***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Reduced cognitive function is common in persons with heart failure ( HF ) . Cardiovascular fitness is a known contributor to cognitive function in many patient population s , but has only been linked to cognition based on estimates of fitness in HF . The current study examined the relationship between fitness as measured by metabolic equivalents ( METs ) from a st and ardized stress test and cognition in persons with HF , as well as the validity of office-based predictors of fitness in this population . Methods Forty-one HF patients enrolled in cardiac rehabilitation completed a st and ardized exercise stress test protocol , a brief neuropsychological battery , the 2-minute step test ( 2MST ) , and a series of medical history and self-report question naires . Results Maximum METs from stress testing demonstrated incremental predictive validity for attention ( β = .41 , p = .03 ) , executive function ( β = .37 , p = .04 ) , and memory domains ( β = .46 , p = .04 ) . Partial correlations accounting for key medical and demographic characteristics revealed greater METs was associated with the 2MST ( r ( 32 ) = .41 , p = .02 ) but not with the Duke Activity Status Index ( DASI ) ( r(32 ) = .24 , p = .17 ) . Conclusion The current findings indicate that better fitness levels measured by METs is independently associated with better cognitive function in older adults with HF . Results also showed that METs was closely associated with one office-based measure of fitness ( 2MST ) , but not another ( DASI ) . Prospect i ve studies are needed to clarify the mechanisms linking fitness and cognitive function in HF Background and Purpose — Age-related impairments in cerebral blood flow and cerebrovascular reactivity to carbon dioxide ( CVRCO2 ) are established risk factors for stroke that respond favorably to aerobic training . The present study examined to what extent cerebral hemodynamics are improved when training is sustained throughout the adult lifespan . Methods — Eighty-one healthy males were prospect ively assigned to 1 of 4 groups based on their age ( young , ⩽30 years versus old , ≥60 years ) and lifetime physical activity levels  ( trained , ≥150 minutes recreational aerobic activity/week versus sedentary , no activity ) . Middle cerebral artery blood velocity ( MCAv , transcranial Doppler ultrasound ) , mean arterial pressure ( MAP , finger photoplethysmography ) , and end-tidal partial pressure of carbon dioxide ( PETCO2 , capnography ) were recorded during normocapnia and 3 mins of iso-oxic hypercapnea ( 5 % CO2 ) . Cerebrovascular resistance/conductance indices ( CVRi/CVCi ) were calculated as MAP/MCAv and MCAv/MAP , respectively , and CVRCO2 as the percentage increase in MCAv from baseline per millimeter of mercury ( mm Hg ) increase in PETCO2 . Maximal oxygen consumption ( O2MAX , online respiratory gas analysis ) was determined during cycling ergometry . Results — By design , older participants were active for longer ( 49±5 versus 6±4 years , P<0.05 ) . Physical activity attenuated the age-related declines in O2MAX , MCAv , CVCi , and CVRCO2 and increase in CVRi ( P<0.05 versus sedentary ) . Linear relationships were observed between O2MAX and both MCAv and CVRCO2 ( r=0.58–0.77 , P<0.05 ) . Conclusions — These findings highlight the importance of maintaining aerobic fitness throughout the lifespan given its capacity to improve cerebral hemodynamics in later-life OBJECTIVE Heart failure ( HF ) is a known risk factor for cognitive impairment .  Cardiac rehabilitation ( CR ) may attenuate poor neurocognitive outcomes in HF via improved physical fitness -- a significant promoter of cognitive function . However , no study has examined the possible acute and lasting benefits of CR on cognitive function in persons with HF . METHODS AND RESULTS Fifty-two patients with HF completed a 12-week Phase II CR program .  