Background and aims
Nitric oxide (NO) may play a critical role in facilitating the delivery of blood to active skeletal muscle, ultimately impacting functional health in older adults. Plasma nitrite is a useful marker of vascular NO bioavailability. The aim of the current investigation was to examine the effect of a widely used physical function test on plasma nitrite concentrations in older adults.
Venous blood was drawn before, immediately following, and 10 minutes following the completion of a 400-m walk test. Blood samples were added to heparin and frozen for subsequent analysis of nitrite levels using chemiluminescence.
Twenty six (79±4 yrs) women participated in this study. Plasma nitrite levels decreased approximately 22% from baseline following a 400-m walk. Percent change in plasma nitrite was related to walking speed (r=−0.550, p=0.004).
These data suggest an alteration in plasma nitrite concentration following a functional test which may impact functional health.
Acute exercise; nitric oxide; plasma nitrite; 400 meter walk
We examine obesity, intentional weight loss, and physical disability in older adults. Based on prospective epidemiological studies, BMI exhibits a curvilinear relationship with physical disability; there appears to be some protective effect associated with older adults being overweight. Whereas the greatest risk for physical disability occurs in older adults who are ≥class II obesity, the effects of obesity on physical disability appears to be moderated by both sex and race. Obesity at age 30 constitutes a greater risk for disability later in life than when obesity develops at age 50 or later; however, physical activity may buffer the adverse effects obesity has on late life physical disability. Data from a limited number of randomized clinical trials (RCTs) reinforce the important role that physical activity plays in weight loss programs for older adults. Furthermore, short-term studies have found that resistance training may be particularly beneficial in these programs since this mode of exercise attenuates the loss of fat-free mass during caloric restriction. Multi-year RCTs are needed to examine whether weight loss can alter the course of physical disablement in aging and to determine the long-term feasibility and effects of combining resistance exercise with weight loss in older adults.
Body-mass index (BMI); physical function; elderly; physical activity; exercise
The startle response has been shown to be useful in studying reactivity to food cues. Following 6h of food deprivation and exposure to neutral and food cues, we examined the role of state craving combined with both a short and long delay of consumption on affect and startle reflex. Participants completed the PANAS, consumed a controlled early morning meal, and experienced 6h of food deprivation. They then reported back to the laboratory, completed a second baseline PANAS, and had their baseline eyeblink EMG startle responses to 100 dB(A) startle probe assessed. Prior to and following the presentation of cues, startle probes were presented and responses were recorded. The PANAS and state craving were also assessed after each cue. Food cues provoked higher levels of state craving than neutral cues and startle responses failed to habituate as quickly to food cues as they did to neutral cues. In addition, cue exposure created the highest NA among high state cravers in the long delay of consumption group. Startle responses differed from NA in that with long delay startle was high irrespective of state craving scores; in the short delay of consumption condition, startle increased linearly with state craving. These results illustrate that state craving and expectations of food availability are important variables in understanding food-related cue reactivity.
Food Craving; Startle; Fasting; Negative Affect; Food Availability
Muscle weakness and obesity are two significant threats to mobility facing the increasing number of older adults. To date, there are no studies that have examined the association of strength and body mass index (BMI) on event rates on a widely used performance measure of major mobility disability.
This study was a secondary analysis of a randomized controlled trial in which sedentary functionally limited participants (70–89 years, Short Physical Performance Battery ≤ 9) who were able to complete a 400-m walk test at baseline were randomized to a physical activity or health education intervention and reassessed for major mobility disability every 6 months for up to 18 months. We evaluated whether baseline grip strength and BMI predicted failure to complete the 400-m walk test in 15 minutes or less (major mobility disability).
Among N = 406 participants with baseline measures, lower grip strength was associated with an increased risk for developing major mobility disability, with and without covariate adjustment (p < .01): The hazard ratio (95% confidence interval) for the lowest versus high sex-specific quartile of grip strength was 6.11 (2.24–16.66). We observed a U-shaped relationship between baseline BMI and the risk of developing major mobility disability, such that the risk for participants with a BMI of 25–29 kg/m2 was approximately half that of participants with BMI less than 25 or 30 kg/m2 or more (p = .04 in fully adjusted analyses).
Our data highlight the importance of muscle weakness, low BMI, and obesity as risk factors for major mobility disability in older adults. Being overweight may be protective for major mobility disability.
