Effect of exercise training in 60- to 69-year-old persons with essential hypertension

Aerobic exercise training does not modify large-artery compliance in isolated systolic hypertension

The present study characterized large-artery properties in patients with isolated systolic hypertension (ISH) and determined the efficacy of exercise training in modifying these properties. Twenty patients (10 male and 10 female) with stage I ISH and 20 age- and gender-matched control subjects were recruited, and large-artery properties were assessed noninvasively. Ten ISH patients (5 male and 5 female) were enrolled in a randomized crossover study comparing 8 weeks of moderate intensity cycling with 8 weeks of sedentary activity. Brachial and carotid systolic, diastolic, mean, and pulse pressures were higher in the ISH group than in the control group. Systemic arterial compliance (0.43+/-0.04 versus 0.29+/-0.02 arbitrary compliance units for the control versus ISH groups, respectively; P=0.01) was lower, and carotid-to-femoral pulse-wave velocity (9.67+/-0.36 versus 11.43+/-0.51 m. s(-1) for the control versus ISH groups, respectively; P=0.007), input impedance (2.39+/-0.19 versus 3.27+/-0.34 mm Hg. s. cm(-1) for the control versus ISH groups, respectively; P=0.04), and characteristic impedance (1.67+/-0.17 versus 2.34+/-0.27 mm Hg. s. cm(-1) for the control versus ISH groups, respectively; P=0.05) were higher in the ISH group than in the control group. Training increased maximal oxygen consumption by 13+/-5% (P=0.04) and maximum workload by 8+/-4% (P=0.05); however, there was no effect on arterial mechanical properties, blood lipids, or left ventricular mass or function. These results suggest that the large-artery stiffening associated with ISH is resistant to modification through short-term aerobic training.

Exercise and diabetes

As rates of diabetes mellitus and obesity continue to increase, physical activity continues to be a fundamental form of therapy. Exercise influences several aspects of diabetes, including blood glucose concentrations, insulin action and cardiovascular risk factors. Blood glucose concentrations reflect the balance between skeletal muscle uptake and ambient concentrations of both insulin and counterinsulin hormones. Difficulties in predicting the relative impact of these factors can result in either hypoglycemia or hyperglycemia. Despite the variable impact of exercise on blood glucose, exercise consistently improves insulin action and several cardiovascular risk factors. Beyond the acute impact of physical activity, long-term exercise behaviors have been repeatedly associated with decreased rates of type 2 diabetes. While exercise produces many benefits, it is not without risks for patients with diabetes mellitus. In addition to hyperglycemia, from increased hepatic glucose production, insufficient insulin levels can foster ketogenesis from excess concentrations of fatty acids. At the opposite end of the glucose spectrum, hypoglycemia can result from excess glucose uptake due to either increased insulin concentrations, enhanced insulin action or impaired carbohydrate absorption. To decrease the risk for hypoglycemia, insulin doses should be reduced prior to exercise, although some insulin is typically still needed. Although precise risks of exercise on existing diabetic complications have not been well studied, it seems prudent to consider the potential to worsen nephropathy or retinopathy, or to precipitate musculoskeletal injuries. There is more substantive evidence that autonomic neuropathy may predispose patients to arrhythmias. Of clear concern, increased physical activity can precipitate a cardiac event in those with underlying CAD. Recognizing these risks can prompt actions to minimize their impact. Positive actions that are part of exercise programs for diabetic patients emphasize SMBG, foot care and cardiovascular functional assessment. SMBG provides critical information on the impact of exercise and is recommended for all patients before, during and after exercise. More frequent monitoring (and for longer periods following exercise) is recommended for those with hypoglycemia unawareness or those performing high-intensity exercise. Preventing the sequelae of an exercise-induced severe hypoglycemic reaction can be as simple as carrying glucose tablets or gel, a diabetic identification bracelet or card, or exercising with an individual who is aware of the circumstances. In addition to blood glucose concentrations, proper foot care is critical to people with diabetes who exercise and includes considering type of shoe, type of exercise, inspection of skin surfaces and appropriate evaluation and treatment of lesions (calluses and others). Those with severe neuropathy can consider alternatives to weight-bearing exercises. Precipitation of clinical CAD is of great concern for all diabetic patients participating in exercise activities. Although a sufficiently sensitive and specific screening test for coronary disease has not been identified, those planning an exercise program of moderate intensity or greater should be evaluated. Initial cardiac assessment should include exercise testing as well as identifying risk for autonomic neuropathy. In addition to noting maximal heart rate and blood pressure as well as ischemic changes, exercise tolerance testing can identify anginal thresholds and patients with asymptomatic ischemia. Those without symptoms should be counseled regarding target pulse rates to avoid inducing ischemia. Ischemic changes need to be evaluated for either further diagnostic testing or pharmacological intervention. For patients with diabetes mellitus, the overall benefits of exercise are clearly significant. Clinicians and patients must work together to maximize these benefits while minimizing risks for negative consequences. Identifying and preventing potential problems beforehand can reduce adverse outcomes and promote this important approach to healthy living.

Exercise as hypertension therapy

In conclusion, the findings of most recent studies show that moderate-intensity aerobic exercise training can lower BP in patients with stage 1 and 2 essential hypertension. The average reduction in BP is 10.5 mm Hg for systolic and 7.6 mm Hg for diastolic BP. The reductions do not appear to be gender- or age-specific. Significant reductions in BP and LVH regression in patients with stage 3 hypertension have also been reported following aerobic exercise training. Resistance training exercise has not consistently shown to significantly lower BP and is not recommended as the only form of exercise for hypertensive patients. The exercise training program for optimal benefits should consist of 3 to 5 times per week, 30 to 60 minutes per session, at 50% to 80% of PMHR. However, exercise programs should be individualized to meet the patient's needs and abilities. Exercise intensity and duration should be manipulated to promote a safe and effective antihypertensive program. Initially, the exercise intensity should be low and the duration short. Both intensity and duration should progressive increase over a period of weeks until the desired goal, is achieved. The rate of progression must be tailored to meet individual patient needs and abilities. The exercise program for overweight or obese hypertensive patients should aim to promote a caloric expenditure of 300 to 500 Kcal per day and 1000 to 2000 Kcal per week. Such an approach, combined with a prudent diet, is likely to reduce body weight. The mechanisms mediating exercise-induced BP reduction are poorly understood. BP reductions appear to be independent of changes in body weight or body composition. There are also no indications of age- or gender-related differences in BP response to exercise. The use of ambulatory blood pressure measuring devices in exercise studies is not extensive. The few studies available indicate a more moderate reduction in BP than that reported by casual observations.

Religious preference, church activity, and physical exercise

BACKGROUND

Utah has the highest percentage of physically active adults in the United States. It also has a high percentage of religiously active people. About 90% of the adult population has a religious preference and 62% of those individuals attend church weekly. This study evaluates the relationship between religious preference, church attendance, and physical activity.

METHODS

Analysis is based on 6,188 adult respondents ages 18 years and older to a cross-sectional random telephone survey involving 12 health districts in the state of Utah from June 1 to August 31, 1996.

RESULTS

Within religious groups, those attending church weekly were more likely to exercise than individuals attending church less than weekly. About 70% of Utah consists of members of the Church of Jesus Christ of Latter-day Saints (LDS). LDS attending church less than weekly were least physically active in Utah. The percentages of those exercising vigorously at least 20 min three times per week were 52.3% (LDS who attend church weekly), 44.5% (LDS who attend church less than weekly), 57.6% (non-LDS who attend church weekly), 54.3% (non-LDS who attend church less than weekly), and 53.1% (no religious preference) (P = 0.0070). When adjustment was made for age, smoking status, education, marital status, and general health, differences in exercise between church activity levels within religious groups became insignificant. Smoking and general health have the greatest influences on the relationship between religious preference, church attendance, and exercise. LDS were significantly less physically active than non-LDS in the adjusted model.

