Postural Blood Pressure Changes Research Articles

Changes in cerebral oxygenation and haemodynamics during postural blood pressure changes in patients with autonomic failure

Patients with autonomic failure suffer severe postural hypotension that may be associated with symptoms of cerebral hypoperfusion. This study utilized near-infrared spectroscopy (NIRS) to measure changes in cerebral oxygenation and haemodynamics during the head-up tilt table test in 18 patients with autonomic failure and 10 healthy age-matched volunteers. Heart rate, blood pressure (MAP), oxygen saturation, cerebral tissue oxygen index (TOI) and total cerebral haemoglobin concentration [HbT] were measured continuously. In patients with autonomic failure there was a mean (SD) reduction in MAP of 46.7 (26.5) mmHg (p < 0.005) associated with a reduction in TOI of 8.6 (6.2)% (p < 0.005) during the head-up tilt table test. In healthy volunteers mean (SD) MAP rose by 12.3 (8.0) mmHg (p < 0.005) and TOI fell by 2.6 (3.2)% (p < 0.05). There was a mean (SD) reduction in [HbT] of 3.09 (2.82) µmol l−1 (p < 0.005) in patients, equivalent to a decrease in cerebral blood volume of 0.2 (0.18) ml/100 g. There were no changes in [HbT] in the healthy volunteers. Postural hypotension in patients with autonomic failure is associated with a substantial decrease in absolute cerebral oxygenation measured by NIRS and this might reflect a critical reduction in cerebral oxygen delivery.

Arterial stiffness as the candidate underlying mechanism for postural blood pressure changes and orthostatic hypotension in older adults: the Rotterdam Study

To investigate whether arterial stiffening, one of the characteristics of the aging vascular system, is associated with orthostatic hypotension. Cross-sectional data of a cohort study in elderly men and women. We investigated the relationship between arterial stiffness and orthostatic hypotension within the framework of the Rotterdam Study, a population-based study in individuals aged 55 and older. The present study included 3362 subjects participating in the third examination phase. The carotid-femoral pulse wave velocity was used as measure of arterial stiffness. Orthostatic hypotension was assessed with blood pressure measurements in supine and standing position. Odds ratios for orthostatic hypotension increased through quartiles of pulse wave velocity; the age, gender and mean arterial pressure adjusted odds ratio in the last quartile of pulse wave velocity was 1.45 (95% confidence interval, 1.09-1.93) when compared with the first quartile (reference). In fully adjusted models estimates remained statistically significant. In subjects with higher stiffness we observed a higher drop in blood pressure but no significant change of heart rate. Arterial stiffness is independently associated with orthostatic hypotension. The drop in blood pressure levels and the contemporary attenuated response of heart rate to orthostatic challenge in subjects with stiffer arteries support the hypothesis that arterial stiffness may explain, at least in part, the reduced baroreflex observed in older adults.

ASSOCIATION BETWEEN RISPERIDONE TREATMENT AND CEREBROVASCULAR ADVERSE EVENTS IN ELDERLY PATIENTS WITH DEMENTIA

ASSOCIATION BETWEEN RISPERIDONE TREATMENT AND CEREBROVASCULAR ADVERSE EVENTS IN ELDERLY PATIENTS WITH DEMENTIA

Association between supine cerebral perfusion and symptomatic orthostatic hypotension

The goal of this study was to investigate whether the supine resting perfusion of brain tissue in symptomatic patients suffering from orthostatic hypotension (OH) is changed compared to control subjects and whether an association exists between the resting perfusion and the severity of OH. Ten symptomatic OH patients and 8 control subjects were included in this study. One patient was retrospectively excluded because he suffered from multiple system atrophy. Systolic and diastolic blood pressure changes were measured during a tilting bed procedure. Cerebral blood flow, cerebral blood volume and mean transit time were determined by bolus-tracking perfusion MRI and correlated with blood pressure changes. Cerebral blood volume was significantly increased in OH patients compared with control subjects for white matter ( P = 0.019) and the mean transit time was significantly increased for gray ( P = 0.010) and white matter ( P = 0.015). The cerebral blood flow of the gray ( r = 0.74, P = 0.022) and white matter ( r = 0.75, P = 0.020) was significantly, positively correlated with systolic blood pressure changes. The mean transit time in white matter was significantly, negatively correlated with systolic blood pressure changes ( r = −0.68, P = 0.045). This study suggests that in symptomatic patients with OH the cerebral perfusion of the brain in the resting, supine position correlates with the severity of OH as measured by postural changes in blood pressure.

