Gender specific age-related changes in bone density, muscle strength and functional performance in the elderly: a-10 year prospective population-based study

Background:&nbsp;Age-related losses in bone mineral density (BMD), muscle strength, balance, and gait have been linked to&nbsp;an increased risk of falls, fractures and disability, but few prospective studies have compared the timing, rate and pattern&nbsp;of changes in each of these measures in middle-aged and older men and women. This is important so that targeted&nbsp;strategies can be developed to optimise specific musculoskeletal and functional performance measures in older adults.&nbsp;Thus, the aim of this 10-year prospective study was to: 1) characterize and compare age- and gender-specific changes in&nbsp;BMD, grip strength, balance and gait in adults aged 50 years and over, and 2) compare the relative rates of changes&nbsp;between each of these musculoskeletal and functional parameters with ageing.Methods: Men (n = 152) and women (n = 206) aged 50, 60, 70 and 80 years recruited for a population-based study had&nbsp;forearm BMD, grip strength, balance and gait velocity re-assessed after 10-years.Results: The annual loss in BMD was 0.5-0.7% greater in women compared to men aged 60 years and older&nbsp;(p &lt; 0.05- &lt; 0.001), but there were no gender differences in the rate of loss in grip strength, balance or gait. From the age&nbsp;of 50 years there was a consistent pattern of loss in grip strength, while the greatest deterioration in balance and gait&nbsp;occurred from 60 and 70 years onwards, respectively. Comparison of the changes between the different measures&nbsp;revealed that the annual loss in grip strength in men and women aged &lt;70 years was 1-3% greater than the decline in&nbsp;BMD, balance and gait velocity.Conclusion: There were no gender differences in the timing (age) and rate (magnitude) of decline in grip strength,&nbsp;balance or gait in Swedish adults aged 50 years and older, but forearm BMD decreased at a greater rate in women than&nbsp;in men. Furthermore, there was heterogeneity in the rate of loss between the different musculoskeletal and function&nbsp;parameters, especially prior to the age of 70 years, with grip strength deteriorating at a greater rate than BMD,&nbsp;balance and gait.</div

Differential Effects of Aging on Fore– and Hindpaw Maps of Rat Somatosensory Cortex

Getting older is associated with a decline of cognitive and sensorimotor abilities, but it remains elusive whether age-related changes are due to accumulating degenerational processes, rendering them largely irreversible, or whether they reflect plastic, adaptational and presumably compensatory changes. Using aged rats as a model we studied how aging affects neural processing in somatosensory cortex. By multi-unit recordings in the fore- and hindpaw cortical maps we compared the effects of aging on receptive field size and response latencies. While in aged animals response latencies of neurons of both cortical representations were lengthened by approximately the same amount, only RFs of hindpaw neurons showed severe expansion with only little changes of forepaw RFs. To obtain insight into parallel changes of walking behavior, we recorded footprints in young and old animals which revealed a general age-related impairment of walking. In addition we found evidence for a limb-specific deterioration of the hindlimbs that was not observed in the forelimbs. Our results show that age-related changes of somatosensory cortical neurons display a complex pattern of regional specificity and parameter-dependence indicating that aging acts rather selectively on cortical processing of sensory information. The fact that RFs of the fore- and hindpaws do not co-vary in aged animals argues against degenerational processes on a global scale. We therefore conclude that age-related alterations are composed of plastic-adaptive alterations in response to modified use and degenerational changes developing with age. As a consequence, age-related changes need not be irreversible but can be subject to amelioration through training and stimulation

The dynamic relationship between cognitive function and walking speed:The English Longitudinal Study of Ageing

Cross-sectional studies show that older people with better cognition tend to walk faster. Whether this association reflects an influence of fluid cognition upon walking speed, vice versa, a bidirectional relationship or the effect of common causes is unclear. We used linear mixed effects models to examine the dynamic relationship between usual walking speed and fluid cognition, as measured by executive function, verbal memory and processing speed, in 2,654 men and women aged 60 to over 90 years from the English Longitudinal Study of Ageing. There was a bidirectional relationship between walking speed and fluid cognition. After adjusting for age and sex, better performance on executive function, memory and processing speed was associated with less yearly decline in walking speed over the 6-year follow-up period; faster walking speed was associated with less yearly decline in each cognitive domain; and less yearly decline in each cognitive domain was associated with less yearly decline in walking speed. Effect sizes were small. After further adjustment for other covariates, effect sizes were attenuated but most remained statistically significant. We found some evidence that walking speed and the fluid cognitive domains of executive function and processing speed may change in parallel with increasing age. Investigation of the association between walking speed and cognition earlier in life is needed to better understand the origins of this relation and inform the development and timing of interventions.<br/

