太极拳运动对中老年女性身体免疫功能的影响

目的：探讨太极拳健身功对中老年女性身体相关免疫参数、bel-2、细胞凋亡状况的影响。方法：于2003-08/09选择石家庄市晨练场所中长期参加太极拳运动3年以上，5-7次/周，60-90min/次的48-55岁的中老年女性10名为练习组，同期选择同年龄段近期身体健康且平时无健身活动的中老年女性10名为对照组。两组均自愿参加测试。取两组中老年女性静脉血采用流式细胞术测定细胞凋亡率、bel-2基因蛋白表达、Ca^2＋浓度及相关免疫参数。均在安静状态下于运动前、运动后即刻，运动后2h测定。每份样本获取10000个细胞，以Cell Quest软件分析。结果：20名中老年女性不同状况下的各项测试值均被测定，全部进入结果分析。①免疫参数CD^＋3运动后即刻有所升高，但差异无显著性；CD^＋4动后即刻有所升高，运动后2h比运动前显著升高，差异显著（P〈0.05）；免疫参数CD^＋8运动后即刻和运动后2h与安静值相比先降低，后升高并超过安静值水平，但差异均无显著性；免疫参数CD^＋15＋56耐运动后即刻和运动后2h，与运动前安静值相比均显著降低，且运动后即刻显著高于运动后2h差异有非常显著性；CD^＋4/CD^＋8比值与测试前安静值相比逐渐升高，但差异无显著性。②练习组安静状态下Ca^2＋度显著降低。bcl-2基因蛋白表达有所升高，但与对照组相比差异无显著性。淋巴细胞凋亡率与对照组相比降低，差异无显著性。结论：长期练习太极拳的中老年女性安静状态血液淋巴细胞凋亡率和Ca^2＋浓度显著降低，bcl-2基因蛋白表达升高。太极拳运动对增强中老年女性机体的免疫应答过程，抑制细胞内Ca^2＋的增多，保证细胞处于正常的生存状态，延缓衰老的进程起着积极作用。     

太极拳运动对中老年女性身体免疫功能的影响

目的:探讨太极拳健身功对中老年女性身体相关免疫参数、bcl-2、细胞凋亡状况的影响。方法:于2003-08/09选择石家庄市晨练场所中长期参加太极拳运动3年以上,5～7次/周,60～90min/次的48～55岁的中老年女性10名为练习组,同期选择同年龄段近期身体健康且平时无健身活动的中老年女性10名为对照组。两组均自愿参加测试。取两组中老年女性静脉血采用流式细胞术测定细胞凋亡率、bcl-2基因蛋白表达、Ca2+浓度及相关免疫参数。均在安静状态下于运动前、运动后即刻,运动后2h测定。每份样本获取10000个细胞,以CellQuest软件分析。结果:20名中老年女性不同状况下的各项测试值均被测定,全部进入结果分析。①免疫参数CD3+运动后即刻有所升高,但差异无显著性;CD4+运动后即刻有所升高,运动后2h比运动前显著升高,差异显著(P<0.05);免疫参数CD8+运动后即刻和运动后2h与安静值相比先降低,后升高并超过安静值水平,但差异均无显著性;免疫参数CD16+56+运动后即刻和运动后2h,与运动前安静值相比均显著降低,且运动后即刻显著高于运动后2h差异有非常显著性;CD4+/CD8+比值与测试前安静值相比逐渐升高,但差异无显著性。②练习组安静状态下Ca2+浓度显著降低。bcl-2基因蛋白表达有所升高,但与对照组相比差异无显著性。淋巴细胞凋亡率与对照组相比降低,差异无显著性。结论:长期练习太极拳的中老年女性安静状态血液淋巴细胞凋亡率和Ca2+浓度显著降低,bcl-2基因蛋白表达升高。太极拳运动对增强中老年女性机体的免疫应答过程,抑制细胞内Ca2+的增多,保证细胞处于正常的生存状态,延缓衰老的进程起着积极作用。     

不同性别静息心率与冠心病的关系

目的观察不同性别静息心率与冠心病的关系。方法观察208例入选者的静息心率,据冠状动脉造影结果将其分为对照组及冠心病组。结果男性冠心病组静息心率（77．7±12．5次／min）显著高于对照组（69．1±9．0次／min）（P〈0．05）;女性冠心病组静息心率（76．25±10．8次／min）与对照组（72．2±11．9次／min）无显著差异（P〉0．05）。结论静息心率与冠心病的关系因性别不同而存在一定差异,其中男性静息心率与冠心病相关性较女性强。     