CONCLUSIONS

Although differential smoking levels and general health status explained differences between church activity levels within religious groups, lower levels of exercise among LDS versus non-LDS could not be explained and require further study.

Absolute versus relative intensity of physical activity in a dose-response context

PURPOSE

To examine the importance of relative versus absolute intensities of physical activity in the context of population health.

METHODS

A standard computer-search of the literature was supplemented by review of extensive personal files.

RESULTS

Consensus reports (Category D Evidence) have commonly recommended moderate rather than hard physical activity in the context of population health. Much of the available literature provides Category C Evidence. It has often confounded issues of relative intensity with absolute intensity or total weekly dose of exercise. In terms of cardiovascular health, there is some evidence for a threshold intensity of effort, perhaps as high as 6 METs, in addition to a minimum volume of physical activity. Decreases in blood pressure and prevention of stroke seem best achieved by moderate rather than high relative intensities of physical activity. Many aspects of metabolic health depend on the total volume of activity; moderate relative intensities of effort are more effective in mobilizing body fat, but harder relative intensities may help to increase energy expenditures postexercise. Hard relative intensities seem needed to augment bone density, but this may reflect an associated increase in volume of activity. Hard relative intensities of exercise induce a transient immunosuppression. The optimal intensity of effort, relative or absolute, for protection against various types of cancer remains unresolved. Acute effects of exercise on mood state also require further study; long-term benefits seem associated with a moderate rather than a hard relative intensity of effort.

CONCLUSIONS

The importance of relative versus absolute intensity of effort depends on the desired health outcome, and many issues remain to be resolved. Progress will depend on more precise epidemiological methods of assessing energy expenditures and studies that equate total energy expenditures between differing relative intensities. There is a need to focus on gains in quality-adjusted life expectancy.

Dose-response: variation with age, sex, and health status

PURPOSE

The purpose of this study was to summarize the literature on the influence of age, sex, and health status on the changes in systolic (SBP) and diastolic blood pressure (DBP), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C) consequent to exercise training.

METHODS

A MEDLINE search was performed from January 1966 through August 2000 to identify studies that have investigated the effects of age, sex, and health status on the changes in the outcome variables with exercise training. References from these studies and from review and meta-analysis studies were also reviewed.

RESULTS AND CONCLUSIONS

The results indicate that age has little or no influence on the changes in SBP, DBP, TG, and HDL-C in response to exercise training. When looking at sex, females appear to have an attenuated response to exercise training compared with males with respect to SBP, DBP, and HDL-C, but the data for TG are equivocal. Finally, there appears to be more favorable changes in resting SBP and DBP, TG, and HDL-C in unhealthy subjects (hypertensive and post-MI patients) when compared with healthy subjects.

Exercise characteristics and the blood pressure response to dynamic physical training

PURPOSE

The purpose of this study was to assess the influence of the characteristics of the exercise program, particularly exercise intensity, on the blood pressure response to dynamic physical training in otherwise healthy normotensive and hypertensive subjects.

METHODS

This study is a meta-analysis of randomized controlled intervention trials and a description of studies in which different training regimens have been compared.

RESULTS

The weighted net reduction of blood pressure in response to dynamic physical training averaged 3.4/2.4 mm Hg (P < 0.001). Interstudy differences in the changes in pressure were not related to weekly frequency, time per session, or exercise intensity, which ranged from approximately 45--85%; these three characteristics combined explained less than 5% of the variance of the blood pressure response. The response of diastolic blood pressure was not different according to training intensity in studies that randomized patients to training programs with different intensities. Some studies reported a greater reduction of systolic blood pressure when intensity was about 40% than when participants exercised at about 70%, but this finding was not consistent, neither within nor between studies.

CONCLUSION

Training from three to five times per week during 30--60 min per session at an intensity of about 40--50% of net maximal exercise performance appears to be effective with regard to blood pressure reduction. The evidence that higher intensity exercise would be less effective is at present inconsistent.

Hypertension in older adults

The high prevalence of hypertension in older persons (nearly one of two subjects aged 60 years and older) suggests that the recognition and treatment should be a priority for physicians. Although diastolic blood pressure is regarded as an important risk factor, it is now clear that isolated systolic hypertension and elevated pulse pressure also play an important role in the development of cerebrovascular disease, congestive heart failure, and coronary heart disease, which are the major causes of cardiovascular morbidity and mortality in the population aged older than 65 years. Controlled, randomized trials have shown that treatment of systolic as well as systolodiastolic hypertension decreases the incidence of cardiovascular and cerebrovascular complications in older adults. The question of whether treatment of hypertension should be maintained in very old persons, those older than 80 years, is still undecided.

Using the exercise test to create the exercise prescription

Exercise testing can provide valuable information to aid the primary care physician in developing a safe and effective exercise program for his or her patients. This review presents the most recent recommendations for the components of an exercise program as well as methods to accomplish appropriate prescription writing for the various subsets of individuals from the healthy patient to the patient with chronic disease. In addition, a plea is made for physicians to encourage all patients to engage in at least some kind of regular exercise activity in an attempt to counteract the increasingly sedentary lifestyles found in our culture.

Aerobic exercise and resting blood pressure: a meta-analytic review of randomized, controlled trials

In this study the authors used the meta-analytic approach to examine the effects of aerobic exercise on resting systolic and diastolic blood pressure in adults. Forty-seven clinical trials representing a total of 72 effect sizes in 2543 subjects (1653 exercise, 890 control) met the criteria for inclusion. Statistically significant exercise-minus-control decreases were found for changes in resting systolic and diastolic blood pressure in both hypertensive (systolic, -6 mm Hg, 95% CI, -8 to -3; diastolic, -5 mm Hg, 95% CI, -7 to -3) and normotensive (systolic, -2 mm Hg, 95% CI, -3 to -1; diastolic, -1 mm Hg, 95% CI, -2 to -1) groups. The differences between groups were statistically significant (systolic, p=0.008; diastolic, p=0.000). Relative decreases were approximately 4% (systolic) and 5% (diastolic) in hypertensives, and 2% (systolic) and 1% (diastolic) in normotensives. It was concluded that aerobic exercise reduces resting systolic and diastolic blood pressure in adults. (c) 2001 by CHF, Inc.

Regular aerobic exercise modulates age-associated declines in cardiovagal baroreflex sensitivity in healthy men

1. Cardiovagal baroreflex sensitivity (BRS), the arterial baroreflex-mediated change in the R-R interval per unit change in systolic blood pressure, decreases with advancing age in sedentary adult humans. We determined the effects of regular aerobic exercise on the age-related decline in cardiovagal BRS. 2. In the cross-sectional study, 133 healthy men 18-79 years of age who were either sedentary, performing moderate aerobic exercise, or endurance exercise trained were studied. Among the sedentary men, cardiovagal BRS (phase IV of Valsalva's manoeuvre) was progressively lower (P < 0.05) in the middle-aged ( approximately 33 %) and older ( approximately 60 %) groups compared with the young group. In contrast, cardiovagal BRS was similar in the young and middle-aged men in the moderate exercise and endurance-trained groups. Cardiovagal BRS was lower (P < 0.05) in the older exercising men, but the magnitude of decline across age ( approximately 30 %) was only half as great as that in sedentary men. Cardiovagal BRS was 40-75 % greater (P < 0.05) in middle-aged and older men who exercised regularly compared with their sedentary peers. 3. In the intervention study, a 3 month aerobic exercise intervention (primarily walking) increased cardiovagal BRS by an average of 25 % (P < 0.05) in 13 previously sedentary middle-aged and older (56 +/- 1 years) healthy men. 4. Our results demonstrate for the first time that regular aerobic exercise: (1) attenuates the age-associated decline in cardiovagal BRS; and (2) partially restores the loss of cardiovagal BRS in previously sedentary middle-aged and older healthy men.

Determinants of body composition in postmenopausal women

BACKGROUND

Little is known about the effects of different levels of long-term physical activity on total body and regional fat and whether hormone replacement therapy interacts with physical activity level to affect body composition in postmenopausal women.

