Effect of moderate physical training on left ventricular mass in mild hypertensive persons

Regular physical activity: a major component of isolated systolic hypertension in the young

In the last few decades there has been much debate about the clinical significance of isolated systolic hypertension in youth (ISHY). Purpose of this article is to discuss the epidemiology and pathophysiology of ISHY focusing on the relationship between ISHY and aerobic exercise. There is evidence to suggest that regular physical activity produces favourable long-standing cardiovascular effects in young individuals including the improvement of arterial elasticity as measured from carotid-femoral pulse wave velocity and from small artery compliance. A recent ESH document recognises the heterogeneity of ISHY which may be associated with multiple factors that can interact to determine this BP phenotype. Several studies have shown that long-term training in aerobic sports is one main factor contributing to ISHY. In the athlete, the increased stroke volume secondary to low heart rate and the high arterial elasticity causes an increase in peripheral pulse pressure. This explains why ISHY is more common in physically trained than in sedentary individuals and is considered by some authors as a spurious hypertension. Recent results from the HARVEST study confirm the existence of an association between ISHY and endurance training. In that study the prevalence of ISHY was directly related to physical activity habits being 8.8% in the sedentary subjects and 25.7% in the athletes. Eligibility to competitive athletics of athletes with ISHY should be based on the results of 24-hour ambulatory BP monitoring and careful clinical assessment of all cardiovascular risk factors and target organ involvement in order to establish the global level of risk.

Influence of Physical Activity on Hypertension and Cardiac Structure and Function

The global burden of hypertension is rising and accounts for substantial morbidity and mortality. Lifestyle factors such as diet and physical inactivity contribute to this burden, further highlighting the need for prevention efforts to curb this public health epidemic. Regular physical activity is associated with lower blood pressure, reduced cardiovascular risk, and cardiac remodeling. While exercise and hypertension can both be associated with the development of left ventricular hypertrophy (LVH), the cardiac remodeling from hypertension is pathologic with an associated increase in myocyte hypertrophy, fibrosis, and risk of heart failure and mortality, whereas LVH in athletes is generally non-pathologic and lacks the fibrosis seen in hypertension. In hypertensive patients, physical activity has been associated with paradoxical regression or prevention of LVH, suggesting a mechanism by which exercise can benefit hypertensive patients. Further studies are needed to better understand the mechanisms underlying the benefits of physical activity in the hypertensive heart.

Evidence for distinct effects of exercise in different cardiac hypertrophic disorders

Aerobic exercise training (AET) attenuates or reverses pathological cardiac remodeling after insults such as chronic hypertension and myocardial infarction. The phenotype of the pathologically hypertrophied heart depends on the insult; therefore, it is likely that distinct types of pathological hypertrophy require different exercise regimens. However, the mechanisms by which AET improves the structure and function of the pathologically hypertrophied heart are not well understood, and exercise research uses highly inconsistent exercise regimens in diverse patient populations. There is a clear need for systematic research to identify precise exercise prescriptions for different conditions of pathological hypertrophy. Therefore, this review synthesizes existing evidence for the distinct mechanisms by which AET benefits the heart in different pathological hypertrophy conditions, suggests strategic exercise prescriptions for these conditions, and highlights areas for future research.

Cardiac benefits of exercise training in aging spontaneously hypertensive rats

OBJECTIVE

To evaluate the effect of low-intensity chronic exercise training (ExT) on blood pressure (BP), as well as the cardiac alterations associated with hypertension in aging hypertensive rats.

METHODS

Male spontaneously hypertensive rats (SHR; 21 months old) and their normotensive control Wistar-Kyoto (WKY) rats were submitted to low-intensity training protocol for 13 weeks. BP, cardiac morphological and morphometric analysis, as well as gene expression of fibrotic and inflammatory factors were analyzed at the end of the training period.

