Neuromuscular determinants of maximum walking speed in well-functioning older adults

Maximum walking speed may offer an advantage over usual walking speed for clinical assessment of age-related declines in mobility function that are due to neuromuscular impairment. The objective of this study was to determine the extent to which maximum walking speed is affected by neuromuscular function of the lower extremities in older adults. We recruited two groups of healthy, well functioning older adults who differed primarily on maximum walking speed. We hypothesized that individuals with slower maximum walking speed would exhibit reduced lower extremity muscle size and impaired plantarflexion force production and neuromuscular activation during a rapid contraction of the triceps surae muscle group (soleus (SO) and gastrocnemius (MG)).     

Comparison of the physical fitness levels in nursing home residents and community-dwelling older adults

PurposeThis study aimed to compare the physical fitness levels of nursing home residents and community-dwelling older adults.Materials and methodsThe 118 older adults aged between 65–85 living in a nursing home or community participated in the study. The Senior Fitness Test assessed the physical fitness levels of older adults. The older adults performed the chair stand test, arm curl test, 2-min step test, chair sit and reach test, back-scratch test, 8-foot up, and go test.ResultsThe age, cognitive status, gender, body weight, height, smoking, and education status were similar between the groups (p > 0.05). Aerobic endurance, balance, and agility were higher in nursing home residents than in the community-dwelling older adults (p < 0.05). Strength, flexibility, and BMI did not differ between groups ​​(p > 0.05).ConclusionAerobic endurance, balance, and agility may vary depending on the living environment of older adults. The determination of differences in physical fitness between community-dwelling older adults and nursing home residents could provide objective information to develop a physical activity program for older adults.     

Sedentary behavior and physical activity are independently related to functional fitness in older adults

The last decades of life have been traditionally viewed as a time of inevitable disease and frailty. Sedentary living and physical activity may influence capacity to perform activities that are needed to maintain physical independence in daily living. A total of 117 males and 195 females, aged 65–103 years, were assessed for physical activity and sedentary time with accelerometers and for functional fitness with the Senior Fitness Test battery. Based on the individual scores for each fitness item, a Z-score was created. Associations between functional fitness with sedentary time and moderate-to-vigorous physical activity (MVPA) were analyzed. A negative association was found between the composite Z-score for functional fitness and the sedentary time, even adjusting for MVPA and other confounders. On the other hand, MVPA was positively associated with the composite Z-score for functional fitness, independently of the sedentary time. In conclusion elderly who spend more time in physical activity or less time in sedentary behaviors exhibit improved functional fitness and other confounders. The results reinforce the importance of promoting both the reduction of sedentary behaviors and the increase of MVPA in this age group, as it may interfere at older ages in order to preserve functional fitness and performance of daily functioning tasks.     

Role of physical activity,physical fitness,and chronic health conditions on the physical independence of community-dwelling older adults over a 5-year period

The variability in the individual characteristics and habits could help determine how older adults maintain independence. The impact of the variability in physical activity, physical fitness, body composition, and chronic health conditions (co-morbidities) on the independence of older adults, especially over time, is seldom examined. This study aims to analyze quantitatively the impact of baseline values and changes in physical activity, physical fitness, body composition, and co-morbidities on the physical independence of community-dwelling, older adults over a 5-year period. Data from 106 and 85 community-dwelling adults (≥60 years) were collected at baseline and after five years, respectively. Linear regression selected the main predictors of changes in physical independence as follows: the baseline physical independence (β = 0.032, R² = 9.9%) and co-morbidities (β = −0.191, R² = 6.3%) and the changes in co-morbidities (β = −0.244, R² = 10.8%), agility (β = −0.288, R² = 6.7%), aerobic endurance (β = 0.007, R² = 3.2%), and walking expenditure (β = 0.001, R² = 5.1%) (p < 0.05). In conclusion, baseline physical independence, baseline co-morbidities, and changes in co-morbidities, walking, agility, and aerobic endurance predicted physical independence over five years regardless of age and gender. Gains of up to 8.3% in physical independence were associated with improvements in these variables, which corresponds to regaining independence for performing one or two activities of daily living.     

Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction

Background Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction. Methods Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake (VO_2peak), oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go (GUG), Comfortable Gait Speed (CGS), Unipedal Stance (US)], and self-reported physical activity (PA). Results Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO_2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO_2peak, but weakly associated with PA. Conclusions Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO_2peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF.     