Physical disability; Physical activity; Older adults
Adults with type 2 diabetes mellitus often have limitations in mobility that increase with age. An intensive lifestyle intervention that produces weight loss and improves fitness could slow the loss of mobility in such patients.
We randomly assigned 5145 overweight or obese adults between the ages of 45 and 74 years with type 2 diabetes to either an intensive lifestyle intervention or a diabetes support-and-education program; 5016 participants contributed data. We used hidden Markov models to characterize disability states and mixed-effects ordinal logistic regression to estimate the probability of functional decline. The primary outcome was self-reported limitation in mobility, with annual assessments for 4 years.
At year 4, among 2514 adults in the lifestyle-intervention group, 517 (20.6%) had severe disability and 969 (38.5%) had good mobility; the numbers among 2502 participants in the support group were 656 (26.2%) and 798 (31.9%), respectively. The lifestyle-intervention group had a relative reduction of 48% in the risk of loss of mobility, as compared with the support group (odds ratio, 0.52; 95% confidence interval, 0.44 to 0.63; P<0.001). Both weight loss and improved fitness (as assessed on treadmill testing) were significant mediators of this effect (P<0.001 for both variables). Adverse events that were related to the lifestyle intervention included a slightly higher frequency of musculoskeletal symptoms at year 1.
Weight loss and improved fitness slowed the decline in mobility in overweight adults with type 2 diabetes. (Funded by the Department of Health and Human Services and others; ClinicalTrials.gov number, NCT00017953.)
Lifestyle interventions have resulted in weight loss or improved physical fitness among individuals with obesity, which may lead to improved physical function. This prospective investigation involved participants in the Action for Health in Diabetes (Look AHEAD) trial who reported knee pain at baseline (n = 2,203). The purposes of this investigation were to determine whether an Intensive Lifestyle Intervention (ILI) condition resulted in improvement in self-reported physical function from baseline to 12 months vs. a Diabetes Support and Education (DSE) condition, and whether changes in weight or fitness mediated the effect of the ILI. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness, and physical function subscales, and WOMAC summary score. ILI participants exhibited greater adjusted mean weight loss (s.e.) vs. DSE participants (−9.02 kg (0.48) vs. −0.78 kg (0.49); P < 0.001)). ILI participants also demonstrated more favorable change in WOMAC summary scores vs. DSE participants (β (s.e.) = −1.81 (0.63); P = 0.004). Multiple regression mediation analyses revealed that weight loss was a mediator of the effect of the ILI intervention on change in WOMAC pain, function, and summary scores (P < 0.001). In separate analyses, increased fitness also mediated the effect of the ILI intervention upon WOMAC summary score (P < 0.001). The ILI condition resulted in significant improvement in physical function among overweight and obese adults with diabetes and knee pain. The ILI condition also resulted in significant weight loss and improved fitness, which are possible mechanisms through which the ILI condition improved physical function.
A prospective design was used to examine predictors of adherence to a physical activity intervention in older adults with compromised function.
The sample included 213 men (31.1%) and women (68.9%) with an average age of 76.53 years.
The predictor variables accounted for 10% of the variance in percent attendance during adoption and transition, respectively. Adding percent attendance during adoption to the prediction of percent attendance during transition increased the explained variance in this phase to 21%. During maintenance, the predictors accounted for 13% of the variance in frequency of physical activity; this estimate increased to 46% when adding in percent attendance from the transition phase.
These results are encouraging in that the physical activity intervention appears to have been well tolerated by diverse subgroups of older adults. The role of prior behavior in predicting downstream adherence underscores the importance of developing proactive interventions for treating nonadherence in older adult populations.
Disability; Physical Activity; Older Adults; Adherence
Although the importance of the context of task performance in the assessment of mobility in older adults is generally understood, there is little empirical evidence that demonstrates how sensitive older adults are to subtle changes in task demands. Thus, we developed a novel approach to examine this issue.
We collected item response data to 81 animated video clips, where various mobility-related tasks were modified in a systematic fashion to manipulate task difficulty.
The participants (N = 234), 166 women and 68 men, had an average age of 81.9 years and a variety of comorbidities. Histograms of item responses revealed dramatic and systematic effects on older adults’ self-reported ability when varying walking speed, use of a handrail during ascent and descent of stairs, walking at different speeds outdoors over uneven terrain, and carrying an object. For example, there was almost a threefold increase in reporting the inability to walk at the fast speed compared with the slow speed for a minute or less, and twice as many participants reported the inability to walk at the fast speed outdoors over uneven terrain compared with indoors.
