Effect of exercise on blood pressure in older persons: a randomized controlled trial.

BACKGROUND: Because of age-related differences in the cause of hypertension, it is uncertain whether current exercise guidelines for reducing blood pressure (BP) are applicable to older persons. Few exercise studies in older persons have evaluated BP changes in relation to changes in body composition or fitness. METHODS: This was a 6-month randomized controlled trial of combined aerobic and resistance training; controls followed usual care physical activity and diet advice. Participants (aged 55-75 years) had untreated systolic BP (SBP) of 130 to 159 mm Hg or diastolic BP (DBP) of 85 to 99 mm Hg. RESULTS: Fifty-one exercisers and 53 controls completed the trial. Exercisers significantly improved aerobic and strength fitness, increased lean mass, and reduced general and abdominal obesity. Mean decreases in SBP and DBP, respectively, were 5.3 and 3.7 mm Hg among exercisers and 4.5 and 1.5 mm Hg among controls (P < .001 for all). There were no significant group differences in mean SBP change from baseline (-0.8 mm Hg; P=.67). The mean DBP reduction was greater among exercisers (-2.2 mm Hg; P=.02). Aortic stiffness, indexed by aortofemoral pulse-wave velocity, was unchanged in both groups. Body composition improvements explained 8% of the SBP reduction (P = .006) and 17% of the DBP reduction (P<.001). CONCLUSIONS: A 6-month program of aerobic and resistance training lowered DBP but not SBP in older adults with mild hypertension more than in controls. The concomitant lack of improvement in aortic stiffness in exercisers suggests that older persons may be resistant to exercise-induced reductions in SBP. Body composition improvements were associated with BP reductions and may be a pathway by which exercise training improves cardiovascular health in older men and women.

Exercise effects on bone mineral density relationships to changes in fitness and fatness.

BACKGROUND: Weight loss typically reduces bone mineral density (BMD). Exercise may preserve or increase BMD even while reducing fatness. We examined the relationships among exercise-induced changes in fitness and fatness with BMD. DESIGN: Randomized controlled trial conducted between July 1999 and November 2003. PARTICIPANTS: Men and women (n =115) aged 55 to 75 years. INTERVENTION: Six months of exercise training. MAIN OUTCOME MEASURES: Fitness measured as peak oxygen uptake and muscle strength, body composition by anthropometry, dual-energy x-ray absorptiometry, and magnetic resonance imaging. RESULTS: A total of 51 men and 53 women completed the trial. Exercise increased aerobic and strength fitness and lean body mass, and reduced general and abdominal obesity. BMD did not change among men in either group. Among women exercisers, there were reductions in total skeleton BMD (p =0.02) and greater trochanter BMD (p =0.02). By bivariate correlation, among women, increased femoral neck BMD was associated with increased aerobic fitness (p =0.01) and with reduced body weight (p =0.02) and BMI (p =0.02). In the final regression model, 13% of the change in femoral neck BMD was explained by the change in aerobic fitness (p <0.01). Among the men, increased total hip BMD and femoral shaft BMD were associated with increased lean mass and lower-body strength. In the final regression models, the change in lean mass explained 9% of the variance in total hip BMD (p =0.04). The change in lean mass explained 20% of the change in femoral shaft BMD (p <0.01), and the change in lower-body strength explained an additional 6% (p <0.04). CONCLUSIONS: When examined by group assignment, 6 months of exercise had no effect on BMD among men, and reduced BMD among women. When examined by change in fitness and fatness, women who had the greatest increases in aerobic capacity and men who had the greatest increases in strength and lean mass were more likely to increase their BMD. Exercise-induced reductions in fatness did not lead to bone loss.

Exercise and risk factors associated with metabolic syndrome in older adults.

