Circadian misalignment on submarines and other non-24-h environments-from research to application

Circadian clocks have important physiological and behavioral functions in humans and other organisms,which enable organisms to anticipate and respond to periodic environmental changes.Disturbances in circadian rhythms impair sleep,metabolism,and behavior.People with jet lag,night workers and shift workers are vulnerable to circadian misalignment.In addition,non-24-h cycles influence circadian rhythms and cause misalignment and disorders in different species,since these periods are beyond the entrainment ranges.In certain special conditions,e.g.,on submarines and commercial ships,non-24-h watch schedules are often employed,which have also been demonstrated to be deleterious to circadian rhythms.Personnel working under such conditions suffer from circadian misalignment with their on-watch hours,leading to increased health risks and decreased cognitive performance.In this review,we summarize the research progress and knowledge concerning circadian rhythms on submarines and other environments in which non-24-h watch schedules are employed.     

Circadian rhythms in two types of anaerobic cycle leg exercise: force-velocity and 30-s Wingate tests

Previous studies investigating the impact of circadian rhythms on performance during anaerobic cycle leg exercise have yielded conflicting results. The purpose of the present investigation was firstly, to determine the effect of the time of day on anaerobic performance during a force-velocity test on a cycle ergometer (F-V) and the Wingate test and secondly, to relate any changes in anaerobic performance to the circadian rhythm in oral temperature. Nineteen subjects volunteered to take part in the study. In a balanced and randomized study design, subjects were measured for maximal power (P (max)) (force-velocity test), peak power (P (peak)) and mean power (P (mean)) (Wingate test) on six separate occasions. These were at 02 : 00, 06 : 00, 10 : 00, 14 : 00, 18 : 00 and 22 : 00 hours on separate days. There was an interval of 28 h between two successive tests. Oral temperature and body mass were measured before each test. Body mass did not vary during the day but a significant time of day effect was observed for the oral temperature with an acrophase at 18 : 22 +/- 00 : 34 hours. A significant circadian rhythm was found for P (max) with an acrophase at 17 : 10 +/- 00 : 52 hours and an amplitude of 7 %. A time-of-day effect was significant for F (0) and V (0). Also a significant circadian rhythm was observed for P (peak) with an acrophase at 17 : 24 +/- 00 : 36 hours and an amplitude of 7.6 % and for P (mean) with an acrophase at 18 : 00 +/- 01 : 01 hours and an amplitude of 11.3 %. The results indicated that oral temperature, P (peak), P (mean) and P (max) varied concomitantly during the day. These results suggest that there was a circadian rhythm in anaerobic performance during cycle tests. The recording of oral temperature allows one to estimate the time of occurrence of maximal and minimal values in the circadian rhythm of anaerobic performance.     

Circadian rhythms in airline pilots submitted to long-haul transmeridian flights

BACKGROUND: Circadian rhythms shift out of phase after transmeridian flights. Desynchronization between body rhythms and the environment is linked to jet lag, which depends on age, flight direction, and number of time zones crossed. METHODS: To investigate this problem in airline pilots, we performed a multivariate analysis of their circadian systems during Madrid-Mexico-Madrid flights (-7 time zones, n = 12) and Madrid-Tokyo-Madrid flights (+8 time zones, n = 21). Telemetry was used to record pilots' activity, skin temperature, and heart rate, obtaining 6 d of continuous data, including 2 d before the flight, the flights themselves, 2 d at the stopover, and 1 d after the return flight. Time series were analyzed by cosinor, and the resulting parameters of the rhythms were compared by ANOVA and Tukey contrasts in every category formed by the age groups (under and over 50 yr old) and flight direction groups. Subjective time estimation of short, intermediate, and long intervals was recorded. Other psychological variables were measured, including anxiety, tiredness, and performance. RESULTS AND CONCLUSIONS: Activity/rest and heart rate rhythms appeared to be linked to a "weak oscillator." Temperature rhythms manifested a rigid response after the phase shifts of the light/dark cycle, closely related to the biological clock. Subjective time appreciation tended to be overestimated without exhibiting a clear circadian component, but attributable to fatigue and stress. Psychometric evaluation showed that desynchronization affected all the pilots. Some results showed an age-related variability with a more marked influence in younger pilots. No consistent effects regarding flight direction were found.     