The data provide clear evidence that varying the contextual features and demands of a simple task such as stair climbing has a significant impact on older adults’ self-reporting of ability related to mobility. More work is needed on the psychometric properties of such assessments and to determine if this methodology has conceptual and clinical relevance in studying mobility disability.
Mobility; Aging; Disability; Physical function
Poor blood flow and hypoxia/ischemia contribute to many disease states and may also be a factor in the decline of physical and cognitive function in aging. Nitrite has been discovered to be a vasodilator that is preferentially harnessed in hypoxia. Thus, both infused and inhaled nitrite are being studied as therapeutic agents for a variety of diseases. In addition, nitrite derived from nitrate in the diet has been shown to decrease blood pressure and improve exercise performance. Thus, dietary nitrate may also be important when increased blood flow in hypoxic or ischemic areas is indicated. These conditions could include age-associated dementia and cognitive decline. The goal of this study was to determine if dietary nitrate would increase cerebral blood flow in older adults.
Methods and Results
In this investigation we administered a high vs. low nitrate diet to older adults (74.7 ± 6.9 years) and measured cerebral perfusion using arterial spin labeling magnetic resonance imaging. We found that the high nitrate diet did not alter global cerebral perfusion, but did lead to increased regional cerebral perfusion in frontal lobe white matter, especially between the dorsolateral prefrontal cortex and anterior cingulate cortex.
These results suggest that dietary nitrate may be useful in improving regional brain perfusion in older adults in critical brain areas known to be involved in executive functioning.
Nitric Oxide; Nitrite; Nitrate; Cerebral Blood Flow; Aging; Magnetic Resonance Imaging
The obesity epidemic had spawned considerable interest in understanding peoples' responses to palatable food cues that are plentiful in obesogenic environments. In this paper we examine how trait mindfulness of older, obese adults may moderate brain networks that arise from exposure to such cues. Nineteen older, obese adults came to our laboratory on two different occasions. Both times they ate a controlled breakfast meal and then were restricted from eating for 2.5 h. After this brief period of food restriction, they had an fMRI scan in which they were exposed to food cues and then underwent a 5 min recovery period to evaluate brain networks at rest. On one day they consumed a BOOST® liquid meal prior to scanning, whereas on the other day they only consumed water (NO BOOST® condition). We found that adults high in trait mindfulness were able to return to their default mode network (DMN), as indicated by greater global efficiency in the precuneus, during the post-exposure rest period. This effect was stronger for the BOOST® than NO BOOST® treatment condition. Older adults low in trait mindfulness did not exhibit this pattern in the DMN. In fact, the brain networks of those low on the MAAS suggests that they continued to be pre-occupied with the elaboration of food cues even after cue exposure had ended. Further work is needed to examine whether mindfulness-based therapies alter brain networks to food cues and whether these changes are related to eating behavior.
networks; mindfulness; food cues; obesity; aging; craving; self-efficacy
This study describes baseline physical activity (PA) patterns of individuals with type 2 diabetes mellitus enrolled in the multi-center Look AHEAD Study using an objective measure of PA (accelerometry).
2,240 participants (age = 59.0±6.8 years; BMI = 36.5±6.0 kg/m2) with type 2 diabetes mellitus (T2DM) provided data for this sub-study. Participants were instructed to wear an accelerometer during waking hours over 7 days. Accelerometry data were analyzed to identify periods meeting the criteria of ≥3 METs per minute for ≥10 minutes (MVPA) and ≥6 METs per minute for ≥10 minutes (VPA). Self-reported PA was also assessed with a questionnaire. Accelerometry and self-reported PA data were compared across categories of BMI, sex, race, age, fitness, diabetes medication usage, and history of cardiovascular disease
Self reported PA was lower at higher levels of BMI, was higher in males, was lowest for African-American/Black, and positively associated with fitness. Multivariate analyses for accelerometer measured MVPA and VPA showed that more PA bouts per day, minutes per bout, METs per minute, and MET-minutes were associated with higher fitness. For MVPA, bouts per day were higher in men, and METs per minute were higher in women. For VPA, bouts per day was positively associated with increasing age and differed by race/ethnicity. METs per minute were significantly lower at higher levels of BMI and in women. Diabetes medication usage and history of cardiovascular disease were not associated with patterns of physical activity examined.