Effects of a High-Fat Meal on the Relative Oral Bioavailability of Piperaquine

Piperaquine (PQ) is an antimalarial drug whose high lipid solubility suggests that its absorption can be increased by a high-fat meal. We examined the pharmacokinetics of PQ phosphate (500 mg given orally) in the fasting state and after a high-fat meal in eight healthy Caucasian volunteers (randomized crossover). Plasma PQ concentration-time profiles were analyzed by using noncompartmental pharmacokinetic analysis. In the fed state, the geometric mean Cmax increased by 213%, from 21.0 to 65.8 microg/liter (P<0.001). The time of Cmax was not significantly different between the fasting and fed states. The geometric mean area under the concentration-time curve from zero onward (AUC0-infinity) increased by 98%, from 3,724 to 7,362 microg h/liter (P=0.006). The oral bioavailability of PQ relative to the fasting state was 121% greater after the high-fat meal (95% confidence interval, 26 to 216% increase; P=0.020). The side effects, postural blood pressure changes, electrocardiographic corrected QT interval, serum glucose, and other biochemical and hematological indices were similar in the fasting and fed states over 28 days of follow-up.

Further Evidence of a Quantitative Trait Locus on Chromosome 18 Influencing Postural Change in Systolic Blood Pressure: The Hypertension Genetic Epidemiology Network (HyperGEN) Study

Postural change in systolic blood pressure (SBP) is prospectively associated with several disease outcomes including hypertension, stroke, and coronary heart disease. The objective of this study was to characterize further a possible quantitative trait locus on chromosome 18q21 influencing SBP response to a postural challenge. A prior genome scan of postural SBP response in 636 subjects of white ethnicity from 285 hypertensive sibships in the Hypertension Genetic Epidemiology Network (HyperGEN) indicated suggestive evidence for linkage on chromosome 18q21. This study included a de novo set of 452 African American pedigrees from the HyperGEN study and an expanded set of 372 white pedigrees. Variance components linkage analysis of postural SBP change was conducted using microsatellite markers on chromosome 18, and association studies were performed with a common single nucleotide polymorphism (variant 13) in the gene encoding NEDD4L, a key regulator of fine sodium reabsorption in the distal nephron. Combined analysis of all white and African American pedigrees yielded a LOD score of 4.25 at 80 cM on chromosome 18q21, with at least nominal evidence of linkage at this position in both white (LOD: 3.43) and African American (LOD: 1.14) subjects. Postural SBP response was associated with variant 13 of the NEDD4L in a subset of white subjects taking medications effective in treating sodium volume-dependent hypertension (alpha1-blockers, calcium channel blockers, and/or diuretics). These data provide further evidence for a quantitative trait locus on chromosome 18q21 influencing postural change in SBP.

Orthostatic Hypotension and Heart Rate Variability as Signs of Cardiac Autonomic Neuropathy in Diabetes Mellitus

Aim: The aim of this study was to emphasize two different points in our work: 1) The well known importance of (subclinical) postural hypotension and reduced heart rate variability as (early) markers of autonomic neuropathy; 2) and the more controversial influence of diabetic control in their worsening. Methods: Two standard cardiovascular response tests (heart rate variability by respiration and orthostatic blood pressure changes) were carried out on 93 diabetic patients with prolonged QT interval in order to determine cardiac dysautonomy. QT segment duration was measured on electrocardiography recordings. Patients with HbA1c levels below 7 were considered as wellcontrolled diabetics. A cut off of 5 years was selected for the known duration of diabetes. The relations between cardiac autonomic neuropathy and diabetic control and the known duration of diabetes were determined. Results: The mean values for the known duration of diabetes and HbA1c level were 10±7.23 years and 9.5±2.3 mg/dl respectively. Median QTc differences, postural change in the systolic blood pressure, and changes of heart rate by respiration were 0.62 sec, 20 mmHg, and 6 beat/min, respectively. There was no difference in QTc values with respect to diabetes control but QTc values were significantly different with regard to the known duration of diabetes. Blood pressure variations with standing were significantly related to control as well as the known duration of diabetes. Variability of hearth rate with respiration on the other hand was significantly related to the duration but not to the control of diabetes. QTc showed a significant correlation with the known duration of diabetes, postural blood pressure changes, and heart rate variability with respiration. Conclusion: Clinician’s should be more alert for the signs of autonomic neuropathy, especially in patients with a history of diabetes for more than five years. Special attention should be given to postural blood pressure changes and heart rate variability with respiration.

