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1.
卧床中及卧床后头高位倾斜时心率及血压变异谱的变化 总被引:3,自引:0,他引:3
观察了男性青年21d头低位6°卧床过程中以及卧床前、后75°头高位倾斜(HUT)时心率变异(HRV)与动脉收缩压变异(SBPV)谱变化。卧床期间,完成者HRV和SBPV谱的低、高频谱峰功率(LF和HF)均显著减小,HRV谱低、高频谱峰功率比值(LF∶HFHRV)在卧床第16d有增大趋势;未完成者的相应谱指标有类似变化趋向。在卧床后HUT初始6min,所有被试者心率显著快于卧床前HUT时相应值,而LF∶HFHRV和SBPV谱的LF与卧床前HUT时相应值比较无显著变化。未完成者在卧床后HUT时,未能出现舒张压与平均动脉压升高反应;而其在卧床前HUT时,以及完成者在卧床前、后HUT时,均出现舒张压与平均动脉压升高反应。结果说明,较长时间卧床后心脏迷走神经与外周血管交感神经的活动水平降低,心脏交感神经活动水平相对增高;但卧床后HUT时心血管自主神经调节反应仍基本存在。未完成者卧床后HUT时血压升高反应消失的机理,可能还与卧床后外周血管的收缩反应性降低有关。 相似文献
2.
下体负压作用下人心率,血压变异性谱的变化及其与心血管反应… 总被引:1,自引:0,他引:1
观察了-6。67kPa下体负压(LBNP)持续作用期间人心率变异性(HRV)、血压变异性(SBPV)谱的变化,并探讨了谱特征与心血管反应之间的关系。结果表明:耐力良好者HRV谱的调频峰功率(HFHRV)显著降低,归一化高频参数(HFHRV,n)与低频参数(LFHRV,n)分别呈明确的降低或升高变化;SBPV谱的低频峰功率(LFSBPV)LBNP作用时降低,后又回升,至实验终止时已超出对照水平。LB 相似文献
3.
观察了-6.67kPa下体负压(LBNP)持续作用期间人心率变异性(HRV)、血压变异性(SBPV)谱的变化,并探讨了谱特征与心血管反应之间的关系。结果表明:耐力良好者HRV谱的高频峰功率(HFHRV)显著降低,归一化高频参数(HFHRV,n)与低频参数(LFHRV,n)分别呈明确的降低或升高变化;SBPV谱的低频峰功率(LFSBPV)LBNP作用时降低,后又回升,至实验终止时已超出对照水平。LBNP作用初期,耐力不良被试者HRV、SBPV谱特征的变化趋势与耐力良好者相同,但在出现晕厥前症状时,LFSBPV及LFSBPV,n均有较大幅度的降低。上述结果提示:耐力不良被试者心血管反应失代偿主要与外周血管交感神经活动水平的迅速降低有关。 相似文献
4.
21天头低位(-6°)卧床前后下体负压和头高位倾斜暴露时的心血管反应 总被引:1,自引:0,他引:1
目的探讨21天头低位(HDT)卧床对人体立位应激下心血管反应的影响,以及比较下体负压(LBNP)和头高位倾斜(HUT)两种立位应激下心血管反应的差异。方法6名受试者在21天HDT前、后分别进行LBNP(-4.00kPa/3min、-6.67kPa/3min及-9.33kPa/3min)和HUT试验(30°/3min、45°/3min、60°/3min及75°/3min),以比较两种检测方法的血压(BP)和心率(HR)的变化情况。结果与LBNP(或HUT)前相比:①LBNP(HUT)时HR显著增加(P<0.01),SBP显著降低(P<0.05);卧床后相应的变化量增加。②LBNP时DBP降低(卧床后达显著,P<0.05);而HUT时DBP增加(卧床后达显著,P<0.05)。③LBNP时MAP均显著降低(P<0.05);而HUT时在卧床前无变化(P>0.05),在卧床后显著增加(P<0.05)。结论LBNP和HUT引起的CVS反应并不相同。笔者认为,HUT更能促进心血管系统对立位应激的调节作用。 相似文献
5.