BACKGROUND: Older people with elevated blood pressure (BP) often have metabolic syndrome, a clustering of central obesity, insulin resistance, dyslipidemia, and hypertension. Exercise reduces many of these risk factors. This study examined whether the benefits of exercise on cardiovascular and metabolic disease risk factors are mediated by exercise-induced changes in fitness or body composition. METHODS: Randomized controlled trial, comprising 6 months of exercise training, conducted between July 1999 and November 2003. Participants included men and women (n =115) aged 55 to 75 years with untreated systolic blood pressure (SBP) of 130 to 159 or diastolic blood pressure of (DPB) 85 to 99 mm Hg. Fitness measures included BP, lipids, lipoproteins, insulin, and glucose; peak oxygen uptake and muscle strength; and body composition measured by anthropometry, dual-energy x-ray absorptiometry, and magnetic resonance imaging. RESULTS: A total of 51 men and 53 women completed the trial. Exercise significantly increased aerobic and muscle fitness, lean mass, and high-density lipoprotein cholesterol and reduced total and abdominal fat. DBP was reduced more among exercisers. There were no associations among changes in fitness with risk factors. Reductions in total body and abdominal fat and increases in leanness, largely independent of weight loss, were associated with improved SBP, DBP, total cholesterol, very low-density lipoprotein cholesterol, triglycerides, lipoprotein(a), and insulin sensitivity. At baseline, 42.3% of participants had metabolic syndrome. At 6 months, nine exercisers (17.7%) and eight controls (15.1%) no longer had metabolic syndrome, whereas four controls (7.6%) and no exercisers developed it (p =0.06). CONCLUSIONS: Although exercise improved fitness, the reductions in total and abdominal fatness and increase in leanness were more strongly associated with favorable changes in risk factors for cardiovascular disease and diabetes, including those that constitute metabolic syndrome.

Peripheral endothelium-dependent flow-mediated vasodilatation is associated with left ventricular mass in older persons with hypertension.

BACKGROUND: Increased left ventricular (LV) mass is associated with greater cardiovascular disease risk. Recent studies have also shown an association of increased LV mass with attenuated endothelium-dependent coronary flow reserve. Less is known about the association between LV mass and endothelium-dependent flow-mediated dilatation (FMD) in peripheral arteries, a noninvasive measure of endothelial function. METHODS: Sixty-two subjects with untreated mild hypertension, aged 55 to 75 years and otherwise healthy, were examined. Resting blood pressure was obtained by the average of 4 to 5 visits, each at least 1 week apart. LV mass was determined from magnetic resonance imaging and was indexed by body surface area, height and height(2.7). Body composition was assessed with dual energy x-ray absorptiometry. FMD was measured as the percent change of brachial artery diameter during reactive hyperemia by use of high-resolution ultrasound. RESULTS: Median LV mass index was 63 g/m2 (interquartile range, 58-73). In bivariate analysis, LV mass was correlated to lean body mass (r = 0.63, P <.001), diastolic blood pressure (r = 0.35, P <.01), and FMD (r = -0.27, P <.05). In multivariate analysis, 44% of the variance in log-LV mass was explained by lean body mass. An additional 6% of the variance was explained by FMD (P <.05). For each 1% point decrease in FMD, LV mass increased by 1.1%. CONCLUSIONS: In addition to the expected influences of body size, impairment of brachial artery FMD was independently related to LV mass in elderly subjects with mild hypertension who did not yet have LV hypertrophy. Whether mild hypertension is the common mechanism linking LV mass and endothelial function has yet to be determined.

Left ventricular remodeling with age in normal men versus women: novel insights using three-dimensional magnetic resonance imaging.

Echocardiographic left ventricular (LV) wall thickness increases with age, suggesting LV hypertrophy. However, autopsy studies have shown no change, or even a decrease, in LV mass with age. With many pathologies, LV remodeling results in changes in ventricular shape. Age-associated LV shape change might explain this discrepancy, although this has not been studied. Magnetic resonance imaging (MRI) was used in 336 healthy, normotensive adults (mean age 56 +/- 18 years; 200 women, 136 men) to measure LV mass, end-diastolic LV wall thickness, length, diameter, and shape. Echocardiographic LV mass was measured in a subset of 86 subjects by a standard algorithm. In women, LV wall thickness increased by 14% (r = 0.19, p <0.02), whereas LV length decreased by 9% (r = -0.26, p = 0.0006); LV diameter was unchanged. Thus, LV mass did not vary with age (r -0.04, p = 0.06) and the sphericity index decreased (r = -0.165, p <0.05). In men, LV wall thickness and diameter were unrelated to age, but there was an 11% decrease in LV length (r = -0.29, p = 0.003); therefore, there was an 11% decrease in LV mass (r = -0.20, p = 0.019) and a decrease in the sphericity index (r = -0.218, p <0.04). No change occurred in echocardiographic LV mass with age in either gender, although echocardiographic LV wall thickness increased in both. The left ventricle becomes more spherical with age in normal adults due to reduced LV length. In women, increased LV wall thickness offsets the decreasing LV length, whereas in men, LV wall thickness fails to compensate, resulting in decreased LV mass with age.

