Cardiovascular control during sleep: “Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects,” by Silvani et al.

2008 ◽  
Vol 294 (5) ◽  
pp. R1684-R1685 ◽  
Author(s):  
John Trinder
Keyword(s):  
Blood Pressure ◽  
Human Subjects ◽  
Cardiovascular Control ◽  
Heart Period

Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects

2008 ◽  
Vol 294 (5) ◽  
pp. R1686-R1692 ◽  
Author(s):  
Alessandro Silvani ◽  
Daniela Grimaldi ◽  
Stefano Vandi ◽  
Giorgio Barletta ◽  
Roberto Vetrugno ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Eye Movement ◽  
Sleep Disordered Breathing ◽  
Human Subjects ◽  
Rapid Eye Movement Sleep ◽  
Heart Period ◽  
Low Frequencies ◽  
Feed Forward ◽  
Finger Blood Pressure ◽  
Spontaneous Fluctuations

We investigated whether in human subjects, the pattern of coupling between the spontaneous fluctuations of heart period (HP) and those of systolic blood pressure (SBP) differs among wake-sleep states. Polysomnographic recordings and finger blood pressure measurements were performed for 48 h in 15 nonobese adults without sleep-disordered breathing. The cross-correlation function (CCF) between the fluctuations of HP and SBP at frequencies <0.15 Hz was computed during quiet wakefulness (QW), light (stages 1 and 2) and deep (stages 3 and 4) nonrapid-eye-movement sleep (NREMS), and rapid-eye-movement sleep (REMS). A positive correlation between HP and the previous SBP values, which is the expected result of baroreflex feedback control, was observed in the sleep states but not in QW. In deep NREMS, the maximum CCF value was significantly higher than in any other state, suggesting the greatest baroreflex contribution to the coupling between HP and SBP. A negative correlation between HP and the subsequent SBP values was also observed in each state, consistent with the mechanical feed-forward action of HP on SBP and with central autonomic commands. The contribution of these mechanisms to the coupling between HP and SBP, estimated from the minimum CCF value, was significantly lower in deep NREMS than either in light NREMS or QW. These results indicate that the pattern of coupling between HP and SBP at low frequencies differs among wake-sleep states in human subjects, with deep NREMS entailing the highest feedback contribution of the baroreflex and a low effectiveness of feed-forward mechanisms.

Potential of Weight Scale Based Ballistocardiography for Identifying Orthostatic Intolerance: A Tilt Table Study

2020 ◽  
Author(s):  
Parshuram N. Aarotale ◽  
Stian N. Henriksen
Keyword(s):  
Blood Pressure ◽  
Orthostatic Intolerance ◽  
Low Frequency ◽  
Cost Effective ◽  
Cardiovascular Control ◽  
Tilt Test ◽  
Heart Period ◽  
Wilcoxon Rank Sum Test ◽  
Before And After ◽  
Effective System

Abstract Autonomic cardiovascular control is critical in regulating blood pressure during postural transition, failure of which could lead to dizziness and fall (orthostatic intolerance). In this study, the feasibility of Ballistocardiography (BCG) for quantifying autonomic nervous system activity in relation to gold standard electrocardiogram (ECG) was tested. Simultaneous ECG, blood pressure, photoplethysmography (PPG), and BCG were continuously acquired during 5-minutes of stand tests (before and after tilt test up to 60°) from 10 participants. Heart period was derived from ECG and BCG represented as RR and JJ intervals, respectively. Spectral analysis of heart period (both RR and JJ) was performed by calculating power distributed in low-frequency (0.04–0.15 Hz) and high-frequency (0.15–0.4 Hz) bands. Strong correlation (r &gt; 0.87 for Pre-tilt and r &gt; 0.97 for Post-tilt, p &lt; 0.001) between ECG and BCG derived LF, HF, and LF/HF was observed, except for LF/HF (r &gt; 0.63 for Pre-tilt). The Wilcoxon rank sum test revealed no difference (p &gt; 0.10) in BCG or ECG LF, HF, and LF/HF during the two stand tests. The findings of the study highlighted the feasibility of monitoring cardiovascular control via weight-scale BCG. Therefore, the developed system can gain utility as a portable and cost-effective system for early detection and mitigation of falls associated with autonomic dysfunction.