Weight change, weight change intention, and the incidence of mobility limitation in well-functioning community-dwelling older adults

BACKGROUND: Obesity increases the risk for functional decline in later years, but the functional consequences of weight change in older adults are currently unclear. The aim of this study was to determine whether weight, weight change, and weight change intention are associated with risk for mobility limitation in elderly persons. METHODS: This study included 2,932 well-functioning black and white men and women aged 70 to 79 years, participating in the Health, Aging and Body Composition (Health ABC) Study, who were followed for 30 months. At baseline, reported weight change of 5 or more pounds during the previous year and weight change intention were assessed. Mobility limitation was defined as reported difficulty or inability to walk one-quarter mile or to climb 10 steps during two consecutive semiannual assessments during a period of 30 months. RESULTS: Approximately 30% of participants developed mobility limitation. Higher body mass index (BMI) was associated with increased risk for mobility limitation. Unintentional weight loss in the previous year was associated with increased risk for mobility limitation in the extremely obese, which was defined as BMI >or= 35 (hazard ratios [HR], =3.79; 95% confidence interval [CI], 1.84--7.79), and the normal BMI, which was defined as BMI<25 (HR, 2.55; 95% CI, 1.80--3.60). In persons with BMI 25 to 29.9, intentional weight loss (HR, 1.59; 95% CI, 1.12--2.25) and weight fluctuation with any intention (HR, 1.59; 95% CI, 1.10--2.28) increased the risk for mobility limitation. Unintentional weight gain or fluctuation did not confer additional risk for mobility limitation compared with weight stability, regardless of the level of body weight. CONCLUSION: In this cohort of well-functioning elderly persons, functional consequences of past weight change depended on the type of weight change, intentionality, and current measured body weight.     

Preservation of eccentric strength in older adults: Evidence,mechanisms and implications for training and rehabilitation

Overall reductions in muscle strength typically accompany the aging process. However, older adults show a relatively preserved capacity of producing eccentric strength. The preservation of eccentric strength in older adults is a well-established phenomenon, occurring indiscriminately across different muscle groups, independent of age-related architectural changes in muscle structure and velocity of movement.     

Estimating cardiorespiratory fitness in well-functioning older adults: treadmill validation of the long distance corridor walk

OBJECTIVES: To determine criterion validity of the 400-m walk component of the Long Distance Corridor Walk (LDCW) and develop equations for estimating peak oxygen consumption (VO2) from 400-m time and factors intrinsic to test performance (e.g., heart rate (HR) and systolic blood pressure (SBP) response) in older adults. DESIGN: Cross-sectional validation study. SETTING: Gerontology Research Center, National Institute on Aging, Baltimore, Maryland. PARTICIPANTS: Healthy volunteers (56 men and 46 women) aged 60 to 91 participating in the Baltimore Longitudinal Study of Aging between August 1999 and July 2000. MEASUREMENTS: The LDCW, consisting of a 2-minute walk followed immediately by a 400-m walk "done as quickly as possible" over a 20-m course was administered the day after maximal treadmill testing. HR and SBP were measured before testing and at the end of the 400-m walk. Weight, height, activity level, perceived effort, and stride length were also acquired. RESULTS: Peak VO2 ranged from 12.2 to 31.1 mL oxygen/kg per minute, and 400-m time ranged from 2 minutes 52 seconds to 6 minutes 18 seconds. Correlation between 400-m time and peak VO2 was -0.79. The estimating equation from linear regression included 400-m time (partial coefficient of determination (R2)=0.625), long versus short stride (partial R2=0.090), ending SBP (partial R2=0.019), and a correction factor for fast 400-m time (<240 seconds; partial R2=0.020) and explained 75.5% of the variance in peak VO2 (correlation coefficient=0.87). CONCLUSION: A 400-m walk performed as part of the LDCW provides a valid estimate of peak VO2 in older adults. Incorporating low-cost, safe assessments of fitness in clinical and research settings can identify early evidence of physical decline and individuals who may benefit from therapeutic interventions.     