Relationships of insulin sensitivity with fatness and fitness and in older men and women.

PURPOSE: Increased body fatness, especially abdominal obesity, and low levels of fitness are associated with decreased insulin sensitivity. Men and women differ in obesity, body fat distribution, and fitness levels. This cross-sectional study evaluated sex differences in the relationships of insulin sensitivity with fatness and fitness and obesity. METHODS: Subjects were nonsmoking, nondiabetic, sedentary men (n = 50) and women (n = 61) aged 55-75 years with mild hypertension. Study measures were insulin sensitivity (QUICKI: 1/[log(fasting insulin) + log(fasting glucose)]), lipids and lipoproteins, total body fatness using dual energy x-ray absorptiometry (DXA), anthropometrics, abdominal obesity using magnetic resonance imaging (MRI), and aerobic fitness assessed as Vo(2) peak during treadmill testing. RESULTS: Women had a higher percentage of body fat and more abdominal subcutaneous and less visceral fat than men. Among women, QUICKI correlated negatively with body mass index (BMI), percent body fat, abdominal total fat, subcutaneous fat, and visceral fat but not with lipids. Among men, QUICKI correlated negatively with total and abdominal fatness and triglycerides. QUICKI correlated with fitness in men only. Using stepwise regression, among women, decreased total abdominal fat accounted for 33%, and postmenopausal hormone therapy accounted for an additional 5% of the variance in QUICKI. Among men, only a higher level of fitness independently correlated with insulin sensitivity, accounting for 21% of the variance (p < 0.01). CONCLUSIONS: Abdominal obesity among women and fitness among men were the strongest determinants of insulin sensitivity in this older cohort. This raises the question whether there are sex differences in the lifestyle changes that would be most effective in improving insulin sensitivity.

Effects of normal aging on left ventricular lusitropic, inotropic, and chronotropic responses to dobutamine.

OBJECTIVES: The purpose of this study was to characterize how aging impacts the left ventricular (LV) functional reserve. BACKGROUND: Early diastolic LV filling slows markedly with advancing age, but the effects of beta-adrenergic stimulation on filling, and its major determinant, relaxation, have not been investigated in an aging population. Although the responses of contractility and heart rate to catecholamines reportedly diminish with age, the effect of age on the responses to steady-state dobutamine infusions is unclear. METHODS: Groups of younger (40 +/- 10 years, n = 26) and older (68 +/- 11 years, n = 24) normal adult patients were studied at baseline and at three progressive dobutamine infusion dosages (5, 10, and 20 mug/kg/min). The LV function was evaluated by two-dimensional and Doppler echocardiography. Myocardial relaxation was evaluated from cardiovascular magnetic resonance (CMR)-based rho, a preload-independent surrogate for tau . Effective LV pump-function index (PFi), defined as systolic blood pressure/end-systolic LV diameter, was measured. RESULTS: Both groups showed expected dose-dependent increases in heart rate and LV systolic function, diastolic function, and relaxation. Early LV filling reserve was much greater in younger than older patients (E-wave increase from baseline to highest dose, 24.0 vs. 9.5 cm/s, p < 0.004), although the dose responses of rho were indistinguishable (0.18% vs. 0.19%/ms, p = 0.22). Whereas dobutamine caused a significantly greater increase of PFi in younger than older patients (30.1 vs. 15.6 mm Hg/cm, p < 0.0001), there was no difference in heart rate augmentation (37 vs. 38 beats/min, p = 0.94). CONCLUSIONS: Aging is accompanied by a blunted inotropic but preserved chronotropic response to steady-state dobutamine infusion. Although LV filling reserve declines with age, relaxation reserve does not.