大学生篮球运动员负荷递增时的心电图变化

目的：就大学生篮球运动员负荷递增时心电图的变化进行分析，为运动干预提供理论依据。方法：于2001／2003选择烟台师范学院女子篮球队队员12人，采用日本三导心电图机，记录运动员安静状态，比赛前，比赛后及训练负荷递增时的心电图。结果：3年中通过对12名队员的心电图追踪检查，共测安静时心电图95人次，均为有效心电图，不同训练强度下心电图196人次，有效心电图189人次，有效率为96％。①12名运动员平均心率为53．9次／min，最低心率46次／min；最高为67次／min，窦性心动过缓8人（60次／min以下者）占66．7％。此外，篮球运动员随运动年限的增加，心率有减慢的趋势。②心电图的变化与训练强度密切相关。当强度负荷递增时，心电图改变增加，递增越快心电图的异常发生率越高，共有7人，可达58％。当心电图有变化的同时，对其进行负荷实验均为不正常型。紧张性增高型3人（43％），紧张性不全性2人（29％），无力型2人（29％）。结论：心电图的变化可反映不同训练阶段的运动员的心血管系统的功能及训练程度。当运动负荷递增时，尤其是强度负荷递增时，心电图的变化增多，其次是当强度符合递增速度过快时，心电图的变化增加。     

有氧运动疗法对老年卧床患者心率变异性的影响

背量：许多研究显示有氧运动疗法可增加迷走神经张力。迷走神经张力决定着稳定的心率，可提高心率变异性，减少心血管事件的发生。目的：观察有氧运动疗法对老年卧床患者迷走神经张力的维持和对心率变异性相关指标的影响。设计：随机对照观察。单位：北京航天中心医院高干病房和解放军烟台疗养院综合内科。对象：选择2002-02／2004-01航天中心医院高干内科和解放军烟台疗养院综合内科卧床老年患者45例。随机分成2组。治疗组23例，均为男性，平均年龄（69．5&;#177;8．0）岁；对照组22例，均为男性，平均年龄（71．4&;#177;6．5）岁。干预：两组患者均给予改善循环和营养神经药物等治疗，在此基础上，治疗组采用有氧运动疗法：以靶心率为指标。即以通过运动获得的个人最高安全心率70％-85％作为每次运动的靶心率，开始时每次运动10-15min，每运动4-6min测一次心率或脉搏，运动以患者心率增加不超过20次／min、患者感觉不疲乏为度，以后逐渐增加运动时间，直至每次活动持续时间30～40min，2次／d．每周治疗不少于5d。两组分别于治疗前和治疗20周后检查24h动态心电图，观察心率变异性各参数指标的变化。主要观察指标：两组患者治疗前和治疗20周后心率变异性各参数指标（以正常R-R间期标准差评估迷走神经活性大小；以总功率谱评估心率变异性大小；以均值标准差评估交感-迷走神经平衡性；以低频段评估交感神经双重调节作用；以均方根评估短期内心率变化和迷走神经功能变化；以爱丁堡指数评估迷走神经活动作用；以高频评估迷走神经调节作用；以低频／高频评估交感神经活性效应）。结果：参与试验者46例，45例达到试验终点进入结果分析，1例死亡。①治疗组治疗20周后心率变异性指标中正常R-R间期标准差、均值标准差、均方根、爱丁堡指数、高频及总功率谱明显高于治疗前（t=12．5～38．4，P〈0．01）。②对照组卧床20周后的心率变异性降低（P〈0．01）。结论：有氧运动疗法能增强卧床不起老年患者迷走神经的功能活性和交感-迷走神经平衡性，提高心率变异性，有助于降低心血管事件的发生。     

