The effect of phenylpropanolamine on blood pressure during upright bicycle exercise in normal subjects

We studied the effect of a single oral dose (37.5 mg immediate release) of phenylpropanolamine (PPA) in six normal subjects during upright incremental bicycle exercise to symptom tolerance. The study was double blind and placebo controlled with a crossover design. The patients rested supine for 90 minutes after dosing, sat quietly on the bicycle for five minutes, and then began exercise. After PPA systolic blood pressure was increased during supine rest (135 +/- 14 mmHg vs 120 +/- 10 mmHg for placebo; P less than 0.01) and while sitting on the bicycle prior to exercise (131 +/- 8 mmHg vs 121 +/- 8 mmHg for placebo; P less than 0.05). However, PPA did not alter the expected increase in systolic blood pressure with progressive exercise. Systolic blood pressure at maximum exercise (254 +/- 43 watts) was 185 +/- 14 mmHg for PPA vs 182 +/- 13 mmHg for placebo (difference not significant). This suggests that the physiological factors controlling blood pressure during exercise (increased cardiac output, vasodilation of vessels in exercising muscles and vasoconstriction of non-exercising vascular beds) are not altered significantly by a dose of PPA sufficient to increase resting systolic blood pressure, at least in normal subjects.     

Decreased exercise capacity in mild essential hypertension: non-invasive indicators of limiting factors.

Available data suggest that exercise capacity is limited in hypertension. The mechanism of this reduced maximal exercise capacity has not been fully elucidated. In this study 22 patients with mild essential hypertension (162 +/- 22 mmHg systolic and 95 +/- 8 mmHg diastolic) and 36 normotensive control subjects (128 +/- 13 mmHg systolic and 80 +/- 7 mmHg diastolic) (P less than 0.01) performed an ergometer test till exhaustion. Body mass index in the two groups did not differ. The maximal oxygen consumption VO2 was lower in the hypertensive group (18 +/- 7 versus 23 +/- 8 ml/kg/min; P less than 0.02) as was the maximal workload (141 +/- 52 vs. 185 +/- 70 Watt; P less than 0.01). Rate pressure product rose only 2.7 fold in hypertensive patients versus 3.5 fold in the control group (P less than 0.001). In hypertensive patients maximal workload decreased with increasing resting systolic blood pressure (P less than 0.05) while in the normotensive subjects maximal workload rose with increasing resting systolic blood pressure (P less than 0.05). In conclusion both high and low blood pressure was associated with a decreased maximal voluntary exercise capacity. Even mild hypertension was accompanied by lower maximal exercise capacity. Hypertensive patients also had a lower maximal VO2 and lower maximal rate pressure product than did normotensive subjects.     

Nocturnal continuous measurement of blood pressure in sleep apnea syndromes. Comparison between normotensive and hypertensive patients

Sleep apnea syndrome and systemic hypertension are frequently associated but their causal relationship is unclear. We compared the oscillations of systemic blood pressure and heart rate during polysomnography in 8 normotensive subjects (2 females) and 5 hypertensive (supine awake blood pressure: 165 +/- 7/96 +/- 5 mmHg) without treatment. Their ages (normotensive: 52.1 +/- 11.0 yrs, hypertensive: 51.2 +/- 6.4 yrs) and body mass indices (32.6 +/- 9.6 kg/m2 vs 33.2 +/- 5.2 kg/m2 respectively) were not statistically different. Systemic blood pressure was continuously monitored by a non invasive digital plethysmography (Finapres). Both groups had similar respiratory events indices (normotensive: 45.2 +/- 18.1/hr, hypertensive: 48.4 +/- 20.5/hr) and minimal oxygen saturations (79.4 +/- 9.1% vs 82.4 +/- 7.0% respectively). During apneas in slow-wave sleep were observed the minimal values for systolic and diastolic pressures which were significantly higher in hypertensive than in normotensive (138.2 +/- 9.6/83.2 +/- 16.1 mmHg vs 105.9 +/- 11.1/60.5 +/- 10.9 mmHg respectively). During resumption of ventilation maximal blood values were recorded which were also higher in hypertensive than in normotensive (185.0 +/- 13.8/113.2 +/- 21.5 mmHg vs 155.9 +/- 19.8/88.7 +/- 17.1 mmHg respectively) (p less than 0.05). Although absolute variations of blood pressure were similar, relative changes in systolic pressure were significantly higher in normotensive (p less than 0.05). Maximal heart rate was 76.8 +/- 6.2 bpm in normotensive and 76.6 +/- 3.9 bpm in hypertensive during resumption of ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Circadian variation and blood pressure: response to rapid weight loss by hypocaloric hyponatraemic diet in obesity.

