Prognostic significance of peak oxygen uptake in hypertension

Effect of exercise on blood pressure control in hypertensive patients

Several large epidemiological studies have reported an inverse relationship between blood pressure and physical activity. However, longitudinal intervention studies are more appropriate for assessing the effects of physical activity. We performed meta-analyses of randomized controlled trials involving dynamic aerobic endurance training or resistance training. The meta-analysis on endurance training involved 72 trials and 105 study groups. After weighting for the number of trained participants, training induced significant net reductions in resting and daytime ambulatory blood pressure of, respectively, 3.0/2.4 mmHg (P<0.001) and 3.3/3.5 mmHg (P<0.01). The reduction in resting blood pressure was more pronounced in the 30 hypertensive study groups (-6.9/-4.9) than in the others (-1.9/-1.6; P<0.001 for all). Systemic vascular resistance decreased by 7.1% (P<0.05), plasma norepinephrine by 29% (P<0.001), and plasma renin activity by 20% (P<0.05). Body weight decreased by 1.2 kg (P<0.001), waist circumference by 2.8 cm (P<0.001), percentage body fat by 1.4% (P<0.001) and the homeostasis model assessment index of insulin resistance by 0.31 units (P<0.01); high-density lipoprotein cholesterol increased by 0.032 mmol/l (P<0.05). Resistance training has been less well studied. A meta-analysis of nine randomized controlled trials (12 study groups) on mostly dynamic resistance training revealed a weighted net reduction in blood pressure of 3.2 (P=0.10)/3.5 (P<0.01) mmHg associated with exercise. Endurance training decreases blood pressure through a reduction in systemic vascular resistance, in which the sympathetic nervous system and the renin-angiotensin system appear to be involved, and favourably affects concomitant cardiovascular risk factors. The few available data suggest that resistance training can reduce blood pressure. Exercise is a cornerstone therapy for the prevention, treatment and control of hypertension.

[Effects of a dance therapy programme on quality of life, sleep and blood pressure in middle-aged women: A randomised controlled trial]

BACKGROUND AND OBJECTIVE

Evidence suggests that dance therapy may have positive effects in areas such as cardiovascular parameters and sleep. The aim of the present study is to explore whether a dance therapy programme improves sleep and blood pressure in a population of middle-aged pre-hypertensive and hypertensive women.

METHODS

A randomised controlled trial was conducted, in which participants were assigned to one of 2 groups: standard care (with usual activities and medication) or dance therapy (in which the participants followed a dance therapy programme, in addition to their medication). The intervention was an 8-week, 3-times-per-week, progressive and specific group dance-training programme. The dance steps were specifically designed to improve balance by shifting the body and relocating the centre of gravity. The main measures obtained were blood pressure, sleep quality and quality of life, measured by the Pittsburgh Sleep Quality Index and the European Quality of Life Questionnaire.

RESULTS

Sixty-seven pre-hypertensive and hypertensive middle-aged women were randomised to either an intervention group (n=35) or a control group (n=32) after baseline testing. The intervention group reported a significant improvement in blood pressure values (P<.01), as well as in sleep quality (P<.05) and quality of life (P<.001), compared to the control group.

CONCLUSION

The dance therapy programme improved blood pressure, sleep and quality of life in pre-hypertensive and hypertensive middle-aged women, and constitutes an interesting basis for larger-scale research.

Evidence-based risk assessment and recommendations for physical activity clearance: established cardiovascular disease1This paper is one of a selection of papers published in this Special Issue, entitled Evidence-based risk assessment and recommendations for physical activity clearance, and has undergone the Journal’s usual peer review process

