Aerobic fitness reduces brain tissue loss in aging humans

BACKGROUND: The human brain gradually loses tissue from the third decade of life onward, with concomitant declines in cognitive performance. Given the projected rapid growth in aged populations, and the staggering costs associated with geriatric care, identifying mechanisms that may reduce or reverse cerebral deterioration is rapidly emerging as an important public health goal. Previous research has demonstrated that aerobic fitness training improves cognitive function in older adults and can improve brain health in aging laboratory animals, suggesting that aerobic fitness may provide a mechanism to improve cerebral health in aging humans. We examined the relationship between aerobic fitness and in vivo brain tissue density in an older adult population, using voxel-based morphometric techniques. METHODS: We acquired high-resolution magnetic resonance imaging scans from 55 older adults. These images were segmented into gray and white matter maps, registered into stereotaxic space, and examined for systematic variation in tissue density as a function of age, aerobic fitness, and a number of other health markers. RESULTS: Consistent with previous studies of aging and brain volume, we found robust declines in tissue densities as a function of age in the frontal, parietal, and temporal cortices. More importantly, we found that losses in these areas were substantially reduced as a function of cardiovascular fitness, even when we statistically controlled for other moderator variables. CONCLUSIONS: These findings extend the scope of beneficial effects of aerobic exercise beyond cardiovascular health, and they suggest a strong solid biological basis for the benefits of exercise on the brain health of older adults.     

Cognitive and Neural Correlates of Aerobic Fitness in Obese Older Adults

Background/Study Context: Aerobic fitness is associated with preserved cognition and brain volume in older adulthood. The current study investigated whether the benefits of aerobic fitness extend to obese older adults, a segment of the population that is rapidly growing and who exhibit compromised cognition and brain structure relative to their nonobese counterparts.

Methods: Measures of obesity, aerobic fitness, cognition (processing speed, executive function, spatial ability, memory), and regional brain volumes (prefrontal gray, prefrontal white, hippocampus) were obtained from 19 obese older adults aged 65 to 75. Hierarchical linear regression analyses were conducted to examine the proportion of unique variance in cognitive and volumetric measures accounted for by aerobic fitness after controlling for covariates (age, gender, and waist circumference).

Results: Aerobic fitness accounted for a significant amount of unique variance in processing speed (adjusted R ² = .44), executive function (adjusted R ² = .34), and hippocampal volume (adjusted R ² = .27).

Conclusion: This novel pattern of results suggests that obesity does not preclude the benefits of fitness for cognition and brain volume in older adults. Fitness appears to be a beneficial factor for maintenance of processing speed, executive function, and hippocampal volume, which are vulnerable to age- and/or obesity-related decline.     

Mode of physical activity and self-efficacy in older adults: a latent growth curve analysis.

A randomized controlled trial examined the effect of two physical activity modes on changes in self-efficacy over the course of a 12-month period in older, formerly sedentary adults (N = 174, M age = 65.5 years). Participants were randomized into either an aerobic activity group or a stretching and toning group. Structural equation modeling was employed to conduct multiple sample latent growth curve analyses of individual growth in exercise and physical self-efficacy over time. Results revealed a curvilinear growth pattern for both types of efficacy with increases occurring over the first 6 months followed by declines at the 6-month follow-up. There was a significant treatment by mean level growth interaction for exercise efficacy with both groups increasing over time, but the aerobic group evidenced a twofold increase in growth over the stretching group. Structural analyses indicated that frequency of exercise participation was a significant predictor of overall growth in efficacy, and improvements in fitness were only related to exercise efficacy growth in the stretching group. Findings are discussed in terms of social cognitive theory and further application of latent growth curve modeling to studies of physical activity effects in older adults.     

Relation between aerobic fitness and brain structures in amnestic mild cognitive impairment elderly