肾气丸对长跑运动员运动能力的影响

目的：探讨中医药提高运动能力，促进人体疲劳恢复的效果。 方法：选择韶关市中学生长跑代表队队员及体育系学生16名，随机分为实验组和对照组。实验组服用中药肾气丸，对照组不服用任何中药。肾气丸是由地黄、山药（莳蓣）、山茱萸、泽泻、茯苓．牡丹皮、桂枝、附子等中药按一定的比例组成，混合碾细，炼蜜和丸，每丸15g。受试者在2004-06—01／2004—07—15（即比赛前1．5个月），早、晚各口服1粒肾气丸，饮食与服药前相同，由韶关市中学生运动队膳食科提供（运动员餐）。韶关市中学生长跑队每周一至周五16：30-18：30训练，于服药后1个月取安静时静脉血，进行运动负荷（在Monark功率计上运动），先作准备活动1min（0负荷），然后以0．5g／kg体质量递增负荷值到70％最大心率（138次／min）后即不再增加负荷量，持续运动至心率超过76％最大心率（150次／min）停止运动。运动中每半小时取血1次，运动结束后3min测量心率、取静脉血。采用福-吴氏法检测血糖，采用杨氏微量改良法检测血乳酸，采用放射免疫药含法（中国原子能研究所生产）检测血清胰岛素，采用高铁氧化钾法检测血红蛋白，采用原予吸收分光光度法检测血清钾和镁。 结果：纳入受试者16名，均进入结果分析。①两组受试者安静状态时血糖水平无明显差别，但运动30，60min时，实验组血糖水平显著高于对照组运动至疲劳状态时，实验组受试者血糖深度明显高于对照组。此外。实验组受试者运动60min时。血糖水平明显高于安静状态。对照组受试者已出现血糖下降趋势，部分运动员的血糖已低于4．4mmol/L的正常低限。②两组受试者安静状态时血乳酸水平无显著差别，运动30min时，实验组受试者的血乳酸显著低于对照组。③两组受试者在运动中均出现血清钾增高的现象，其中以实验组受试者血清钾浓度变化的幅度稍小。实验组受试者运动后血清镁浓度显著高于对照组。对照组受试者在运动后血清镁出现下降趋势，而实验组的血清镁有轻度增加的趋势。运动后实验组受试者的血清镁浓度显著高于对照组（P〈0．01），对照组受试者血清镁在运动60min和疲劳状态时低于安静状态时水平。④两组受试者中以实验组耐力和做功量最大。两组受试者在运动结束后3min心率分别是（116&;#177;11），（111&;#177;20）次／min，实验组略高于对照组，但差异无显著性。 结论：肾气丸使长跑运动员长时间运动中保持良好的运动能力，且能较好的促进疲劳的恢复。     

中老年体育工作者心脏康复运动处方

用功率车及活动平板递增负荷运动试验,测定了18名患有各种慢性病受试者的心脏功能能力及运动中所达到的最高心率。按实测结果确定锻炼强度及靶心率。令受试者按照运动处方进行锻炼,并观察锻炼效果。对比中老年体育工作者与一般中老年人的心脏功能能力和靶心率,以及实测靶心率及推测的运动强度,结果表明,中老年体育工作者的心脏功能能力,较一般中老年人要好,靶心率平均值较高。一般中老年慢性病患者可用公式:170-年龄,或(195-年龄)×80％来推测运动强度,而患有慢性病的中老年体育工作者可用公式:170-年龄及180-年龄作为锻炼时应保持的心率范围。     

心率过快及心率波动对64层螺旋CT冠状动脉成像质量的影响

目的：探讨心率过快及心率波动对冠状动脉图像质量的影响。方法：回顾性分析搜集心率过快及心率波动患者366例,根据心率过快程度分为3组,再将每组病例按照心率波动范围分为4个亚组。选取心率＜70次／min,无明显心率波动患者50例作为对照组,比较实验组与对照组间冠状动脉图像质量是否存在差异,判断心率过快程度及心率波动的范围对冠状动脉成像质量影响的程度。结果：当心率＜80次／min,心率波动＜10次／min时,冠状动脉图像质量与对照组之间无显著统计学意义,当心率＜80次／min时,冠状动脉图像质量与对照组之间存在显著统计学意义。心率波动范围对冠状动脉图像质量的影响大于心率过快程度。结论：当心率＜80次／min,心率波动＜10次／min时,可以进行64层螺旋CT冠状动脉检查,当心率＞80次／min且心率波动＜10次／min或心率＜80次／min且心率波动在11～15次／min时,可谨慎进行冠状动脉检查,而当心率＞80次／min且心率波动在11～15次／min时或当心率波动＞15次／min,不推荐此检查。     