Problem of desynchronosis during space flight

Major problems of biorhythm are discussed. Among the numerous and diverse rhythms inherent in the human body (which is the subject matter of the present paper) circadian (essentially 24-hour) variations play the leading role. This kind of rhythm is of universal and mandatory character which makes it possible to categorize it as a law. The system of circadian rhythms incorporates elements of both synchronization and desynchronization. In the welfare state synchronization elements are prevailing while in space flight the specific weight of desynchronization increases due to the permanent desynchronization factor--weightlessness. Due to this, crewmembers are to adhere strictly to the work-sleep regimen.     

高血压病合并2型糖尿病患者动态血压变异与靶器官损害的关系

 目的探讨高血压病合并2型糖尿病患者的动态血压变异与靶器官损害的关系.方法对40例高血压及糖尿病患者、45例单纯高血压病患者行24 h动态血压监测.以24 h血压、收缩压及舒张压负荷、血压昼夜节律为监测指标.结果两组的nSBP、dSL、nSL及血压昼夜节律比较,均有差异(P＜0.05).结论血压及其昼夜节律与靶器官损害有关.     

Circadian rhythm of body temperature during prolonged undersea voyages

Circadian rhythms of oral temperature were assessed in 12 watchkeepers during a prolonged submarine voyage and compared with a "standard" rhythm obtained from nonwatchkeepers ashore. Initially, the parameters of the rhythms were similar to those of the standard; however, among eight ratings working 4-h watches in a rapidly rotating cycle, considerable changes in the rhythms occurred as the voyage progressed, and concurrent alterations in sleep patterning were observed. The most characteristic change in the rhythm was a marked decline in its amplitude. In most subjects, the rhythm also tended to depart from its original circadian pattern; in at least one case, it effectively disintegrated. One subject's rhythm appeared to "free-run" with a period greater than 24 h. A strong circadian rhythm was maintained in only one of these eight subjects. In four officers whose watch times were at fixed hours, adaptation of the rhythm to unusual times of sleep occurred in 2 of 3 cases where the schedule demanded it. The results are discussed in relation to the design of optimal watchkeeping systems for submariners.     

Some circulatory responses to exercise at different times of day

Circadian rhythms in heart rate were examined at rest, immediately pre-exercise, during submaximal and maximal exercise on a cycle ergometer, and during recovery post-exercise (N = 10). Observations were made under controlled conditions at 0300, 0900, 1500, and 2100 hours. A significant circadian rhythm was found for resting heart rate lying supine and sitting pre-exercise (P less than 0.05), peak values being measured at 1500 hours. The acrophase in the oral temperature rhythm at 1739 hours was not significantly out of phase with that of resting heart rate (P greater than 0.05). The rhythm in heart rate persisted during submaximal exercise (150 W) and at the maximal rate (P less than 0.05); the amplitude of the rhythm was attenuated at maximum. Ratings of perceived exertion at submaximal and maximal exercise intensities, and time of day (P greater than 0.05). The increment of 0.2 degrees C in oral temperature during exercise did not exhibit circadian variation (P greater than 0.05). A significant rhythm was found for recovery heart rates in minutes 2, 3, 4, and 5 post-exercise (P less than 0.05). Observations of systolic and diastolic pressures pre- and post-exercise were inconclusive. Therefore, the circadian rhythm in heart rate responses to exercise should be considered when a heart rate variable is used as a criterion in fitness testing or as an index of physiological strain.     

Effect of low-dose temazepam on physiological variables and performance tests following a westerly flight across five time zones