Results provide information of factors that contribute to PA patterns in adults with T2DM when PA is assessed using both objective and subjective measures. These data may inform interventions to improve PA in adults with T2DM.
exercise; obesity; accelerometry
To determine if participation in usual moderate-intensity or more vigorous physical activity (MVPA) is associated with physical function performance and to identify socio-demographic, psychosocial and disease-related covariates that may also compromise physical function performance.
Cross-sectional analysis of baseline variables of randomized controlled intervention trial.
Four separate academic research centers.
Four hundred twenty-four older adults aged 70–89 years at risk for mobility-disability (scoring <10 on the Short Physical Performance Battery, SPPB) and able to complete the 400 m walk test within 15 minutes.
Minutes of MVPA (dichotomized according to above or below 150 min•wk−1 of MVPA) assessed by the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire, SPPB score, 400 M walk test, gender, body mass index (BMI), depressive symptoms, age and number of medications.
The SPPB summary score was associated with minutes of MVPA (ρ = 0.16, P = 0.001). In multiple regression analyses, age, minutes of MVPA, number of medications and depressive symptoms were associated with performance on the composite SPPB (P < 0.05). There was an association between 400 m walk time and minutes of MVPA (ρ = −0.18; P = 0.0002). In multiple regression analyses, age, gender, minutes of MVPA, BMI and number of medications were associated with performance on the 400 m walk test (P < 0.05).
Minutes of MVPA, gender, BMI, depressive symptoms, age, and number of medications are associated with physical function performance and all should be taken into consideration in the prevention of mobility-disability.
older adults; mobility-disability; physical function performance; older adults; mobility-disability; physical function performance
As the number of older adults in the United States rises, maintaining functional independence among older Americans has emerged as a major clinical and public health priority. Older people who lose mobility are less likely to remain in the community; demonstrate higher rates of morbidity, mortality, and hospitalizations; and experience a poorer quality of life. Several studies have shown that regular physical activity improves functional limitations and intermediate functional outcomes, but definitive evidence showing that major mobility disability can be prevented is lacking. A Phase 3 randomized controlled trial is needed to fill this evidence gap.
The Lifestyle Interventions and Independence for Elders (LIFE) Study is a Phase 3 multicenter randomized controlled trial designed to compare a supervised moderate-intensity physical activity program with a successful aging health education program in 1,600 sedentary older persons followed for an average of 2.7 years.
LIFE's primary outcome is major mobility disability, defined as the inability to walk 400 m. Secondary outcomes include cognitive function, serious fall injuries, persistent mobility disability, the combined outcome of major mobility disability or death, disability in activities of daily living, and cost-effectiveness.
Results of this study are expected to have important public health implications for the large and growing population of older sedentary men and women.
Disability; Physical activity; Exercise; Geriatrics; Physical function
Chronic obstructive pulmonary disease (COPD) patients have lower levels of physical activity compared to age-matched controls, and they limit physical activities requiring normal exertion. Our purpose was to compare the effectiveness of a traditional exercise therapy (TET) program with a behavioral lifestyle activity program (LAP) in promoting physical activity.
Moderate physical activity (kcal/week) was assessed in 176 COPD patients using the Community Health Activities Model for Seniors questionnaire. Patients were randomized to either a three month TET program that meet thrice weekly or a LAP. The LAP was designed to teach behavioral skills that encouraged the daily accumulation of self-selected physical activities of at least moderate intensity. Interventionist contact was similar (36 hours) between the two groups. Patients were assessed at baseline and 3, 6 and 12 months.
Compared to baseline values, self-reported moderate physical activity increased three months post-randomization with no significant difference (p = 0.99) found between the TET (2,501 ± 197 kcal/week) and the LAP (2,498 ± 211 kcal/week). At 6 and 12 months post-randomization, there were no significant differences (p = 0.37 and 0.69, respectively) in self-reported levels of moderate physical activity between the TET (2,210 ± 187 and 2,213 ± 218 kcal/week, respectively) and the LAP (2,456 ± 198 and 2,342 ± 232 kcal/week, respectively).
Although there was no difference between treatment groups, the TET and the LAP were both effective at in increasing moderate levels of physical activity at 3 months and maintaining moderate physical activity levels 12 months post-randomization.