METHODS

We determined the associations between different levels of habitual physical activity, hormone replacement therapy (HRT), and total and regional body composition in postmenopausal women. Twenty sedentary, 20 active nonathletic, and 23 endurance-trained women (approximately half on HRT) had total and regional body composition assessed by dual-energy x-ray absorptiometry. The athletes and active nonathletic women had been active for the same number of years and the same number of hours per week.

RESULTS

The athletes and sedentary women weighed the same, but the active nonathletic groups on and not on HRT weighed 3-12 kg more (p < .05). Athletes had less trunk, arm, leg, and total body fat than sedentary and active nonathletic women (p < .05). Women on HRT tended to have lower total body (p = .07), but not regional, fat values. Linear regression analyses indicated that VO2max in ml/kg/min was the major independent determinant of total and regional body fat accounting for 52% to 70% of their variances. Athletes had greater caloric and carbohydrate intake than their less active peers, but all groups had similar protein, fat, saturated fat, monounsaturated fat, and polyunsaturated fat intakes.

CONCLUSIONS

Intense training, but not low- to moderate-intensity physical activity, is associated with markedly lower levels of total and regional body fat in postmenopausal women. HRT has less of an effect on body composition than intense exercise training in postmenopausal women.

The role of exercise training in the treatment of hypertension: an update

Hypertension is a very prevalent cardiovascular (CV) disease risk factor in developed countries. All current treatment guidelines emphasise the role of nonpharmacological interventions, including physical activity, in the treatment of hypertension. Since our most recent review of the effects of exercise training on patients with hypertension, 15 studies have been published in the English literature. These results continue to indicate that exercise training decreases blood pressure (BP) in approximately 75% of individuals with hypertension, with systolic and diastolic BP reductions averaging approximately 11 and 8mm Hg, respectively. Women may reduce BP more with exercise training than men, and middle-aged people with hypertension may obtain greater benefits than young or older people. Low to moderate intensity training appears to be as, if not more, beneficial as higher intensity training for reducing BP in individuals with hypertension. BP reductions are rapidly evident although, at least for systolic BP, there is a tendency for greater reductions with more prolonged training. However, sustained BP reductions are evident during the 24 hours following a single bout of exercise in patients with hypertension. Asian and Pacific Island patients with hypertension reduce BP, especially systolic BP, more and more consistently than Caucasian patients. The minimal data also indicate that African-American patients reduce BP with exercise training. Some evidence indicates that common genetic variations may identify individuals with hypertension likely to reduce BP with exercise training. Patients with hypertension also improve plasma lipoprotein-lipid profiles and improve insulin sensitivity to the same degree as normotensive individuals with exercise training. Some evidence also indicates that exercise training in hypertensive patients may result in regression of pathological left ventricular hypertrophy. These results continue to support the recommendation that exercise training is an important initial or adjunctive step that is highly efficacious in the treatment of individuals with mild to moderate elevations in BP.

Therapeutic and physical fitness exercise prescription for older adults with joint disease: an evidence-based approach

Aging with joint disease does necessarily result in chronic pain, adoption of a sedentary lifestyle, and functional dependency. Several randomized controlled trials clearly show that regular exercise does not exacerbate pain or accelerate disease progression. On the contrary, these studies suggest that exercise training may increase the physiologic reserve and reduce the risk for functional dependency in older adults with joint disease. The goals for an exercise program should be directed toward increasing flexibility, muscle strength, endurance, and cardiovascular fitness. An exercise training program that is tailored specifically to an older adult's physical limitations may achieve these goals, and by optimizing patient safety lead to improve long-term exercise compliance.

Effect of physical exercise on lipoprotein(a) and low-density lipoprotein modifications in type 1 and type 2 diabetic patients

To evaluate the effect of physical exercise on blood pressure, the lipid profile, lipoprotein(a) (Lp(a)), and low-density lipoprotein (LDL) modifications in untrained diabetics, 27 diabetic patients (14 type 1 and 13 type 2) under acceptable and stable glycemic control were studied before and after a supervised 3-month physical exercise program. Anthropometric parameters, insulin requirements, blood pressure, the lipid profile, Lp(a), LDL composition, size, and susceptibility to oxidation, and the proportion of electronegative LDL (LDL(-)) were measured. After 3 months of physical exercise, physical fitness improved (maximal O2 consumption [VO2max], 29.6 +/- 6.8 v 33.0 +/- 8.4 mL/kg/min, P < .01). The body mass index (BMI) did not change, but the waist circumference (83.2 +/- 11.8 to 81.4 +/- 11.2 cm, P < .05) decreased significantly. An increase in the subscapular to triceps skinfold ratio (0.91 +/- 0.37 v 1.12 +/- 0.47 cm, P < .01) and midarm muscle circumference ([MMC], 23.1 +/- 3.4 v 24.4 +/- 3.7 cm, P < .001) were observed after exercise. Insulin requirements (0.40 +/- 0.18 v 0.31 +/- 0.19 U/kg/d, P < .05) and diastolic blood pressure (80.2 +/- 10 v 73.8 +/- 5 mm Hg, P < .01) decreased in type 2 diabetic patients. High-density lipoprotein cholesterol (HDL-C) increased in type 1 patients (1.48 +/- 0.45 v1.66 +/- 0.6 mmol/L, P < .05), while LDL cholesterol (LDL-C) decreased in type 2 patients (3.6 +/- 1.0 v3.4 +/- 0.9 mmol/L, P < .01). Although Lp(a) levels did not vary in the whole group, a significant decrease was noted in patients with baseline Lp(a) above 300 mg/L (mean decrease, -13%). A relationship between baseline Lp(a) and the change in Lp(a) (r = -.718, P < .0001) was also observed. After the exercise program, 3 of 4 patients with LDL phenotype B changed to LDL phenotype A, and the proportion of LDL(-) tended to decrease (16.5% +/- 7.4% v 14.0% +/- 5.1%, P = .06). No changes were observed for LDL composition or susceptibility to oxidation. In addition to its known beneficial effects on the classic cardiovascular risk factors, regular physical exercise may reduce the risk of cardiovascular disease in diabetic patients by reducing Lp(a) levels in those with elevated Lp(a) and producing favorable qualitative LDL modifications.

Hypertension in the Elderly

Hypertension as a risk factor for cardiac and cerebrovascular morbidity and mortality poses a major health problem for our increasingly elderly population. Recent trials have shown large reductions in stroke, heart failure, and coronary artery disease when elderly hypertensive patients are treated. These benefits are also seen in elderly patients with isolated systolic hypertension. The elderly patient with hypertension should be investigated and managed in a similar manner to their younger counterpart. Nonpharmacological measures, such as dietary salt and calorie restriction, regular exercise, cessation of smoking, and reduction of excess alcohol intake, should be recommended. If these are insufficient, pharmacological treatment should be tailored to the individual patient. Diuretics have been shown to improve outcome measures in the elderly. Other antihypertensive drugs may be added or substituted depending on the patient's blood pressure response to therapy and their comorbid conditions. If all elderly hypertensive patients were treated, a major reduction in cardiovascular and cerebrovascular mortality and morbidity would result. Consideration also needs to be given to nonpharmacological treatment, particularly salt restriction in older subjects where blood pressure is at the upper limit of normal, as this would also result in a major reduction in cardiovascular morbidity and mortality. (c) 2000 by CVRR, Inc.

Effect of endurance exercise training on left ventricular size and remodeling in older adults with hypertension

BACKGROUND

It is not known whether exercise training can induce a reduction of blood pressure (BP) and a regression of left ventricular hypertrophy (LVH) in older hypertensive subjects. This study was designed to determine whether endurance exercise training, by lowering BP, can induce regression of LVH and left ventricular (LV) concentric remodeling in older hypertensive adults.