RESULTS

ExT reduced BP and heart rate in aged SHR. Left ventricle hypertrophy, collagen volume fraction and wall-to-lumen ratio of myocardium arterioles were also decreased in trained SHR. However, ExT was unable to reverse the either reduced capillary density or the cardiac myocyte hypertrophy observed in SHR as compared with WKY rats. Trained SHR showed higher metalloproteinase-2/tissue inhibitor metalloproteinase-2 (MMP-2/TIMP-2) ratio and lower levels of α-smooth muscle actin, but similar levels of connective tissue growth factor, transforming growth factor beta or IL-1 beta to that of nontrained SHR.

CONCLUSION

Low to moderate-intensity chronic ExT reverses the cardiac alterations associated with hypertension: myocardial arteriole, left ventricle hypertrophy, collagen content and tachycardia. These changes could be consequence or cause of the reduction in BP observed in trained SHR. In addition, ExT does not worsen the underlying inflammatory burden associated with hypertension. Therefore, the data support a beneficial effect of ExT in aging SHR similar to that reported in young or middle-aged individuals, confirming that exercise is a healthy habit that induces cardiac improvements independently of age.

Regular physical activity prevents development of left ventricular hypertrophy in hypertension

AIMS

The longitudinal relationship between aerobic exercise and left ventricular (LV) mass in hypertension is not well known. We did a prospective study to investigate the long-term effect of regular physical activity on development of LV hypertrophy (LVH) in a cohort of young subjects screened for Stage 1 hypertension.

METHODS AND RESULTS

We assessed 454 subjects whose physical activity status was consistent during the follow-up. Echocardiographic LV mass was measured at entry, every 5 years, and/or at the time of hypertension development before starting treatment. LVH was defined as an LV mass >/=50 g/m(2.7) in men and >/=47 g/m(2.7) in women. During a median follow-up of 8.3 years, 32 subjects developed LVH (sedentary, 10.3%; active, 1.7%, P = 0.000). In a logistic regression, physically active groups combined (n = 173) were less likely to develop LVH than sedentary group with a crude OR = 0.15 (CI, 0.05-0.52). After controlling for sex, age, family history for hypertension, hypertension duration, body mass, blood pressure, baseline LV mass, lifestyle factors, and follow-up length, the OR was 0.24 (CI, 0.07-0.85). Blood pressure declined over time in physically active subjects (-5.1 +/- 17.0/-0.5 +/- 10.2 mmHg) and slightly increased in their sedentary peers (0.0 +/- 15.3/0.9 +/- 9.7 mmHg, adjusted P vs. active = 0.04/0.06). Inclusion of changes in blood pressure over time into the logistic model slightly decreased the strength of the association between physical activity status and LVH development (OR = 0.25, CI, 0.07-0.87).

CONCLUSION

Regular physical activity prevents the development of LVH in young stage 1 hypertensive subjects. This effect is independent from the reduction in blood pressure caused by exercise.

Comparison of effects of exercise and diuretic on left ventricular geometry, mass, and insulin resistance in older hypertensive adults

To compare the effects of exercise training and hydrochlorothiazide on left ventricular (LV) geometry and mass, blood pressure (BP), and hyperinsulinemia in older hypertensive adults, we studied 28 patients randomized either to a group (age 66.4 ± 1.3 yr; n = 16) that exercised or to a group (age 65.3 ± 1.2 yr; n = 12) that received hydrochlorothiazide for 6 mo. Endurance exercise training induced a 15% increase in peak aerobic power. The reduction in systolic BP was twofold greater with thiazide than with exercise (26.6 ± 12.2 vs. 11.5 ± 10.9 mmHg). Exercise and thiazide reduced LV wall thickness, LV mass index (14% in each group), and the LV wall thickness-to-radius ratio ( h/ r) similarly (exercise: before 0.48 ± 0.2, after 0.42 ± 0.01; thiazide: before 0.47 ± 0.04, after 0.40 ± 0.04; P = 0.017). The reductions in systolic BP and h/ r were correlated in the exercise group ( r = 0.70, P = 0.005) but not in the thiazide group. Exercise training reduced glucose-stimulated hyperinsulinemia (before: 13.65 ± 2.6 vs. 9.84 ± 1.5 mU·ml−1·min; P = 0.04) and insulin resistance. Thiazide did not affect plasma insulin levels. The results suggest that although exercise is less effective in reducing systolic BP than thiazide, it can induce regression of LV hypertrophy similar in magnitude to thiazide. Unlike hydrochlorothiazide, exercise training can improve insulin resistance and aerobic capacity in older hypertensive people.