A self-sampling method to obtain large volumes of undiluted cervicovaginal secretions.

BACKGROUND: Studies of vaginal physiology and pathophysiology sometime require larger volumes of undiluted cervicovaginal secretions than can be obtained by current methods. A convenient method for self-sampling these secretions outside a clinical setting can facilitate such studies of reproductive health. GOAL: The goal was to develop a vaginal self-sampling method for collecting large volumes of undiluted cervicovaginal secretions. STUDY DESIGN: A menstrual collection device (the Instead cup) was inserted briefly into the vagina to collect secretions that were then retrieved from the cup by centrifugation in a 50-ml conical tube. RESULTS: All 16 women asked to perform this procedure found it feasible and acceptable. Among 27 samples, an average of 0.5 g of secretions (range, 0.1-1.5 g) was collected. CONCLUSIONS: This is a rapid and convenient self-sampling method for obtaining relatively large volumes of undiluted cervicovaginal secretions. It should prove suitable for a wide range of assays, including those involving sexually transmitted diseases, microbicides, vaginal physiology, immunology, and pathophysiology.

MRI and echocardiographic assessment of the diastolic dysfunction of normal aging: altered LV pressure decline or load?

Changes in diastolic indexes during normal aging, including reduced early filling velocity (E), lengthened E deceleration time (DT), augmented late filling (A), and prolonged isovolumic relaxation time (IVRT), have been attributed to slower left ventricular (LV) pressure (LVP) decay. Indeed, this constellation of findings is often referred to as the "abnormal relaxation" pattern. However, LV filling is determined by the atrioventricular pressure gradient, which depends on both LVP decline and left atrial (LA) pressure (LAP). To assess the relative influence of LVP decline and LAP, we studied 122 normal subjects aged 21-92 yr by Doppler echocardiography and MRI. LVP decline was assessed by color M-mode (V(p)) and the LV untwisting rate. Early diastolic LAP was evaluated using pulmonary vein flow systolic fraction, pulmonary vein flow diastolic DT, color M-mode (E/V(p)), and tissue Doppler (E/E(m)). Linear regression showed the expected reduction of E, increase in A, and prolongation of IVRT and DT with advancing age. There was no relation of age to parameters reflecting the rate of LVP decline. However, older age was associated with reduced E/V(p) (P = 0.008) and increased pulmonary vein systolic fraction (P < 0.001), pulmonary vein DT (P = 0.0026), and E/E(m) (P < 0.0001), all suggesting reduced early LAP. Therefore, reduced early filling in older adults may be more closely related to a reduced early diastolic LAP than to slower LVP decline. This effect also explains the prolonged IVRT. We postulate that changes in LA active or passive properties may contribute to development of the abnormal relaxation pattern during the aging process.

Usefulness of anthropometrics and dual-energy x-ray absorptiometry for estimating abdominal obesity measured by magnetic resonance imaging in older men and women.

PURPOSE: Increasing evidence suggests that abdominal obesity may be a better predictor of disease risk than total fatness. This study sought to determine how obesity and fat distribution measured by readily available anthropometric and dual-energy x-ray absorptiometry (DXA) methods is related to abdominal obesity assessed by magnetic resonance imaging (MRI). METHODS: Men (n = 43) and women (n = 47), ages 55 to 75 years, were assessed for body mass index, waist-to-hip ratio, waist circumference, and skin folds by anthropometric methods; for percentage of body fat by DXA; and for abdominal total, subcutaneous, and visceral fat by MRI. RESULTS: In stepwise regression models, the waist-to-hip ratio explained 50% of the variance in abdominal visceral fat among men (P <.01), and body mass index explained an additional 6% of the variance (P <.01). Among women, waist circumference was the only independent correlate of abdominal visceral fat, accounting for 52% of the variance (P <.01). Among men, the percentage of body fat was the only independent correlate of abdominal subcutaneous fat, explaining 65% of the variance (P <.01). Among women, the percentage of body fat explained 77% of the variance in abdominal subcutaneous fat and body mass index explained an additional 3% (P <.01). CONCLUSIONS: Obesity and body composition obtained by readily available anthropometric methods and DXA provide informative estimates of abdominal obesity assessed by MRI imaging.