METHODS

We studied 11 older adults with mild to moderate hypertension (BP 152.0 +/- 2.5/91.3 +/- 1.5 mm Hg, mean +/- SE), 65.5 +/- 1.2 years old, who exercised for 6.8 +/- 3.8 months. Seven sedentary hypertensive (BP 153 +/- 3/89 +/- 2 mm Hg) subjects, 68.5 +/- 1 years old, served as controls. LV size and geometry and function were assessed with the use of two-dimensional echocardiography.

RESULTS

Exercise training increased aerobic power by 16% (p < .001), and it decreased systolic (p < .05) and diastolic (p < .05) BP, LV wall thickness (from 12.8 +/- 0.4 mm to 11.3 +/- 0.3 mm; p < .05), and the wall thickness-to-radius (h/r) ratio (from 0.48 +/- 0.02 to 0.41 +/- 0.01; p < .05). There were no significant changes in the controls. The changes in LV mass index (deltaLVMI) were different between the two groups. LV mass index decreased in the exercise group (deltaLVMI - 14.3 +/- 3.3 g) but not in the controls (deltaLVMI 1.4 +/- 4.1 g; p = .009). A multiple stepwise regression analysis showed that among clinical and physiological variables including changes in resting systolic BP, aerobic power, body mass index, and systolic BP during submaximal and maximal exercise, only the reduction in resting systolic BP correlated significantly with a regression of concentric remodeling (delta h/r ratio r = .80; p = .003). The other variables did not add to the ability of the model to predict changes in the h/r ratio.

CONCLUSIONS

The data suggest that exercise training can reduce BP and induce partial regression of LVH and LV concentric remodeling in older adults with mild or moderate hypertension.

Effects of exercise rehabilitation on cardiovascular risk factors in older patients with peripheral arterial occlusive disease

OBJECTIVE

The purpose of this study was to determine whether a 6-month exercise rehabilitation program can improve cardiovascular risk factors in patients with peripheral arterial occlusive disease (PAOD).

METHODS

Thirty-four patients (mean age, 68 +/- 8 years; range 54-84 years) with PAOD with intermittent claudication (Fontaine stage II) and 14 longitudinal controls of comparable age with stage II PAOD enrolled in an exercise intervention at the University Medical Center and Veterans Affairs Medical Center at Baltimore, Maryland. The main outcome measures were lipid profile (total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol [LDL-C]), fasting glucose, blood pressure, body mass index, treadmill times to onset and maximal claudication pain, cardiopulmonary function (peak oxygen uptake), and ankle/brachial index.

RESULTS

With exercise rehabilitation, treadmill times to onset and maximal claudication pain increased by 106% and 64% (P <.0001), whereas peak oxygen uptake increased 7% (P <.05). Exercise rehabilitation lowered total cholesterol and LDL-C levels by 5.2% (P <.005) and 8% (P <.01), respectively. Systolic blood pressure declined by 5.7% (P <.05) with no change in diastolic blood pressure. These changes in cholesterol and LDL-C concentrations were related to their initial values. All other cardiovascular risk factors measured did not change. There was no correlation between improvement of cardiovascular risk factors and functional performance measurements. None of the variables measured changed significantly in the control group.

CONCLUSIONS

Exercise rehabilitation not only improves functional performance, but also results in favorable alterations in cardiovascular risk factor profile, which is an important element in the management of PAOD.

Genomics, genes, and environmental interaction: the role of exercise

Regular exercise has been shown to improve control of lipid abnormalities, diabetes mellitus, hypertension, and obesity, with the greatest benefits realized by sedentary individuals who begin to exercise. Responses to exercise interventions are often highly variable among individuals, however, and research has indicated that response to exercise may be mediated in large part by variation in genes. As we strive to unravel the complex etiology of diseases like obesity, diabetes, and cardiovascular disease through the use of molecular and genetic tools now available, understanding the interaction and influence of environmental factors, such as exercise, on gene expression and function has taken on increasing importance. This review briefly summarizes strategies presently being used to elucidate genes and genetic effects that may be mediated or influenced by exercise and serves to illustrate the importance of considering the effect of exercise when investigating genes related to health or other physiological outcomes.

Physical activity in the prevention and treatment of hypertension in the obese

Physical activity in the prevention and treatment of hypertension in the obese.

PURPOSE

The purpose of this paper was to assess the value of physical exercise in the prevention and treatment of hypertension with particular attention to possible interactions with relative weight.

METHODS

We describe epidemiological studies and report meta-analyses of randomized intervention trials, i.e., randomized controlled trials on dynamic physical training and randomized comparative trials of exercise and diet.

RESULTS

Epidemiological studies show an inverse relationship between physical activity or fitness and the incidence of hypertension, which was either independent of body size or more pronounced in the overweight. The weighted net reduction of blood pressure in response to dynamic physical training averages 3.4/2.4 mm Hg (P < 0.001), which appears to be unrelated to the initial body mass index (BMI) and to its training-induced changes. Exercise is less effective than diet in lowering blood pressure (P < 0.02), and adding exercise to diet does not appear to further reduce blood pressure. Future studies should observe scientific criteria more strictly, address the truly obese (BMI > or = 30 kg x m(-2)) and attempt to resolve the blood pressure lowering mechanisms.

CONCLUSION

Physical activity contributes to the control of blood pressure in overweight as well as in lean subjects.

Strength training normalizes resting blood pressure in 65- to 73-year-old men and women with high normal blood pressure

OBJECTIVE

To determine the effects of heavy resistance strength training (ST) on resting blood pressure (BP) in older men and women.

DESIGN

Prospective intervention study.

SETTING

University of Maryland Exercise Science Laboratory.

PARTICIPANTS

Twenty-one sedentary, healthy older men (69 +/- 1 year, n = 11) and women (68 +/- 1 year, n = 10) served as subjects for the study.

INTERVENTION

Six months of progressive whole body ST performed 3 days per week using Keiser K-300 air-powered resistance machines.

MEASUREMENTS

One-repetition maximum (1 RM) strength was measured for seven different exercises before and after the ST program. Resting BP was measured on six separate occasions before and after ST for each subject.

RESULTS

Substantial increases in 1 RM strength were observed for upper body (UB) and lower body (LB) muscle groups for men (UB: 215 vs 265 kg; LB: 694 vs 838 kg; P < .001) and women (UB: 128 vs 154 kg; LB: 441 vs 563 kg; P < .001). The ST program led to reductions in both systolic (131 +/- 2 vs 126 +/- 2 mm Hg, P < .010) and diastolic (79 +/- 2 vs 75 +/- 1 mm Hg, P < .010) BP. Systolic BP was reduced significantly in men (134 +/- 3 vs 127 +/- 2 mm Hg, P < .01) but not in women (128 +/- 3 vs 125 +/- 3 mm Hg, P < .01), whereas diastolic BP was reduced following training in both men (81 +/- 3 vs 77 +/- 1, mm Hg, P = .054) and women (78 +/- 2 vs 74 +/- 2 mm Hg, P = .055).

CONCLUSIONS

Six months of heavy resistance ST may reduce resting BP in older persons. According to the latest guidelines from the Joint National Committee for the Detection, Evaluation, and Treatment of Hypertension, the changes in resting BP noted in the present study represent a shift from the high normal to the normal category.

Influence of age and gender on exercise training-induced blood pressure reduction in systemic hypertension

Regular exercise has been reported to lower blood pressure in young and older adults with essential hypertension. However, it is not known how age and gender influence the hypotensive effects of exercise. A total of 109 sedentary subjects with stage 1 or 2 essential hypertension performed exercise training at mild intensity for 8 weeks with a combination of various exercises at 22 fitness clubs. Blood pressure (BP) was reduced significantly during the program in all of the 4 exercise subgroups classified by age and gender (-15/-11 mm Hg in men aged 30 to 49 years, -10/-5 mm Hg in men aged 50 to 69 years, -16/-14 mm Hg in women aged 30 to 49 years, and -10/-6 mm Hg in women aged 50 to 69 years). There was a significant (p <0.01) age x time interaction for both systolic and diastolic BP. However, no significant gender x time interaction was observed over the same time period. After adjustment for baseline BP, exercise duration, and changes in body mass and salt intake, a significant (p <0.01) age effect difference also was observed with reduction in BP at weeks 4 and 8. There were no significant changes in any of these variables in the 42 other hypertensive control subjects. Thus, (1) a clinically significant reduction in BP was produced with the combination of various exercises performed at fitness clubs, (2) older hypertensive subjects experienced smaller reductions in BP than younger counterparts at weeks 4 and 8, and (3) gender did not influence the efficacy of physical activity for lowering elevated BP.