Rapid travel across multiple time zones disturbs circadian rhythms and induces "jet lag". The aims of this study were 1) to monitor a selection of subjective, physiological and performance variables in elite athletes and sedentary subjects following a westerly flight across five time zones, and 2) to examine whether the promotion of sleep by means of a low-dose benzodiazepine drug influences these responses to transmeridian travel. Subjects comprised eight members of the British men's gymnastics squad, aged 18-30 years, and nine members of the British Olympic Association's support staff, aged 24- 55 years (4 females, 5 males). Subjects were pair-matched for age, sex and athleticism (apart from one person) and assigned to either the treatment (n = 9) or placebo (n = 8) group. All subjects travelled from U.K., arriving at Tallahassee, Florida, at approximately 22:00 hours local time. A test battery was administered to the subjects at 07:00, 12:00, 17:00 and 21:00 hours on the first full day of arrival (this was designated day one) and then on alternate days (day 3, day 5 and day 7). Immediately before retiring to bed on days 1, 2 and 3, subjects were administered, in a double-blind fashion, either 10mg of temazepam or a placebo. Measures in the test battery included sleep quality, sleep length, subjective jet lag (one-to-ten simple analogue scale), tympanic temperature, one-, two-, four- and eight-choice reaction time, grip strength (left and right), leg strength and back strength. Over the 24 h of each test day, subjects also recorded the volume of each urine voided. Data were analysed with a repeated measures general linear model. Alpha was set at 0.01 to control for type I errors with multiple dependent variables.Mean subjective jet lag reduced from 4.6 units to baseline, and mean sleep quality improved by 2.0 units from day 1 to day 5 (P<0.001), after which no further alterations were noted. Subjective jet lag, left and right grip strength and choice reaction time all showed post-flight day x time of day interactions (P < 0.01). On day 1, these variables deteriorated as the day progressed to the worst recorded values. On days 3, 5 and 7, diurnal variations with the conventional high in the early evening and morning-to-evening differences of about 10% were evident. There was a trend for the reduction in subjective jet lag over the post-flight days to be more rapid following ingestion of a low dose of temazepam (P= 0.037). We cannot rule out the possibility that this could be a type I error, since none of the treatment by day interactions reached the alpha level of significance (set at 0.01). The morning-to-evening variations of body temperature and grip strength were greater in the young athletes than in the older sedentary support staff (P < 0.01). Sleep quality was greater in the athletic subjects after the first full day in Tallahassee. These results suggest that the nightly administration of a low dose (10 mg) of temazepam has little influence on the recovery of subjective, physiological and performance measures following a westward flight across five time zones. In both the treatment and control groups, subjective jet lag and performance were worst in the evening of the first full day after arrival, and the young athletes slept better than the older support staff that same night. This illustrates the importance of monitoring jet lag symptoms and performance variables at different times of day following a flight to a new time zone.     

Exercise and the circadian variation in body temperature measures

This study examined the existence of circadian rhythms in rectal temperature (Tr) and selected skin temperatures at rest and during light (82 W) and medium (147 W) exercise on a cycle ergometer. Each intensity was sustained for 5 min and then followed by a graded exercise test to exhaustion. The Tr and skin temperatures were also measured on cessation of exercise and 4 min post-exercise. Fifteen males participated, measurements covering six interspersed times of day. The mean exercise time to exhaustion of 19.83 min was independent of the time of day and caused a constant rise of 0.7 degree C in Tr. Significant rhythms were observed in Tr, Tc (chest), and Ta (arm) under all conditions: findings for Tl (leg) were nonsignificant at maximal exercise and post-exercise (P greater than 0.05). The crest time for Tl had a significant lead over that of Tr and the other skin sites which were in phase concordance, mean difference in crest times being 4.73 h at rest and 4.42 h during submaximal exercise. The results demonstrated constancy with time of day in the thermal load imposed by fixed exercise. This was reinforced when mean skin and mean body temperatures were computed. The general pattern did not apply to the exercised limb, the pre-exercise rhythm disappearing after 10 min exercise. Differential heat conductances according to skin sites are implicated in the phase differences between the leg and the other temperature sites.     

Effects of personality on body temperature and mental efficiency following transmeridian flight

Examination of the oral temperature rhythms in a group of young men after an eastward jet-flight across eight time-zones revealed a specific disruption in the rhythm that gradually disappeared over a period of some 10 d. In the first 2 d, the magnitude of the disruption in individual subjects was significantly correlated with the extent of mean postflight loss of speed in performing an arithmetic calculations test, given four times per day in local daytime hours. Within the group, neurotic introverts exhibited the greatest, and neurotic extroverts the least initial rhythm disruption; these two personality groups also showed opposing time-of-day trends in postflight changes in the performance measure. The results are discussed in relation to flight scheduling and to other studies of shifts in activity schedule; they are tentatively accounted for in terms of a postulated dimension of circadian rhythm lability that could be primarily related to extraversion.     

Free course of circadian rhythms in Trigonoscelis gigas beetles after space flight

Before and after space flight on Cosmos-1887 motor activity of Trigonoscelis gigas beetles kept in darkness was recorded. After flight 6 out of 7 beetles showed reduction of periods of free running circadian rhythms. The fact that the change was not observed in controls suggests that it can be attributed to the effects of O G. It is assumed that in space flight the biological requirements for the day duration are modified.     