Oxidative stress in older adults: effects of physical fitness

Acute exercise results in transient change in redox balance. High concentrations of reactive oxygen species (ROS) can lead to oxidative damage to macromolecules. However, moderate periodic increases in ROS, such as experienced with habitual exercise, may activate signal transduction pathways which stimulate increases in endogenous antioxidant systems. This study tested the hypothesis that physically fit older adults would have less oxidative stress than unfit age-matched controls, due to greater circulating concentrations of non-enzymatic antioxidants and greater capacity to upregulate antioxidant enzymes. We compared 37 fit (mean age 65.2 ± 5 years) and 35 unfit (mean age 67.7 ± 4 years) men and women. Fitness status was classified by VO_2 max and maximal leg power. Basal levels of oxidative stress were assessed by measuring urinary markers of nucleic acid damage and lipid peroxidation. Antioxidant status was assessed by measuring total antioxidant power and ratios of reduced to oxidized glutathione in plasma, at rest. The capacity to counteract an oxidative insult was assessed by measuring changes in plasma F₂-isoprostanes in response to forearm ischemia–reperfusion. The fit individuals had significantly lower levels of urinary markers of oxidative damage (all P <0.05) and lower F₂-isoprostane response to the oxidative challenge (P < 0.05), but there were no group differences in antioxidant status. The lower levels of oxidative stress in the fit individuals were not mediated by known effects of exercise training such as adiposity, HDL concentrations, or small molecular weight antioxidants. These data suggest that reduced oxidative stress associated with physical fitness results from differences in activity of antioxidant enzymes.

Electronic supplementary material

The online version of this article (doi:10.1007/s11357-011-9277-6) contains supplementary material, which is available to authorized users.     

Relationship between physical fitness and arterial stiffness in Korean older adults

Pulse-wave velocity (PWV) is a widely used clinical marker of arterial stiffness. Associations between several physical fitness measures and arterial stiffness have been examined. However, these results were inconsistent. Therefore, we conducted a cross-sectional study to assess the relationship between various physical fitness parameters and arterial stiffness in older adults. From January 2014 to December 2015, 1500 participants (men, n = 587; mean age, 71.78 ± 5.10 years) in South Korea were enrolled in the study. Koreans aged >65 years who agreed to participate in the study were enrolled. Individuals who were unable to exercise because of underlying conditions were excluded. VO₂ max (mL/kg/min), handgrip strength (kg), handgrip strength (kg)/body weight (kg) ratio, one-leg standing time (s), and 10-meter walking speed (m/s) were measured. The brachial-ankle pulse wave velocity (baPWV) was measured using a VP-1000 instrument. VO₂ max (mL/kg/min), handgrip (kg)/body weight (kg) ratio, one-leg standing time (s), and 10-meter walking speed (m/s) were significantly inversely associated with baPWV. This association was consistent even after adjusting for confounding factors. Our study revealed a significant association between various aspects of physical fitness and arterial stiffness. This study suggests that physical fitness is a useful predictor of arterial stiffness in older adults.     

Diet quality and cognition among older adults from the NuAge study

Background and objectives

A healthy diet may prevent cognitive decline either directly, or by decreasing risk of nutrition-related chronic diseases associated with cognitive decline. This study examined the relationships between diet quality (DQ) and cognition for over 3 years among 1488 older adults (52.6% female) from the NuAge study, aged 67 to 84 years at recruitment.

Methods

Cognition was assessed at four annual visits using the modified mini-mental status examination (3MS); rate of cognitive decline was computed for each participant over the 3 years of follow-up using mixed model analyses and the individual-specific number of months between 3MS assessments. Dietary data were collected at recruitment using a validated 78-item, semi-quantitative food frequency questionnaire (FFQ). DQ was characterized as the Canadian Healthy Eating Index (C-HEI), a 9-component global DQ index (maximum score = 100) computed from the FFQ output. Other variables were collected by questionnaire or direct measurement. Multivariate analyses were carried out to assess the association of DQ controlled for confounders on cognition.

Results

Total C-HEI was better in females (78.7 ± 9.1 vs 75.7 ± 9.4, p < .0001) as were C-HEI component subscores. Males, the less educated, smokers, those with poor social engagement, symptoms of depression, a higher waist:hip ratio and who reported financial insecurity had a poor quality diet that could contribute to chronic diseases associated with cognition. Along with functional autonomy, most of these variables emerged as covariates of baseline 3MS and predictors of cognitive decline. While certain C-HEI subscores and total C-HEI were positive univariate correlates of 3MS at recruitment, total DQ was not associated with cognition in multivariate analyses, either at baseline or over 3 years of follow-up.