Walking to work and the risk for hypertension in men: the Osaka Health Survey

BACKGROUND

It is not known whether physical activity is effective in reducing the risk for hypertension.

OBJECTIVE

To investigate the association of the duration of the walk to work and leisure-time physical activity with the risk for hypertension.

DESIGN

Prospective cohort study.

SETTING

Work site in Osaka, Japan.

PARTICIPANTS

6017 Japanese men 35 to 60 years of age with systolic blood pressure less than 140 mm Hg, diastolic blood pressure less than 90 mm Hg, normal glucose intolerance, and no history of hypertension or diabetes at baseline.

MEASUREMENTS

Data on physical activity were obtained by using questionnaires. Blood pressure was measured by using a standard technique; a value of at least 160/95 mm Hg was used to diagnose hypertension.

RESULTS

During 59,784 person-years of follow-up, 626 cases of hypertension were confirmed. The duration of the walk to work was associated with a reduction in the risk for incident hypertension; multivariate-adjusted relative risks were 1.00 for a walk of 10 minutes or less (reference category), 0.88 (95% CI, 0.75 to 1.04) for an 11- to 20-minute walk, and 0.71 (CI, 0.52 to 0.97) for a walk of 21 minutes or more (P for trend = 0.02). For every 26.3 men who walk more than 20 minutes to work, one case of hypertension will be prevented.

CONCLUSIONS

Walking to work and other types of physical activity decreased the risk for hypertension in Japanese men. Regular exercise can prevent hypertension.

Nonpharmacologic therapies that reduce blood pressure: a fresh perspective

Traditional approaches to control the epidemic of blood pressure-related atherosclerotic cardiovascular disease (ASCVD) have largely focused on drug therapy in persons with hypertension. Still, nonpharmacologic therapy, also termed lifestyle modification, has an important and expanding role that complements drug therapy. Specifically, nonpharmacologic therapies can serve as initial therapy in Stage 1 hypertensive patients, facilitate medication step down or withdrawal in patients with well-controlled hypertension, prevent hypertension in high-risk populations, and reduce blood pressure in normotensive individuals and thereby lower their risk of ASCVD. Traditional lifestyle modifications that reduce blood pressure include sodium reduction, weight loss, moderation of alcohol intake, and increased physical activity. Such strategies have been prominently advocated in the Fifth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Recommendations to increase potassium, magnesium, and calcium intake were based primarily on general health considerations, not for control of high blood pressure. In its sixth and most recent report (JNC VI) published in 1997, the Joint National Committee has extended its recommendations. In addition to the traditional lifestyle recommendations, the JNC VI advocates increased potassium intake for control of high blood pressure. Furthermore, this policy-making body now recommends a healthy dietary pattern, that is, one that is rich in fruits, vegetables, and low-fat dairy products, and reduced in saturated fat, total fat, and cholesterol. This diet, which was rigorously evaluated in the Dietary Approaches to Stop Hypertension (DASH) clinical trial, substantially lowered blood pressure in normotensive and hypertensive individuals. These recent developments reinforce the hypothesis that multiple dietary factors influence blood pressure. Nonpharmacologic approaches have enormous potential as a means to reduce blood pressure and control hypertension, thereby preventing the occurrence of ASCVD. The current challenge to health care providers, government officials, and the general public is to develop and implement effective clinical and public health strategies that lead to desirable lifestyle modifications.

Physical activity and incident hypertension in black and white adults: the Atherosclerosis Risk in Communities Study

BACKGROUND

The epidemiologic observation that physical activity reduces the risk for hypertension has only been made for white men who self-reported hypertension. This study examined physical activity and clinically determined incident hypertension in black and white men and women of the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

ARIC is a population-based prospective study with four U.S. clinic centers. The present analyses included 7,459 black and white adults 45-65 years of age. Hypertension (systolic/diastolic blood pressure >/= 140/90 mm Hg) was defined by blood pressure measured by a random-zero device or medication use. Physical activity was assessed with the Baecke questionnaire.

RESULTS

After adjustment for age, baseline blood pressure, ARIC center, education, body mass index, waist-hip ratio, parental history of hypertension, cigarette smoking, alcohol consumption, and diet, white men in the highest quartile of leisure activity (primarily cycling and walking) had a 34% lower odds of developing hypertension over 6 years compared to the least active (OR = 0.66, 95% CI = 0.47-0.94; P for quartile trend = 0.01). Baseline activity was not associated with incident hypertension in white women or blacks.

CONCLUSIONS

Leisure-time physical activity reduces the odds of hypertension in middle-aged white men. Additional studies in women and blacks are needed.

The effects of aerobic exercise and T'ai Chi on blood pressure in older people: results of a randomized trial

OBJECTIVE

To compare the effects on blood pressure of a 12-week moderate-intensity aerobic exercise program and a T'ai Chi program of light activity.

DESIGN

A randomized clinical trial.

SETTING

A suburban clinic in the Baltimore, MD, area.

PARTICIPANTS

Sixty-two sedentary older adults (45% black, 79% women, aged > or = 60 years) with systolic blood pressure 130-159 mm Hg and diastolic blood pressure < 95 mm Hg (not on antihypertensive medication).

INTERVENTION

Participants were randomized to a 12-week aerobic exercise program or a light intensity T'ai Chi program. The goal of each condition was to exercise 4 days per week, 30 minutes per day.

MEASUREMENTS

Blood pressure was measured during three screening visits and every 2 weeks during the intervention. Estimated maximal oxygen uptake and measures of physical activity level were determined at baseline and at the end of the intervention period.

RESULTS

Mean (SD) baseline systolic and diastolic blood pressures were 139.9 (9.3) mm Hg and 76.0 (7.3) mm Hg, respectively. For systolic blood pressure, adjusted mean (SE) changes during the 12-week intervention period were -8.4 (1.6) mm Hg and -7.0 (1.6) mm Hg in the aerobic exercise and T'ai Chi groups, respectively (each within-group P < .001; between-group P = .56). For diastolic blood pressure, corresponding changes were -3.2 (1.0) mm Hg in the aerobic exercise group and -2.4 (1.0) mm Hg in the T'ai Chi group (each within-group P < .001; between-group P = .54). Body weight did not change in either group. Estimated maximal aerobic capacity tended to increase in aerobic exercise (P = .06) but not in T'ai Chi (P = .24).

CONCLUSIONS

Programs of moderate intensity aerobic exercise and light exercise may have similar effects on blood pressure in previously sedentary older individuals. If additional trials confirm these results, promoting light intensity activity could have substantial public health benefits as a means to reduce blood pressure in older aged persons.

Lifestyle physical activity interventions. History, short- and long-term effects, and recommendations

INTRODUCTION

Lifestyle physical activity interventions have resulted in response to the public health problem of promoting regular amounts of physical activity to the majority of U.S. adults who remain inadequately or completely inactive. These lifestyle interventions allow a person to individualize his/her physical activity programs to include a wide variety of activities that are at least of moderate intensity and to accumulate bouts of these activities in a manner befitting his/her life circumstances.

METHODS

We reviewed the history of lifestyle physical activity interventions and defined lifestyle physical activity based on this review. We located 14 studies that met this definition.