6名年龄35±6岁男性受试者作为对照组,6名年龄36±6岁练气功的男性受试者为练气功组。实验程序包括2d的准备期,7d的头低位-6°卧床(HDBR-6°)期和2d的恢复期。每天收集24h全尿,测定尿皮质醇(UCOR)和尿醛固酮(UALD);每两天采集耳血一次,测定超氧化物歧化酶(SOD)的活性。结果表明:卧床前两组间UCOR和SOD没有显著差异,而HDBR-6°后对照组UCOR和SOD明显增加(P<0.01),练功组仅有增加的趋势,对照组和练功组相比在HDBR-6°期间差别显著(p<0.01)。这表明练气功组比对照组有较好的耐受HDBR-6°的应激能力,对保持机体内环境稳定具有重要的意义。 相似文献
6.
为探讨卧床模拟失重对机体缺氧耐力的影响,对6名受试者,头低位4°卧床(-4°HDBR)7d,检查了卧床前后缺氧耐力和立位耐力,记录了ECG、BP及HR的变化。结果表明:-4°HDBR模拟失重降低了机体的缺氧耐力;缺氧耐力与心血管失调间有很好的相关性。 相似文献
7.
下体负压下的心率变异分析 总被引:2,自引:2,他引:0
为探讨下体负压下的心率变异变化及其与血液动力这指标的关系,40名健康男性参加了下体负压实验,用Holter记录了受试者V5导联心电图,并进行了心率变异(HRV)分析;用超声多谱勒技术测定SV,CO。结果表明:在LBNP过程中两组受试者均出现了HRV的降低,尤以高频谱质量(HF)降低显著,LF/HF在LBNP过程中呈升高趋势,耐力低者的LF/HF升高比耐力良好者明显,提示:晕厥前症状的发生可能是由于 相似文献
8.
有氧锻炼前后立位应激下血压变异性的比较 总被引:5,自引:3,他引:2
目的阐明下体负压(LBNP)作用下血压变异性的特征,以及有氧锻炼是否对其有一定影响。方法用常规AR谱、时变AR谱、粗粒化谱分析(CGSA)及近似熵(ApEn)四种方法,分析六个月有氧锻炼前、后大学生在两种LBNP作用下的收缩压变异性(SBPV),并与一组中、长跑运动员的结果进行横向比较。结果LBNP作用时,SBPV信号谐波成份的总功率及低频段(LF)功率增大,分形成份的谱指数(无显著变化,而ApEn则呈持续升高变化。有氧锻炼后,LBNP作用下各种SBPV指标的响应变化较锻炼前并无显著差别。大学生组与运动员组之间亦无显著差别。结论SBPV信号与心率变异性(HRV)迥然不同:LBNP作用下,SBPV的LF成份被进一步激活,信号的复杂度显著升高;但SBPV信号的这种特征性变化并不受有氧锻炼的影响。 相似文献
9.
前庭刺激对飞行人员心率变异的影响 总被引:4,自引:1,他引:3
为探讨前庭刺激对飞行人员的心率变异性(HRV)及植物神经功能的影响,对两组飞行员在不同强度的科里奥利加速度刺激时,用时域分析和频域分析法对实验前和实验中的HRV进行了检测和分析。结果表明;原始均值,标准差,最小值,最大值,极差,相关均值,R-R间期差值的均方根(RMSSD),谱总功率(TP),低频(LF),高频(HF),LF/TP,HF/TP,LF/HF均有不同程度的增加(P〈0.05~0.01) 相似文献
10.
为研究心肺压力感受器卸荷对人心血管自主神经调节的影响,采用心率变异性(HRV)和血压变异性(SBPV和DBPV)谱分析方法考察了在-2kPa下体负压(LBNP)条件下,心血管自主神经活动水平的变化。结果表明:LBNP作用1~7min时基础胸阻抗(Zo)明显升高,心脏每搏量(SV)明显减少,致使前臂血管阻力(FVR)明显增加、血流下降(FBF),而心率(HR)及HRV谱参数未发生显著变化,进一步证实了心肺压力感受器对外周血管交感神经和心脏自主神经活动的调节存在机能分化现象;LBNP作用时尽管有外周血管交感神经兴奋现象,但血压变异性谱参数均未发生显著改变,表明这两者在心肺压力感受器卸荷时的变化趋向存在差异。 相似文献
11.