Physical activity is an effective lifestyle therapy for patients at risk for, or with, documented cardiovascular disease (CVD). Current screening tools — the Physical Activity Readiness Questionnaire (PAR-Q) and the Physical Activity Readiness Medical Evaluation (PARmed-X) — require updating to align with risk/benefit evidence. We provide evidence-based recommendations to identify individuals with CVD at lower risk, intermediate risk, or higher risk of adverse events when participating in physical activity. Forms of exercise and the settings that will appropriately manage the risks are identified. A computer-assisted search of electronic databases, using search terms for CVD and physical activity risks and benefits, was employed. The Appraisal of Guidelines for Research and Evaluation were applied to assess the evidence and assign a strength of evidence rating. A strength rating for the physical activity participation clearance recommendation was assigned on the basis of the evidence. Recommendations for physical activity clearance were made for specific CVD groups. Evidence indicates that those who are medically stable, who are involved with physical activity, and who have adequate physical ability can participate in physical activity of lower to moderate risk. Patients at higher risk can exercise in medically supervised programs. Systematic evaluation of evidence indicates that clinically stable individuals with CVD may participate in physical activity with little risk of adverse events. Therefore, changes in the PAR-Q should be undertaken and a process of assessment and consultation to replace the PARmed-X should be developed. Patients at lower risk may exercise at low to moderate intensities with minimal supervision. Those at intermediate risk should exercise with guidance from a qualified exercise professional. Patients at higher risk should exercise in medically supervised programs.

Exercise capacity and mortality in hypertensive men with and without additional risk factors

We assessed the association between exercise capacity and mortality in hypertensive men with and without additional cardiovascular risk factors. A cohort of 4631 hypertensive veterans, who successfully completed a graded exercise test at the Veterans Affairs Medical Center in Washington, DC, and Palo Alto, California, was followed for 7.7+/-5.4 years (35,629 person-years) for all-cause mortality. Fitness categories were established based on peak metabolic equivalent (MET) levels achieved. In each fitness category, we defined individuals with and without additional cardiovascular risk factors. Exercise capacity was the strongest predictor of all-cause mortality. The adjusted mortality risk was 13% lower for every 1-MET increase in exercise capacity. Compared with the very low fit (< or =5.0 MET), the adjusted risk was 34% lower for those achieving 5.1 to 7.0 MET (low fit; hazard ratio: 0.66; CI: 0.58 to 0.76; P<0.001), 59% lower for the moderate fit (7.1 to 10.0 MET; hazard ratio: 0.41; CI: 0.35 to 0.50; P<0.001), and 71% lower for the high-fit category (>10.0 MET; hazard ratio: 0.29; CI: 0.21 to 0.40; P<0.001). Within the very-low-fit category, mortality risk was 47% higher for those with additional risk factors compared with individuals with no risk factors. This risk was eliminated for those in the next fitness category (5.1 to 7.0 MET) and was progressively reduced for the moderate and high-fit categories regardless of the presence or absence of additional risk factors. In conclusion, exercise capacity was the strongest predictor of all-cause mortality in hypertensive men. The increased risk imposed by low fitness and additional cardiovascular risk factors was eliminated by relatively small increases in exercise capacity and declined progressively with higher exercise capacity.

Exercise is good for your blood pressure: effects of endurance training and resistance training