RESULTS

Lifestyle physical activity interventions are effective at increasing and maintaining levels of physical activity that meet or exceed public health guidelines for physical activity in representative samples of previously sedentary adults and obese children. The majority of these interventions have been delivered by face-to-face contact in small groups, which limits their public health impact. However, a small number of studies demonstrate that these interventions can be delivered by mail and telephone, which may enhance their generalizability. Most of these studies utilized behavior change theories such as Social Cognitive Theory, the Transtheoretical Model, and Behavior Learning to shape the interventions. Lifestyle interventions aimed at modifying the environment, such as signs posted to increase stair climbing, also have been shown to be effective over the short term.

CONCLUSIONS

The major issues concerning lifestyle physical activity interventions are: (1) testing their ability to be implemented on a large scale; (2) examining cost-effectiveness for different modes of delivery; and (3) researching the efficacy in populations such as the elderly, minorities, economically disadvantaged, and individuals with concurrent disease. More studies aimed at manipulating the environment to increase physical activity need to be tested over periods of one year or longer. It is possible that lifestyle interventions could be integrated and delivered by new technologies such as interactive computer-mediated programs, telephone, or computer web-based formats. All of these recommended approaches should utilize valid and reliable measures of physical activity and should examine the health effects, particularly on a longitudinal basis. Basic dose-response studies in controlled settings also are needed to help us understand the health effects of accumulated moderate intensity activity.

Hypertension in master endurance athletes

OBJECTIVE

To determine whether long-term very vigorous endurance training prevents hypertension.

DESIGN

Cohort study of master orienteering runners and controls.

SETTING

Finland.

SUBJECTS AND METHODS

In 1995, a health questionnaire was completed by 264 male orienteering runners (response rate 90.4%) who had been top-ranked in competitions among men aged 35-59 years in 1984, and by 388 similarly aged male controls (response rate 87.1%) who were healthy at the age of 20 years and free of overt ischemic heart disease in 1985.

MAIN OUTCOME MEASURE

Self-report of medication for hypertension.

RESULTS

In the endurance athlete group, the crude prevalence (8.7%) of subjects who had used medication for hypertension was less than a third of that in the control group (27.8%). Even after adjusting for age and body mass index, the difference between the groups was still significant (odds ratio for athletes 0.43, 95% confidence interval 0.25-0.76).

CONCLUSIONS

Long-term vigorous endurance training is associated with a low prevalence of hypertension. Some of the effect can be explained by a lower body mass, but exercise seems to induce a lower rate of hypertension by other mechanisms than by decreasing body weight

Physical activity and stroke incidence: the Harvard Alumni Health Study

BACKGROUND AND PURPOSE

Physiologically, it appears plausible for physical activity to decrease stroke risk; however, epidemiological studies have produced mixed findings. Furthermore, few studies have examined specific kinds and intensities of activities. The purpose of this study was to examine the association between physical activity, including its various components (walking, climbing stairs, participation in sports and recreational activities), and stroke risk.

METHODS

This was a prospective cohort study of 11 130 Harvard University alumni (mean age, 58 years) without cardiovascular disease and cancer at baseline. Men reported their walking, stair climbing, and participation in sports or recreation on baseline questionnaires in 1977. Stroke occurrence was assessed with another questionnaire in 1988. Death certificates were obtained for decedents through 1990 to determine strokes not previously reported (total strokes=378). We used Cox proportional hazards regression to estimate the relative risks and 95% CIs for stroke occurrence associated with physical activity.

RESULTS

After adjustment for age, smoking, alcohol intake, and early parental death, the relative risks of stroke associated with <1000, 1000 to 1999, 2000 to 2999, 3000 to 3999, and >/=4000 kcal/wk of energy expenditure at baseline were 1.00 (referent), 0.76 (95% CI, 0.59 to 0.98), 0.54 (0.38 to 0. 76), 0.78 (0.53 to 1.15), and 0.82 (0.58 to 1.14), respectively; P=0. 05 for linear trend. Walking >/=20 km/wk was associated with significantly lower risk, independent of other physical activity components. Climbing stairs and activities of at least moderate intensity (>/=4.5 METs, or multiples of resting metabolic rate) each showed U-shaped relations to stroke risk, with the risk being significantly lower at the nadir of the curve. Light intensity activities (<4.5 METs), however, were unrelated to stroke risk.

CONCLUSIONS

Physical activity is associated with decreased stroke risk in men. A decreased risk was observed at energy expenditures of 1000 to 1999 kcal/wk, with further risk decrement seen at 2000 to 2999 kcal/wk but not beyond. Confirmation of the U-shaped relation observed in these data requires similar observations in other populations.

Evaluation and treatment of hypertension in active individuals

Hypertension is a very common vascular disease. It is seen in adolescents, obese persons, postmenopausal women, and the elderly. A nonpharmacologic approach to treatment is a critical first step in management. The modalities include a diet low in salt and saturated fat, exercise, less than 2 ounces of alcohol daily, and abstinence from smoking. Dynamic (aerobic) exercise is effective in lowering blood pressure (BP) only if performed regularly. Weight reduction by diet must be combined with exercise if there is to be a reduction in BP. Strength training is not to be considered as an alternative to aerobic training for reducing BP. Antihypertensive mediation can be added to nonpharmacologic interventions for additional BP reduction. Beta-blockade is not a contraindication to exercise training.

Blood pressure lowering effect of low intensity aerobic training in elderly hypertensive patients

PURPOSE

The purpose of this investigation was to determine the effect of 9 months of low intensity aerobic training on blood pressure in elderly hypertensive patients who were receiving antihypertensive medication.

METHODS

The training group (N = 13; mean age 75.4 +/- 5.4 yr) agreed to take part in physical training using a treadmill with an exercise intensity at the blood lactate threshold (LT) for 30 min three to six times a week for 9 months. The rest (N = 13; mean age 73.1 +/- 4.2 yr) served as controls.

RESULTS

The resting systolic (-15 +/- 8 mm Hg), mean (-11 +/- 6 mm Hg), and diastolic blood pressures (-9 +/- 9 mm Hg) decreased significantly after 3 months of training and the blood pressure of all participants stabilized at a significantly lower level by the end of the study (9 months) in the training group, whereas no significant changes in blood pressure were found in the control group. Both the pretraining systolic and diastolic blood pressure of those recruited patients negatively correlated with those changes after the training (SBP: P < 0.01; DBP: P < 0.05, respectively). After 1 month of detraining in five patients, the blood pressure levels were similar to those in the pretraining state. The LT increased significantly in the training group (P < 0.01).

CONCLUSION

In conclusion, an additional antihypertensive effect of mild aerobic training at the LT was confirmed in elderly patients receiving antihypertensive medication. The cessation of such training in five patients, however, resulted in a relatively rapid return to pretraining levels within a month.

Exercise and its role in the prevention and rehabilitation of cardiovascular disease

The purpose of this article is to review the beneficial effects of regular exercise in the primary and secondary prevention of coronary artery disease (CAD). Epidemiologic studies indicate that a physically inactive life-style is associated with twice the risk of developing CAD. The magnitude of risk is similar to that of other modifiable risk factors. Meta-analysis of studies of cardiac rehabilitation after myocardial infarction demonstrate that cardiac rehabilitation participants lower their risk of death by 20% to 25% compared to controls. Exercise training results in several beneficial physiological changes including an increase in exercise endurance, higher resting and exercise stroke volumes, lower resting and submaximal exercise heart rates, and increased capillary density and oxidative enzyme capacity in skeletal muscle. In patients with established CAD, exercise training improves symptoms of angina and congestive heart failure and attenuates the severity of exercise-induced ischemia. Regular exercise can favorably modify other risk factors, but the benefits are modest. Reductions in systolic and diastolic blood pressure readings average 6 to 9 mm Hg; decreases in total and low-density lipoprotein (LDL) cholesterol approximate 5 to 10 mg/dL; and increases in high-density lipoprotein (HDL) cholesterol approximate 2 mg/dL. Exercise training as a sole intervention does not appear to enhance smoking cessation. Regular exercise does improve psychosocial well-being. Most studies of physical activity have enrolled predominantly middle-aged men; however, available evidence suggests similar cardiovascular benefits for women, the elderly, and children and youth. Physical activity levels decrease substantially during the school-age-adolescent transition in both males and females. More than half of the adult population is sedentary or inactive. Collectively, accumulated data suggest the need for both individualized/high-risk and population-based approaches to increasing physical activity across the life span.

