was an exaggerated elevation in plasma glucose concentration. No alterations were found with haematocrit, plasma osmolality or electrolytes, or total protein and albumin. The data suggest that heat exposure may have been more stressful for the subjects with high BP than for their controls. This finding implies that phasic depressor responses may be as important as phasic pressor episodes in the aetiology of established essential hypertension.Training Grant HL07050 from the National Institutes of Health supported this project     

Diabetes affects blood pressure and heart rate responses during acute hypothermia

Many diabetics are cold-intolerant and experience dramatic changes in normal systemic function during hypothermia. Little is known of the cardiovascular adjustments in diabetics exposed to an acute cold stress. In an effort to identify the alterations in mean arterial blood pressure (MAP) and heart rate (HR) in the diabetic during environmental cooling (10 ± 2 °C), we compared the in vivo MAP and HR responses of urethane-anaesthetized (1.5 g kg^?1), streptozotocin-diabetic (STZ, 65 mg kg^?1, n = 12) and control (CON, n = 10) rats during acute hypothermia. MAP was measured directly via an indwelling carotid artery cannula and HR was calculated from the peak systolic pressure waves. Overall, the STZ rats were more cold-intolerant than CON as evidenced by the greater rate of decline in colonic temperature (T_c) from 36 to 28 °C (STZ, 0.16 °C min^?1 vs. CON, 0.06 °C min^?1; P < 0.05). Prior to cooling, HR was significantly lower (P < 0.05) in STZ (282 ± 9 beats min^?1) than in CON rats (399 ± 24 beats min^?1); however, during the acute hypothermic period, HR displayed a similar rate of decline in both groups. With respect to MAP, both groups demonstrated similar pre-experimental pressor responses (CON, 81.7 ± 5.4 vs. STZ, 83.2 ± 5.1 mmHg, P > 0.05). During progressive hypothermia, MAP gradually increased (P < 0.05) in the CON group from baseline (T_c = 36 °C) and reached peak values (118.4 ± 2.5 mmHg) at T_c = 30 °C, while the STZ group failed to exhibit any cold pressor response. At the conclusion of the experiment (T_c = 28 °C), the STZ group pressor response to hypothermia was not different from baseline (T_c = 36 °C, 83.2 ± 5.1 vs. T_c = 28 °C, 77.4 ± 3.4 mmHg; P > 0.05). The absence of any pressor response in the diabetic group during progressive hypothermia reflects the poor overall vasoconstrictive capacity to cooling and could partially explain the rapid decline of core temperature in this group.     

Causal relationship between heart rate and arterial blood pressure variability signals

A method is described which allows the determination of the causal relationship existing between two biological signals (heart rate and arterial blood pressure variability signals) which carry information about the role of control elicited by the autonomic nervous system. This method assumes an autoregressive (AR) model for the two signals to check the cross-correlation of the two residuals after AR identification. This information, together with the classical parameters of the spectral analysis (mean, variance, frequency and power in two typical bands, gain, phase and coherence) may provide a more precise evaluation of the complex mechanisms involved in the control of heart rate and blood pressure in numerous physiopathological situations.     

低体温与心率变异性和血压变异性的关系

目的: 研究低体温与自主神经功能变化的关系。方法: 采用体表物理降温法逐步降低直肠温度,直肠温度变化范围为19-37 ℃。分别记录不同直肠温度下大鼠动态心电和血压信号。应用心率变异性和血压变异性分析系统评价低体温对心率变异性和收缩压变异性的影响。结果: 心率变异分析表明，直肠温度下降到29 ℃以下,R-R间期均延长（P<0.01）,提示心率明显降低;当直肠温度下降到19-21 ℃时,心率变异归一化低频功率降低（P<0.05）和归一化高频功率增加（P<0.05），而且自主神经的平衡向心迷走神经张力增强的方向发生了转移（P<0.05）。血压变异性分析表明，体温下降到31℃时与呼吸有关的归一化高频功率开始增加（P<0.01）；直肠温度下降到29 ℃以下(除27 ℃外),与呼吸有关的归一化高频功率增加（P<0.05或P<0.01），同时自主神经的平衡也发生了改变（P<0.05）。结论： 随着体温的降低，心血管迷走神经活性增加，自主神经的平衡向迷走神经张力增强的方向转移。低体温对血压变异性的影响敏感于心率变异性。     

Integrated circuit system for digitizing arterial blood pressure and heart rate

The measurement of arterial blood pressure during physiological, pharmacological or behavioral manipulations generates a vast amount of data which must be reduced. Hand scoring is both time consuming and inaccurate, while on-line computer analysis may be prohibitively expensive. As an alternative, an inexpensive circuit is described which digitizes, stores, and prints out mean systolic and diastolic blood pressure, as well as heart rate, from up to four analog channels. Channels are sequentially digitized, each for an interval dialed on the front panel (1–999 sec). For each beat, a peak and trough detector enables the systolic and diastolic accumulators, respectively, thus storing two ten bit words from the analog to digital converter. For each systolic occurrence, a count of one is added to the heart rate counter. At the end of the recording interval, an output routine prints the interval number, mean systolic pressure, mean diastolic pressure, and total heart beats. Offset and gain controls allow precise calibration of various transducer and polygraph amplifiers.     

Effect of beta-adrenomimetics on formation of blood pressure and heart rate rhythms

Chronobiological Laboratories, University of Minnesota, Minneapolis, USA. Department for Newborn and Premature Infants, Research Institute of Pediatrics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR M. Ya. Studenikin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 8, pp. 202–205, August, 1991.