Identifying some determinants of "jet lag" and its symptoms: a study of athletes and other travellers

BACKGROUND: Travelling across multiple time zones disrupts normal circadian rhythms and induces "jet lag". Possible effects of this on training and performance in athletes were concerns before the Sydney Olympic Games. OBJECTIVE: To identify some determinants of jet lag and its symptoms. METHODS: A mixture of athletes, their coaches, and academics attending a conference (n = 85) was studied during their flights from the United Kingdom to Australia (two flights with a one hour stopover in Singapore), and for the first six days in Australia. Subjects differed in age, sex, chronotype, flexibility of sleeping habits, feelings of languor, fitness, time of arrival in Australia, and whether or not they had previous experience of travel to Australia. These variables and whether the body clock adjusted to new local time by phase advance or delay were tested as predictors for jet lag and some of its symptoms by stepwise multiple regression analyses. RESULTS: The amount of sleep in the first flight was significantly greater in those who had left the United Kingdom in the evening than the morning (medians of 5.5 hours and 1.5 hours respectively; p = 0.0002, Mann-Whitney), whereas there was no significant difference on the second flight (2.5 hours v 2.8 hours; p = 0.72). Only the severity of jet lag and assessments of sleep and fatigue were commonly predicted significantly (p<0.05) by regression analysis, and then by only some of the variables. Thus increasing age and a later time of arrival in Australia were associated with less jet lag and fatigue, and previous experience of travel to Australia was associated with an earlier time of getting to sleep. Subjects who had adjusted by phase advance suffered worse jet lag during the 5th and 6th days in Australia. CONCLUSIONS: These results indicate the importance of an appropriate choice of itinerary and lifestyle for reducing the negative effects of jet lag in athletes and others who wish to perform optimally in the new time zone.     

Circadian rhythmicity and sleep of aircrew during polar schedules

Sleep and circadian rhythms of aircrew were studied during a 7-d polar schedule operated between London and Tokyo. Sleep, rectal temperature, and subjective alertness were recorded for 2 d before departure during the schedule, and for 10 d after the return. Changes in sleep during the early part of the trip were due to sleep loss on the outward journey, but later these changes were related to the displacement of the circadian rhythm. The acrophases of the circadian rhythms of temperature were delayed by the outward journey, and amplitudes were reduced throughout the trip. During the return, aircrew reported high levels of tiredness which persisted until the second recovery night. Though the amounts of sleep obtained during the schedule were satisfactory for the aircrew as a group, some crewmembers experienced difficulties. Realignment of circadian rhythms was attained by an advance of the circadian phase in eight aircrew and by a delay in three, and resynchronization was achieved in all cases within 6 d.     

力竭运动后大鼠脑皮质运动区谷氨酸受体NR2A蛋白含量及酪氨酸磷酸化水平的变化

目的:观察力竭运动前后大鼠脑皮质运动区NR2A蛋白含量及其自身酪氨酸磷酸化水平变化,分析二者之间的相关关系,为探讨中枢兴奋信号在运动中的传递机理以及运动性疲劳的中枢机制提供实验依据。方法:SD大鼠进行一次性力竭跑台运动。采用抗NR2A抗体和抗磷酸酪氨酸单抗以免疫沉淀法和免疫印迹法检测皮质运动区NR2A蛋白含量及酪氨酸磷酸化水平。结果:力竭运动后即刻,大鼠脑皮质运动区NR2A蛋白含量与安静组相比无显著性变化,运动后1小时与安静组和运动后即刻比较显著升高(P<0.05,P<0.01),运动后3小时NR2A蛋白含量下降,运动后恢复24小时大鼠脑皮质中NR2A蛋白含量显著低于安静组和运动后即刻组(P<0.01,P<0.05)。NR2A酪氨酸磷酸化水平力竭运动后与对照组相比呈升高趋势但无显著性差异,NR2A酪氨酸磷酸化水平与NR2A蛋白含量变化无显著相关。结论:(1)大鼠在力竭运动后即刻及恢复期过程中,大脑皮质运动区NR2A蛋白含量变化表现为下降,上升,再下降,表明运动过程中NR2A蛋白含量变化具有较敏感的可调控性,力竭运动后即刻NR2A蛋白含量的下降可能是导致中枢抑制的一个因素。(2)NR2A酪氨酸磷酸化水平在力竭运动后呈升高趋势,可能有利于维持中枢的兴奋性,提示运动过程中NR蛋白含量的变化可能是多方面原因造成的,受体蛋白含量与受体活性之间可能存在较为复杂的关系。     

