oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
A review of cardiorespiratory fitness-related neuroplasticity in the aging brain  [PDF]
Scott M. Hayes,Jasmeet P. Hayes,Mieke Verfaellie
Frontiers in Aging Neuroscience , 2013, DOI: 10.3389/fnagi.2013.00031
Abstract: The literature examining the relationship between cardiorespiratory fitness and the brain in older adults has increased rapidly, with 30 of 34 studies published since 2008. Here we review cross-sectional and exercise intervention studies in older adults examining the relationship between cardiorespiratory fitness and brain structure and function, typically assessed using Magnetic Resonance Imaging (MRI). Studies of patients with Alzheimer's disease are discussed when available. The structural MRI studies revealed a consistent positive relationship between cardiorespiratory fitness and brain volume in cortical regions including anterior cingulate, lateral prefrontal, and lateral parietal cortex. Support for a positive relationship between cardiorespiratory fitness and medial temporal lobe volume was less consistent, although evident when a region-of-interest approach was implemented. In fMRI studies, cardiorespiratory fitness in older adults was associated with activation in similar regions as those identified in the structural studies, including anterior cingulate, lateral prefrontal, and lateral parietal cortex, despite heterogeneity among the functional tasks implemented. This comprehensive review highlights the overlap in brain regions showing a positive relationship with cardiorespiratory fitness in both structural and functional imaging modalities. The findings suggest that aerobic exercise and cardiorespiratory fitness contribute to healthy brain aging, although additional studies in Alzheimer's disease are needed.
Caudate Nucleus Volume Mediates the Link between Cardiorespiratory Fitness and Cognitive Flexibility in Older Adults  [PDF]
Timothy D. Verstynen,Brighid Lynch,Destiny L. Miller,Michelle W. Voss,Ruchika Shaurya Prakash,Laura Chaddock,Chandramallika Basak,Amanda Szabo,Erin A. Olson,Thomas R. Wojcicki,Jason Fanning,Neha P. Gothe,Edward McAuley,Arthur F. Kramer,Kirk I. Erickson
Journal of Aging Research , 2012, DOI: 10.1155/2012/939285
Abstract: The basal ganglia play a central role in regulating the response selection abilities that are critical for mental flexibility. In neocortical areas, higher cardiorespiratory fitness levels are associated with increased gray matter volume, and these volumetric differences mediate enhanced cognitive performance in a variety of tasks. Here we examine whether cardiorespiratory fitness correlates with the volume of the subcortical nuclei that make up the basal ganglia and whether this relationship predicts cognitive flexibility in older adults. Structural MRI was used to determine the volume of the basal ganglia nuclei in a group of older, neurologically healthy individuals (mean age 66 years, ?? = 1 7 9 ). Measures of cardiorespiratory fitness ( V O 2 m a x ), cognitive flexibility (task switching), and attentional control (flanker task) were also collected. Higher fitness levels were correlated with higher accuracy rates in the Task Switching paradigm. In addition, the volume of the caudate nucleus, putamen, and globus pallidus positively correlated with Task Switching accuracy. Nested regression modeling revealed that caudate nucleus volume was a significant mediator of the relationship between cardiorespiratory fitness, and task switching performance. These findings indicate that higher cardiorespiratory fitness predicts better cognitive flexibility in older adults through greater grey matter volume in the dorsal striatum. 1. Introduction Age-related cognitive decline is an unfortunate, but nearly ubiquitous, characteristic of late life that is preceded by atrophy of several brain regions including the prefrontal cortex, medial temporal lobe, and basal ganglia [1, 2]. Because of the expected increase in the proportion of adults over the age of 65 in the next forty years, it has become a major public health initiative to identify methods to prevent or reverse regional brain atrophy with the hope that this might concurrently improve cognitive performance [3]. Randomized trials of aerobic exercise have proven promising from this regard, with participation in exercise programs leading to greater prefrontal [4] and hippocampal volumes [5]. Nonrandomized longitudinal studies of physical activity [6, 7] and cross-sectional studies of cardiorespiratory fitness [8–10] have shown similar results, with more physical activity and higher fitness levels associated with greater volumes. Unfortunately, few studies have examined whether cardiorespiratory fitness levels in older adult humans are associated with brain areas other than the prefrontal cortex and hippocampus
Shorter term aerobic exercise improves brain, cognition, and cardiovascular fitness in aging  [PDF]
Sandra B. Chapman,Sina Aslan,Molly W. Keebler,Nyaz Didehbani
Frontiers in Aging Neuroscience , 2013, DOI: 10.3389/fnagi.2013.00075
Abstract: Physical exercise, particularly aerobic exercise, is documented as providing a low cost regimen to counter well-documented cognitive declines including memory, executive function, visuospatial skills, and processing speed in normally aging adults. Prior aging studies focused largely on the effects of medium to long term (>6 months) exercise training; however, the shorter term effects have not been studied. In the present study, we examined changes in brain blood flow, cognition, and fitness in 37 cognitively healthy sedentary adults (57–75 years of age) who were randomized into physical training or a wait-list control group. The physical training group received supervised aerobic exercise for 3 sessions per week 1 h each for 12 weeks. Participants' cognitive, cardiovascular fitness and resting cerebral blood flow (CBF) were assessed at baseline (T1), mid (T2), and post-training (T3). We found higher resting CBF in the anterior cingulate region in the physical training group as compared to the control group from T1 to T3. Cognitive gains were manifested in the exercise group's improved immediate and delayed memory performance from T1 to T3 which also showed a significant positive association with increases in both left and right hippocampal CBF identified earlier in the time course at T2. Additionally, the two cardiovascular parameters, VO2 max and rating of perceived exertion (RPE) showed gains, compared to the control group. These data suggest that even shorter term aerobic exercise can facilitate neuroplasticity to reduce both the biological and cognitive consequences of aging to benefit brain health in sedentary adults.