1. Although several epidemiological studies have not observed significant independent relationships between physical activity or fitness and blood pressure, others have concluded that blood pressure is lower in individuals who are more fit or active. However, longitudinal intervention studies are more appropriate for assessing the effects of physical activity on blood pressure. 2. Previously, we have performed meta-analyses of randomized controlled trials involving dynamic aerobic endurance training or resistance training. Inclusion criteria were: random allocation to intervention and control; physical training as the sole intervention; inclusion of healthy sedentary normotensive and/or hypertensive adults; intervention duration of at least 4 weeks; availability of systolic and/or diastolic blood pressure; and publication in a peer-reviewed journal up to December 2003. 3. The meta-analysis on endurance training involved 72 trials and 105 study groups. After weighting for the number of trained participants, training induced significant net reductions of resting and day time ambulatory blood pressure of 3.0/2.4 mmHg (P < 0.001) and 3.3/3.5 mmHg (P < 0.01), respectively. The reduction of resting blood pressure was more pronounced in the 30 hypertensive study groups (-6.9/-4.9) than in the others (-1.9/-1.6; P < 0.001 for all). Systemic vascular resistance decreased by 7.1% (P < 0.05), plasma noradrenaline by 29% (P < 0.001) and plasma renin activity by 20% (P < 0.05). Bodyweight decreased by 1.2 kg (P < 0.001), waist circumference by 2.8 cm (P < 0.001), percentage body fat by 1.4% (P < 0.001) and the Homeostatic Model Assessment (HOMA) index of insulin resistance by 0.31 units (P < 0.01). High-density lipoprotein-cholesterol increased by 0.032 mmol/L (P < 0.05). 4. Resistance training has been less well studied. A meta-analysis of nine randomized controlled trials (12 study groups) on mostly dynamic resistance training revealed a weighted net reduction of diastolic blood pressure of 3.5 mmHg (P < 0.01) associated with exercise and a non-significant reduction of systolic blood pressure of 3.2 mmHg (P = 0.10). 5. In conclusion, dynamic aerobic endurance training decreases blood pressure through a reduction of systemic vascular resistance, in which the sympathetic nervous system and the renin-angiotensin system appear to be involved, and favourably affects concomitant cardiovascular risk factors. In addition, the few available data suggest that resistance training is able to reduce blood pressure.

Effects of endurance training on blood pressure, blood pressure-regulating mechanisms, and cardiovascular risk factors

Previous meta-analyses of randomized controlled trials on the effects of chronic dynamic aerobic endurance training on blood pressure reported on resting blood pressure only. Our aim was to perform a comprehensive meta-analysis including resting and ambulatory blood pressure, blood pressure-regulating mechanisms, and concomitant cardiovascular risk factors. Inclusion criteria of studies were: random allocation to intervention and control; endurance training as the sole intervention; inclusion of healthy sedentary normotensive or hypertensive adults; intervention duration of > or =4 weeks; availability of systolic or diastolic blood pressure; and publication in a peer-reviewed journal up to December 2003. The meta-analysis involved 72 trials, 105 study groups, and 3936 participants. After weighting for the number of trained participants and using a random-effects model, training induced significant net reductions of resting and daytime ambulatory blood pressure of, respectively, 3.0/2.4 mm Hg (P<0.001) and 3.3/3.5 mm Hg (P<0.01). The reduction of resting blood pressure was more pronounced in the 30 hypertensive study groups (-6.9/-4.9) than in the others (-1.9/-1.6; P<0.001 for all). Systemic vascular resistance decreased by 7.1% (P<0.05), plasma norepinephrine by 29% (P<0.001), and plasma renin activity by 20% (P<0.05). Body weight decreased by 1.2 kg (P<0.001), waist circumference by 2.8 cm (P<0.001), percent body fat by 1.4% (P<0.001), and the homeostasis model assessment index of insulin resistance by 0.31 U (P<0.01); HDL cholesterol increased by 0.032 mmol/L(-1) (P<0.05). In conclusion, aerobic endurance training decreases blood pressure through a reduction of vascular resistance, in which the sympathetic nervous system and the renin-angiotensin system appear to be involved, and favorably affects concomitant cardiovascular risk factors.

Clinical and demographic predictors of exercise capacity in end-stage renal disease

Patients on maintenance hemodialysis therapy for end-stage renal disease have reduced exercise tolerance. Multiple processes related to uremia and hemodialysis have been implicated in the pathophysiology of this impairment. However, limited data are available to identify the separate and combined effects of clinical factors on the degree of impairment for individuals within this population. For this purpose, data from 193 patients who had undergone exercise testing for two clinical trials were retrospectively analyzed. Univariate and multiple linear regression analyses were used to identify demographic and clinical correlates of peak exercise oxygen uptake (VO2). Peak VO2 averaged 18.5 +/- 6.4 mL/min/kg. On univariate analysis, peak VO2 correlated positively with male sex and hemoglobin, serum albumin, and serum creatinine concentrations and correlated negatively with dialytic age and diagnosis of diabetes or chronic heart failure. In a multiple linear regression model, sex, hemoglobin concentration, age, and diagnosis of diabetes each remained statistically significant. Together, factors included in the model accounted for 41% of the variability in peak VO2 (P = 0.0001). Among factors not correlating significantly with peak VO2 were resting blood pressure, serum carnitine level, and urea clearance assessed by Kt/V. Findings show the range of exercise impairment among clinically stable ambulatory hemodialysis patients, which may be sufficient to interfere with normal daily activities for many of these patients. Although this impairment may be broadly attributable to physiological consequences of uremia, the degree of impairment for individual patients is predicted by demographic factors, coexistent disease, and factors potentially modified by medical therapeutics.

