Temporal stability of the hemodynamics of cardiovascular reactivity (original) (raw)
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Hemodynamic response patterns: Responder type differences in reactivity and recovery
Psychophysiology, 2002
We examined whether responder type groups reflecting patterns of hemodynamic reactivity might also differ in recovery responses. Cardiac output~CO!, total peripheral resistance~TPR!, systolic and diastolic blood pressure, heart rate, and Heather index were assessed at rest and during speech and cold pressor tasks in young adults. Participants~n ϭ 152! were classified as myocardial, vascular, or mixed-mild responders based on CO and TPR responses to speech presentation. Vascular responders exhibited slower CO and TPR speech recovery than the myocardial and0or mixedmild groups. Responder type differences in reactivity showed limited task-generalizability. The sustained vascular response pattern of the vascular group is consistent with that seen in hypertension. In light of associations of heightened TPR with markers of disease risk, this suggests potentially negative health implications for vascular responders.
Psychophysiological correlates of individual differences in patterns of hemodynamic reactivity
International Journal of Psychophysiology, 2001
The present study delineates a method for the quantification of six hemodynamic reactivity patterns, in response to a laboratory stressor, and examines the psychophysiological correlates of individual differences in these patterns. One hundred and ninety-four young adult men and women participated in rest periods and two laboratory stressors, mental arithmetic and an anger recall interview. Measures were taken of blood pressure, heart rate, and cardiac output, from which total peripheral resistance was derived, as well as state reports of feelings during the tasks. Six hemodynamic reactor patterns were identified: Non-reactors, Mild Myocardials, Mild Vasculars, Myocardials, Vasculars, and Dual Reactors, each associated with a unique profile of cardiac output and total peripheral resistance change. Myocardial reactors to the interview had the highest resting levels of blood pressure and total peripheral resistance. Dual reactors had the largest increases in diastolic reactivity; Dual and Myocardial reactors had the Ž. largest increases in systolic reactivity. The extreme reactor groups Dual, Myocardial, Vascular all reported greater task invigoration than the Non-reactors, who reported greater efforts to relax. Reactor groups were similar on anger-related trait affect. Based on both resting blood pressure and magnitude of task-induced reactivity, Myocardial and Dual reactors may be at the greatest risk for subsequent hypertension.
Aim was to elucidate autonomic responses to dynamic and static (isometric) exercise of the lower limbs eliciting the same moderate heart rate (HR) response. Method: 23 males performed two kinds of voluntary exercise in a supine position at similar heart rates: static exercise (SE) of the lower limbs (static leg press) and dynamic exercise (DE) of the lower limbs (cycling). Subjective effort, systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), rate pressure product (RPP) and the time between consecutive heart beats (RR-intervals) were measured. Time-domain (SDNN, RMSSD), frequency-domain (power in the low and high frequency band (LFP, HFP)) and geometric measures (SD1, SD2) as well as non-linear measures of regularity (approximate entropy (ApEn), sample entropy (SampEn) and correlation dimension D2) were calculated. Results: Although HR was similar during both exercise conditions (88±10 bpm), subjective effort, SBP, DBP, MAP and RPP were significantly enhanced during SE. HRV indicators representing overall variability (SDNN, SD 2) and vagal modulated variability (RMSSD, HFP, SD 1) were increased. LFP, thought to be modulated by both autonomic branches, tended to be higher during SE. ApEn and SampEn were decreased whereas D 2 was enhanced during SE. It can be concluded that autonomic control processes during SE and DE were qualitatively different despite similar heart rate levels. The differences were reflected by blood pressure and HRV indices. HRV-measures indicated a stronger vagal cardiac activity during SE, while blood pressure response indicated a stronger sympathetic efferent activity to the vessels. The elevated vagal cardiac activity during SE might be a response mechanism, compensating a possible co-activation of sympathetic cardiac efferents, as HR and LF/HF was similar and LFP tended to be higher. However, this conclusion must be drawn cautiously as there is no HRV-marker reflecting "pure" sympathetic cardiac activity.