秧歌与太极拳对中老年女性健身作用的比较

目的：比较分析秧歌和太极拳锻炼对中老年女性的健身作用。方法：调查于．2003—07／2004-01完成，通过发放问卷的形式选取90名女性作为观察对象，均自愿参加观察。随机分为3组，秧歌组30人，太极拳组31人，对照组29人。首先对秧歌组和太极拳组进行锻炼前的身体测试，然后分别进行自编秧歌和杨式太极拳的锻炼，每周锻炼三四次，1h／次，持续6个月。锻炼前及锻炼6个月后监测各组观察对象的身高、体质量、腰围、腹部皮褶厚度、血压、安静心率、肺活量，握力、坐位体前屈距离、反复横跨步频率．闭目单足立时间、简单反应时间及台阶指数，并进行比较分析。结果：秧歌组和太极拳组分别脱落9人和8人。对照组锻炼6个月前后的指标与太极拳、秧歌舞锻炼前的指标比较差异均无显著性意义，本文不再进行分析。进入结果分析有2组，秧歌组21人，太极拳组23人。①锻炼前及锻炼6个月后自身对照：秧歌组体质量、腹部皮褶厚度、体脂率、体质量指数、安静心率均显著下降（P〈0．05），肺活量、台阶指数均显著升高（P〈0．05～0．01）；而太极拳组腹部皮褶厚度、体脂率及安静心率均显著下降（P〈0．05），而台阶指数显著升高（P〈0．05）。除握力外，两组坐位体前屈距离、反复横跨步频率及闭目单足立时间均显著增加（P〈0．05—0．01）；简单反应时间显著缩短（P〈0．05）。②锻炼6个月后两组比较：秧歌组的体质量、腹部皮褶厚度、体脂率和体质量指数均显著低于太极拳组（P〈0．05），肺活量和台阶指数显著高于太极拳组（P〈0．05）。与秧歌组相比，锻炼后太极拳组坐位体前屈距离及闭目单足立时间均显著增加（P〈0．05）；但反复横跨步频率显著低于秧歌组（P〈0．05）。结论：中老年女性参加秧歌和太极拳锻炼均可以有效提高身体素质，达到健美体形和减肥的作用。但秧歌在身体形态、身体成分、呼吸和心血管系统及下肢的协调与灵敏性方面的锻炼效果明显优于太极拳，但太极拳的平衡能力、柔韧素质明显优于秧歌。     

癫痫发作期心脏自主神经功能的研究

目的通过视频脑电-心电监测,研究部分性癫痫发作期心率变化,探讨不同部位起源、不同发作形式以及睡眠与觉醒对心率变化的影响,总结并分析癫痫发作前后心率演变规律。方法回顾性分析2011-2013年81例癫痫患者181次发作的视频脑电-心电监测资料,将癫痫发作期心率变化幅度分成5种类型,绘制心率变化曲线图,并从发作部位（额、颞、枕）、发作形式（SPS、CPS和CPS．G）、睡眠与觉醒等方面分析癫痫发作对心率变化的影响。结果181次发作心率差值（53．2±26．7）次/min,额、颞、枕心率差值分别为（53．3±28．5）次／min、（53．2±24．1）次／min和（52．8±31．9）次／min;睡眠期（72次）和清醒期（109次）发作心率差值分别为（62．8±25．4）次／min和（46．8±25．7）次,min;SPS、CPS和CPS-G发作心率差值分别为（32．8±24．4）次/min、（47．7±20．6）次／min和（79．3±22．4）次／min。结论发作类型为CPS．G、睡眠期、右侧起源、男性、年龄大于14岁的患者心率变化显著,癫痫发作期的心率随时间变化有一定的演变规律。     

Heart rate changes following knee extensor muscles isometric exercise and Russian stimulation