Prognostic significance of exercise versus resting blood pressure in patients with chronic heart failure

BACKGROUND

Results on the prognostic value of exercise blood pressure differ among studies; this may be related to the characteristics of the studied population.

OBJECTIVE

To assess the prognostic significance of blood pressure measured during exercise in patients with chronic heart failure being considered for heart transplantation.

DESIGN AND METHODS

Symptom-limited bicycle exercise testing with measurement of blood pressure and respiratory gas analysis was performed in 274 potential candidates for heart transplantation. They were then followed up for mortality and cardiovascular events.

RESULTS

Results are given as the mean +/- SD. The age of the patients was 51.5+/-11.0 years, the resting blood pressure was 114+/-20/75+/-12 mmHg, the peak work load was 91+/-33 W and the peak oxygen uptake was 15.1+/-5.0 ml/min per kg. The systolic blood pressure increased to 128+/-21 mmHg at 30 W and to 133+/-23 mmHg at 50% of the peak work load. During the total follow-up time of 513 years, 55 patients died and 145 suffered at least one cardiovascular event. After controlling for age, gender and body mass index, mortality and incidence of events were inversely related to the systolic pressure at 30 W or at 50% of the peak work load, or to both (P < 0.05). The inverse associations of outcome with the systolic pressure at 50% of the peak work load persisted after additional adjustment for resting pressure and for peak oxygen uptake.

CONCLUSION

The data indicate that a lower exercise systolic pressure, particularly at 50% of the peak work load, is associated with a higher mortality and a greater incidence of cardiovascular events.

Adverse prognostic value of a blunted circadian rhythm of heart rate in essential hypertension

BACKGROUND

Previous studies revealed a direct association between resting heart rate and risk of mortality in essential hypertension. However, resting heart rate is a highly variable measure since it is affected by the alerting reaction to the visit.

OBJECTIVE

To investigate whether the heart rate values recorded during the 24 h of ambulatory blood pressure monitoring are independent predictors of survival of uncomplicated subjects with essential hypertension.

METHODS

We followed up 1942 initially untreated and uncomplicated subjects with essential hypertension (mean age 51.7 years, 52% men) for an average of 3.6 years (range 0-10 years). All subjects underwent baseline procedures including 24 h non-invasive blood pressure monitoring with simultaneous assessment of heart rate, one reading every 15 min for 24 h.

MAIN OUTCOME MEASURES

All-cause mortality and cardiovascular morbidity.

RESULTS

During follow-up there were 74 deaths from all causes (1.06 per 100 person-years) and 182 total (fatal plus non-fatal) cardiovascular morbid events (2.66 per 100 person-years). Clinic, average 24 h, daytime and night-time heart rates exhibited no association with total mortality. However, the subjects who subsequently died had had a blunted reduction of heart rate on going from day to night during the baseline examination. After adjustment for age (P < 0.001), diabetes (P < 0.001) and average 24 h systolic blood pressure (SBP, P= 0.002) in a Cox model, for each 10% less reduction in the heart rate from day to night the relative risk of mortality was 1.30 (95% confidence interval 1.02-1.65, P = 0.04). Rates of death were 0.38, 0.71, 0.94 and 2.0 per 100 person-years among subjects in the four quartiles of the distribution of the percentage reduction in heart rate from day to night The baseline day-night changes in the heart rate exhibited an inverse correlation to age and to clinic and ambulatory SBP and a direct association with the day-night changes in blood pressure. The degree of reduction of heart rate from day to night also had an independent inverse association with total cardiovascular morbidity after adjustment for age, diabetes and left ventricular hypertrophy, but this association did not remain significant when average 24 h SBP and the degree of day-night reduction in SBP were entered into the equation.