Ambulatory intra-arterial blood pressure was monitored in 15 obese hypertensive and 10 obese normotensive subjects weighing more than 30% of their ideal body weight. Measurements were taken before and after 1 month in hospital on a diet of 330kCal/day designed to ensure 34 g protein and 65 mmol sodium. Mean +/- s.d. body mass index in the whole group fell from 40.8 +/- 7.6 to 37.2 +/- 7.4 kg/m2 (P less than 0.0001). Daytime intra-arterial blood pressure fell from 176 +/- 19/102 +/- 14 to 162 +/- 16/95 +/- 14 mmHg (P less than 0.0005 and P less than 0.002) in the hypertensive group and from 141 +/- 15/82 +/- 5 to 131 +/- 13/79 +/- 4 mmHg (P less than 0.005 for systolic pressure) in the normotensive group. Circadian variation of systolic intra-arterial blood pressure comparing the mean daytime with the mean night-time blood pressure recordings showed a day-night difference of 27 +/- 10 mmHg in the normotensive group compared with 12 +/- 13 mmHg in the hypertensive group (P less than 0.01). This trend was reversed after weight loss, when the normotensive group showed a day-night difference of 20 +/- 13 mmHg compared with 18 +/- 17 mmHg in the hypertensive group. Thus, circadian variation of systolic intra-arterial blood pressure in the hypertensive group was significantly (P less than 0.01) reduced compared with the normotensive group prior to, but not after, weight loss. These data show that, in obese subjects, weight loss produced a significant reduction in ambulatory intra-arterial blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Augmented norepinephrine and renin output in response to maximal exercise in hypertensive coarctectomy patients.

To evaluate a possible neural or renal contribution to the hypertension that occurs in some patients following coarctation of aorta repair, 35 patients underwent graded bicycle exercise with serial measurements of plasma norepinephrine concentrations and plasma renin activity. Sixteen patients with coarctectomy who had systolic or diastolic hypertension at peak exercise were compared with 19 normotensive patients with coarctectomy. The average time interval between coarctation repair and study was significantly longer (p less than 0.05) in the hypertensive group than in the normotensive patients (12.8 +/- 4.8 versus 8.7 +/- 2.2 years). The heart rate response to exercise was similar for both patient groups. The systolic blood pressure in the hypertensive group was higher than in the normotensive group at rest in the supine and upright positions and at 5 minutes of recovery, in addition to peak exercise, and the diastolic blood pressure was increased at peak exercise. Plasma norepinephrine concentrations were significantly higher at peak exercise and during recovery in the hypertensive group than in the normotensive patients. Plasma renin activity was also significantly higher in the hypertensive group at peak exercise. These data suggest that patients with coarctectomy who have a hypertensive response to exercise have an augmented sympathetic nervous system output and increased plasma renin activity that may lead to peripheral vasoconstriction at peak exercise and that may contribute to the development of their hypertension.     

Prevalence of sustained hypertension and obesity in urban and rural school going children in Ludhiana