Mild cognitive impairment (aMCI) is a clinical condition, with high risk to develop Alzheimer’s disease. Physical exercise may have positive effect on cognition and brain structure in older adults. However, it is still under research whether these influences are true on aMCI subjects with low Ab_42 and high total tau in cerebrospinal fluid (CSF), which is considered a biomarker for AD. Therefore, we aimed to investigate a possible relation between aerobic fitness (AF) and gray matter (GM) volume and AF and white matter (WM) integrity in aMCI with a CSF biomarker. Twenty-two participants with aMCI acquired the images on a 3.0-T MRI. AF was assessed by a graded exercise test on a treadmill. Voxel-based morphometry and tract-based spatial statistic methods were used to analyze the GM volume and WM microstructural integrity, respectively. We correlated AF and GM volume and WM integrity in aMCI (p < 0.05, FWE corrected, cluster with at least five voxels). There was a positive relation between AF and GM volume mostly in frontal superior cortex. In WM integrity, AF was positively correlated with fractional anisotropy and negatively correlated with mean diffusivity and radial diffusivity, all in the same tracts that interconnect frontal, temporal, parietal, and occipital areas (longitudinal fasciculus, fronto-occipital fasciculus, and corpus callosum). These results suggest that aerobic fitness may have a positive influence on protection of brain even in aMCI CSF biomarker, a high-risk population to convert to AD.     

A regions-of-interest volumetric analysis of mobility limitations in community-dwelling older adults

BACKGROUND: In community-dwelling older adults, greater mobility impairment is associated with greater burden of diffuse brain structural abnormalities, such as higher white matter hyperintensities. This study examined the association between gray matter volumes of regions related to motor control, gait, and balance and whether this association is independent of burden of white matter hyperintensities. METHODS: A random sample of 327 participants of the Cardiovascular Health Study (78.3 +/- 4.1 years old, 57% women) contributed brain magnetic resonance imaging (MRI) and mobility data. A brain imaging automated method measured gray matter volume in cerebellum, basal ganglia, and prefrontal and parietal cortex in both hemispheres. Gait speed was measured while walking 15 feet at usual pace. Standing balance was assessed by timing tandem stance. Associations between each region's volume and gait speed or balance were measured before and after adjustment for demographics, head size, cardiovascular risk factors, and 0-9 grading scores of white matter hyperintensities. RESULTS: Smaller left cerebellum and left prefrontal regions were associated with slower gait, independently of covariates and of white matter hyperintensities. Smaller right putamen, right posterior superior parietal cortex, and both left and right cerebellum were associated with balance difficulty, independently of covariates and white matter hyperintensities. CONCLUSIONS: Smaller gray matter volumes in regions crucial for motor control are associated with slower gait and poorer balance, and the association appears to be independent of other diffuse brain abnormalities such as white matter hyperintensities.     

Aging of the cerebral cortex differs between humans and chimpanzees

Several biological changes characterize normal brain aging in humans. Although some of these age-associated neural alterations are also found in other species, overt volumetric decline of particular brain structures, such as the hippocampus and frontal lobe, has only been observed in humans. However, comparable data on the effects of aging on regional brain volumes have not previously been available from our closest living relatives, the chimpanzees. In this study, we used MRI to measure the volume of the whole brain, total neocortical gray matter, total neocortical white matter, frontal lobe gray matter, frontal lobe white matter, and the hippocampus in a cross-sectional sample of 99 chimpanzee brains encompassing the adult lifespan from 10 to 51 y of age. We compared these data to brain structure volumes measured in 87 adult humans from 22 to 88 y of age. In contrast to humans, who showed a decrease in the volume of all brain structures over the lifespan, chimpanzees did not display significant age-related changes. Using an iterative age-range reduction procedure, we found that the significant aging effects in humans were because of the leverage of individuals that were older than the maximum longevity of chimpanzees. Thus, we conclude that the increased magnitude of brain structure shrinkage in human aging is evolutionarily novel and the result of an extended lifespan.     

Frontal Lobe Volume Loss Observed with Magnetic Resonance Imaging in Older Chronic Alcoholics

This study used magnetic resonance imaging to quantify the extent and pattern of tissue volume deficit and cerebrospinal fluid volume enlargement in younger versus older chronic alcoholics relative to normal controls. In the present analysis, we divided our previously reported group of 62 alcoholic men into a younger group (n = 33, age mean = 37.5 ± 4.5, and range = 26 to 44 years) and an older group ( n = 29, age mean = 52.7 ± 6.0, and range = 45 to 63 years) to examine whether, in addition to extent, the two age groups differed in pattern of tissue type and regional brain volume abnormalities quantified with magnetic resonance imaging. Brain volumes were adjusted for normal variation in head size and age established from a group of healthy controls and were expressed as Z-scores. The younger group had significant cortical gray, but not white, matter volume deficits and sulcal and ventricular enlargement relative to age-matched controls. The older group had volume deficits in both cortical gray and white matter and sulcal and ventricular enlargement that significantly exceeded the younger alcoholic group. An analysis of six cortical regions revealed that, although both age groups had gray matter volume deficits throughout the cortex, the older alcoholic group had a selectively more severe deficit in prefrontal gray matter relative to the younger alcoholic group. Similarly, the cortical white matter volume deficit in the older alcoholics was especially severe in the prefrontal and frontal regions. The differences in brain dysmorphology between the two alcoholic groups cannot easily be attributed to potential alcohol history differences typically related to age because the two groups had similar disease durations and amounts of lifetime alcohol consumption. These results provide in vivo evidence that the frontal lobes are especially vulnerable to chronic alcoholism in older men.     