The Obesity Paradox and Cardiorespiratory Fitness
Paul A. McAuley,Nancy S. Smith,Brian T. Emerson,Jonathan N. Myers
Journal of Obesity , 2012, DOI: 10.1155/2012/951582
Abstract: Cardiorespiratory fitness as an explanation for the obesity paradox warrants further examination. We evaluated independent and joint associations of cardiorespiratory fitness and adiposity with all-cause mortality in 811 middle-aged (age, 53.3±7.2 years) male never smokers without documented cardiopulmonary disease or diabetes from the Veterans Exercise Testing Study (VETS). Cardiorespiratory fitness was quantified in metabolic equivalents (METs) using final treadmill speed and grade achieved on a maximal exercise test. Subjects were grouped for analysis by METs: unfit (lowest third) and fit (upper two-thirds); and by body mass index (kg/m2): nonobese (18.5−29.9) and obese (≥30.0). Associations of baseline fitness and adiposity measures with all-cause mortality were determined by Cox proportional hazards analysis adjusted for age, ethnicity, hypertension, hypercholesterolemia, family history of coronary artery disease, and cardiovascular medication use. In multivariate analysis, mortality risk for obese/fit men did not differ significantly from the nonobese/fit reference group. However, compared to the reference group, nonobese and obese unfit men were 2.2 (=0.01) and 1.9 (=0.03) times more likely to die, respectively. Cardiorespiratory fitness altered the obesity paradox such that mortality risk was lower for both obese and nonobese men who were fit.
Cardiorespiratory Fitness, Metabolic Risk, and Inflammation in Children  [PDF]
Antonios D. Christodoulos,Helen T. Douda,Savvas P. Tokmakidis
International Journal of Pediatrics , 2012, DOI: 10.1155/2012/270515
Abstract: The aim of this study was to investigate the independent associations among cardiorespiratory fitness, metabolic syndrome (MetS), and C-reactive protein (CRP) in children. The sample consisted of 112 children (11.4  ±  0.4 years). Data was obtained for children’s anthropometry, cardiorespiratory fitness, MetS components, and CRP levels. MetS was defined using criteria analogous to the Adult Treatment Panel III definition. A MetS risk score was also computed. Prevalence of the MetS was 5.4%, without gender differences. Subjects with low fitness showed significantly higher MetS risk (<0.001) and CRP (<0.007), compared to the high-fitness pupils. However, differences in MetS risk, and CRP between fitness groups decreased when adjusted for waist circumference. These data indicate that the mechanisms linking cardiorespiratory fitness, MetS risk and inflammation in children are extensively affected by obesity. Intervention strategies aiming at reducing obesity and improving cardiorespiratory fitness in childhood might contribute to the prevention of the MetS in adulthood.