BACKGROUND: Increasing trend of hypertension is a worldwide phenomenon. The data on sustained hypertension in school going children is scanty in India. The present study was conducted to evaluate the prevalence of sustained hypertension and obesity in apparently healthy school children in rural and urban areas of Ludhiana using standard criteria. METHODS AND RESULTS: A total of 2467 apparently healthy adolescent school children aged between 11-17 years from urban area and 859 students from rural area were taken as subjects. Out of total 3326 students, 189 were found to have sustained hypertension; in urban areas prevalence of sustained hypertension was 6.69% (n=165) and in rural area it was 2.56% (n=24). Males outnumbered females in both rural and urban areas. The mean systolic and diastolic blood pressure of hypertensive population in both urban and rural population was significantly higher than systolic and diastolic blood pressure in their normotensive counterparts (urban normotensive systolic blood pressure:115.48+/-22.74 mmHg, urban hypertensive systolic blood pressure: 137.59+/-11.91 mmHg, rural normotensive systolic blood pressure: 106.31+/-19.86 mmHg, rural hypertensive systolic blood pressure: 131.63+/-10.13 mmHg, urban normotensive diastolic blood pressure: 74.18+/-17.41 mmHg, urban hypertensive diastolic blood pressure: 84.58+/-8.14 mmHg, rural normotensive diastolic blood pressure: 68.84+/-16.96 mmHg, rural hypertensive diastolic blood pressure: 79.15+/-7.41 mmHg). Overweight populationwas significantly higher in urban area. There were 287 (11.63%) overweight students and 58 (2.35%) were obese. In rural population overweight and obese students were 44 (4.7%) and 34 (3.63%) respectively. There was significant increase in prevalence of hypertension in both rural and urban population with increased body mass index in urban students; those with normal body mass index had prevalence of hypertension of 4.52% (n=96), in overweight it was 15.33% (n=44) and in obese it was 43.10% (n=25). In rural area, the overweight students showed prevalence of sustained hypertension in 6.82% (n=3) and in obese group it was 61.76% (n=21). None of the student with normal body mass index in rural area was found to be hypertensive. The mean body mass index of hypertensive population in both rural and urban areas was significantly higher than respective normotensive population (mean body mass index in urban normotensive group: 20.34+/-3.72 kg/m2, hypertensive group: 24.91+/-4.92 kg/m2; mean body mass index in rural normotensive group: 18.41+/-3.41 kg/m2, hypertensive group: 21.37+/-3.71 kg/m2, p<0.01). CONCLUSIONS: Prevalence of sustained hypertension is on the rise in urban area even in younger age groups. Blood pressure is frequently elevated in obese children as compared to lean subjects. This is possibly related to their sedentary lifestyle, altered eating habits, increased fat content of diet and decreased physical activities.     

Changes in the blood pressure during an exercise test in children and adolescents. Results with reference to height

The variations of blood pressure (BP) during exercise are important when there is a doubt about the normality of the values or a possibility of future abnormality. This is particularly true in children and adolescents with borderline or variable values, whose capacity of cardiovascular adaptation to sport is to be evaluated or who have a family history of hypertension. This study was undertaken to establish the profile of blood pressure on exercise during bicycle ergometry with reference to the height of the child or adolescent. BP and heart rate were measured in 651 healthy children aged 5 to 18 years during stress testing by bicycle ergometry. The sample was divided according to sex and height (120-139, 140-159, 160-180 cm), and according to resting BP values. During simple progressive exercise, the work required is increased by 10 watts every 2 minutes for children less than 140 cm tall, and by 20 watts when over 140 cm tall. BP and heart rate were measured during the last 30 seconds of each stage. Heart rate and systolic BP increased progressively with work load; on the other hand, the diastolic pressure did not change on exercise. The regression equation and the slope of systolic BP with respect to heart rate are reported, and allow comparison of different groups according to height, sex and resting systolic BP. The increase in systolic BP was the same in all groups except for boys taller than 160 cm in whom it was significantly greater (p less than 0,01). Sex and resting BP had no significant effect on the slope of systolic BP on exercise. The same applied to exercise lasting more than 6 minutes. The mean values and standard deviation of systolic BP at a heart rate of 150/min were, for each height group in ascending order: 121.5 +/- 19, 129 +/- 22 and 151 +/- 26 mmHg for boys, and 118.5 +/- 26, 126 +/- 21 and 137 +/- 26 mmHg for girls. In order to simplify the interpretation of the results obtained individually, charts in the form of an ellipse were plotted containing the usual values (95% of a healthy population) of systolic BP on exercise at the heart rate of 150/min, for each sex. They were established with reference to resting systolic BP and height. The diagnostic and prognostic value of this test will have to be evaluated by comparison with values obtained in hypertensive children.     