The Role of Exercise in the Treatment of Cardiovascular Disease Associated with Type 2 Diabetes Mellitus

The role of exercise training in the prevention and treatment of type 2 diabetes mellitus has been studied extensively over the past two decades. Although the primary treatment aim for patients with type 2 diabetes is metabolic control, the morbidity and mortality associated with the disease is more a function of cardiovascular disease. As exercise is associated with favourable reductions in the risk for cardiovascular disease in other high-risk populations, here we explore the role of exercise in the treatment of cardiovascular maladaptations associated with type 2 diabetes. The cardiovascular adaptation to type 2 diabetes is characterised by hypertrophy, stiffening and loss of functional reserve. Clinically, the cardiovascular adaptations to the diabetic state are associated with an increased risk for cardiovascular disease. Functionally, these adaptations have been shown to contribute to a reduced exercise capacity, which may explain the reduced cardiovascular fitness observed in this population. Exercise training is associated with improved exercise capacity in various populations, including type 2 diabetes. Several structural and functional adaptations within the cardiovascular system following exercise training could explain these findings, such as reductions in ventricular and vascular structural hypertrophy and compliance coupled with increased functional reserve. Although these cardiovascular adaptations to aerobic exercise training have been well documented in older populations with similar decrements in cardiovascular fitness and function, they have yet to be examined in patients with type 2 diabetes. For this reason, we contend that exercise training may be an excellent therapeutic adjunct in the treatment of diabetic cardiovascular disease.

Exercise in patients with hypertension

A progressive increase in arterial stiffness with aging contributes to systolic hypertension that results in left ventricular hypertrophy and concentric remodeling in the elderly. Lowering of blood pressure in older adults reduces cardiovascular risks. Endurance exercise training can lower blood pressure in older adults with mild (grade I) hypertension. However, the blood pressure-lowering effect of exercise training, compared with antihypertensive medications, is generally modest for both systolic and diastolic blood pressure. Exercise training alone is likely to be ineffective in lowering blood pressure sufficiently in older adults with moderate to severe (grade II and higher) hypertension. However, exercise and weight loss may potentiate the effects of antihypertensive medications in these subjects. Low-intensity endurance exercise training appears to be most effective in reducing blood pressure in older hypertensive adults. Metabolic adaptations to exercise training can significantly reduce other risk factors for coronary artery disease and atherosclerosis, in addition to reducing blood pressure. Endurance exercise training improves exercise capacity and quality of life, and can induce a modest but significant regression of left ventricular hypertrophy and remodeling in older adults with hypertension.

Exercise in the healthy older adult

Habitual exercise provides numerous health benefits to the older adult. While dynamic aerobic activities increase stamina and lung capacity, isometric or resistance training improves muscle strength and endurance. Long-term benefits of continued exercise include a decreased risk of death from heart disease, enhanced balance and mobility, a decreased risk of diabetes, and an improvement in depressive symptoms. While the hazards of exercise relate predominantly to extremes of intensity and duration, all older adults should consult with a physician before beginning a new activity program. A prescription for exercise should include both aerobic and resistance training components, and frequent follow-up to improve adherence is highly recommended.

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.