Brain Gray and White Matter Volume Loss Accelerates with Aging in Chronic Alcoholics: A Quantitative MRI Study

Magnetic resonance imaging (MRI) was used to study in vivo the brains of 49 patients with chronic alcoholism, 3 to 4 weeks post-withdrawal, and 43 normal healthy controls, all right-handed male veterans between the ages of 23 and 70 years. MRI scans were analyzed using a semi-automated procedure, which allowed the subcortical regions to be segmented into cerebrospinal fluid (CSF) and brain tissue and the cortical regions to be segmented into CSF, gray matter, and white matter. An age regression model was used to examine the effects of alcohol on brain structure, over and above that expected from the normal aging process. The alcoholics exhibited decreased tissue and increased CSF after correcting for aging. In the cortex, there was significant loss of both gray matter and white matter volume. In this sample of alcoholics, no particular cortical region was preferentially affected or spared. Furthermore, brain tissue volume loss increased with advanced age in the alcoholics. In this group of alcoholics there was no relationship between length of illness and age, i.e., the younger alcoholics had as heavy alcohol use histories as did the older alcoholics. Thus, the increased brain tissue loss with advanced age is interpreted as evidence for age-related increase in brain vulnerability to chronic alcohol abuse.     

Longitudinal Changes in Magnetic Resonance Imaging Brain Volumes in Abstinent and Relapsed Alcoholics

Chronic alcoholism is associated with smaller volumes of cortical gray matter and white matter and a complementary increase in brain cerebrospinal fluid (CSF) volumes, relative to age norms. This longitudinal study quantified the extent of brain volume changes associated with abstinence and drinking at three time points in chronic alcoholics. We obtained magnetic resonance imaging (MRI) on 58 alcoholic men after an average of 12 days (MRI-1) and 32 days (MRI-2) of sobriety. In addition, 58 healthy control subjects were scanned at a comparable interval. At MRI-3, 11 controls and 39 alcoholics were rescanned, 2–12 months after MRI-2; 19 alcoholics had abstained, and 20 had resumed drinking. Axial MRI slices were segmented into cortical gray matter, white matter, and CSF and summed over seven slices; lateral and third ventricular volumes were also estimated. MRI volume changes were corrected using an estimate of interscan measurement error caused by head positioning differences, and then divided by the interval to yield rates of change (slopes). From MRI-1 to MRI-2, the alcoholic group showed declines in CSF volumes of the lateral ventricles and posterior cortical sulci, and a trend toward an increase in anterior cortical gray matter volume relative to the control group. From MRI-2 to MRI-3, third ventricular volumes decreased in the abstainers relative to the relapsers and controls; cortical white matter volume decreased in the relapsers. In the relapsers, lifetime consumption of alcohol (as of MRI-1) predicted later vulnerability to white matter volume decline and third ventricular enlargement with resumption of drinking. These data suggest that improvement in cortical gray matter, sulcal, and lateral ventricular volumes occur early in the course of abstinence, and that improvement in third ventricular volume appears later with continued abstinence. Resumption of drinking after a short period of abstinence arrests third ventricular volume improvement and produces white matter volume loss.     

Exercise training increases size of hippocampus and improves memory

The hippocampus shrinks in late adulthood, leading to impaired memory and increased risk for dementia. Hippocampal and medial temporal lobe volumes are larger in higher-fit adults, and physical activity training increases hippocampal perfusion, but the extent to which aerobic exercise training can modify hippocampal volume in late adulthood remains unknown. Here we show, in a randomized controlled trial with 120 older adults, that aerobic exercise training increases the size of the anterior hippocampus, leading to improvements in spatial memory. Exercise training increased hippocampal volume by 2%, effectively reversing age-related loss in volume by 1 to 2 y. We also demonstrate that increased hippocampal volume is associated with greater serum levels of BDNF, a mediator of neurogenesis in the dentate gyrus. Hippocampal volume declined in the control group, but higher preintervention fitness partially attenuated the decline, suggesting that fitness protects against volume loss. Caudate nucleus and thalamus volumes were unaffected by the intervention. These theoretically important findings indicate that aerobic exercise training is effective at reversing hippocampal volume loss in late adulthood, which is accompanied by improved memory function.     