CONCLUSIONS

A flattened diurnal rhythm of heart rate in uncomplicated subjects with essential hypertension is a marker of risk for subsequent all-cause mortality and this association persists after adjustment for several risk factors. For assessing these subjects, a limited and uniformly distributed period of ambulatory heart rate recording during the 24 h is clinically valuable.

The association between physical fitness and diagnosed chronic disease in health maintenance organization members

PURPOSE

The purpose of this investigation was to determine the relationship between predicted cardiorespiratory fitness (predicted VO2max) and diagnosed chronic disease.

DESIGN

A stratified random sample of individuals was surveyed.

SETTING

Large Health Maintenance Organization (HMO) in the upper Midwest.

SUBJECTS

HMO members (N = 8000), age 40 and over, with none, one, or two or more of the following diagnosed chronic conditions: hypertension, diabetes, dyslipidemia, and heart disease.

MEASURES

Predicted VO2max was estimated for those respondents who completed the survey providing all critical data elements (n = 4121; representing 51.5% of total sample). Predicted VO2max was compared across chronic conditions using analysis of variance. The proportion of subjects across fitness quintiles by number of chronic conditions was tested using the chi 2 test.

RESULTS

Subjects without chronic conditions showed higher predicted VO2max values (29.8 +/- 7.7 ml/kg/min) than those with one (25.9 +/- 7.8 ml/kg/min) or two or more conditions (25.7 +/- 7.9 ml/kg/min) (p < .0001). Subjects with diabetes, hypertension, and heart disease reported lower predicted VO2max than their healthier counterparts (p < .0001), but this was not the case for dyslipidemia subjects (27.6 +/- 7.6 vs. 27.4 +/- 8.2 ml/kg/min, respectively; p > .58). A larger proportion of diseased subjects was in the lowest fitness quintile for diabetes, hypertension, and heart disease, but not for dyslipidemia.

CONCLUSIONS

As a group, chronic disease patients appear to have lower levels of physical fitness than subjects without chronic disease. Physical fitness improvement in diseased populations should be supported in the clinical setting.

Reduction of left ventricular mass by antihypertensive treatment does not improve exercise performance in essential hypertension

OBJECTIVE

To test the hypothesis that a reduction in left ventricular mass by long-term antihypertensive treatment, possibly associated with an improvement of diastolic function, would increase exercise performance in patients with essential hypertension. DESIGNS After a placebo run-in period, 27 patients with essential hypertension World Health Organization stages I and II were assigned randomly to 6-month double-blind treatment with either a diuretic (hydrochlorothiazide plus triamterene) or a converting enzyme inhibitor (trandolapril), to which the calcium antagonist amlodipine could be added after 3 months if required for better blood pressure control.

METHOD

Investigations included clinic and ambulatory blood pressure measurements, left ventricular imaging and transmitral Doppler echocardiography and graded maximal exercise testing on the bicycle ergometer with respiratory gas analysis.

RESULTS

Six-month antihypertensive therapy, which caused significant (P < 0.001) reductions in blood pressure (by 16% for clinic pressure) and in left ventricular mass (by 13%), but without convincing evidence of improved diastolic function, did not affect exercise performance or peak oxygen uptake. The influence on clinic, exercise and ambulatory blood pressures and on the peak oxygen uptake was similar in the two treatment arms but left ventricular wall thickness decreased to a greater extent in the trandolapril group (P< 0.05 at 3 months and P= 0.06 at 6 months).

CONCLUSIONS

Regression of left ventricular mass caused by 6-month antihypertensive therapy does not improve exercise performance of patients with essential hypertension.