急性轻中度缺氧条件下心率及收缩压变异性谱变化 总被引:6,自引:3,他引:3
目的:应用心率及收缩压变异性(HRV、SBPV)谱分析方法评价急性轻中度缺氧条件下心血管自主神经调节的变化。方法:10名健康男性青年分别吸入氧13.7%(相当于海拔3500m)和11%(相当于海拔5000m)两种氮-氧混合气各20min,将对照和缺氧条件下的HRV和SBPV谱变化进行对比分析。结果:在两种缺氧条件下,受试者均出现血压下降、心率增快反应,HRV谱总功率(TP)和高频成分(HF)功率均显著减小,低频成分(LF)功率与LF/HF功率比值无显著变化,SBPV谱LF功率显著增大,3名缺氧耐力不良受试者尤为明显。不同水平缺氧之间的数值比较差异均无显著性意义。结论:急性轻中度缺氧条件下,人副交感神经抑制,交感神经兴奋,联合应用HRV与SBPV谱分析方法可对心血管自主神经调节活动进行评定;但HRV的LF成分变化机理较为复杂。 相似文献
12.
Aerobic training and cardiovascular responses at rest and during exercise in older men and women 总被引:7,自引:0,他引:7
Perini R Fisher N Veicsteinas A Pendergast DR 《Medicine and science in sports and exercise》2002,34(4):700-708
PURPOSE: The effects of an intense 8-wk aerobic training program on cardiovascular responses at rest and during exercise, including heart rate variability (HRV) as an expression of autonomic modulation, were evaluated in subjects over 70 yr (mean: 73.9 +/- 3.5 yr). METHODS: Before and after training in 7 men and 8 women: a) heart rate (HR), blood pressures (BPs), pulse pressure (PP), and oxygen uptake were measured at rest, during, and after exhausting incremental exercise; b) HRV power spectra were calculated at rest in supine and sitting, and during and after two submaximal constant loads (5 min). Power in low-frequency (LF, 0.04-0.15 Hz) and high-frequency (HF, >0.15 Hz) bands were expressed as a percent of total power minus power < 0.04 Hz. RESULTS: After training: a) at rest HR and HRV parameters (in both body positions) were unchanged, whereas BPs decreased; b) peak cycle resistance and oxygen consumption increased by 25% and 18%, respectively, but no change in maximal HR and BPs were found; c) during submaximal loads HR was unchanged at the same metabolic demand, whereas SBP and DBP were lower than before at low loads whereas PP was unchanged. LF power decreased and HF increased at oxygen uptakes above about 0.7 L.min-1 similarly before and after training; and d) recovery of all parameters was similar to pretraining and complete after 10 min CONCLUSIONS: The increase in exercise capacity without changes in cardiovascular parameters suggests that 8 wk of aerobic training augmented peripheral gas exchange but not delivery to muscle. The lack of effect on HRV indicates that the improvements in aerobic power and cardiac autonomic modulation, at least in subjects over 70 yr, are dissociated. Moreover, the metabolic demand seems to be the main factor for the changes in HRV power spectra that occur during exercise. 相似文献
13.
Kamiya A Iwase S Sugiyama Y Mano T Sudoh M 《Aviation, space, and environmental medicine》2000,71(2):142-149
BACKGROUND: Alterations in autonomic function are commonly seen during and after spaceflight, and its ground-based analog, 6 degrees head-down bed rest (HDBR). They may include peripheral vascular regulation, but vasomotor sympathetic efferent nerve discharges to peripheral vasculatures have not been examined. The aim of our study was to examine changes in vasomotor sympathetic nerve activity during HDBR and under orthostasis after HDBR. METHODS: We performed 6 d of HDBR on six male subjects, and measured muscle sympathetic nerve activity (MSNA) together with plasma norepinephrine concentrations in the supine position before HDBR and in 6 degrees head-down position on the sixth day (HDBR6) of HDBR. We also measured MSNA in head-up tilt (HUT) test before and after HDBR. RESULTS: On HDBR6, MSNA burst rate was the same (17+/-4 bursts x min(-1)) as that in supine position before HDBR (15+/-2 bursts min(-1)), but plasma norepinephrine concentrations were decreased to 1.14+/-0.10 pmol x ml(-1) compared with the supine value before HDBR (1.56+/-0.20 pmol x ml(-1), p<0.05). After HDBR, supine MSNA burst rate significantly increased by 58% to 24+/-4 bursts x min(-1). MSNA increment in response to HUT was similar between before (34+/-3 bursts min(-1) x sin HUT(-1)) and after (40+/-6 bursts x min(-1) x sin HUT(-1)) HDBR. CONCLUSIONS: Our findings suggest that: a) the relationship between MSNA and plasma norepinephrine concentrations was altered on the sixth day during HDBR; b) the vasomotor sympathetic nerve activity was enhanced after HDBR; and c) the augmentation of vasomotor sympathetic outflow to muscles under orthostasis was preserved after HDBR. 相似文献
14.