Optimal retraining time for regaining functional fitness using multicomponent training after long-term detraining in older adults

ObjectivesLittle is known about the optimal retraining time for regaining functional fitness through multicomponent training following long-term detraining in older adults. This study first investigated the time course of functional fitness changes during 12-month multicomponent training, 12-month detraining, and 9-month retraining in 18 older adults (68.33 ± 3.46) and then determined the optimal retraining time for regaining the post-training functional fitness level after a 12-month detraining period.MethodsFunctional fitness, including lower and upper limb strength, lower and upper limb flexibility, aerobic endurance, and dynamic balance, was assessed at baseline, 12 months post-training, 12 months post-detraining, and 3, 6, and 9 months post-retraining.ResultsThere were significant increases in all of the functional fitness components except upper limb flexibility at post-training and no significant decreases at post-detraining. For lower and upper limb strength and lower limb flexibility, a 3-month period was required to regain the post-training condition. For aerobic endurance and dynamic balance, a retraining period ≥9 months was necessary to regain the post-training functional fitness condition.ConclusionsTo regain the post-training condition of all functional fitness components, a retraining period ≥9 months was required. This information might be useful for health professionals to encourage older adults not to interrupt retraining until they regain their post-training functional fitness condition.     

皮质下脑梗死患者初级运动皮质结构损伤和运动功能恢复的相关性研究

目的探讨脑梗死后结构损伤和功能代偿脑区的相关性,为阐述脑梗死后运动功能恢复的机制提供理论基础。方法选择运动功能恢复较好的慢性期单侧基底节区脑梗死患者28例(脑梗死组),健康体检者25例(对照组),功能MRI采用组块设计,进行患手虚握运动以及高分辨率结构像采集,采用统计参数图比较2组脑灰质体积和执行运动任务时脑激活的不同。结果与对照组比较,脑梗死组患侧半球M1区(感兴趣区1)及丘脑灰质体积减少。患手运动时,脑梗死组患侧半球M1区(感兴趣区2)及颞上回激活增强。感兴趣区1和感兴趣区2重叠,重叠区占灰质体积减少脑区(感兴趣区1)的21.9%。结论 M1结构损伤区及其周围正常脑区均参与运动功能的恢复,而与感觉功能有密切关系的M1区背侧的持续性激活增强可能对运动功能的恢复起更主要的作用。     

A controlled study of MRI signal hyperintensities in older depressed patients with and without hypertension

OBJECTIVES: To compare the frequency/severity of signal hyperintensities--likely markers of cerebrovascular disease--in the subcortical gray and deep white matter on magnetic resonance imaging (MRI) scans of brains of hypertensive and normotensive older depressed and nondepressed comparison subjects. DESIGN: Between-groups comparison of cross-sectional MRI data employing analyses of covariance controlling for the effects of age, gender, and height. SETTING: A comprehensive inpatient-outpatient geriatric psychiatry service in a university hospital. PARTICIPANTS: Nondemented older depressed (n = 81) and nondepressed comparison (n = 70) subjects divided into four groups (hypertensive depressed (n = 40), hypertensive normals (n = 21), normotensive depressed (n = 41), normotensive normals (n = 49)). MEASUREMENTS: Signal hyperintensities were rated on T-2 weighted MRI scans blind to patient diagnoses employing two standardized hyperintensity rating systems (Fazekas, Boyko). RESULTS: Hypertensive depressives had significantly more- severe hyperintensity ratings in both subcortical gray and deep white matter than did normotensive depressives and controls (P < .05) and significantly more-severe hyperintensity ratings only in subcortical gray matter (P < .05) than did hypertensive controls. Hypertensive controls had significantly more-severe ratings in deep white matter than either normotensive group (P < .05). CONCLUSIONS: Findings suggest a relationship between deep white matter hyperintensities and hypertension (regardless of depressive state), and a particular role of subcortical gray matter hyperintensities (possibly interacting with more-severe deep white matter lesions) in older depressed hypertensives, as compared with older depressed normotensives of similar ages and severity of depression. These data support possible heterogeneous pathogenic contributions in late-life depression subgroups, one of which appears to be influenced by cerebrovascular disease.     

Acute exercise increases systemic arterial compliance after 6-month exercise training in older women.