Impaired left ventricular functional reserve in hypertensive patients with left ventricular hypertrophy

To determine whether patients with hypertension and especially those with left ventricular hypertrophy have subtle changes in cardiac function, we measured the increase in left ventricular ejection fraction and in systolic blood pressure to end-systolic volume index ratio with exercise in 40 hypertensive patients and 16 age-matched normotensive volunteers. Twenty-two hypertensive patients without hypertrophy had normal end-systolic wall stress at rest and exercise responses. In contrast, the 18 patients with echocardiographic criteria for left ventricular hypertrophy demonstrated a significant increase in end-systolic wall stress at rest compared with normal subjects (69 +/- 16 vs. 55 +/- 15 10(3) x dyne/cm2, p less than 0.05) despite having normal resting left ventricular size and ejection fraction. In patients with left ventricular hypertrophy, the increase in ejection fraction with exercise was less than in the normotensive control subjects (7 +/- 7 vs. 12 +/- 8 units, p less than 0.05), and delta systolic blood pressure to end-systolic volume with exercise was reduced (3.3 +/- 3.8 vs. 8.3 +/- 7.7 mm Hg/ml/m2, p less than 0.05). The hypertensive patients with hypertrophy displayed a shift downward and to the right in the relation between systolic blood pressure to end-systolic volume ratio and end-systolic wall stress compared with control subjects and hypertensive patients without left ventricular hypertrophy. Thus, hypertensive patients with left ventricular hypertrophy by echocardiography and normal resting ejection fraction exhibit abnormal ventricular functional responses to exercise. This finding may have implications in identifying patients at higher risk for developing heart failure.     

Postexercise hypotension is not sustained in normal and hypertensive humans

Blood pressure falls after a single session of exercise. The duration for which this fall in blood pressure persists is not known. Sustained hypotension after a single session of exercise may have important implications in the treatment of patients with mild hypertension. We studied 24 subjects (12 normotensive subjects and 12 patients with mild or borderline hypertension). Blood pressure was measured in the laboratory for 30 minutes before and for an hour after graded bicycle exercise to maximal voluntary capacity. Subjects then left the hospital and measured their blood pressures at home (three measurements every 2 hours) following a strict measurement protocol for the rest of the day (usually between 8 and 12 hours). These home blood pressure measurements were compared with home blood pressure measurements recorded at the same times on a nonexercise control day. At 30 minutes after the graded maximal exercise test, the hypertensive patients experienced a fall in blood pressure from 142 +/- 3.5/93 +/- 6.5 mm Hg (mean +/- SEM) to 124 +/- 4.5/79 +/- 2.8 mm Hg (p less than 0.01). For the normotensive subjects, blood pressure after exercise fell from 117 +/- 3.1/70 +/- 2.1 mm Hg to 109 +/- 3.1/62 +/- 2.8 mm Hg (p less than 0.01). Despite these striking blood pressure reductions for the second half hour after exercise, blood pressure measurements recorded at home were not significantly different on the exercise and control days in either group. We conclude that although a single bout of exercise lowers blood pressure for a short (1-hour) period, this hypotension is not sustained.     