Training-induced alterations in fat and carbohydrate metabolism during exercise in elderly subjects

Compared with young adults, fat oxidation is lower in elderly persons during endurance exercise performed at either the same absolute or relative intensity. We evaluated the effect of 16 wk of endurance training on fat and glucose metabolism during 60 min of moderate intensity exercise [50% of pretraining peak oxygen consumption (VO2peak)] in six elderly men and women (74 +/- 2 yr). Training caused a 21% increase in mean VO2peak. The average rate of fat oxidation during exercise was greater after (221 +/- 28 mumol/min) than before (166 +/- 17 mumol/min) training (P = 0.002), and the average rate of carbohydrate oxidation during exercise was lower after (3,180 +/- 461 mumol/min) than before (3,937 +/- 483 mumol/min) training (P = 0.003). Training did not cause a significant change in glycerol rate of appearance (Ra), free fatty acid (FFA) Ra, and FFA rate of disappearance during exercise. However, glucose Ra during exercise was lower after (1,027 +/- 95 mumol/min) than before (1,157 +/- 69 mumol/min) training (P = 0.01). These results demonstrate that a 16-wk period of endurance training increases fat oxidation without a significant change in lipolysis (glycerol Ra) or FFA availability (FFA Ra) during exercise in elderly subjects. Therefore, the training-induced increase in fat oxidation during exercise is likely related to alterations in skeletal muscle fatty acid metabolism.

Regular walking increases peak limb vasodilatory capacity of older hypertensive humans: implications for arterial structure

BACKGROUND

Although regular aerobic exercise has been shown to lower arterial blood pressure in older adult humans with essential hypertension, the mechanisms responsible for this hypotensive effect remain largely unknown.

OBJECTIVE

To examine the hypothesis that the reduction in arterial blood pressure in older hypertensive humans with regular exercise is accompanied by evidence of a change in arterial structure.

METHODS

We measured peak limb vascular conductance, a well-established noninvasive measure of arterial structure, both in the forearm (untrained limb) and in the calf (exercise-trained limb) of 22 older adults (aged 51-74 years) with stage 1 or 2 essential hypertension. Eleven subjects walked 3-4 days/week at a mild exercise intensity (45% of heart rate reserve) for 6 months. Eleven other subjects served as nonexercising controls.

RESULTS

Maximal oxygen consumption of subjects in the exercise group increased by 17% (P < 0.05) with no change in body mass and body fat. Systolic and diastolic arterial blood pressures at rest were reduced by 7 +/- 4 and 5 +/- 2 mmHg, respectively (P < 0.05). There were roughly 20% increases in peak forearm blood flow and peak forearm vascular conductance (both P < 0.05). Similar increases in peak calf blood flow and vascular conductance were observed (both P < 0.01). There were no significant changes in any of these variables over the same time period for the nonexercising controls.

CONCLUSIONS

The decrease in resting blood pressure in older adults with stage 1 or 2 essential hypertension in response to regular aerobic exercise is associated with an increase in peak limb vascular conductance, which could be due in part to favorable changes in arterial structure. These exercise-induced functional and, possibly, structural changes are not confined to the exercise-trained limbs, but rather are more systemic in nature. These apparent beneficial changes in limb vasodilatory capacity and vascular structure can be produced with a mode, intensity, and frequency of aerobic exercise that can be tolerated and is commonly performed by older adults.

Active control of hypertension

Hypertension is common, and even slight elevations in blood pressure can be associated with health risks. Regular aerobic exercise helps prevent hypertension. In patients who already have hypertension, such exercise has been shown to lower systolic and diastolic blood pressure by a mean of 10 mm Hg. For mild or labile hypertension, lifestyle modification that includes at least a half hour of moderate aerobic exercise at least 3 days a week should be tried before using drug therapy. If medication is needed, one that is not likely to impede the patient's ability to exercise should be considered.

Physical activity and cardiovascular health in the elderly

People over the age of 65 constitute a growing proportion of the world population both in western and in developing countries. A unique feature of this group is the high prevalence of cardiovascular diseases, which negatively affect its quality of life as well as its life expectancy. Among the interventions able to reduce the health burden of cardiovascular diseases is physical activity. The benefits of physical activity have been demonstrated both in healthy and chronically ill elderly subjects, while the risks have been found to be modest. Physicians should recommend moderate-intensity physical activity to sedentary older subjects, who are still the majority within the elderly population.

Leisure-time physical activity and ischemic stroke risk: the Northern Manhattan Stroke Study

BACKGROUND AND PURPOSE

Physical activity reduces the risk of premature death and cardiovascular disease, but the relationship to stroke is less well studied. The objective of this study was to investigate the association between leisure-time physical activity and ischemic stroke in an urban, elderly, multiethnic population.

METHODS

The Northern Manhattan Stroke Study is a population-based incidence and case-control study. Case subjects had first ischemic stroke, and control subjects were derived through random-digit dialing with 1:2 matching for age, sex, and race/ethnicity. Physical activity was recorded through a standardized in-person interview regarding the frequency and duration of 14 activities over the 2 prior weeks. Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals after adjustment for medical and socioeconomic confounders.

RESULTS

Over 30 months, 369 case subjects and 678 control subjects were enrolled. Mean age was 69.9 +/- 12 years; 57% were women, 18% whites, 30% blacks, and 52% Hispanics. Leisure-time physical activity was significantly protective for stroke after adjustment for cardiac disease, peripheral vascular disease, hypertension, diabetes, smoking, alcohol use, obesity, medical reasons for limited activity, education, and season of enrollment (OR = 0.37; 95% confidence interval=0.25 to 0.55). The protective effect of physical activity was detected in both younger and older groups, in men and women, and in whites, blacks, and Hispanics. A dose-response relationship was shown for both intensity (light-moderate activity OR = 0.39; heavy OR = 0.23) and duration (<2 h/wk OR = 0.42; 2 to <5 h/wk OR = 0.35; > or =5 h/wk OR = 0.31) of physical activity.

CONCLUSIONS

Leisure-time physical activity was related to a decreased occurrence of ischemic stroke in our elderly, multiethnic, urban subjects. More emphasis on physical activity in stroke prevention campaigns is needed among the elderly.

Low-intensity exercise training decreases cardiac output and hypertension in spontaneously hypertensive rats

The decrease in cardiac sympathetic tone and heart rate after low-intensity exercise training may have hemodynamic consequences in spontaneously hypertensive rats (SHR). The effects of exercise training of low and high intensity on resting blood pressure, cardiac output, and total peripheral resistance were studied in sedentary (n = 17), low- (n = 17), and high-intensity exercise-trained (n = 17) SHR. Exercise training was performed on a treadmill for 60 min, 5 times per week for 18 weeks, at 55% or 85% maximum oxygen uptake. Blood pressure was evaluated by a cannula inserted into the carotid artery, and cardiac output was evaluated by a microprobe placed around the ascending aorta. Low-intensity exercise-trained rats had a significantly lower mean blood pressure than sedentary and high-intensity exercise-trained rats (160 +/- 4 vs. 175 +/- 3 and 173 +/- 2 mmHg, respectively). Cardiac index (20 +/- 1 vs. 24 +/- 1 and 24 +/- 1 ml.min-1 x 100 g-1, respectively) and heart rate (332 +/- 6 vs. 372 +/- 14 and 345 +/- 9 beats/min, respectively) were significantly lower in low-intensity exercise-trained rats than in sedentary and high-intensity exercise-trained rats. No significant difference was observed in stroke volume index and total peripheral resistance index in all groups studied. In conclusion, low-intensity, but not high-intensity, exercise training decreases heart rate and cardiac output and, consequently, attenuates hypertension in SHR.

What is the optimal type of physical activity to enhance health?