Heart rate variability during high-intensity field exercise in female distance runners 总被引:1,自引:0,他引:1
Sumi K Suzuki S Matsubara M Ando Y Kobayashi F 《Scandinavian journal of medicine & science in sports》2006,16(5):314-320
The purposes of this study were to demonstrate the transition of heart rate variability (HRV) during trials in the field and to examine the relationship between peak frequency of high-frequency band (HF) and stride frequency. Ten healthy long-distance college female runners (age 19-21 years) performed a 3000 m realistic time trial. The time-series power spectrum analysis by maximum entropy method was used to evaluate cardiac autonomic nervous activity during the race. Cross-correlation coefficients were calculated to estimate the degree of linear co-ordination between the central peak frequency of HF and stride frequency. Just after starting, the decrease in HF (0.15-1.00 Hz) and a transient increase of low-frequency band (LF)/HF were found. After that, the HF remained at a low level and LF/HF decreased sharply. These findings suggested that the parasympathetic activity was suppressed and sympathetic activity increased just after starting, and the sympathetic activity reached the saturated level according to continuation of high-intensity exercise. In spite of the significant decrease of HRV during trials, peak frequency of HF could be differentiated clearly. The cross-correlation coefficient of peak frequency of HF and stride frequency was from 0.703 to 0.868. This finding indicated that exercise rhythm reflected HRV during high-intensity running in the field. 相似文献
15.
急性缺氧条件下的心率变异性分析 总被引:11,自引:1,他引:10
目的 以心率变异性(HRV)为定量评价心血管自主神经调节变化的指标,观察模拟5000m急性缺氧条件下,自主神经变化特点,并探讨预测缺氧耐力不良的方法。方法 被试者为11名18-30岁的健康男性,以呼吸10.5%的低氧混合气30min模拟5000m急性缺氧,以时域和频域(粗粒化谱分析,CGSA)方法进行HRV分析。并根据是否完成实验过程将被试者分为耐力良好组(A组)和耐力不良组(B组)。结果 耐力良好组在缺氧时心率显著增快,相邻RR间期之差的均方根值(RMSSD)显著减小,LFn.u(LF的标准单位)和LF/HF显著增大,HF和HFn.u.(HF的标准化单位)显著减小。两组比较,缺氧5-10min时,LFn.u.和LF/HF在B组显著大于A组,缺氧10-15min时,RMSSD在B组显著小于A组。结论 在模拟5000m急性缺氧条件下,交感神经活动增强,迷走神经活动减弱;HRV分析对评价缺氧耐力有一定的预测性。 相似文献
16.
卧床不同训练方法对心血管自主神经调节变化的影响 总被引:8,自引:0,他引:8
目的以心率变异性 (HRV)频域变量 ,作为定量评价心血管自主神经调节变化的指标 ,观察卧床条件下 ,不同训练方法对心血管自主神经调节变化的影响。方法被试者为 1 5名年龄 1 9~ 2 2岁的健康男性 ,分为对照组、放松训练组和低氧训练组 ,每组 5人 ,头低位 (- 6°)卧床模拟失重时的心血管变化。在对照期 (第 2天 )、卧床期 (第 3、1 4、1 8天 )和恢复期 (第 7天 )记录 2 4h动态心电图 ,采用自回归模型进行 2 4h全程、放松和低氧训练前、中、后的心率变异性谱分析 ,其标准化的低频 (LF % ,0 .0 4~ 0 .1 5Hz)成分表示心交感神经的紧张度 ,标准化的高频 (HF % ,0 .1 5~ 0 .40Hz)成分独立地反映心迷走神经的活性 ,LF/HF的比值表明交感和迷走神经张力的平衡关系。结果卧床期对照组的LF %和HF %成分显著下降 (P <0 .0 5) ,LF/HF无明显变化。放松组在放松训练中HRV谱的HF %成分明显增加 (P <0 .0 5) ,而低氧组在低氧训练中 ,LF %成分显著增加 (P <0 .0 5)。结论卧床使交感和迷走神经的活性都降低 ,放松训练明显提高了迷走神经的兴奋性 ,而低氧训练明显提高了交感神经的兴奋性。提示 ,HRV指标有可能作为定量评价失重对抗措施的客观指标 ,值得进一步深入研究。 相似文献
17.