Chronic obstructive pulmonary disease; Exercise; Physical activity; Behavioral intervention
We examined the costs of a physical activity (PA) and an educational comparison intervention. 424 older adults at risk for mobility disability were randomly assigned to either condition. The PA program consisted of center-based exercise sessions 3× weekly for 8 weeks, 2× weekly for weeks 9 to 24 and weekly behavioral counseling for 10 weeks. Optional sessions were offered during maintenance weeks (25–52). The comparison intervention consisted of weekly education meetings for 24 weeks, and then monthly for 6 months. Cost analyses were conducted from the “payer’s” perspective, with a 1-year time horizon. Intervention costs were estimated by tracking personnel activities and materials used for each intervention and multiplying by national unit cost averages. The average cost/participant was $1134 and $175 for the PA and the comparison interventions, respectively. A preliminary cost/effectiveness analysis gauged the cost/disability avoided to be $28,206. Costs for this PA program for older adults are comparable to those of other PA interventions. The results are preliminary and a longer study is required to fully assess the costs and health benefits of these interventions.
aging; health behavior; physical activity; interventions
Using the weight efficacy lifestyle questionnaire (WEL), we examined whether a group-mediated intervention for weight loss among older, obese adults resulted in changes in self-regulatory self-efficacy for eating behavior and whether these changes mediated weight loss.
This was a randomized controlled design, and 288 older adults received 1 of 3 treatments for 6 months: physical activity only (PA), weight loss + physical activity (WL + PA), or a successful aging (SA) health education program. The WEL was administered prior to randomization and again at the 6-month follow-up visit.
A significant treatment effect was observed for the WEL, F (2,249) = 15.11, p < .0001, partial eta2 = .11, showing that improvement occurred only in the WL + PA group as compared with PA and SA. Changes in WEL scores partially mediated the effects of the WL + PA intervention on weight loss.
These results illustrate that WL + PA can be effective in improving older adults’ self-efficacy for the self-regulation of eating behavior and that these changes are prospectively related to the amount of weight loss. Further research is warranted on an expanded concept of self-efficacy as well as controlled experimental studies on eating behavior in older adults.
Mindfulness; Older adults; PA; Self-efficacy; Weight loss
Although the Diabetes Prevention Program (DPP) developed a lifestyle weight loss intervention that has been demonstrated to prevent type 2 diabetes in high-risk individuals, it has yet to be widely adopted at the community level. The Healthy Living Partnership to Prevent Diabetes study (HELP PD) was designed to translate the DPP approach for use in community settings as a cost-effective intervention led by Community Health Workers (CHW's) and administered through a Diabetes Care Center (DCC). Approximately 300 overweight and obese (BMI 25-40 kg/m2) individuals with prediabetes (fasting blood glucose 95-124 mg/dl) were randomly assigned to either a lifestyle weight loss intervention (LW) or an enhanced usual care comparison condition (UC). The goal of LW is ≥7% weight loss achieved through increases in physical activity (180 min/wk) and decreases in caloric intake (approximately 1500 kcal/day). The intervention consists of CHW-led group-mediated cognitive behavioral meetings that occur weekly for 6 months and monthly thereafter for 18 months. UC consists of 2 individual meetings with a registered dietitian and a monthly newsletter. The primary outcome is change in fasting blood glucose. Secondary outcomes include cardiovascular risk factors, health-related quality of life, and social cognitive variables. Outcomes are masked and are collected every 6 months. The cost-effectiveness of the program will also be assessed. A community-based program that is administered through local DCC's and that harnesses the experience of community members (CHW's) may be a promising strategy for the widespread dissemination of interventions effective at preventing type 2 diabetes in high risk individuals.
translational research; randomized controlled trial; weight loss; prevention; type 2 diabetes; obesity
The late life disability instrument (LLDI) was developed to assess limitations in instrumental and management roles using a small and restricted sample. In this paper we examine the measurement properties of the LLDI using data from the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study.
LIFE-P participants, aged 70-89 years, were at elevated risk of disability. The 424 participants were enrolled at the Cooper Institute, Stanford University, University of Pittsburgh, and Wake Forest University. Physical activity and successful aging health education interventions were compared after 12-months of follow-up. Using factor analysis, we determined whether the LLDI's factor structure was comparable with that reported previously. We further examined how each item related to measured disability using item response theory (IRT).
The factor structure for the limitation domain within the LLDI in the LIFE-P study did not corroborate previous findings. However, the factor structure using the abbreviated version was supported. Social and personal role factors were identified. IRT analysis revealed that each item in the social role factor provided a similar level of information, whereas the items in the personal role factor tended to provide different levels of information.