Background. Static exercise leads to a greater heart rate increase than comparable dynamic effort, which matters in cardiovascular disorders. Neuromuscular electrical stimulation is an alternative to volitional isometric exercise. Heart rate increases following both kinds of static effort to knee extensor muscles were compared. Material and Methods. 65 healthy volunteers (33 males, 32 females), aged 20 - 22 (mean 20.94) years, completed the trial. Isometric exercise and electrical stimulation were performed randomly, with 48 hours' rest period. Each repetition's peak contraction forces were measured. Heart rate was recorded at rest and post- effort. Results. Contraction forces decreased in subsequent repetitions. First and last repetition measurements were 380.7 N (+/-6.9), 349.2 N (+/-51.9), 635.3 N (+/-120.0) and 562.1 N (+/-102.7), in females and males, respectively. In the same manner, electrically evoked contraction forces were as follows: 126.7 N (+/-84.5), 137.63 N (+/-7.1), 28.2 N (+/-102.81) and 262.2 N (+/-117.7). Heart rate increased immediately after exercise in females by 52.2 beats/min and differences (p< 0.001, p< 0.01) existed for 2 minutes during recovery. In males the increase was 56.9 beats/min and differences were significant (p< 0.001, p< 0.01) for 3 minutes post-exercise. Heart rate increased immediately after stimulation by 12,9 beats/min (p<0.001) in females and by 9,9 beats/min (p<0,001) in males. Conclusions. In young, healthy males and females, intensive voluntary isometric exercise leads to bigger and more prolonged heart rate increase than Russian electrical stimulation.     

Age and Gender Influences on Rate and Duration of Paroxysmal Atrial Fibrillation

The influence of age and gender on the character of paroxysmal atrial fibrillation (PAF) has not been described. Methods: The heart rate (HR) during PAF in patients receiving placebo or antiarrhythmic therapy was analyzed. Data from 177 24-hour Holter recordings were analyzed to mark the onset and termination of PAF and converted into RR interval files. PAF episodes lasting at least 2 minutes and containing ± 20% noise were included. HR during the first 30-second segment versus during the remainder of the episode, and the duration of PAF episodes were compared among groups of different ages and sex (Wilcoxon test). Results: 236 episodes from 55 recordings in 32 patients (all patients: 61.4 ± 12.8 years; men (19): 58.5 ± 12.6 years; women (13) 65.5 ± 12.4 years, P = ns for difference in age) fulfilled the inclusion criteria. Women had a higher mean heart rate at AF onset (123 ± 35 beats/min vs 115 ± 20 beats/min, P = 0.02) and during the remainder of the episode (120 ± 25 beats/min vs 112 ± 22 beats/min at the start, P = 0.01, and 116 ± 26 beats/min vs 108 ± 18 beats/min subsequently, P = 0.01). Episodes tended to be longer in women (mean 89.8 min vs 50.5 min, P = NS) and in the aged (mean 83.8 min vs 46.9 min, P = NS). Conclusion: PAF episodes are associated with faster heart rates and last longer in women, which may reflect differing autonomic responses to AF. A slower ventricular rate during PAF in older patients probably reflects an increasing prevalence of impaired atrioventricular conduction.     

A New Motion Responsive Pacemaker: First Clinical Experience with an Acceleration Sensor Pacemaker

A new accelerometer-based adaptive rate pacemaker (OEXCELVR^TM) was evaluated to investigate its behavior at nominal settings during treadmill exercise testing and postural changes. Eight patients with sinus rhythm were selected to compare intrinsic heart rate to sensor mediated rate. Throughout exercise treadmill testing, changes in the sensor mediated rate closely paralleled actual physiological changes. The Pearson product moment correlation of pacing rate with sinus frequency, calculated for all patients, was r = 0.82 (P = 0.001). Change in the patient's physical position resulted in immediate change in sensor rate, which corresponded appropriately to the type of position change and activity level. Average (± SD) pacing rate was 62.4 ± 2.7 beats/min supine; 67 ± 3.8 beats/min sitting; 69.8 ± 6.4 beats/min standing; 81.6 ± 8.7 beats/min slow walking; and 96.8 ± 1.3 beats/min fast walking. After 4 minutes of recovery, the average pacing rate dropped to 65 ± 3 beats/min. The interaction between the accelerameter and the pulse generator at nominal settings was accurate and infrequently required the use of its many programming options. The accelerometer sensor and pulse generator algorithm in this device during postural change and exercise resulted in physiological-like changes in sensor mediated heart rate.     