High physical activity or aerobic exercise training increases central arterial distensibility in older humans. However, the effect of a single bout of exercise on central arterial distensibility in older humans is unknown. Furthermore, the effect of exercise training on central arterial distensibility during exercise is unclear. We investigated whether systemic arterial compliance (SAC) changes after acute exercise in older humans, and, if so, whether this change in SAC is enhanced by aerobic exercise training. Seven untrained older women (61-69 years old) participated in a 6-month exercise intervention study. We measured SAC after acute exercise (cycling exercise at 80% of their individual ventilatory threshold for 30 min) before and after 6 months of aerobic exercise training. After exercise training, the individual ventilatory threshold was significantly increased. In addition, both the SAC at rest and that 30 min after acute exercise were significantly increased after the exercise training program. Before exercise training, there was no significant increase in SAC after acute exercise, whereas, after exercise training, the SAC was significantly increased 30 min after acute exercise. The present study suggests that, after aerobic exercise training, SAC increases after acute exercise in older humans, and that the SAC at rest and after acute exercise is enhanced by aerobic exercise training, thereby causing an effective adaptation in increase in cardiac output during exercise.     

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.     

Quantitative brain MRI in alcohol dependence: preliminary evidence for effects of concurrent chronic cigarette smoking on regional brain volumes

BACKGROUND: Recent in vivo research using magnetic resonance spectroscopy demonstrated that chronic cigarette smoking exacerbates regional chronic alcohol-induced brain injury. Other studies associated cigarette smoking with gray matter volume reductions in healthy adults, with greater brain atrophy in aging, and with poorer neurocognition. Although cigarette smoking is common among alcohol-dependent individuals, previous research did not account for the potential effects of chronic smoking on regional brain volumes in alcoholism. METHODS: High-resolution T1-weighted magnetic resonance images from one-week-abstinent, alcohol-dependent individuals and light drinkers were automatically segmented into gray matter, white matter, and cerebral spinal fluid of lobes and subcortical structures. A brief neuropsychological test battery was used to assess cognition in alcohol-dependent individuals. The alcoholic and nondrinking groups were retrospectively divided into chronic smokers and nonsmokers, and the volumetric data were analyzed as a function of alcohol and smoking status. RESULTS: Chronic alcohol dependence was associated with smaller volumes of frontal and parietal white matter, parietal and temporal gray matter, and thalami, accompanied by widespread sulcal but not ventricular enlargements. Chronic cigarette smoking was associated with less parietal and temporal gray matter and with more temporal white matter. Among alcoholics, better visuospatial learning and memory and greater visuomotor scanning speed were correlated with larger lobar white matter volumes in the nonsmoking alcohol-dependent group only. CONCLUSIONS: These data provide preliminary evidence that comorbid chronic cigarette smoking accounts for some of the variance associated with cortical gray matter loss and appears to alter relationships between brain structure and cognitive functions in alcohol-dependent individuals.     

Long-term exercise and its effect on balance in older, osteoarthritic adults: results from the Fitness, Arthritis, and Seniors Trial (FAST)

OBJECTIVES: To examine the effects of 18-month aerobic walking and strength training programs on static postural stability among older adults with knee osteoarthritis. DESIGN: Randomized, single-blind, clinical trial of therapeutic exercise. SETTING: Both center-based (university) and home-based. PARTICIPANTS: A cohort of 103 older adults (age = 60 years) with knee osteoarthritis who were participants in a large (n = 439) clinical trial and who were randomly assigned to undergo biomechanical testing. INTERVENTION: An 18-month center- (3 months) and home-based (15 months) therapeutic exercise program. The subjects were randomized to one of three treatment arms: (1) aerobic walking; (2) health education control; or (3) weight training. MEASUREMENTS: Force platform static balance measures of average length (Rm) of the center of pressure (COP), average velocity (Vel) of the COP, elliptical area (Ae) of the COP, and balance time (T). Measures were made under four conditions: eyes open, double- and single-leg stances and eyes closed, double- and single-leg stances. RESULTS: In the eyes closed, double-leg stance condition, both the aerobic and weight training groups demonstrated significantly better sway measures relative to the health education group. The aerobic group also demonstrated better balance in the eyes open, single-leg stance condition. CONCLUSIONS: Our results suggest that long-term weight training and aerobic walking programs significantly improve postural sway in older, osteoarthritic adults, thereby decreasing the likelihood of larger postural sway disturbances relative to a control group.     