卧床期间体表温度和心率节律的动态变化

由于生理节律与人体生理系统的稳定性调节状态有密切关系,考察在模拟失重时生理节律的动态变化是航天生理医学的一个重要方面。本文研究了6名健康青年被试者在15天头低位4°卧床的第2、第7和第14天中体表温度(BT)和心率活动(HR)的昼夜及超昼夜节律变化。在测试的的三个昼夜中,每20分钟同时记录一次6名被试者的BT和HR数据。三个体表温度传感器分别置于被试者的胸及腹部,取三点的三次读数的均值为一个BT数据。心率以记录在磁带机(SONY A69)上的ECG信号脱机计算。用FFT方法计算BT及HR的波动在24小时内的功率谱,并对三个测试日的功率谱进行逐点统计比较。用256阶非递归数字滤波方法将BT及HR的昼夜节律及12小时节律滤出,用相关方法得出它们在不同被试者之间及不同测试日之间的同步性,在对相关系数进行统计比较时,先进行z变换,即z=1/2×1n[(1+r)/(1-r)]。结果得出,除功率最大的昼夜节律外,BT和HR均含有丰富的超昼夜节律,在24—1.5小时范围内随节律周期变短,BT节律功率皆比其相邻的较长周期的节律显著下降,而HR节律的功率随周期的下降的一致性较差,仅12小时和3小时节律的功率分别三天一致地显著小于24小时及3.43小时的节律。BT与HR节律的另一重要差别,表现在1.33—1.09小时范围BT有一个超昼夜节律群,而HR却无。BT和HR的24小时节律在不同被试者之间及不同测试日之间均有较高的同步性,但HR的12小时节律的同步性显著大于BT。在卧床的第2天,BT和HR典型节律的功率显著小于第7天和第14天,如BT的昼夜节律,HR的12小时和3.43小时节律,BT的1.09—1.33 小时节律群不如第7天,更不如第14天时显著、一致,BT的昼夜节律的同步性亦偏低。上述结果表明,虽然BT和HR节律有不同的调节机制,HR活动与机体的睡眠一觉醒及休息一活动周期关系更密切,但在卧床初期均发生一定程度的紊乱,而在第7天时已基本适应.第14天时则可认为达到新的稳态。这一适应过程提示,在航天初期几天内机体功能的紊乱是广泛而深刻的,此期间空间适应综合症的发生很可能与此有一定的联系。     

跨时区飞行对飞行员心率变异性的影响

目的　探讨跨时区飞行对飞行员心率变异性的影响 ,以评价其对飞行员自主神经系统的作用。　方法　采用 2 4h动态心电图方法检测 16名跨时区国际长途飞行的飞行员动态心电图及心率变异性 (HRV) ;另外检测 10名国内昼间飞行的飞行员动态心电图及HRV作为对照。检查指标 :①HRV的低频功率 (0 .0 4～ 0 .15Hz ,LF) ;②HRV的高频功率 (0 .15～ 0 .4 0Hz,HF) ;③HRV的总频功率 (0 .0 4～ 0 .4 0Hz,TF)。计算飞行员HRV谱成份的夜间调节指数。用两组飞行员调节指数的差值作为自主神经负荷程度的定量估计。　结果　对照组飞行员的HF反映迷走神经活性在 2 4h中显示明显的昼夜节律 ,即夜间HF增高 ,LF降低 ;白天HF降低 ,LF增高。交感神经活性在跨时区飞行组上述谱成份的昼夜节律性明显降低。②对照组飞行员的HF夜间调节指数为 0 .32± 0 .11,而跨时区飞行组HF夜间调节指数为 0 .0 6± 0 .0 2 (P <0 .0 5 )。对照组LF夜间调节指数为 - 0 .0 2± 0 .0 8,而跨时区飞行组LF夜间调节指数为 - 0 .0 9± 0 .0 4 (P <0 .0 5 )。　结论　跨时区飞行使飞行员HRV谱成份的昼夜周期节律显著降低     