Conclusions

DQ was not independently associated with cognition. However, the study demonstrates relationships between diet quality and risk factors for chronic diseases associated with cognition. Consequently, older adults might benefit from a healthy diet to decrease risk of nutrition-related chronic diseases established as risk factors for cognitive decline. Further work in diverse older populations, use of dietary data collected earlier in life, finer cognitive measures and longer follow-up are necessary to better elucidate relationships between diet quality, chronic diseases and cognition.     

Association between physical activity and cognition in Mexican and Korean older adults

IntroductionAs the world's population ages, the prevalence of cognitive impairment associated with age increases. This increase is particularly pronounced in Asia and South-America. The objective of this study was to investigate separately the longitudinal association of physical activity and cognitive function in; older adults in Mexico and South Korea.Materials and MethodsThis is a secondary analysis of two surveys, The Mexican Health and aging Study (MHAS) (n = 5853) and Korean Longitudinal Study of aging (KLoSA) (n = 5188), designed to study the aging process of older adults living in Mexico and South Korea. Participants older than 50 years were selected from rural and urban areas achieving a representative sample. Physical activity was assessed using self-report. Cognition was assessed using Cross-Cultural Cognitive Examination (CCCE) and Minimental state examination (MMSE) in Mexico and South Korea respectively. Here we investigate the longitudinal association between physical activity and cognition during 3 years for MHAS and 4 years for KLoSA using multiple linear regression analyses.ResultsThe prevalence of physical activity was 40.68 % in MHAS and 35.57 % in KLoSA. In the adjusted longitudinal multivariate analysis, an independent association was found between physical activity and MMSE score OR 0.0866 (CI 0.0266-0.1467 p-value 0.0047) in the Korean older adults, while there was no significant association in MHAS.ConclusionsPhysical activity could have a protective effect on the cognitive decline associated with aging in the Korean population.     

Changes in physical activity and cognitive decline in older adults living in the community

Accumulating evidence suggests that physical activity may be beneficial in preserving cognition in late life. This study examined the association between baseline and changes in physical activity and cognitive decline in community-dwelling older people. Data were from the Korean Longitudinal Study of Aging, with 2605 aged 65 years and older subjects interviewed in 2006 and followed up for 2 years. Cognitive decline was defined by calculating the Reliable Change Index using the Mini-Mental State Examination. Physical activity levels were categorized as sedentary, low, or high. Changes in physical activity were classified as inactive, decreaser, increaser, or active. Logistic regression analysis of baseline and changes in physical activity with cognitive decline was performed. Compared with the sedentary group at baseline, both the low and high activity groups were less likely to experience cognitive decline. The active (odds ratio [OR] = 0.40, 95 % confidence interval [CI] 0.23–0.68) and increaser (OR = 0.45, 95 % CI 0.27–0.74) group, compared with the inactive counterpart, demonstrated a significantly lower likelihood of cognitive decline. Older adults who remained active or increased activity over time had a reduced risk of cognitive decline. Engagement in physical activity in late life may have cognitive health benefits.     

Clinically significant cognitive impairment in older adults with type 1 diabetes

Aims

Little is known about cognition in older adults with type 1 diabetes. The aim of this study was to identify correlates of clinically significant cognitive impairment.

Gender differences in the association between migration and cognitive function among older adults in China and India

ObjectiveThis study aims to examine gender differences in the association between migration and cognitive function among adults in China and India.MethodsData from the World Health Organization Study on global AGEing and adult health (SAGE) study were used that included adults aged 50 + from China (N = 12,937) and India (N = 6244). Migration status included: urban residents, rural residents, urban-to-urban, rural-to-urban, rural-to-rural, and urban-to-rural migrants. Cognitive function was assessed by immediate and delayed recall tests, digit span tests, and verbal fluency test. Ordinary least square regression models were used to adjust for sociodemographic characteristics, psychosocial factors, health behaviors, and physical health status.ResultsControlling for multiple covariates, significant differences in cognitive function were found between men and women, and across migration groups. A consistent female disadvantage was found in China and India for cognitive function. Women who were rural residents or rural-to-rural migrants had the poorest cognitive function in both the Chinese and the Indian samples. Among males in China, rural residents had poorer cognitive function than urban residents, while urban-to-urban migrants had highest cognition scores; however, for male counterparts in India, rural-to-rural migrants had the poorest cognitive function.ConclusionsThe results suggest that the association between migration and cognitive function differs by gender and country. In our study populations, major sociodemographic characteristics play a key role in accounting for the differences in cognitive function.     