Patterns of Cerebral Blood Flow and Systemic Hemodynamics During Arithmetic Processing

2008 ◽  
Vol 22 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Natalie Werner ◽  
Neval Kapan ◽  
Gustavo A. Reyes del Paso
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Time Course ◽  
Doppler Sonography ◽  
Transcranial Doppler Sonography ◽  
Systemic Hemodynamics ◽  
Heart Period ◽  
Blood Flow Velocities ◽  
Flow Velocities

The present study explored modulations in cerebral blood flow and systemic hemodynamics during the execution of a mental calculation task in 41 healthy subjects. Time course and lateralization of blood flow velocities in the medial cerebral arteries of both hemispheres were assessed using functional transcranial Doppler sonography. Indices of systemic hemodynamics were obtained using continuous blood pressure recordings. Doppler sonography revealed a biphasic left dominant rise in cerebral blood flow velocities during task execution. Systemic blood pressure increased, whereas heart period, heart period variability, and baroreflex sensitivity declined. Blood pressure and heart period proved predictive of the magnitude of the cerebral blood flow response, particularly of its initial component. Various physiological mechanisms may be assumed to be involved in cardiovascular adjustment to cognitive demands. While specific contributions of the sympathetic and parasympathetic systems may account for the observed pattern of systemic hemodynamics, flow metabolism coupling, fast neurogenic vasodilation, and cerebral autoregulation may be involved in mediating cerebral blood flow modulations. Furthermore, during conditions of high cardiovascular reactivity, systemic hemodynamic changes exert a marked influence on cerebral blood perfusion.

Effects of Fear Induction on Heart Period Variability

1999 ◽  
Vol 13 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Rudolf Stark ◽  
Alfons Hamm ◽  
Anne Schienle ◽  
Bertram Walter ◽  
Dieter Vaitl
Keyword(s):  
Blood Pressure ◽  
Trait Anxiety ◽  
State Anxiety ◽  
Self Report ◽  
Emotional States ◽  
Heart Period ◽  
Experimental Conditions ◽  
Heart Period Variability ◽  
Physiological Variables ◽  
Period Variability

Abstract The present study investigated the influence of contextual fear in comparison to relaxation on heart period variability (HPV), and analyzed differences in HPV between low and high anxious, nonclinical subjects. Fifty-three women participated in the study. Each subject underwent four experimental conditions (control, fear, relaxation, and a combined fear-relaxation condition), lasting 10 min each. Fear was provoked by an unpredictable aversive human scream. Relaxation should be induced with the aid of verbal instructions. To control for respiratory effects on HPV, breathing was paced at 0.2 Hz using an indirect light source. Besides physiological measures (HPV measures, ECG, respiration, forearm EMG, blood pressure), emotional states (pleasure, arousal, dominance, state anxiety) were assessed by subjects' self-reports. Since relaxation instructions did not have any effect neither on the subjective nor on the physiological variables, the present paper focuses on the comparison of the control and the fear condition. The scream reliably induced changes in both physiological and self-report measures. During the fear condition, subjects reported more arousal and state anxiety as well as less pleasure and dominance. Heart period decreased, while EMG and diastolic blood pressure showed a tendency to increase. HPV remained largely unaltered with the exception of the LF component, which slightly decreased under fear induction. Replicating previous findings, trait anxiety was negatively associated with HPV, but there were no treatment-specific differences between subjects with low and high trait anxiety.

Plasma ascorbic acid concentrations relate inversely to blood pressure in human subjects

1993 ◽  
Vol 57 (2) ◽  
pp. 213-217 ◽  
Author(s):  
J P Moran ◽  
L Cohen ◽  
J M Greene ◽  
G Xu ◽  
E B Feldman ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Ascorbic Acid ◽  
Human Subjects ◽  
Plasma Ascorbic Acid

Abstract 047: Genetics and Environmental Influences on Ambulatory Blood Pressure in Rats Compared With Circadian Blood Pressure Variability in Human