Nycthemeral variations of 99Tcm-labelled heparin pharmacokinetic parameters

Six healthy volunteers (5 males and one female) received four i.v. boluses of 160 U.I. of 99Tcm-heparin at 8.00, 14.00, 20.00 and 02.00 hours at seven-day intervals. Nine blood samples were taken covering a period of 2 h after administration. Simultaneously urine was collected and diuresis was noted. Plasma and urinary radioactivity were measured and standard pharmacokinetic parameters were calculated. Nycthemeral variations of these kinetic parameters were detected by means of distribution-free tests. Circadian rhythms (period = 24 h) were analysed by means of the cosinor method and the Gauss-Marquardt method. The mean raw value of the following parameters: apparent volume of distribution, plasmatic clearance and extra-renal metabolic clearance, increased significantly between 8.00 and 14.00 (p less than 0.01) and decreased between 14.00 and 20.00 (p less than 0.05). A circadian rhythm was found for the plasmatic clearance only (p less than 0.04). On the other hand the elimination half-lives and the renal clearance were unaffected by the time of the injections. These results obtained for low doses of 99Tcm-heparin suggest a circadian rhythm of the bio-availability of heparin in man. This fact should be taken into account for the use of 99Tcm-heparin in the diagnosis of deep-vein thrombosis and for the safe adjustment of the heparin dosages in the treatment of severe thromboembolism.     

Circadian rhythms and athletic performance

Daily or circadian rhythmical oscillations occur in several physiological and behavioral functions that contribute to athletic performance. These functions include resting levels of sensory motor, perceptual, and cognitive performance and several neuromuscular, behavioral, cardiovascular, and metabolic variables. In addition, circadian rhythms have been reported in many indices of aerobic capacity, in certain physiological variables at different exercise levels, and, in a few studies, in actual athletic performance proficiency. Circadian rhythmicity in components of athletic performance can be modulated by workload, psychological stressors, motivation, "morningness/eveningness" differences, social interaction, lighting, sleep disturbances, the "postlunch dip" phenomenon, altitude, dietary constituents, gender, and age. These rhythms can significantly influence performance depending upon the time of day at which the athletic endeavor takes place. Disturbance of circadian rhythmicity resulting from transmeridian flight across several time zones can result in fatigue, malaise, sleep disturbance, gastrointestinal problems, and performance deterioration in susceptible individuals (circadian dysrhythmia or "jet-lag"). Factors influencing the degree of impairment and duration of readaptation include direction of flight, rhythm synchronizer intensity, dietary constituents and timing of meals, and individual factors such as morningness/eveningness, personality traits, and motivation. It is the intent of the authors to increase awareness of circadian rhythmic influences upon physiology and performance and to provide a scientific data base for the human circadian system so that coaches and athletes can make reasonable decisions to reduce the negative impact of jet-lag and facilitate readaptation following transmeridian travel.     

Adaptation of sleep and circadian rhythms to the Antarctic summer: a question of zeitgeber strength.

Adaptation of sleep and circadian rhythms was examined in three temperate zone dwellers arriving in Antarctica during summer. Rectal temperature, wrist activity, and heart rate were monitored continuously, sleep timing and quality noted on awakening, and mood and fatigue rated every 2 h while awake. Sleep was poorer in 2/3 subjects in Antarctica, where all subjects reported more difficulty rising. Sleep occurred at the same clock times in New Zealand and Antarctica, however, the rhythms of temperature, activity, and heart rate underwent a delay of about 2 h. The subject with the most Antarctic experience had the least difficulty adapting to sleeping during constant daylight. The subject with the most delayed circadian rhythms had the most difficulty. The delay in the circadian system with respect to sleep and clock time is hypothesized to be due to differences in zeitgeber strength and/or zeitgeber exposure between Antarctica and New Zealand.     

硝苯地平控释片治疗老年性高血压的临床疗效评价

目的　观察硝苯地平控释片对老年高血压治疗的临床疗效。方法　本研究采用 2 4h动态血压、超声心动图和平板运动的检查 ,评价硝苯地平控释片对老年高血压患者左室肥厚和运动血压的影响 ,3 6例按WHO标准确诊为老年高血压者 ,排除继发性高血压 ,停降压药 2周后给硝苯地平控释片 ,初始剂量为 3 0mg/d ,晨 8:0 0服 ,1周末有 6例未达显效而增量为 60mg/d治疗 4个月。观察治疗前后 2 4h动态血压 ,超声心动图和平板运动实验结果。结果　硝苯地平控释片治疗后 2 4h收缩压、舒张压及白昼夜间收缩压、舒张压均明显低于治疗前 ;左室质量、室间隔厚度及左室后壁厚度也明显减少 ;治疗后运动高峰时收缩压、运动停止后 3min收缩压亦明显降低。结论　硝苯地平控释片能有效降低老年高血压患者 2 4h收缩压、舒张压 ,逆转左室肥厚 ,并明显降低运动时收缩压 ,但对运动时舒张压及血压昼夜节律无明显影响