Exercise hypertension: its measurement and evaluation

Blood pressure, the central parameter in the diagnosis of arterial hypertension, is subject to a high degree of variability. The dilemma for the evaluating physician is that he has no true value for the resting blood pressure that is both comparable and reproducible. Reproducibility, however, is an essential requirement for all diagnostic procedures in medicine. A standardized ergometric procedure (at workloads of 50 to 100 watts [W]; incremented 10 watts/min; cuff blood pressure measurements) is suitable to obtain comparable, reproducible monitoring of the blood pressure response in both pressure response in both normotensive subjects and hypertensive patients. The blood pressure behavior during and after ergometric exercise was investigated in 552 males in order to clarify if this standardized procedure is suitable for differentiating between normotensive subjects and hypertensive patients. The following normal upper limits for blood pressure values in men and women between the ages of 20 and 50 years of 200/100 mmHg (mean + 1 SD) at a workload of 100 W as well as 140/90 mmHg in the fifth minute of the recovery phase were obtained. Patients suffering from mild hypertension showed significantly (p less than 0.001) higher blood pressures (213 +/- 22/116 +/- 11 mmHg) at 100 W and after exercise than age-matched normotensives (188 +/- 14/92 +/- 9 mmHg) but significantly (p less than 0.001) lower values than hypertensives with stable hypertension (225 +/- 22/126 +/- 11 mmHg). Moreover, the systolic pressure response to ergometric work was significantly (p less than 0.05 to p less than 0.01) influenced by age. Using the normal upper limits for blood pressure during and after ergometry, the ergometric procedure revealed that 50% of the patients with borderline hypertension at rest could be classified as hypertensives. Their blood pressure response at 100 W (216 +/- 21/113 +/- 8 mmHg) did not significantly differ from the patients with mild hypertension. In contrast, in the 50% who reacted negatively to ergometric testing, the systolic blood pressure response at 100 W (204 +/- 18 mmHg) was significantly (p less than 0.01) lower than that of those who demonstrated a positive reaction, revealing exactly the same diastolic blood pressure value of 92 mmHg as the normotensives. Follow-up examinations several years (average 3.8 years) subsequently showed that 97% of the ergometric-positive borderline hypertensives developed established hypertension. Thus an early diagnosis of arterial hypertension was achieved years before its established manifestation.(ABSTRACT TRUNCATED AT 400 WORDS)     

The effects of enalapril on basal arterial pressure at rest and during exercise and on cardiac performance in hypertensive athletes

A dose of 10 mg of enalapril was administered once a day to regularly trained hypertensive athletes (mean age 39 +/- 8.9 range 29-51) in order to evaluate the effect of the drug on ambulatory blood pressure and on blood pressure and physical performance during stress testing. STUDY DESIGN. This investigation was a randomized, double blind, cross-over versus placebo trial. At first, subjects whose blood pressure met the entry criteria (casual diastolic blood pressure greater than or equal to 95 mmHg), were subjected to 24-hour ambulatory blood pressure monitoring and maximal upright bicycle stress testing including measurement of O2 uptake. Then they were randomly assigned to treatment with placebo or enalapril. After one month they repeated stress testing and then they were crossed over. Stress testing was repeated in all subjects after two months. The 24-hour ambulatory blood pressure monitoring was repeated in all subjects during enalapril treatment only, by a non-blind investigator. RESULTS. Ambulatory blood pressure decreased significantly during enalapril and no changes in heart rate were observed during the monitoring. The results of bicycle stress testing, both in basal and during the placebo test were comparable as regards blood pressure response, maximal workload, effort duration, maximal heart rate and VO2 max. With enalapril systolic and diastolic blood pressure decreased significantly during stress testing both versus basal test and placebo test at each workload considered including maximal workload. No changes were observed during enalapril as regards maximal workload, effort duration, maximal heart rate and VO2 max. CONCLUSION. Our results suggest that enalapril could be effective in treating hypertensive athletes because it reduces blood pressure during physical effort without affecting physical performance. We conclude that enalapril could be considered a first-choice drug in hypertensive athletes doing aerobic sports.     

Role of the Gly460Trp polymorphism of the alpha-adducin gene in primary hypertension in Scandinavians

Previous studies have suggested that the Trp460 allele of the Gly460Trp polymorphism in the alpha-adducin gene is associated with salt sensitivity and primary hypertension. The present study was undertaken to evaluate if the Trp460 allele of this polymorphism is associated with primary hypertension in Scandinavians. To address this issue, 294 patients with primary hypertension and 265 normotensive control subjects from Sweden were examined and genotyped for the Gly460Trp polymorphism using polymerase chain reaction and restriction fragment length polymorphism methods. We then used a population of 80 patients with primary hypertension and 154 normotensive control subjects from Finland to replicate the findings. The frequency of the Trp460 allele was lower in hypertensive patients than in normotensive controls in the Swedish population (17.7% vs 23.0%; P = 0.03) and in the Finnish population (14.4% vs 19.5%; NS). Therefore we also performed a pooled analysis in which the frequency of the Trp460 allele was significantly lower in hypertensive patients than in normotensive controls (17.0% vs 21. 7%; P = 0.02). In subjects who did not receive antihypertensive medication (n = 447) there was no difference between carriers of the three different codon 460 genotypes (Trp-Trp; Trp-Gly and Gly-Gly) either for systolic (128 +/- 18; 127 +/- 15 and 129 +/- 17 mm Hg, NS) or for diastolic blood pressure (75.6 +/- 12.1; 74.7 +/- 9.3 and 75.0 +/- 10.4 mm Hg, NS). In conclusion, the lower frequency of the Trp460 allele in hypertensive patients than in normotensive controls strongly argues against a pathogenic role of this allele in primary hypertension. The results rather suggest that another variant in linkage disequilibrium with the Gly460Trp polymorphism increases susceptibility for hypertension.Journal of Human Hypertension (2000) 14, 43-46.     