All participants were administered neuropsychological testing  and completed a brief physical fitness assessment  at baseline , completion of CR ( i.e. 12 weeks ) , and 12-month follow-up . Repeated measures analyses showed a significant time effect for both attention/executive function and memory ( P < 0.05 ) . Attention/executive function performance increased from baseline to 12 weeks and these gains remained up to 12 months ; memory was unchanged from baseline to 12 weeks , but then improved between the 12-week and 12-month time points . Physical fitness improved from baseline to 12 weeks and these benefits were maintained 12 months later . Changes in physical fitness and cognitive function over time did not reach a statistically significant association , though poorer physical fitness was associated with decreased cognitive performance at the baseline and 12-month time points . CONCLUSIONS CR is associated with both acute and lasting cognitive benefits in patients with HF . Prospect i ve studies with extended follow-ups are needed to clarify the mechanisms that underpin cognitive improvements following CR ( e.g. , improved cerebral perfusion ) and whether CR can ultimately reduce risk for cognitive decline and conditions like Alzheimer 's disease in HF Summary Background The associations of blood pressure with the different manifestations of incident cardiovascular disease in a contemporary population have not been compared . In this study , we aim ed to analyse the associations of blood pressure with 12 different presentations of cardiovascular disease . Methods We used  linked electronic health records from 1997 to 2010 in the CALIBER ( CArdiovascular research using LInked Bespoke studies and Electronic health Records ) programme to assemble a cohort of 1·25 million patients , 30 years of age or older and initially free from cardiovascular disease , a fifth of whom received blood pressure-lowering treatments . We studied the heterogeneity in the age-specific associations of clinical ly measured blood pressure with 12 acute and chronic cardiovascular diseases , and estimated the lifetime risks ( up to 95 years of age ) and cardiovascular disease-free life-years lost adjusted for other risk factors at index ages 30 , 60 , and 80 years . This study is registered at Clinical Trials.gov , number NCT01164371 . Findings During 5·2 years median follow-up , we recorded 83 098 initial cardiovascular disease presentations . In each age group , the lowest risk for cardiovascular disease was in people with systolic blood pressure of 90–114 mm Hg and diastolic blood pressure of 60–74 mm Hg , with no evidence of a J-shaped increased risk at lower blood pressures . The effect of high blood pressure varied by cardiovascular disease endpoint , from strongly positive to no effect . Associations with high systolic blood pressure were strongest for intracerebral haemorrhage ( hazard ratio 1·44 [ 95 % CI 1·32–1·58 ] ) , subarachnoid haemorrhage ( 1·43 [ 1·25–1·63 ] ) , and stable angina ( 1·41 [ 1·36–1·46 ] ) , and weakest for abdominal aortic aneurysm ( 1·08 [ 1·00–1·17 ] ) . Compared with diastolic blood pressure , raised systolic blood pressure had a greater effect on angina , myocardial infa rct ion , and peripheral arterial disease , whereas raised diastolic blood pressure had a greater effect on abdominal aortic aneurysm than did raised systolic pressure . Pulse pressure associations were inverse for abdominal aortic aneurysm ( HR per 10 mm Hg 0·91 [ 95 % CI 0·86–0·98 ] ) and strongest for peripheral arterial disease ( 1·23 [ 1·20–1·27 ] ) . People with  hypertension ( blood pressure ≥140/90 mm Hg or those receiving blood pressure-lowering drugs ) had a lifetime risk of overall cardiovascular disease at 30 years of age of 63·3 % ( 95 % CI 62·9–63·8 ) compared with 46·1 % ( 45·5–46·8 ) for those with normal blood pressure , and developed cardiovascular disease 5·0 years earlier ( 95 % CI 4·8–5·2 ) . Stable and unstable angina accounted for most ( 43 % ) of the cardiovascular disease-free years of life lost associated with hypertension from index age 30 years , whereas heart failure and stable angina accounted for the largest proportion ( 19 % each ) of years of life lost from index age 80 years . Interpretation The widely held assumptions that blood pressure has strong associations with the occurrence of all cardiovascular diseases across a wide age range , and that diastolic and systolic associations are concordant , are not supported by the findings of this high-resolution study . Despite modern treatments , the lifetime burden of hypertension is substantial . These findings emphasise the need for new  blood pressure-lowering strategies , and will help to inform the design of r and omised trials to assess them . Funding Medical Research Council , National Institute for Health Research , and Wellcome Trust BACKGROUND The present study examined whether aerobic fitness training of older humans can increase brain volume in regions associated with age-related decline in both brain structure and cognition . METHODS Fifty-nine healthy but sedentary community-dwelling volunteers , aged 60 - 79 years , participated in the 6-month r and omized clinical trial . Half of the older adults served in the aerobic training group , the other half of the older adults participated in the toning and stretching control group .  