This review examines the potential of active daily living as a means of gaining the cardiovascular and health rewards previously sought through vigorous aerobic fitness programmes. Cross-sectional studies of occupational and leisure activity show encouraging associations between such activity and good health; in workers, the gross intensity of effort needed for health benefits has seemed to be 20 kJ/min. There has been less unanimity on the threshold intensity needed in leisure activities, but various recent "position statements" have decreased the recommendation to 50% of an individual's maximal oxygen intake, sustained for one hour three to five times per week. Life-style activities such as walking seem likely to reach this intensity in older individuals, but are unlikely to do so in young adults. A growing number of controlled longitudinal studies of walking programmes have demonstrated gains in aerobic fitness, modest reductions in blood pressure, improvements in lipid profile, increased bone density, and enhanced mood state, with less consistent reductions of body fat. However, gains have been greatest in the elderly, sedentary, and obese populations. The main component of active living, fast walking, seems likely to enhance health in such populations, but it is unlikely to be effective in young adults who are in good initial health.

Atividade física na terceira idade

A população de idosos vem crescendo de forma importante no mundo e o que parecia ser um problema dos países desenvolvidos vem se reproduzindo nos países mais pobres. A atividade física aparece como uma forma de permitir que os indivíduos mais velhos tenham mais saúde e se tornem mais independentes. Para que isso possa ocorrer, o programa de exercícios deve ser feito com segurança, habitualmente precedido de um teste ergométrico com protocolo individualizado, com programas de atividades apresentando períodos de aquecimento e relaxamento mais longos e graduais. Os benefícios são evidentes tanto na aptidão física quanto na esfera psicológica, levando essa população a maior integração na sociedade.

Reduction in cardiovascular disease risk factors: 6-month results from Project Active

BACKGROUND

Project Active is a randomized clinical trial that compares a lifestyle physical activity intervention with a traditional structured exercise intervention. The purpose of this paper is to report 6-month results of these interventions on cardiovascular disease (CVD) risk factors among healthy, sedentary, middle-aged men and women, and to examine the psychological strategies used in each group (Lifestyle and Structured) to reach the level of physical activity recommended by the Centers for Disease Control and Prevention (CDC) and American College of Sports Medicine (ACSM) and to achieve changes in these CVD risk factors.

METHODS

A total of 116 initially sedentary men (mean +/- SD self-reported physical activity, 33.2 +/- 1.4 kcal.kg-1.day-1) and 119 women (32.9 +/- 1.0 kcal.kg-1.day-1), ages 35-60 years (46.0 +/- 6.7 years) were randomly assigned to a 6-month lifestyle physical activity counseling intervention or a 6-month gymnasium-based structured program. At baseline and 6 months, changes in lipid and lipoprotein-cholesterol concentrations, blood pressure, and body composition and cognitive and behavioral measures of change were assessed. One-way analyses of variance with covariate adjustment were used to test for between-group differences in CVD risk factors. Associations between achieving the CDC/ACSM criterion and changes in cognitive and behavioral measures were assessed with multiple logistic regression models.

RESULTS

After 6 months of intervention, 78% of Lifestyle participants and 85% of Structured participants were meeting or exceeding the CDC/ACSM recommendation of accumulating 30 min or more of moderate-intensity physical activity on most, preferably all, days of the week. This was verified by a significant increase in cardiorespiratory fitness in both groups. The adjusted mean increase in maximal METs (VO2peak divided by 3.5 ml.kg-1.min-1) between treadmill tests was 0.4 kcal.kg-1.hr-1 (P < 0.001) for Lifestyle and 1.1 kcal.kg-1.hr-1 (P < 0.001) for Structured. There was a significant difference between intervention groups for this outcome. Both groups had significant reductions in total cholesterol, total cholesterol/HDL-C ratio, diastolic blood pressure, and percentage of body fat. There were no significant between-group differences in changes in these outcomes. Adjusted mean changes in total cholesterol, systolic blood pressure, and percentage of body fat in Lifestyle [in Structured] participants were -0.2 [-0.3] mmol.L-1, -3.2[-1.8] mm Hg, and -1.4 [-1.7] %, respectively. There were significant associations between achieving the CDC/ACSM physical activity criterion and greater use of the cognitive and behavioral strategies of change. Both groups changed self-efficacy and many of the behavioral measures, but there were no significant differences between intervention groups.

CONCLUSIONS

These results demonstrate that lifestyle physical activity counseling is as effective as structured exercise programs in increasing physical activity and improving CVD risk factors after 6 months among initially sedentary men and women. Furthermore, specific cognitive and behavioral counseling strategies were increased significantly as a result of the intervention. These strategies are effective and could be used in a wide variety of settings.

Effects of endurance training on the cardiovascular system and water compartments in elderly subjects

The effects of endurance training on the water compartments and the cardiovascular system were determined in 10 elderly subjects [age 62 +/- 2 yr, pretraining maximal oxygen consumption (VO2 max)/kg = 25 +/- 2 ml . min-1 . kg-1 body wt]. They trained on a cycloergometer 3 times/wk for 16 wk (50-80% VO2 max, then 80-85% VO2 max). They were checked at 8 wk, 16 wk, and 4 mo after detraining. Training improved VO2 max (+16%) and induced plasma volume expansion (+11%). No change in total body water, extracellular fluid, interstitial and intracellular fluid volumes, fat-free mass, and body weight was detected in this small sample with training. Body fat mass decreased (-2.1 +/- 2.2 kg). Echocardiography at rest showed increased fractional shortening and ejection fraction and decreased left ventricular end-systolic dimension (P < 0.05). Blood volume expansion correlates with cardiac contractility and has an impact on cardiac function. These improvements are precarious, however, and are completely lost after 4 mo of detraining, when elderly subjects lose the constraints and the social stimulation of the imposed protocol.

Acute and chronic effects of exercise on baroreflexes in spontaneously hypertensive rats

We studied the effects of acute and chronic exercise on the arterial baroreflex and chemosensitive cardiopulmonary baroreflex (CCB) in spontaneously hypertensive rats (SHR). Arterial baroreflex and CCB were evaluated in normotensive rats (NR, n=11) and SHR (n=5) at rest and after 30 minutes of an acute bout of exercise (45 minutes at 50% of VO2max). In addition, these baroreflexes were evaluated in sedentary (n=5) and exercise-trained (n=9) SHR. Exercise training was performed on a motor treadmill, 5 days/week, during 60 minutes, at 50% of VO2max. Baroreflex bradycardia and tachycardia, analyzed by baroreflex sensitivity index (delta heart rate/delta mean arterial pressure), were significantly lower in SHR than in NR (0.7+/-0.1 versus 2.0+/-0.1 and 1.8+/-0.2 versus 3.4+/-0.1 beats per minute [bpm]/mm Hg, respectively). During the recovery period from acute exercise, baroreflex bradycardia was significantly higher than at rest only in SHR (1.7+/-0.1 versus 0.7+/-0.1 bpm/mm Hg). Hypotension and bradycardia induced by CCB stimulation (5-hydroxytryptamine, I.V.) were similar between SHR and NR, and an acute exercise bout did not change these responses. Exercise training markedly improved baroreflex bradycardia and tachycardia in SHR (1.9+/-0.1 versus 0.7+/-0.1 and 2.9+/-0.1 versus 1.8+/-0.2 bpm/mm Hg, respectively). Exercise-trained rats had greater bradycardiac (118+/-26 versus 14+/-2 and 209+/-30 versus 19+/-5 bpm to 1 and 2 microg/kg 5-HT, respectively) and hypotensive (30+/-6 versus 15+/-3 and 45+/-7 versus 17+/-2 mm Hg to 1 and 2 microg/kg 5-hydroxytryptamine, respectively) responses to CCB stimulation. In conclusion, an acute bout of exercise increases baroreflex bradycardia in SHR, and exercise training attenuates hypertension concomitant with improved arterial baroreflex and CCB sensitivity in SHR.