Reproducibility of cardiovascular responses to mental and static tasks
Stress and Health, 2001
Temporal stability and transsituational consistency are important characteristics of cardiovascular responses to mental or static load. While in the literature stability is generally estimated as the relationship between only two test sessions, it is unknown whether these stability estimates can be generalized across multiple replications of the test situations. Forty subjects (20 males and 20 females) were tested four times with intervals of 1 day, 1 week, and 1 month. Each test session comprised two mental tasks (mental arithmetic and colour-word test) and a static (fingergrip) task. The physiological variables recorded were heart rate, systolic blood pressure, and diastolic blood pressure. The adaptation processes in the course of the four test sessions are more pronounced for the mental tests than for the static test. The temporal stability, restricted to test sessions 1 and 2, can be used to estimate the general stability across all pairs of test sessions. However, there are some non-systematic differences which indicate that more than two test sessions yield more reliable results. Averaging across two test sessions, compared with the stability of single test sessions, increases the stability of heart rate reactivity from 0.60 to 0.73. Low correlations between the responses to mental and static load indicate that there are different underlying regulatory mechanisms. The results show that the responsivity can be assessed more reliably when more than two tests are performed. The responses to one type of stressors (mental or static) cannot be generalized to an overall responsivity.
[Reactivity of blood pressure during physical exercise]
Arquivos brasileiros de cardiologia, 1994
Borderline hypertension (BH) has been associated with an exaggerated blood pressure (BP) response during laboratory stressors. However, the incidence of target organ damage in this condition and its relation to BP hyperreactivity is an unsettled issue. Thus, we assessed the Doppler echocardiographic profile of a group of BH men (N = 36) according to office BP measurements with exaggerated BP in the cycloergometric test. A group of normotensive men (NT, N = 36) with a normal BP response during the cycloergometric test was used as control. To assess vascular function and reactivity, all subjects were submitted to the cold pressor test. Before Doppler echocardiography, the BP profile of all subjects was evaluated by 24-h ambulatory BP monitoring. All subjects from the NT group presented normal monitored levels of BP. In contrast, 19 subjects from the original BH group presented normal monitored BP levels and 17 presented elevated monitored BP levels. In the NT group all Doppler echocardiographic indexes were normal. All subjects from the original BH group presented normal left ventricular mass and geometrical pattern. However, in the subjects with elevated monitored BP levels, fractional shortening was greater, isovolumetric relaxation time longer, and early to late flow velocity ratio was reduced in relation to subjects from the original BH group with normal monitored BP levels (P<0.05). These subjects also presented an exaggerated BP response during the cold pressor test. These results support the notion of an integrated pattern of cardiac and vascular adaptation during the development of hypertension.
Scandinavian journal of medicine & science in sports, 2014
To compare post-resistance exercise hypotension (PREH) and its mechanisms in normotensive and hypertensive individuals, 14 normotensives and 12 hypertensives underwent two experimental sessions: control (rest) and exercise (seven exercises, three sets, 50% of one repetition maximum). Hemodynamic and autonomic clinic measurements were taken before (Pre) and at two moments post-interventions (Post 1: between 30 and 60 min; Post 2: after 7 h). Ambulatory blood pressure (BP) was monitored for 24 h. At Post 1, exercise decreased systolic BP similarly in normotensives and hypertensives (-8 ± 2 vs -13 ± 2 mmHg, P > 0.05), whereas diastolic BP decreased more in hypertensives (-4 ± 1 vs -9 ± 1 mmHg, P < 0.05). Cardiac output and systemic vascular resistance did not change in normotensives and hypertensives (0.0 ± 0.3 vs 0.0 ± 0.3 L/min; -1 ± 1 vs -2 ± 2 U, P > 0.05). After exercise, heart rate (+13 ± 3 vs +13 ± 2 bpm) and its variability (low- to high-frequency components ratio, 1.9...
The repeatability of the cardiovascular responses to reflex tests has been the subject of several studies. We have studied heart rate and blood pressure response to mental arithmetic. Mental arithmetic has used as means of assessing cardiovascular autonomic reactivity to mental load. Ten healthy subjects were recruited for the mental arithmetic task. Same task was repeated by the same individuals for 5 successive days. Reliability or reproducibility of the mental task responses was measured using the intraclass correlation coefficient. We observed a significant declining trend in heart rate response to mental arithmetic task. It shows that the individuals become more and more familiar with a particular task if it is carried out repeatedly.