Povea C Schmitt L Brugniaux J Nicolet G Richalet JP Fouillot JP 《High altitude medicine & biology》2005,6(3):215-225
Changes in heart rate variability induced by an intermittent exposure to hypoxia were evaluated in athletes unacclimatized to altitude. Twenty national elite athletes trained for 13 days at 1200 m and either lived and slept at 1200 m (live low, train low, LLTL) or between 2500 and 3000 m (live high, train low, LHTL). Subjects were investigated at 1200 m prior to and at the end of the 13-day training camp. Exposure to acute hypoxia (11.5% O(2)) during exercise resulted in a significant decrease in spectral components of heart rate variability in comparison with exercise in normoxia: total power (p < 0.001), low-frequency component. LF (p < 0.001), high-frequency component, HF (p < 0.05). Following acclimatization, the LHTL group increased its LF component (p < 0.01) and LF/HF ratio during exercise in hypoxia after the training period. In parallel, exposure to intermittent hypoxia caused an increased ventilatory response to hypoxia. Acclimatization modified the correlation between the ventilatory response to hypoxia at rest and the difference in total power between normoxia and hypoxia (r (2) = 0.65, p < 0.001). The increase in total power, LF component, and LF/HF ratio suggests that intermittent hypoxic training increased the response of the autonomic nervous system mainly through increased sympathetic activity. 相似文献
18.
平行秋千摆动刺激中的心率变异分析 总被引:2,自引:2,他引:0
目的 观察飞行员在平行秋千摆动前、中、后反映心脏植物神经调节功能的心率变异性(HRV)特点,搪塞以此评价线性加速度作用下前庭=植物神经反应性的可能性。方法记录37名飞行员在秋千摆动前、中、后的连续心电图,进行频率谱分析并计算低频成分(LF)和高频成分(HF)之幽会对被试者中LF/HF值在不同摆动阶段变化类型及分布耐受摆动时间的关系进行初步分析。结果 摆动中的LF明显降低,HF明显增高,LF/HJF 相似文献
19.
PURPOSE: Chronic exercise training has been shown to have a positive influence on cardiac autonomic function as assessed by measures of heart rate variability (HRV). Recent evidence indicates that several benefits associated with exercise training (e.g., improved insulin action, reduced blood pressure, improved blood lipid profile) may be realized transiently after a single bout of exercise. As many of these effects of recent exercise are linked to cardiovascular control systems, the purpose of this investigation was to test the hypothesis that a single bout of exercise would result in favorable changes in cardiac autonomic function as assessed by frequency-domain measures of HRV. METHODS: Subjects were 11 healthy male volunteers ages 18-35 yr. Resting HRV measures were obtained during 5 min of paced breathing before and 1, 3, 6, and 22 h after a 60-min bout of cycling exercise at approximately 65% of peak oxygen uptake. Identical measures were obtained in a nonexercise condition based on a randomized crossover design. RESULTS: Exercise resulted in increased high-frequency HRV, decreased low-frequency HRV, and consequently a decrease in the ratio of low-frequency to high-frequency HRV compared with the nonexercise condition. Additionally, a time-domain measure of HRV (pNN50) was markedly higher in the exercise condition as compared to nonexercise. CONCLUSION: The changes in cardiac autonomic function observed are similar to those seen in investigations of long-term training. These changes indicate a shift in autonomic function toward increased parasympathetic nervous system activity and decreased sympathetic nervous system activity, suggesting a more stable autonomic environment for the heart. These results may provide further evidence of the cardioprotective effects of a single bout of submaximal exercise. 相似文献
20.
重力应激下非平稳心率变异性的时变自回归谱分析方法 总被引:1,自引:0,他引:1
为分析重力应激下非平稳心率变异性信号,建立了时变自回归模型谱估计方法,藉此可得到各项谱指标随时间变化的曲线,以动态地观察,研究不同重力应激作用下心脏自主神经调节的过程,曾利用该方法处理8名被试者有氧锻炼前、后坐位下体负压高频谱成分逐步降低,以及低、高频谱成分比值(LF/HF)逐步升高直至稳定水平的过程;前者反映心迷走撤除,后者反应心交感激活的动态过程。还可以观察到有氧锻炼6个月后HFn、LFn变化 相似文献