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Mary S Lee ◽  
John S Lee ◽  
Jong Y Lee ◽  
Silvia H Azar ◽  
Franz Halberg
Keyword(s):  
Blood Pressure ◽  
Human Subjects ◽  
Disease Status ◽  
Least Square ◽  
Spontaneously Hypertensive ◽  
Adolescents And Adults ◽  
Nursing Mothers ◽  
Uterine Environment ◽  
Elder Adults ◽  
Circadian Blood Pressure Variability

Genetic susceptibility is an important factor in raising blood pressure (BP). Daily (circadian) rhythm characteristics are considered essential parameters for recognizing and treating increased risks in BP. To examine BP in genetics with environmental modifications, one-cell homozygous embryos were transferred into spontaneously hypertensive (SHR, pup:shr) or normotensive (WKY, pup:wky) rats' oviducts (embryos: s, w; oviduct-uterine: S, W) in a reciprocal fashion. Pups were cross-suckled at birth (nurses S, W) and weaned to normal diets at day-21. At Day-120, telemetered BPs were monitored for 5 consecutive days every 4 min and analyzed by the method of ANOVA. Ambulatory BP in 20 adolescents and adults were monitored automatically around the clock at 30-min to hourly intervals and analyzed by the least square rhythmometry method. As expected, shr BPs were markedly reduced when they were transplanted to the W-uterine and/or the W-lactation milieu (sSS vs. sSW, sWS and sWW: 197 vs.178, 147 and 178 mm Hg). BP in wky was significantly altered only in the wSW group (wWW vs, wSW: 127 vs.131 mm Hg). All subjects showed significant circadian fluctuations with a peak in the late afternoon hours in most human subjects and rats as a nocturnal animal mostly close to midnight hours, while shr with W-uterine (sWS) a bit delayed peak hour (00:45) and with combined W-uterine/W-nursing (sWW) a bit earlier peak hour (20:12). Circadian double amplitudes (2A) in the human subjects varied from 8 to 26 mm Hg with higher 2A in elder adults, and 3-8 mm Hg in rats with significantly higher fluctuations in shr groups as compared to that of wWW (7.5±0.7 for sSS, 8.3±0.6 for sSW vs. 4.7±0.3 mm Hg for wWW). The hypertensive-prone shr strain showed significantly lowered BPs in a normotensive WKY uterine environment and/or by WKY nursing mothers, indicating that environment influences can strongly modify genetic factors, yet the lowered shr MESORs by the WKY environments remained above the MESORs encountered in wky donors. Chronomes broader than circadian should be considered in interpreting BP responses as a gauge of vascular disease status.

scholarly journals Effect of capsinoids on energy metabolism in human subjects

2009 ◽  
Vol 103 (1) ◽  
pp. 38-42 ◽  
Author(s):  
Jose E. Galgani ◽  
Donna H. Ryan ◽  
Eric Ravussin
Keyword(s):  
Blood Pressure ◽  
Energy Metabolism ◽  
Metabolic Rate ◽  
Human Subjects ◽  
Acute Effect ◽  
Molecular Structures ◽  
Acute Effects ◽  
Axillary Temperature ◽  
Double Blind ◽  
Different Doses

Capsinoids are non-pungent compounds with molecular structures similar to capsaicin, which has accepted thermogenic properties. To assess the acute effect of a plant-derived preparation of capsinoids on energy metabolism, we determined RMR and non-protein respiratory quotient (NPRQ) after ingestion of different doses of the capsinoids. Thirteen healthy subjects received four doses of the capsinoids (1, 3, 6 and 12 mg) and placebo using a crossover, randomised, double-blind trial. After a 10 h overnight fast as inpatients, RMR was measured by indirect calorimetry for 45 min before and 120 min after ingesting capsinoids or placebo. Blood pressure and axillary temperature were measured before ( − 55 and − 5 min) and after (60 and 120 min) dosing. Before dosing, mean RMR was 6247 (se92) kJ/d and NPRQ was 0·86 (se0·01). At 120 min after dosing, metabolic rate and NPRQ remained similar across the four capsinoids and placebo doses. Capsinoids also had no influence on blood pressure or axillary temperature. Capsinoids provided in four doses did not affect metabolic rate and fuel partitioning in human subjects when measured 2 h after exposure. Longer exposure and higher capsinoids doses may be required to cause meaningful acute effects on energy metabolism.

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