Cardiorespiratory fitness in breast cancer survivors
David Burnett, Patricia Kluding, Charles Porter, Carol Fabian and Jennifer Klemp
SpringerPlus , 2013, DOI: 10.1186/2193-1801-2-68
Abstract: Maximal oxygen uptake (VO2max) has been used to assess risk for all-cause mortality and cardiovascular disease (CVD), and low VO2max has recently been associated with increased mortality from breast cancer. The purpose of this study was to determine the proportion of breast cancer survivors with 2 or more risk factors for CVD exhibiting a low VO2max and to determine whether sub-maximal endpoints which could be applied more readily to intervention research would correlate with the maximal treadmill test. We performed a single VO2max test on a treadmill with 30 breast cancer survivors age 30--60 (mean age 50.5 +/- 5.6 years) who had 2 or more cardiac risk factors for CVD not related to treatment and who had received systemic therapy and or left chest radiation. Submaximal VO2 endpoints were assessed during the VO2max treadmill test and on an Arc trainer. Resting left ventricular ejection fraction (LVEF) was also assessed by echocardiogram (ECHO) or multi-gated acquisition scan (MUGA). A majority (23/30) of women had a VO2max below the 20th percentile based on their predicted normal values. The group mean resting LVEF was 60.5 +/- 5.0%. Submaximal VO2 measures were strongly correlated with the maximal test including; 1) 85% age predicted maximum heart rate VO2 on treadmill, (r = .89; p < 0.001), 2) treadmill VO2 at anaerobic threshold (AT), (r = .83; p < 0.001), and 3) Arc VO2 at AT, (r = .80; p < 0.001). Breast cancer survivors with 2 or more CVD risk factors but normal LVEF had a low cardiorespiratory fitness level compared to normative values in the healthy population placing them at increased risk for breast cancer and cardiovascular mortality. Submaximal VO2 exercise testing endpoints showed a strong correlation with the VO2max test in breast cancer survivors and is a good candidate for testing interventions to improve cardiorespiratory fitness.
Cardiorespiratory Fitness, Metabolic Risk, and Inflammation in Children  [PDF]
Antonios D. Christodoulos,Helen T. Douda,Savvas P. Tokmakidis
International Journal of Pediatrics , 2012, DOI: 10.1155/2012/270515
Abstract: The aim of this study was to investigate the independent associations among cardiorespiratory fitness, metabolic syndrome (MetS), and C-reactive protein (CRP) in children. The sample consisted of 112 children (11.4??±??0.4 years). Data was obtained for children’s anthropometry, cardiorespiratory fitness, MetS components, and CRP levels. MetS was defined using criteria analogous to the Adult Treatment Panel III definition. A MetS risk score was also computed. Prevalence of the MetS was 5.4%, without gender differences. Subjects with low fitness showed significantly higher MetS risk ( ) and CRP ( ), compared to the high-fitness pupils. However, differences in MetS risk, and CRP between fitness groups decreased when adjusted for waist circumference. These data indicate that the mechanisms linking cardiorespiratory fitness, MetS risk and inflammation in children are extensively affected by obesity. Intervention strategies aiming at reducing obesity and improving cardiorespiratory fitness in childhood might contribute to the prevention of the MetS in adulthood. 1. Introduction The prevalence and severity of obesity is increasing dramatically among children and adolescents in many parts of the world, whereas prevalence rates are estimated to increase in the next decades [1]. In children, excess body fat appears to be strongly associated with the clustering of risk factors, such as hyperglycemia, dyslipidemia, and hypertension, which play a key role in the pathogenesis of the metabolic syndrome (MetS) [2]. Obesity and the MetS risk in children have been recently associated with systemic inflammatory markers, in particular C-reactive protein (CRP) [3, 4], implying that low-grade inflammation can already exist in childhood and may be a potential link between the obesity and the MetS. Among behavioral variables, cardiorespiratory fitness has a protective role in MetS and inflammatory factors; however, it is not entirely clear if the interrelations among cardiorespiratory fitness, MetS risk, and inflammation in children are independent or partly due to the mediating effect of obesity, since the existing data are limited and equivocal [5, 6]. Recent evidence indicates that the prevalence rates of childhood obesity in Greece remain high [1, 7] and often coexist with low cardiorespiratory fitness [8] and an unfavorable cardiometabolic risk profile [9]. For the Greek pediatric population these data suggest an increased cardiovascular morbidity in adulthood, given that high-risk children and adolescents are likely to become high-risk adults [10]. Although the
Relationships between Obesity, Cardiorespiratory Fitness, and Cardiovascular Function  [PDF]
Kade Davison,Stefan Bircher,Alison Hill,Alison M. Coates,Peter R. C. Howe,Jonathan D. Buckley
Journal of Obesity , 2010, DOI: 10.1155/2010/191253