New ergometric reference values for clinical exercise tests

A group of 301 apparently healthy men and women were studied using bicycle ergometry in order to obtain generally applicable reference values for clinical exercise testing. The subjects, aged 30-67 years, were derived from a comprehensive health survey carried out on a population sample representative of adult Finns. The exercise test was a standardized heart rate conducted programme in which workload was regulated so as to increase heart rate by 5 beats/min every min up to subjective maximum. Three indicators of exercise capacity are presented: maximal workload (Wmax), mean workload attained during the last 4 min of the test (Wlast4') and hypothetical maximal workload sustainable for 6 min (Wmax6'). All showed wide inter-individual variation even when related to age and body weight. The ergometric results depended significantly on age and height in men and on age and weight in women. We present formulas for the calculation of expected values of Wlast4' and Wmax6' on the basis of sex, age, height and weight. We suggest that the measured values be given in percentages of those expected.     

Clinical Study of a New Activity Sensor for Rate Adaptive Pacing Controlled by Electrical Signals Generated by the Kinetic Energy of a Moving Magnetic Ball

A new rate adaptive pacemaker (Sensorithm) controlled by an activity sensor providing electrical signals induced by a magnetic ball moving freely in an elliptical cavity surrounded by two copper coils, was implanted in ten patients; mean age of 75 years (range 64–89). Six patients had atrioventricular block and four had sinus node disease. In auto-set testing procedure during a 1-minute walk in the corridor, a slope resulting in a maximum rate of 95 beats/min was selected in every patient, and a medium reaction time was programmed. During graded treadmill exercise tests the heart rate increased 63 ± 7 beats/min to 135 ± 6 beats/min in rate adaptive pacing mode (VVIR), and 15 ± 6 beats/min (P < 0.0001) in ventricular pacing mode (VVI). The symptom-limited exercise time was 9.1 ± 1.1 minutes and 8.2 ±1.2 minutes (P = NS), and the exercise distance was 501 ± 95 meters and 428 ± 92 meters (P < 0.05) in VVIR and VVI pacing mode, respectively. The maximum oxygen uptake was 20.6 ± 2.6 mL/kg per minute in VVIR pacing and 18.1 ± 2.1 mL/kg per minute (P < 0.05) in VVI pacing. The delay time until the pacing rate increased 10% of the total rate increase at onset of treadmill exercise was 4.4 ± 0.7 seconds. Assuming a linear relation between metabolic workload and heart rate response from rest to the age predicted maximum heart rate, a deviation of heart rate ranging from 13.5 ± 11.2% to –1.6 ± 5.2% from the expected heart rate at mid-point and endpoint of each quartile of workload was observed during treadmill testing. Conclusions : By using a 1 -minute walk test for selecting an appropriate slope setting, Sensorithm provided a significant and proportional heart rate increase during exercise resulting in an improvement of exercise capacity during VVIR pacing compared to VVI pacing.     

Comparison between arm and leg exercise in women and men.

Arm and leg work was performed on bicycle ergometers in sitting position by fourteen women and sixteen men. Heart rate, minute volume of ventilation (VE), and oxygen consumption (VO2) were measured. Arm exercise was performed until (muscular) exhaustion, leg exercise up to a heart rate of circa 170 beats/min. At comparable work loads arm exercise evoked higher VO2, VE, and heart rate than leg exercise irrespective of sex. At comparable VO2, the heart rate and VE were higher during arm work in both sexes, VE more so among the men. With the same limbs working, the mechanical efficiency was equal in both sexes. The regression coefficients of heart rate on load or VO2 was higher for the women irrespective of work type. A close correlation was obtained between working capacity at a heart rate of 170 beats/min (W170) during leg and arm exercise and between W170 of leg exercise and W150, similarly calculated during arm work. Thus W170 of leg exercise could be calculated from either a maximal or submaximal arm work.     