Daily life blood pressure changes are steeper in hypertensive than in normotensive subjects

Target organ damage in hypertensive patients is related to their increased average blood pressure and greater 24-hour blood pressure variability. Whether the rate of blood pressure changes is also greater in hypertension, producing a greater stress on arterial walls, is not known, however. Our study aimed at addressing this issue by computer analysis of 24-hour ambulatory intra-arterial blood pressure recordings in 34 subjects (29 males), 13 normotensive subjects and 21 uncomplicated hypertensive subjects (mean age+/-SD, 40.4+/-11.8 years). The number, slope (mm Hg/s), and length (beats) of systolic blood pressure ramps of 3 or more consecutive beats characterized by a progressive increase (+) or reduction (-) in systolic blood pressure of at least 1 mm Hg per beat were computed for each hour and for the whole 24-hour period. Twenty-four-hour average systolic blood pressure was 112.9+/-2.1 and 159.4+/-5.7 mm Hg in normotensive and hypertensive subjects, respectively. Over the 24 hours, the number and length of systolic blood pressure ramps were similar in both groups, whereas the slope was markedly different (24-hour mean+/-SE slope, 4.80+/-0.30 in normotensives and 6.50+/-0.40 mm Hg/s in hypertensives, P<0.05). Ramp slope was not influenced by age or reflex pulse interval changes, but it was greater for higher ramp initial systolic blood pressure values. Thus, in daily life, hypertensive subjects are characterized by steeper blood pressure changes than normotensives, and this, regardless of the mechanisms, may have clinical implications, because it may be associated with greater traumatic effect on the vessel walls of hypertensive patients.     

Decreased central dopaminergic activity in essential hypertension

Baseline serum prolactin (PRL) was found to be similar in 35 men with untreated essential hypertension (149 +/- 2/98 +/- 1 mmHg; means +/- s.e.) and 44 healthy normotensive men (126 +/- 1/80 +/- 1 mmHg), all 40 years old. A correlation between baseline PRL and aldosterone was found in the normotensive (r = 0.534, P less than 0.001), but not in the hypertensive group (r = -0.011, NS). Ten subjects from each group received intravenous metoclopramide, a competitive dopamine antagonist, while another 12 normotensive subjects were given saline only, and the effect on PRL, vasopressin (AVP) and catecholamines was followed. An exaggerated PRL response to metoclopramide was observed in the hypertensive group compared with the normotensive (P less than 0.05), and the mean normotensive peak value never exceeded the hypertensive. Plasma noradrenaline increased significantly compared with baseline (P less than 0.05) and the control group (P less than 0.001), concomitant with increased heart rate (P less than 0.05), after the administration of metoclopramide both in the hypertensive and normotensive group. After intravenous injection of metoclopramide, forearm blood flow increased significantly by 50% in the hypertensive (P less than 0.001), and 80% in the normotensive group (P less than 0.001) compared with the control group. Mean blood pressure remained unchanged as did plasma AVP, dopamine and adrenaline. The present study indicates an altered central dopaminergic activity in essential hypertension. Even at rest, endogenous dopamine exerts a modulating effect on noradrenaline release in both hypertensive and normotensive men.     