The effect of moderate weight loss on echocardiographic parameters in obese female patients

Based on the data collected by KNOLL Hungary Ltd. in Hungary in 1999, 37% of the adult population is overweight while 23% is obese. Inappropriate diet containing excess calories and physical inactivity are responsible for these statistical values. In their former studies, the authors investigated the effects of different stages of obesity on the cardiovascular system, and have verified that even moderate obesity elicits pathological geometric and functional changes in the heart. In the present study, effect of a half-year-long life-style modification program on the morphologic and functional characteristics of the heart was investigated in twenty-one obese women. Life-style modification contained a diet with reduced energy uptake (1000-1300 Cal/day) and a regular physical training of minimum 3-4 hours weekly. By the end of the sixth month the weight loss was 5.1 kg (5.9%) on an average. There was a marked reduction in cardiac dimensions measured by echocardiography, with a very slight, non-significant decrease in left ventricular internal diameter, and a marked, significant reduction in the left ventricular wall thickness. Decrease of the left ventricular muscle mass exceeded the decrease of body weight. A marked elevation was found in the E/A quotient that reflected a definite improvement in diastolic function. Results indicate that physical training programs have a favourable effect on the echocardiographic parameters, therefore the process is reversible even without a pharmacological intervention.

The metabolic syndrome and related cardiovascular risk

The metabolic syndrome is a complex association of several risk factors including insulin resistance, dyslipidemia, and essential hypertension. Insulin resistance has been associated with sympathetic activation and endothelial dysfunction, which are the main mechanisms involved in the pathophysiology of hypertension and its related cardiovascular risk. According to the Sixth Report of the Joint National Committee, and guidelines of the World Health Organization/International Society of Hypertension, the presence of multiple risk markers suggests that both hypertension and risk factors should be aggressively managed in order to obtain a better outcome. Primary prevention of obesity at different levels--individual, familial, and social-- starting early in childhood has proven to be cost effective, and will be mandatory to reduce the world epidemic of obesity and its severe consequences.

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.

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.

Exercise and hypertension

Randomized, well-controlled exercise intervention studies have shown consistently that regularly performed aerobic exercise significantly lowers blood pressure in patients with essential hypertension. Mild to moderate intensity exercise may be more effective in lowering blood pressure than higher intensity exercises. Such exercise is also safe and effective in lowering blood pressure in treated patients with severe hypertension and left ventricular hypertrophy. A significant reduction in blood pressure and regression of left ventricular hypertrophy may be achieved in these patients even after substantial reductions in antihypertensive medication. Recent findings have also shown that exercise training attenuates exaggerated blood pressure response during physical exertion. The safety and efficacy of mild to moderate exercise has significant and positive clinical implications for all hypertensive patients. Exercise-induced reductions in resting blood pressure and prevention of abnormal increases in blood pressure during physical exertion can lead to fewer cardiovascular events. They may also reduce antihypertensive medication requirements, cost, and medication-related side-effects, and improve quality of life.

Relation of maximum blood pressure during exercise and regular physical activity in normotensive men with left ventricular mass and hypertrophy. MARATHOM Investigators. Medida de la Actividad fisica y su Relación Ambiental con Todos los Lípidos en el HOMbre

The relation between maximum systolic blood pressure (BP) during exercise and left ventricular (LV) mass is controversial. Physical activity also induces LV mass increase. The objective was to assess the relation between BP response to exercise and LV mass in normotensive men, taking into account physical activity practice. A cross-sectional study was performed. Three hundred eighteen healthy normotensive men, aged between 20 and 60 years, participated in this study. The Minnesota questionnaire was used to assess physical activity practice. An echocardiogram and a maximum exercise test were performed. LV mass was calculated and indexed to body surface area. LV hypertrophy was defined as a ventricular mass index > or =134 g/m2. BP was measured at the moment of maximum effort. Hypertensive response was considered when BP was > or =210 mm Hg. In the multiple linear regression model, maximum systolic BP was associated with LV mass index and correlation coefficient was 0.27 (SE 0.07). Physical activity practice and age were also associated with LV mass. An association between hypertensive response to exercise and LV hypertrophy was observed (odds ratio 3.16). Thus, BP response to exercise is associated with LV mass and men with systolic BP response > or =210 mm Hg present a 3-times higher risk of LV hypertrophy than those not reaching this limit. Physical activity practice is related to LV mass, but not to LV hypertrophy.