Mood is a key determinant of cognitive performance in community-dwelling older adults: a cross-sectional analysis

Identification of predictors of cognitive trajectories through the establishment of composite or single-parameter dimensional categories of cognition and mood may facilitate development of strategies to improve quality of life in the elderly. Participants (n = 487, aged 50+ years) were representative of the Portuguese population in terms of age, gender, and educational status. Cognitive and mood profiles were established using a battery of neurocognitive and psychological tests. Data were subjected to principal component analysis to identify core dimensions of cognition and mood, encompassing multiple test variables. Dimensions were correlated with age and with respect to gender, education, and occupational status. Cluster analysis was applied to isolate distinct patterns of cognitive performance and binary logistic regression models to explore interrelationships between aging, cognition, mood, and socio-demographic characteristics. Four main dimensions were identified: memory, executive function, global cognitive status, and mood. Based on these, strong and weak cognitive performers were distinguishable. Cluster analysis revealed further distinction within these two main categories into very good, good, poor, and very poor performers. Mood was the principal factor contributing to the separation between very good and good, as well as poor and very poor, performers. Clustering was also influenced by gender and education, albeit to a lesser extent; notably, however, female gender × lower educational background predicted significantly poorer cognitive performance with increasing age. Mood has a significant impact on the rate of cognitive decline in the elderly. Gender and educational level are early determinants of cognitive performance in later life.

Electronic supplementary material

The online version of this article (doi:10.1007/s11357-012-9482-y) contains supplementary material, which is available to authorized users.     

The association between pain and prevalent and incident motoric cognitive risk syndrome in older adults

BackgroundThe Motoric Cognitive Risk Syndrome (MCR) is a pre-dementia syndrome characterized by subjective cognitive complaints and slow gait in the absence of dementia and mobility disability. Worse cognitive and motoric function is associated with chronic pain in older adults. Our aim was to study the association between pain and prevalent and incident MCR in adults aged 65 years and older.MethodsWe analyzed the cross-sectional association between severity of pain and prevalent MCR in 3244 older adults participating in the Health and Retirement Study (2008 wave) using logistic regression analysis adjusting for demographic, peripheral, central or biological risk factors. Additionally, we analyzed the longitudinal association between severity of pain and incident MCR in 362 participants in the Central Control of Mobility in Aging Study, using Cox regression analysis.ResultsThe 155 Health and Retirement Study participants with severe pain had an increased risk of prevalent MCR (n = 249), compared to 2245 individuals without pain (adjusted for demographics OR: 2.78, 95 % CI:1.74–4.45).Over a mean follow-up of 3.01 years (SD 1.38), 29 individuals in the Central Control of Mobility in Aging Study developed incident MCR. Older adults with severe pain had over a five times increased risk of developing incident MCR, compared to those without pain even after adjusting for demographic variables (HR: 5.44, 95 % CI: 1.81–16.40).ConclusionOlder adults with severe pain have a higher prevalence and incidence of MCR. These findings should be further explored to establish if pain is a potentially modifiable risk factor to prevent cognitive decline.     

Measuring higher level physical function in well-functioning older adults: expanding familiar approaches in the Health ABC study

BACKGROUND: To evaluate development and progression of functional limitation and retain comparability with established approaches, we raised the measurement ceiling of commonly used self-report and performance-based measures of function. This study evaluated the utility and concurrent validity of these expanded measures. METHODS: The study population consisted of 3075 black and white men and women aged 70 to 79 years, with no reported mobility limitations or disability, participating in the Health, Aging, and Body Composition, or Health ABC study. Self-report measures were expanded by ascertaining ease of performance and including more demanding levels of some tasks. A single foot stand and narrow walk supplemented an established performance battery. For walking endurance, we developed the Long Distance Corridor Walk (LDCW), which includes distance covered in 2 minutes and the time to walk 400 m. RESULTS: The expanded self-report items identified one half of the men and one third of the women as exceptionally well functioning and 10% to 13% of men and 21% to 36% of women with lower capacity. The supplemented and rescored performance battery discriminated function over the full range. The LDCW further differentiated walking capacity at the high end and also identified a subgroup with limitations. The self-report and performance measures were significantly, but weakly, correlated (0.13-0.35) and were independent predictors of walking endurance. CONCLUSIONS: Well-functioning persons in their 70s exhibit a broad range of functional capacity readily ascertained by expanded self-report and performance tests. Significant associations among these measures support their concurrent validity, but generally weak correlations indicate they tap different, but important, dimensions of physical function.