Twenty young adults served as controls for the magnetic resonance imaging ( MRI ) , and did not participate in the exercise intervention . High spatial resolution estimates of gray and white matter volume , derived from 3D spoiled gradient recalled acquisition MRI images , were collected before and after the 6-month fitness intervention . Estimates of maximal oxygen uptake ( VO2 ) were also obtained . RESULTS Significant increases in brain volume , in both gray and white matter regions , were found as a function of fitness training for the older adults who participated in the aerobic fitness training but not for the older adults who participated in the stretching and toning ( nonaerobic ) control group . As predicted , no significant changes in either gray or white matter volume were detected for our younger participants . CONCLUSIONS These results suggest that cardiovascular fitness is associated with the sparing of brain tissue in aging humans . Furthermore , these results suggest a strong biological basis for the role of aerobic fitness in maintaining and enhancing central nervous system health and cognitive functioning in older adults OBJECTIVE To determine the effects of high versus low-intensity exercise on cognitive function  following stroke . DESIGN Secondary analysis from a r and omized controlled trial with blinded assessors . SUBJECTS 50 - 80 years old , living in the community , > 1 year post-stroke . METHODS Participants were r and omized into a high-intensity Aerobic Exercise or low-intensity non-aerobic Balance/Flexibility program . Both programs were 6 months long , with 3 60-min sessions/week . Verbal item and working memory , selective attention and conflict resolution , set shifting were assessed before and after the program . RESULTS Forty-seven participants completed the study ( 22/25 in Aerobic Exercise group , 25/25 in Balance/Flexibility group ) . There was an improvement in verbal item memory in both groups ( time effect p = 0.04 ) , and no between-group differences in improvement in the other outcomes ( p > 0.27 ) . There was no association between pre-exercise cognitive function and post-exercise improvement . CONCLUSIONS In contrast to a small body of previous research suggesting positive benefits of exercise on cognition post-stroke , the current study found that 6 months of high or low intensity exercise was not effective in improving cognitive function , specifically executive functions . Further research in this area is warranted to establish the effectiveness of post-stroke exercise programs on cognition , and examine the mechanisms that underlie these changes PURPOSE The purpose of this study was to assess the impact of 24 wk of resistance training at two different intensities on cognitive functions in the elderly . METHODS Sixty-two elderly individuals were r and omly assigned to three groups : CONTROL ( N = 23 ) , experimental moderate ( EMODERATE ; N = 19 ) , and experimental high ( EHIGH ; N = 20 ) . The volunteers were assessed on physical , hemodynamic , cognitive , and mood parameters before and after the program . RESULTS On the 1 RM test ( P < 0.001 ) , the two experimental groups performed better than the CONTROL group , but they did not show differences between themselves . The EHIGH group gained more lean mass ( P = 0.05 ) than the CONTROL group and performed better on the following tests : digit span forward ( P < 0.001 ) , Corsi 's block-tapping task backward ( P = 0.001 ) , similarities ( P = 0.03 ) , Rey-Osterrieth complex figure immediate recall ( P = 0.02 ) , Toulouse-Pieron concentration test errors ( P = 0.01 ) , SF-36 ( general health ) ( P = 0.04 ) , POMS ( tension-anxiety , P = 0.04 ; depression-dejection , P = 0.03 ; and total mood disorder , P = 0.03 ) . The EMODERATE group scored higher means than the CONTROL group on digit span forward ( P 
    Output:
    
Exercise is able to positively affect cognitive performance in those with known vascular disease .
There is evidence to suggest a dose⁻response relationship .