Left ventricular performance during prolonged exercise: absence of systolic dysfunction

We assessed left ventricular systolic and diastolic performance during and after prolonged exercise under controlled conditions in a group of healthy, trained men. Previous studies have examined the effects of prolonged effort on left ventricular function, yet it remains unclear whether or not left ventricular dysfunction (e.g. cardiac fatigue) can be produced under such conditions. We studied 15 healthy men, aged 27+/-1 years (mean+/-S.E.M.). Subjects exercised on bicycles at a constant work rate (60% of maximum oxygen uptake per min) for 150 min. Measurements of gas exchange, blood pressure and haematocrit were obtained, concurrent with the assessment of left ventricular function using equilibrium radionuclide angiography, at rest, during exercise (every 30 min) and after 30 min of recovery. Fluid replacement was provided and monitored during the exercise period. The baseline resting and exercise ejection fractions were 66+/-2% and 78+/-2% respectively. During exercise, subjects consumed 1816+/-136 ml of fluid, and the haematocrit had increased at 120 min of exercise (from 47.2%+/-0.6 to 49.9+/-0.8%; P<0.05). There was no change in either systolic or diastolic blood pressure throughout the exercise period, but heart rate drifted upwards from 141+/-2 beats/min after 30 min to 154+/-3 beats/min after 150 min (P<0.05). There was a small decline (8%; P<0.05) in end-diastolic volume at 150 min. No changes were observed in left ventricular ejection fraction, the pressure/volume ratio or end-systolic volume. After 30 min of sitting in recovery, heart rate was still higher than the pre-exercise value (84+/-3 compared with 69+/-2 beats/min; P<0.05), as were measures of peak filling rate and time to peak filling (P<0.05). The ejection fraction in the post-exercise recovery period was similar to the pre-exercise value. The results indicate that prolonged exercise of moderate duration may not induce abnormal left ventricular systolic function or cardiac fatigue during exercise.     

Head-Up Tilt Testing With and Without Isoproterenol Infusion in Healthy Subjects of Different Ages

Passive head-up tilt testing with or without infusion of isoproterenol is used in the investigation and management of patients with syncope. Twenty-five healthy asymptomatic volunteers prospectively grouped according to age (young [28 ± 1.7 years]: n = 9; middle [51 ± 3.3 years]: n = 11; elderly [81 ± 2.4 years]; n = 5; mean ± SE) were studied during: (1) supine carotid sinus massage: (2) 60° head-up tilt aione; and (3) infusion of isoproterenoJ to raise the heart rate 20% above supine baseline, prior to a 10-minute repeat tilt. Symptoms occurred in three subjects (12%) and only occurred with passive tilting alone. Two young subjects had syncope with sinus pauses greater than 10 seconds, One elderly subject developed atrial flutter. No subject had symptoms or hypotension during tilt plus isoproterenol or a pause greater than 3 seconds with carotid sinus massage. With passive tilt, mean heart rate increased by 16 ± 6 beats/min and 18 ± 7.8 beats/min in the young and middle aged subjects (P < 0.05), but only by 6 ± 5 beats/min in the elderly (P = NS, supine vs 60° in each group). With head-up tilt plus isoproterenol infusion, the mean heart rate elevation in response to tilt was 17 ± 9 beats/ min, 8 ± 3 beats/min, and 12 ± 4 beats/min for the young, middle, and elderly subjects, respectively (P < 0.05, supine vs 60° in each group). Supine serum norepinephrine concentration values were 229 ± 33 pg/mL, 374 ± 107 pg/mL, and 409 ± 41 pg/mL (mean ± SE) in the young, middle aged, and elderly groups, respectively (P = 0.05, young vs elderly). With head-up tilt, these significantly rose in the three groups. With tilt, serum epinephrine tended to rise (P < 0.10) only in the young and middle aged groups. Serum dopamine did not significantly increase in response to tilt in any of the groups. These studies suggest that tilt testing protocols need to be assessed against age and protocol matched controls.     

New ergometric reference values for clinical exercise tests

A group of 301 apparently healthy men and women were studied using bicycle ergometry in order to obtain generally applicable reference values for clinical exercise testing. The subjects, aged 30-67 years, were derived from a comprehensive health survey carried out on a population sample representative of adult Finns. The exercise test was a standardized heart rate conducted programme in which workload was regulated so as to increase heart rate by 5 beats/min every min up to subjective maximum. Three indicators of exercise capacity are presented: maximal workload (W_max), mean workload attained during the last 4 min of the test (W]_as,₄) and hypothetical maximal workload sustainable for 6 min (W_max6.). All showed wide inter-individual variation even when related to age and body weight. The ergometric results depended significantly on age and height in men and on age and weight in women. We present formulas for the calculation of expected values of W_last4 and W_max6- on the basis of sex, age, height and weight. We suggest that the measured values be given in percentages of those expected.