The pressor response to exercise and stress in uncomplicated insulin-dependent diabetes

We investigated whether or not an increased pressor response to exercise or stress is a feature of the diabetic state per se or a feature of its complications was investigated. Twelve insulin-dependent diabetic patients without clinical evidence of complications and with normal albumin excretion rates (less than 20 micrograms/min) were studied together with 12 matched control subjects. Each underwent a study protocol of isometric handgrip exercise at 30% of maximum capacity for four minutes, a cold pressor test with immersion of one hand in ice-cold water for two minutes, and bicycle ergometry at a resistance of 105 watts per minute for six minutes. The tests were undertaken in the same order in all subjects. There was, in both groups, a similar and significant rise in systolic blood pressure and pulse rate in response to each stimulus. Diastolic pressure also rose significantly in response to handgrip exercise and to cold pressor stimulation, but fell slightly during bicycle ergometry in both groups. Mean plasma noradrenaline concentration rose in response to each stimulus but the changes reached conventional significance in both groups only in response to handgrip exercise. Pressor responses to exercise and stress, as tested here, are concluded to be normal in insulin-dependent diabetic patients without complications due to their disease.     

Short-term effect of dynamic exercise on arterial blood pressure

BACKGROUND. To quantify the duration of postexercise hypotension at different exercise intensities, we studied six unmedicated, mildly hypertensive men matched with six normotensive controls. METHODS AND RESULTS. Each subject wore a 24-hour ambulatory blood pressure monitor at the same time of day for 13 consecutive hours on 3 different days. On each of the 3 days, subjects either cycled for 30 minutes at 40% or 70% maximum VO2 or performed activities of daily living. There was no intensity effect on the postexercise reduction in blood pressure, so blood pressure data were combined for the different exercise intensities. Postexercise diastolic blood pressure and mean arterial pressure were lower by 8 +/- 1 (p less than 0.001) and 7 +/- 1 mm Hg (p less than 0.05), respectively, than the preexercise values for 12.7 hours in the hypertensive group. These variables were not different before and after exercise in the normotensive group. Systolic blood pressure was reduced by 5 +/- 1 mm Hg (p less than 0.05) for 8.7 hours after exercise in the hypertensive group. In contrast, systolic blood pressure was 5 +/- 1 mm Hg (p less than 0.001) higher for 12.7 hours after exercise in the normotensive group. When the blood pressure response on the exercise days was compared with that on the nonexercise day, systolic blood pressure (135 +/- 1 versus 145 +/- 1 mm Hg) and mean arterial pressure (100 +/- 1 versus 106 +/- 1 mm Hg) were lower (p less than 0.05) on the exercise days in the hypertensive but not in the normotensive group. We found a postexercise reduction in mean arterial pressure for 12.7 hours independent of the exercise intensity in the hypertensive group. Furthermore, mean arterial pressure was lower on exercise than on nonexercise days in the hypertensive but not in the normotensive group. CONCLUSION. These findings indicate that dynamic exercise may be an important adjunct in the treatment of mild hypertension.     

Water loading and restriction in essential hypertension

Blood pressure, plasma arginine vasopressin (AVP), and renal excretory responses to short-term water loading (oral load of 20 ml/kg body weight over 30-45 minutes) were compared in 10 normotensive and 13 mild to moderately essential hypertensive subjects. In addition, we examined the renal concentrating ability of an additional group of 10 normotensive subjects and 12 hypertensive subjects in response to a 24-hour water restriction and intranasal administration of 10 micrograms of [1-deamino,8-D-arginine]vasopression. The hypertensive subjects exhibited both an exaggerated diuresis and natriuresis to the water load. At 20- and 60-minutes after water loading, hypertensive subjects had excreted 34 and 55% of the load, respectively, compared with 15 and 35% in normotensive subjects. Mean blood pressure rose significantly in both groups and hypertensive subjects exhibited a greater rise of systolic blood pressure (16 mm Hg) than normotensive subjects (8 mm Hg) 20 minutes after water loading. The maximum diuresis and natriuresis corresponded to the period in which the rise of blood pressure was greatest. The hypertensive subjects diluted and concentrated their urine as well as normotensive subjects did, indicating normal renal responsiveness to AVP. Plasma Na, osmolality, and AVP decreased similarly in both groups after water loading and rose similarly in the two groups after water restriction. This finding suggests that osmotic responsiveness of AVP is not altered in hypertensive subjects. In conclusion, the data suggest that the exaggerated renal response to water loading could be explained by the greater rise of blood pressure in hypertensive subjects rather than by altered AVP responses.     