Anterior Hippocampal Volume Deficits in Nonamnesic, Aging Chronic Alcoholics

Magnetic resonance imaging was used to quantify the volume of the hippocampus in 47 men with chronic alcoholism and 72 healthy male control subjects. The subjects ranged in age from 21 to 70 years, thus permitting a test of whether older alcoholics suffer greater brain tissue volume reduction than do younger ones. Comparison brain regions included temporal lobe gray matter, white matter, and cerebrospinal fluid, as well as measures of the lateral ventricles, third ventricle, and temporal horns. The results of this cross-sectional study showed that the anterior, but not the posterior, portions of the hippocampus in both hemispheres were significantly smaller in the alcoholic than the healthy control group. Furthermore, the bilateral anterior hippocampal volume loss was greater in older than younger alcoholics. Despite the hippocampal volume deficit, these alcoholics did not demonstrate an explicit memory impairment; furthermore, memory test scores did not correlate significantly with hippocampal volumes. In the alcoholics, the age-related volume loss, which was over and above that expected in normal aging, was also evident in the temporal cortex and white matter. Likewise, alcoholic ventricular enlargement was age-related. Analysis of covariance revealed that the anterior hippocampal deficit persisted after accounting for the temporal lobe gray matter volume deficit. Multiple regression analysis revealed that the age-related brain volume abnormalities observed in the alcoholics could not be attributed to duration of alcoholism or total lifetime consumption of alcohol.     

Effects of exercise training on bone density in older men and women.

OBJECTIVES: To determine the effects of up to 14 months of aerobic exercise on measures of bone density in older adults. DESIGN: Randomized controlled trial with subjects assigned to either an aerobic exercise condition, non-aerobic yoga, or a wait list non-exercise control group for 4 months. Aerobic fitness and bone density were evaluated in all subjects at baseline (Time 1) and after 4 months (Time 2). A semi-crossover design was utilized with all subjects completing 4 months of aerobic exercise, followed by another evaluation (Time 3). All subjects were then given the option of 6 additional months of aerobic exercise, after which they had a fourth evaluation (Time 4). SETTING: An outpatient exercise rehabilitation facility at a large, major medical center. SUBJECTS: One-hundred-one healthy men (n = 50) and women (n = 51) over age 60 (Mean age = 67.0), recruited from the community. INTERVENTION: The exercise program included stretching, cycle ergometry, and walking three times per week for 60 minutes throughout the course of the study. OUTCOME MEASURES: Aerobic fitness (VO2max) as assessed by cycle ergometry, and bone density (bone mineral content) measured by single photon absorptiometry. RESULTS: Subjects achieved a 10%-15% increase in VO2max after 4 months of exercise training, and 1%-6% further improvement with additional training. Aerobic fitness was associated with significant increases in bone density in men, but not women, who maintained aerobic exercise for 14 months.     

Coronary artery calcium: associations with brain magnetic resonance imaging abnormalities and cognitive status

OBJECTIVES: To evaluate the association between coronary atherosclerosis and subclinical brain magnetic resonance imaging (MRI) abnormalities and between coronary atherosclerosis and abnormal cognitive function (dementia/mild cognitive impairment). DESIGN: Cross-sectional. SETTING: The Cardiovascular Health Study (CHS), an epidemiological study of risk factors for cardiovascular disease in older adults. PARTICIPANTS: Four hundred nine men and women, mean age 79, recruited from the Pittsburgh center of the CHS. MEASUREMENTS: Coronary atherosclerosis was defined according to the level of coronary artery calcification (CAC), as measured using electronic beam tomography. Subclinical brain MRI abnormalities included ventricular enlargement, white matter hyperintensities, and number of subcortical brain infarcts. Brain MRI and CAC measurements were performed between 1998 and 2000 at the Pittsburgh center of the CHS. Prevalence of brain MRI abnormalities and abnormal cognitive status were examined across quartiles of the CAC score, before and after controlling for age. Multivariate logistic regression models were used to assess whether CAC level was associated with abnormalities of brain MRI or abnormal cognitive status. RESULTS: Older adults with high CAC scores were more likely to have more-severe brain MRI abnormalities, including subcortical infarction and high white matter hyperintensities. The associations between CAC and ventricular enlargement showed a similar but not significant trend. The presence of any of the MRI abnormalities attenuated the association between CAC and abnormal cognitive status. CONCLUSION: Older adults with higher levels of CAC were more likely to have more-severe brain MRI abnormalities and abnormal cognitive status.