Assessment of dizziness among older patients at a family practice clinic: a chart audit study

BackgroundDizziness is a common complaint among the elderly with a prevalence of over 30% in people over the age of 65. Although it is a common problem the assessment and management of dizziness in the elderly is challenging for family physicians. There is little published research which assesses the quality of dizziness assessment and management by family physicians.MethodsWe conducted a retrospective, chart audit study of patients with dizziness attending the Sunnybrook Family Practice Center of Sunnybrook and Women's College Health Sciences Center (SWCHSC) in Toronto. We audited a random sample of 50 charts of patients from 310 eligible charts. Quality indicators across all dizziness subtypes were assessed. These quality indicators included: onset and course of symptoms; symptoms in patients' own words; number of medications used; postural blood pressure changes; symptoms of depression or anxiety; falls; syncope; diagnosis; outcome; specialty referrals. Quality indicators specific to each dizziness subtype were also audited.Results310 charts satisfied inclusion criteria with 20 charts excluded and 50 charts were randomly generated. Documentation of key quality indicators in the management of dizziness was sub-optimal. Charts documenting patients' dizziness symptoms in their own words were more likely to have a clinical diagnosis compared to charts without (P = 0.002).ConclusionsDocumentation of selected key quality indicators could be improved, especially that of patients' symptoms in their own words.

Postural Blood Pressure Changes and Orthostatic Hypotension in the Elderly Patient

With age our ability to maintain haemodynamic homeostasis during position changes becomes less effective. This predisposes elderly patients to significant changes in blood pressure upon standing and orthostatic hypotension (OH). The prevalence of OH varies according to the population being studied. A range of between 5% and 60% has been reported with the lower rate in elderly individuals living in the community and higher rates in those living in an institution or in the acute-care setting. Multiple factors have been linked to OH including age, bed rest, low body mass index and medications. Although antihypertensive medications can theoretically, as a group, worsen OH, the majority of cross-sectional studies have found no association. In addition, prospective randomised trials have demonstrated an improvement in postural blood pressure (PBP) changes with antihypertensive medications. When considering the individual classes, peripheral vasodilators, specifically alpha-adrenoceptor antagonists and nondihydropyridine calcium channel antagonists, can exacerbate PBP changes and lead to OH. ACE inhibitors, angiotensin-receptor antagonists and beta-adrenoceptor antagonists with intrinsic sympathomimetic activity are less likely to worsen OH. Careful management of electrolyte disturbance can decrease the risk of developing OH with diuretic use. With the aging population, this problem will be encountered by the clinicians at a much higher rate. A detailed patient history, an accurate orthostatic blood pressure measurement and careful evaluation of the autonomic nervous system can provide clinical guidance for management of OH. In hypertensive individuals with no pre-treatment OH, the use of antihypertensive medication can be safe and lead to a low risk of developing OH. In individuals with pre-treatment OH or who develop OH while on antihypertensive medications avoidance of the classes that may exacerbate OH and a judicious use of antihypertensive classes that may improve PBP changes may be safe and adequate treatment.

The Degree and Timing of Orthostatic Blood Pressure Changes in Relation to Falls in Nursing Home Residents

Background Orthostatic hypotension (OH) is traditionally defined as a decline in systolic or diastolic blood pressure of >20 or >10 mm Hg, respectively, after 1 or 3 minutes of upright posture. OH is common in the elderly, but has not been consistently demonstrated to be an independent risk factor for falls in nursing home residents. Previous studies have used the standard definition of OH in assessing fall risk. No study has sought to determine if the timing of postural changes in blood pressure adds prognostic value; if changes in systolic, diastolic, or mean blood pressure are equivalent in predicting subsequent falls; and what degree of decline in blood pressure has the best predictive value. Objective We sought to define the timing and degree of orthostatic changes in blood pressure in a cohort of elderly nursing home residents during active standing and to explore the relationship to subsequent falls to test the hypothesis that orthostatic changes in blood pressure with noninvasive beat-to-beat technology would predict falls in nursing home residents better than the standard definition of OH. Methods One hundred eleven elderly (88 ± 7 years) residents of a long-term care facility had measurement of orthostatic blood pressure changes during active standing for up to 3 minutes with a real-time continuous, noninvasive beat-to-beat blood pressure device. Falls were determined prospectively over a median follow-up period of 270 days (range, 8–657 days). The degree and timing of declines in systolic, diastolic, or mean blood pressure and their association with subsequent falls was determined using a time-to-event analysis. Results Forty-six subjects (41%) fell. The standard definition of OH was not predictive of subsequent falls (hazard ratio 1.03 at 1 minute and 1.32 at 3 minutes, P = not significant). Other measures of orthostatic blood pressure changes were also not associated with a significant increase in risk for subsequent falls, including declines in blood pressure within the first minute of standing. Conclusion The standard definition of OH was not an independent predictor of falls in frail nursing home residents. A one-time measure for the presence of postural hypotension using beat-to-beat tonometry was not predictive of fall risk. The timing and degree of orthostatic changes in blood pressure does not significantly enhance risk prediction for falls.