Longitudinal mitral annulus velocities are reduced in hypertensive subjects with or without left ventricle hypertrophy

Normotensive and hypertensive subjects with and without left ventricular (LV) hypertrophy (LV mass index [LVMI] >51 g/m(2.7)) were examined by conventional echocardiography and tissue Doppler imaging of mitral annulus motion. The subgroups included nonobese normotensive subjects (n=16; age 51+/-9 years; 11 female; systolic blood pressure [SBP] 109+/-11 mm Hg, body mass index [BMI] 24+/-2.7 kg/m2; LVMI 32+/-5.5 g/m(2.7)), nonobese hypertensive subjects without LV hypertrophy (n=16; age 54+/-12 years; 12 female; SBP 166+/-15 mm Hg; BMI 25+/-2.7 kg/m2; LVMI 42+/-5.5 g/m(2.7)), and hypertensive subjects with LV hypertrophy (n=22; age 56+/-10 years; 10 female; SBP 181+/-19 mm Hg; BMI 26+/-2.3 kg/m2; LVMI 69+/-16 g/m(2.7)). Ejection fraction was comparable among the subgroups, but midwall fractional shortening was reduced in hypertensive subjects with LV hypertrophy (approximately 26%). Isovolumic relaxation time was increased in subjects with LV hypertrophy, whereas mitral wave A velocity was increased in hypertensive subjects with and without LV hypertrophy. Tissue Doppler imaging mitral annulus systolic (SM) and diastolic (EM) velocities were reduced in subjects with and without LV hypertrophy compared with normotensive subjects. There was a positive correlation between SM and EM (r=0.68; P<0.0001) and negative correlations between these 2 variables and LVMI (SM, r=-0.41; P=0.002; EM, r=-0.56; P<0.0001). Thus, reductions in mitral annulus systolic and diastolic velocities parallel increases in LV mass in hypertensive subjects, beginning at LV mass within the clinically defined normal values.     

Relationship between ambulatory blood pressure monitoring and response of blood pressure in male hypertensive adolescents to exercise

BACKGROUND: High blood pressure in the young has been related to the development of hypertension in adults; hence the importance of identifying adolescents with the risk of developing it.OBJECTIVE: To investigate the relationship between 24 h ambulatory blood pressure monitoring and the response of blood pressure in adolescents to exercise. DESIGN: A prospective and cross-sectional study. METHODS: We classified 101 men aged 13-18 years as obese hypertensive, lean hypertensive, obese normotensive, and lean normotensive. Mean blood pressure and variability were measured with ambulatory blood pressure monitoring, and expressed as 24 h, awake, and sleeping periods. Treadmill tests were also performed. RESULTS: Hypertensives and obese normotensives had higher ambulatory blood pressure monitoring values (P< 0.0001). Systolic blood pressure during sleep in obese subjects was significantly higher than that in lean usbjects (119.9 +/- 9 versus 113.6 +/- 8 mmHg, P < 0.001, obese hypertensives versus lean hypertensives; and 113.6 +/- 2 versus 103.0 +/- 2 mmHg, P < 0.002, obese normotensives versus lean normotensives) and nocturnal drop of systolic blood pressure was lower in obese subjects. We found a significant correlation between systolic blood pressure during ambulatory blood pressure monitoring and systolic blood pressure during moderate and maximal exercise for all periods (P < 0.0001). Blood pressure variability during awake period was higher in subjects with maximum exercise systolic blood pressure >/= 200 mmHg (7.4 +/- 2 versus 6.4 +/- 2%, P < 0.01).CONCLUSION: Systolic blood pressure measured by ambulatory blood pressure monitoring is related to response of systolic blood pressure to exercise and ambulatory blood pressure monitoring can identify groups of subjects at greater than normal risk through their higher blood pressure during sleep. Greater than normal blood pressure variability in adolescents is an indicator of the risk of reaching abnormal exercise values of systolic blood pressure. Higher casual blood pressure than ambulatory blood pressure monitoring values for adolescents should be considered abnormal.