Abstract: Background. Obesity and low cardiorespiratory fitness (CRF) have been shown to independently increase the risk of CVD mortality. The aim of this study was to investigate the relationship between CRF, body fatness and markers of arterial function. Method and Results. Obese (9 male, 18 female; BMI 35.3 ± 0.9 kg·m-2) and lean (8 male, 18 female; BMI 22.5 ± 0.3?kg·m-2) volunteers were assessed for body composition (DXA), cardiorespiratory fitness (predicted max), blood pressure (BP), endothelial vasodilatator function (FMD), and arterial compliance (AC) (via radial artery tonometry). The obese group had more whole body fat and abdominal fat (43.5 ± 1.2% versus 27.2 ± 1.6%; and 48.6 ± 0.9% versus 28.9 ± 1.8%; resp.), and lower FMD (3.2 ± 0.4% versus 5.7 ± 0.7%; ) than the lean subjects, but there was no difference in AC. AC in large arteries was positively associated with CRF ( ; ) but not with fatness. Conclusion. These results indicate distinct influences of obesity and CRF on blood vessel health. FMD was impaired with obesity, which may contribute to arterial and metabolic dysfunction. Low CRF was associated with reduced elasticity in large arteries, which could result in augmentation of aortic afterload. 1. Introduction Obesity and cardiorespiratory fitness (CRF) are independent predictors of cardiovascular (CV) and all-cause mortality [1–5]. Furthermore, it appears that CRF may be protective against the cardiovascular risk associated with obesity [6]. The mechanisms which mediate the relationships between obesity, CRF, and CV mortality risk are not entirely understood [5, 7]. However, given that the protective effects of CRF and the detrimental effects of obesity appear to influence CV mortality independently of other CV risk factors, it is of interest to investigate their influences on established markers of subclinical CV function. This will allow for a better understanding of the potential mechanisms by which obesity and CRF may influence the risk of CV mortality. Increased adiposity, in particular visceral adiposity, is associated with reduced vascular endothelial function [8, 9]. Endothelial function refers to the general functional capacity of vascular endothelial cells, primarily mediated by their capacity to synthesize and release nitric oxide (NO) [10]. Reduced synthesis and/or availability of NO is associated with increased vascular permeability, inflammation, adhesion and thrombosis, and a reduced vasodilatory capacity, and abnormalities of endothelial function have been associated with a number of CV risk factors [11]. The noninvasive
Determinant factors of cardiorespiratory fitness in Portuguese adolescents of different ethnicities
Santos, Diana Aguiar;Silva, Analiza Mónica;Santa-Clara, Helena;Matias, Catarina Nunes;Fields, David A.;Sardinha, Luís Bettencourt;
Revista Brasileira de Cineantropometria & Desempenho Humano , 2011, DOI: 10.5007/1980-0037.2011v13n4p243
Abstract: cardiorespiratory fitness is an important health indicator in young people. the aim of this study was to investigate the effects of age, gender, body adiposity, and ethnicity on cardiorespiratory fitness in a sample of portuguese adolescents. the sample consisted of 266 adolescents aged 12-18 years [112 boys (80 caucasians and 32 african-portuguese, ap) and 154 girls (109 caucasians and 45 ap)]. percent body fat was estimated with a hand-to-hand bioelectrical impedance device (bf300, omrom). cardiorespiratory fitness was assessed by a shuttle run test (fitnessgram battery). multiple regression models were used for statistical analysis. the results showed that girls presented lower maximal oxygen consumption and higher percent body fat than boys. cardiorespiratory fitness was lower in caucasian than in ap girls. multiple regression analysis showed that percent body fat, age and the interaction of age with being caucasian and age with female gender were significant determinants that were negatively associated with cardiorespiratory fitness. the results suggest that maximal oxygen consumption is lower in adolescents with higher adiposity and in older adolescents. the findings highlight the importance of promoting physical fitness in schools across ages, especially in older adolescents, adjusting for determinant factors such as gender and ethnicity.
Relationships between Obesity, Cardiorespiratory Fitness, and Cardiovascular Function  [PDF]
Kade Davison,Stefan Bircher,Alison Hill,Alison M. Coates,Peter R. C. Howe,Jonathan D. Buckley
Journal of Obesity , 2010, DOI: 10.1155/2010/191253
Abstract: Background. Obesity and low cardiorespiratory fitness (CRF) have been shown to independently increase the risk of CVD mortality. The aim of this study was to investigate the relationship between CRF, body fatness and markers of arterial function. Method and Results. Obese (9 male, 18 female; BMI 35.3 ± 0.9 kg·m-2) and lean (8 male, 18 female; BMI 22.5 ± 0.3 kg·m-2) volunteers were assessed for body composition (DXA), cardiorespiratory fitness (predicted ?VO2max), blood pressure (BP), endothelial vasodilatator function (FMD), and arterial compliance (AC) (via radial artery tonometry). The obese group had more whole body fat and abdominal fat (43.5 ± 1.2% versus 27.2 ± 1.6%; <.001 and 48.6 ± 0.9% versus 28.9 ± 1.8%; <.001, resp.), and lower FMD (3.2 ± 0.4% versus 5.7 ± 0.7%; <.01) than the lean subjects, but there was no difference in AC. AC in large arteries was positively associated with CRF (R=0.5; <.01) but not with fatness. Conclusion. These results indicate distinct influences of obesity and CRF on blood vessel health. FMD was impaired with obesity, which may contribute to arterial and metabolic dysfunction. Low CRF was associated with reduced elasticity in large arteries, which could result in augmentation of aortic afterload.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.