Orthostatic hypotension in the elderly: are the diagnostic criteria adequate?

Orthostatic hypotension (OH) is a common finding in the elderly. OH is defined as a fall of at least 20 mmHg in systolic blood pressure (BP) and/or 10 mmHg in diastolic BP upon assuming an upright posture. Some patients exhibit a fall in BP of less than the defined OH upon standing. The aim of this study was to estimate the prevalence of BP changes not defined as OH among elderly in-patients and to assess the relationship between these changes in the morning and the occurrence of OH during the day. Postural BP measurements were performed in 502 in-patients; in the morning, early afternoon, and in the evening. We defined intermediate postural drop (ID) in BP as a decrease of 10-19 mmHg in systolic BP and/or of 5-9 mmHg in diastolic BP. We observed that OH and ID occurred in 39.2 and 18.5% of the measurements in the morning, respectively. The prevalence of OH and ID was lower in the evening than in the morning (P<0.05) and afternoon (P<0.005). Postural BP changes in the morning correlated with those occurring later in the day. Patients who had ID in the morning had a 57% probability of having OH later during the day. In conclusions, ID is prevalent in elderly in-patients. ID in the morning predicts OH later in the day. Thus, postural BP drops below the OH range may be an important finding in the geriatric population.

Familial and genomic analyses of postural changes in systolic and diastolic blood pressure.

The physiological adaptation to the erect posture involves integrated neural and cardiovascular responses that might be determined by genetic factors. We examined the familial- and individual-specific components of variance for postural changes in systolic and diastolic blood pressure in 767 volunteer nuclear adult families from the Victorian Family Heart Study. In 274 adult sibling pairs, we made a genome-wide scan using 400 markers for quantitative trait loci linked with the postural changes in systolic and diastolic pressures. Overall, systolic pressure did not change on standing, but there was considerable variation in this phenotype (SD=8.1 mm Hg). Familial analyses revealed that 25% of the variance of change in systolic pressure was attributable to genetic factors. In contrast, diastolic pressure increased by 6.3 mm Hg (SD=7.0 mm Hg) on standing and there was no evidence of contributory genetic factors. Multipoint quantitative genome linkage mapping suggested evidence (Z=3.2) of linkage of the postural change in systolic pressure to chromosome 12 but found no genome-wide evidence of linkage for the change in diastolic pressure. These findings suggest that genetic factors determine whether systolic pressure decreases or increases when one stands, possibly as the result of unidentified alleles on chromosome 12. The genetics of postural changes in systolic blood pressure might reflect the general buffering function of the baroreflex; thereby, the predisposition to sudden decreases or increases in systolic pressure might cause postural hypotension or vessel wall disruption, respectively.

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Common variant of human NEDD4L activates a cryptic splice site to form a frameshifted transcript.

The ubiquitin ligase NEDD4L is a candidate gene for essential hypertension on both functional and genetic grounds. By targeting the epithelial sodium channel (ENaC) for degradation, NEDD4L is a significant determinant of sodium reabsorption in the distal nephron. Genetic linkage has been reported to a region of chromosome 18q harboring the gene, with phenotypes that include a rare orthostatic hypotension disorder, essential hypertension, and postural change in systolic blood pressure. A systematic search for genetic polymorphisms by resequencing exons and intron boundaries in 48 Caucasians yielded 38 variants. Among these, variant 13 is common, with either G (70%) or A (30%) as the last nucleotide of a putative exon 1. This mutation could affect the generation of a previously unrecognized splice isoform. In subsequent experiments, (1) we confirmed the presence of this putative isoform in both kidney and adrenals; (2) we established that variant 13-A leads to the systematic use of an alternative splice site, generating a transcript encoding a nonfunctional protein; and (3) we demonstrated differences in tissue-specific expression of the novel isoform relative to its previously reported counterpart. Variant 13-A precludes the formation of a transcript encoding a full-length Ca2+-dependent lipid-binding (C2) domain with very high evolutionary conservation among NEDD4L orthologs. A similar C2 domain in the paralogous NEDD4 gene plays a significant role in the transfer of its product to the apical membrane of epithelial cells. Differential function of NEDD4L isoforms could prove significant in blood pressure regulation through an effect on ENaC-dependent sodium reabsorption.