Effects of regular exercise on blood pressure and left ventricular hypertrophy in African-American men with severe hypertension

BACKGROUND

The prevalence of hypertension and its cardiovascular complications is higher in African Americans than in whites. Interventions to control blood pressure in this population are particularly important. Regular exercise lowers blood pressure in patients with mild-to-moderate hypertension, but its effects in patients with severe hypertension have not been studied. We examined the effects of moderately intense exercise on blood pressure and left ventricular hypertrophy in African-American men with severe hypertension.

METHODS

We randomly assigned 46 men 35 to 76 years of age to exercise plus antihypertensive medication (23 men) or antihypertensive medication alone (23 men). A total of 18 men in the exercise group completed 16 weeks of exercise, and 14 completed 32 weeks of exercise, which was performed three times per week at 60 to 80 percent of the maximal heart rate.

RESULTS

After 16 weeks, mean (+/- SD) diastolic blood pressure had decreased from 88 +/- 7 to 83 +/- 8 mm Hg in the patients who exercised, whereas it had increased slightly, from 88 +/- 6 to 90 +/- 7 mm Hg, in those who did not exercise (P = 0.002). Diastolic blood pressure remained significantly lower after 32 weeks of exercise, even with substantial reductions in the dose of antihypertensive medication. In addition, the thickness of the interventricular septum (P = 0.03), the left ventricular mass (P = 0.02), and the mass index (P = 0.04) had decreased significantly after 16 weeks in the patients who exercised, whereas there was no significant change in the nonexercisers.

CONCLUSIONS

Regular exercise reduced blood pressure and left ventricular hypertrophy in African-American men with severe hypertension.

Relation between physical training and ambulatory blood pressure in stage I hypertensive subjects. Results of the HARVEST Trial. Hypertension and Ambulatory Recording Venetia Study

BACKGROUND

This study was undertaken to assess whether ambulatory blood pressure (BP) in a population of stage I hypertensive individuals was lower in the subjects performing regular exercise training.

METHODS AND RESULTS

The study was carried out in 796 young hypertensive patients (592 men) who had never been treated who took part in the HARVEST trial. The diagnosis of stage I hypertension was made on the basis of six office BP measurements. Subjects underwent noninvasive 24-hour ambulatory BP monitoring, 24-hour urine collection for catecholamine assessment, and echocardiography (n = 457). They were classified as exercisers if they reported at least one session of aerobic sports per week and as nonexercisers if they did not engage regularly in sports activities. Age (P < .0001), body mass index (P = .002), 24-hour heart rate (P < .0001), alcohol intake (P = .02), smoking (P = .02), and norepinephrine output (P = .04) were lower in the active (n = 153) than the inactive (n = 439) men. Physically active men exhibited a lower 24-hour and daytime diastolic BP than the inactive men, while there were no group differences in office BP or in nighttime diastolic BP and in ambulatory systolic BP. The between-group ambulatory diastolic BP difference remained statistically significant after adjustment for age, body mass index, alcohol intake, and smoking (P < .0001). Of the nonexercisers, 46.2% were confirmed hypertensives, compared with only 26.8% of the exercisers (P < .0001), on the basis of daytime diastolic BP. Echocardiographic left ventricular dimensional and functional indexes were similar in the two groups of men. Similar findings were shown by the 16 women who engaged in aerobic sports.

CONCLUSIONS

These data suggest that participation in aerobic sports may attenuate the risk of hypertension in young subjects whose office BP is in the stage I hypertensive range at office measurement.