Walking cadence (steps/min) and intensity in 21-40 year olds: CADENCE-adults

Background: Previous studies have reported that walking cadence (steps/min) is associated with absolutely-defined intensity (metabolic equivalents; METs), such that cadence-based thresholds could serve as reasonable proxy values for ambulatory intensities.Purpose: To establish definitive heuristic (i.e., evidence-based, practical, rounded) thresholds linking cadence with absolutely-defined moderate (3 METs) and vigorous (6 METs) intensity.Methods: In this laboratory-based cross-sectional study, 76 healthy adults (10 men and 10 women representing each 5-year age-group category between 21 and 40 years, BMI = 24.8 +/- 3.4 kg/m 2 ) performed a series of 5-min treadmill bouts separated by 2-min rests. Bouts began at 0.5 mph and increased in 0.5 mph increments until participants: 1) chose to run, 2) achieved 75% of their predicted maximum heart rate, or 3) reported a Borg rating of perceived exertion > 13. Cadence was hand-tallied, and intensity (METs) was measured using a portable indirect calorimeter. Optimal cadence thresholds for moderate and vigorous ambulatory intensities were identified using a segmented regression model with random coefficients, as well as Receiver Operating Characteristic (ROC) models. Positive predictive values (PPV) of candidate heuristic thresholds were assessed to determine final heuristic values.Results: Optimal cadence thresholds for 3 METs and 6 METs were 102 and 129 steps/min, respectively, using the regression model, and 96 and 120 steps/min, respectively, using ROC models. Heuristic values were set at 100 steps/min (PPV of 91.4%), and 130 steps/min (PPV of 70.7%), respectively.Conclusions: Cadence thresholds of 100 and 130 steps/min can serve as reasonable heuristic thresholds representative of absolutely-defined moderate and vigorous ambulatory intensity, respectively, in 21-40 year olds. These values represent useful proxy values for recommending and modulating the intensity of ambulatory behavior and/or as measurement thresholds for processing accelerometer data.Peer reviewedCommunity Health Sciences, Counseling and Counseling Psycholog

Age and gender differences in physical capability levels from mid-life onwards: The Harmonisation and meta-analysis of data from eight UK cohort studies

Using data from eight UK cohorts participating in the Healthy Ageing across the Life Course (HALCyon) researchprogramme, with ages at physical capability assessment ranging from 50 to 90+ years, we harmonised data on objectivemeasures of physical capability (i.e. grip strength, chair rising ability, walking speed, timed get up and go, and standingbalance performance) and investigated the cross-sectional age and gender differences in these measures. Levels of physicalcapability were generally lower in study participants of older ages, and men performed better than women (for example,results from meta-analyses (N = 14,213 (5 studies)), found that men had 12.62 kg (11.34, 13.90) higher grip strength thanwomen after adjustment for age and body size), although for walking speed, this gender difference was attenuated afteradjustment for body size. There was also evidence that the gender difference in grip strength diminished with increasingage,whereas the gender difference in walking speed widened (p,0.01 for interactions between age and gender in bothcases). This study highlights not only the presence of age and gender differences in objective measures of physicalcapability but provides a demonstration that harmonisation of data from several large cohort studies is possible. Theseharmonised data are now being used within HALCyon to understand the lifetime social and biological determinants ofphysical capability and its changes with age

Sleep-wake rhythm and physical fitness in relation to activities of daily living in stroke survivors residing at home

To clarify the relationship between sleep-wake rhythm, physical fitness, and competence level of elderly stroke survivors living at home, thirty-seven stroke survivors living at home (65.4 ± 7.3 years) voluntarily participated in a cross-sectional study with an interview survey and measurement of physical fitness. All subjects lived in a community and received community home health care services. Sleep-wake rhythm and competence were evaluated by the questionnaire method. Physical fitness in relation to daily living activities was measured by both die time needed to walk 10 meters and that needed to stand up from bed rest position. There was a significant positive correlation between rising time and the 10 meter walking time. Regarding rising time and the competence score, there was a significant negative correlation. Stroke survivors who actively participated in community activities arose earlier than those who had a negative attitude toward participation in community activities. The sleep-wake rhydim, especially rising time, and the participation in community activities were related to the high competence level of stroke survivors living at home. Strengthening the synchronization of the sleep-wake rhythm and increasing the social network may serve as useful procedures to improve the competence of stroke survivors living at home