Association between the blood pressure response to a change in posture and the 6-year incidence of hypertension: prospective findings from the ARIC study.

The association between the blood pressure response to a change from the supine to the standing position and the 6-year incidence of hypertension was studied in a bi-ethnic, middle-aged cohort of 6951 normotensive men and women free of coronary heart disease at baseline. Postural change in systolic blood pressure (SBP) was categorized into deciles, and the middle four deciles served as the referent (no change) group. In unadjusted analyses, the incidence of hypertension was higher among both those with SBP increases and decreases relative to those in the referent group. Associations were modestly attenuated after controlling for age, ethnicity, and gender and cardiovascular disease risk factors. However, after adjustment for baseline, seated SBP, a modest association with incident hypertension persisted only for SBP decreases. Orthostatic hypotension (upon standing) was associated with incident hypertension and isolated systolic hypertension and, unexpectedly, this increased risk was highest among those with the lowest levels of baseline, resting SBP.

Effect of doxazosin on postural changes in blood pressure using a multibiomedical recorder

To investigate the effect of doxazosin on orthostatic blood pressure changes with daily activity, the relationship among blood pressure, physical position and physical activities using an ambulatory multibiomedical monitoring system(TM2425) were studied. The subjects were 22 patients with essential hypertension(EHT group), 23 patients with diabetic mellitus(DM group) and 17 healthy volunteers for the control. Patients were administered doxazosin at 2-8 mg/day for 0.5 month to 12 months. Twenty-four-hour blood pressure, posture and activity were monitored. Systolic blood pressure was higher in the standing position than that in the sitting position in the control group, but there were no differences between these values in the EHT group and DM groups. During the awake, sleep, and standing periods, doxazosin significantly decreased blood pressure in the EHT group; however, it significantly decreased only the standing systolic blood pressure in the DM group. Absolute changes in blood pressure after the administration of doxazosin were not significantly different between the standing and sitting periods in each group. These findings suggest that doxazosin decreases the blood pressure of both patients with essential hypertension and patients with diabetic mellitus without an excessive decrease in standing blood pressure.

Cardiovascular dysfunction in multiple sclerosis.

Cardiovascular dysfunction (CD) in multiple sclerosis (MS) is related to involvement of reflex pathways in the brainstem. The battery of CD tests was applied to a group of 40 healthy subjects and 40 patients with MS, divided in 2 subgroups according to the expanded disability status scale (EDSS). The tests included: 1) postural blood pressure changes, 2) postural heart rate changes, 3) heart rate changes on inspiration/forced expiration and 4) ECG R-R interval measurement on the Valsalva maneuver. Both groups were subjected to the functional independence scale (FIM). Imaging studies were reviewed and autonomic dysfunction at other levels was explored. The results showed a statistically significant difference (P < 0.05) in all tests when comparing patients to controls. Tests 1 and 4 had the highest significance, with findings of more severe involvement in patients with a higher EDSS and lower FIM. A correlation was also found between CD and brainstem lesions on MRI (P < 0.01). A significant number of MS patients had evidence of CD. Test 1 may be considered a simple marker, in daily clinical practice, to detect subclinical CD. Subclinical CD is a cause of disability in this group of patients.

Intraindividual variability in orthostatic blood pressure changes among older adults: the influence of meals.

To examine the influence of time of day and of meals on postural blood pressure (BP) changes in older adults. Prevalence study of BP changes in response to orthostasis. A geriatric short-stay department A total of 126 inpatients (91 women and 35 men; mean age: 81.4+/-7.9, range 61-95 years) were included in the study. Two sets of BP and heart rate measurements were obtained for each subject by one examiner using a standard mercury manometer: (1) in mid-morning (between 10:00 and 10:30 a.m.) and (2) within 30 to 60 minutes after lunch (between 1:00 and 1:30 p.m.). Orthostatic hypotension (OH) was defined as a systolic blood pressure (SBP) decline > or = 20 mm Hg within 3 minutes after standing. Sixty-one participants (48%) experienced significant orthostatic BP decline on at least one reading. Among them, 46 (37%) had OH in the mid-morning, and 32 (25%) had OH after lunch (P = .05). Only 17 (13%) had OH on both readings (persistent OH). Forty-four patients (35%) had variable OH. Patients with persistent OH were more likely to exhibit symptoms of dizziness and had a lower body mass index and a higher mean basal supine SBP. There was a positive correlation between basal supine SBP and postural SBP decline. Because of the variability of postural BP changes, the diagnosis of OH should not be based on a single orthostatic BP measurement but requires repeated testing, at best under circumstances similar to those in which the symptoms occurred. The postprandial period is not particularly favorable to OH, suggesting that the ingestion of a meal does not worsen orthostatic BP changes in most aged patients.

Orthostatic blood pressure changes and arterial baroreflex sensitivity in elderly subjects.

orthostatic hypotension in elderly people is often attributed to diminished afferent baroreflex sensitivity, but this has not been demonstrated. We examined the hypothesis that postural change in blood pressure is related to baroreflex sensitivity, independent of the confounding effect of baseline blood pressure. we studied 25 active, untreated elderly subjects free of postural symptoms (mean age 70 +/- 1 years): 16 with hypertension (clinic blood pressure 194 +/- 6/98 + 3 mmHg) and nine normotensive controls (clinic blood pressure 134 + 3/77 + 3 mmHg). We assessed baroreflex sensitivity from the heart rate and blood pressure responses to the Valsalva manoeuvre and a pressor and depressor stimulus (bolus phenylephrine injection or sodium nitroprusside infusion respectively). Subjects were then passively tilted to 60 degrees and maximum changes in systolic blood pressure, heart rate, forearm blood flow and forearm vascular resistance recorded. maximum change in systolic blood pressure with head-up tilt was correlated with supine systolic blood pressure (r = 0.60, P = 0.001). Maximum change in systolic blood pressure with orthostasis was greater in the hypertensive subjects (45 +/- 4 mmHg versus 29 +/- 6, P = 0.04) and the heart rate increment was less (16 +/- 2 bpm versus 24 +/- 4, P = 0.02). The increase in forearm vascular resistance with tilt was similar in the two groups (47 +/- 11 versus 38 +/- 7 units, P = 0.52). All three methods of assessing baroreflex sensitivity showed a reduction in the hypertensive subjects (all P < or = 0.02). Lower values of baroreflex sensitivity were related to greater falls in systolic blood pressure with tilt, after adjustment for the baseline level of systolic blood pressure. we found a relationship between baroreflex sensitivity and the systolic blood pressure fall with orthostasis, even after adjustment for prevailing systolic blood pressure. Despite equivalent changes in forearm vascular resistance with tilt, greater falls in systolic blood pressure were seen in hypertensive subjects than in normotensive controls, due in part to an inadequate baroreflex-mediated heart rate response. The postural fall in blood pressure often observed in elderly hypertensive subjects may be related to the reduced baroreflex sensitivity seen in this condition.

Measuring postural changes in blood pressure in the healthy elderly.

Background The reproducibility of postural changes in blood pressure of a healthy elderly population determined using standard clinical measurements is not known. To assess the differences in reproducibility of postural changes in blood pressure in healthy elderly subjects 1 and 3 min after standing within a day and between visits spaced 6 weeks apart. Casual readings of blood pressures of supine and standing subjects were measured twice during the day by the same observer on two occasions 6 weeks apart using a semi-automatic syphgmomanometer. Twenty-two subjects with no known risk factors for orthostatic hypotension (13 men) aged 69+/-3 years (mean+/-SD) with a mean initial screening supine blood pressure of 153+/-19/88+/-11 mmHg were recruited. There were significant differences(P<0.001) between the postural changes both for systolic and for diastolic blood pressure between 1 and 3 min of standing, the largest falls occurring after 1 min of standing, though we found no variation between morning and afternoon measurements and between visits. The coefficients of reproducibility between visits for the postural changes in blood pressure after 1 and 3 min of standing were large both for systolic and for diastolic blood pressure, ranging from 9.8 to 29.3 mmHg. There was a consistent and significant difference between the postural changes in blood pressure after 1 and 3 min of standing for this healthy elderly population, but there was no significant difference between the postural changes in morning and afternoon measurements and between visits. This marked variability in the postural change in blood pressure with duration of standing must be taken into account when assessing the prevalence of orthostatic hypotension and the effects of treatment in patients with orthostatic falls in blood pressure.