Within the context of community-based clinical intervention research in aged populations, an abbreviated version of the LLDI performed better than the full 16-item version. In addition, the personal subscale would benefit from additional research using IRT.
The protocol of LIFE-P is consistent with the principles of the Declaration of Helsinki and is registered at http://www.ClinicalTrials.gov (registration # NCT00116194).
To demonstrate how principal components analysis can be used to describe patterns of weight changes in response to an intensive lifestyle intervention
Principal components analysis was applied to monthly percent weight changes measured on 2,485 individuals enrolled in the lifestyle arm of the Action for Health in Diabetes (Look AHEAD) clinical trial. These individuals were 45–75 years of age, with Type 2 diabetes and body mass indices >25 kg/m2. Associations between baseline characteristics and weight loss patterns were described using analyses of variance.
Three components collectively accounted for 97.0% of total intra-subject variance: a gradually decelerating weight loss (88.8%), early versus late weight loss (6.6%), and a mid-year trough (1.6%). In agreement with previous reports, each of the baseline characteristics we examined had statistically significant relationships with weight loss patterns. As examples, males tended to have a steeper trajectory of percent weight loss and to lose weight more quickly than women. Individuals with higher HbA1c tended to have a flatter trajectory of percent weight loss and to have mid-year troughs in weight loss compared to those with lower HbA1c.
Principal components analysis provided a coherent description of characteristic patterns of weight changes and is a useful vehicle for identifying their correlates and potentially for predicting weight control outcomes.
Principal components analysis; intervention studies; weight loss
The purpose of this study was to conduct a pilot clinical trial to test the feasibility and efficacy of an exercise program and anti-depressant treatment compared with usual care in improving the emotional and physical functioning of older adults with minor depression. Participants were 37 older adults with minor depression who were randomized to exercise, sertraline, or usual care; 32 participants completed the 16 week study. Outcomes included measures of both emotional (clinician and self-report) and physical (observed and self-report) functioning. There were trends for the superiority of the exercise and sertraline conditions over usual care in improving SF-36 mental health scores and clinician-rated depression scores. Individuals in the exercise condition showed greater improvements in physical functioning than individuals in the usual care condition. Both sertraline and exercise show promise as treatments for late-life minor depression. However, exercise has the added benefit of improving physical functioning as well.
Existing self-report measures of mobility ignore important contextual features of movement and require respondents to make complex judgments about specific tasks. Thus, we describe the development and validation of a short form (sf) video-animated tool for assessing mobility, the Mobility Assessment Tool—MAT-sf.
This study involves cross-sectional and longitudinal analyses examining the measurement properties of the MAT-sf. The MAT-sf consists of 10 animated video clips that assess respondents’ level of proficiency in performing each task. The main outcome measures used for validation included the Pepper Assessment Tool for Disability (PAT-D), the Short Physical Performance Battery (SPPB), and 400-m walk test.
Participants (n = 234), 166 women and 68 men, had an average age of 81.9 years and a variety of comorbidities with 65.4% having high blood pressure. An average SPPB score of 8.6 (range 2–12) suggests that the study sample had evidence of compromised physical function but was quite heterogeneous. The MAT-sf had good content validity, excellent test–retest reliability (r = .93), and criterion-related validity with the PAT-D. Moreover, the MAT-sf added considerable variance to the prediction of both SPPB scores and 400-m gait speed over and above the PAT-D mobility subscale. The MAT-sf also discriminated between older adults who completed or failed the 400-m walk test.
The MAT-sf is an innovative psychometrically sound measure of mobility. It has utility in epidemiological studies, translational science, and clinical practice.
Mobility; Aging; Measurement; Disability
It is well recognized that physical activity (PA) is important for older adults; yet, clinicians remain pessimistic about the ability of older adults with compromised function to adhere to long-term treatment and to maintain behavior change once treatment has been terminated.
We examined the functional status of older adults at a field center (Wake Forest University) 2 years after completing 12 months of treatment in the Lifestyle Interventions and Independence for Elders Pilot study. At baseline, participants were randomized to either a PA or a successful aging (SA) control group. Outcome measures included an interview assessment of PA, the Short Physical Performance Battery (SPPB), and performance on a 400-m self-paced walking test.
Two years after the formal intervention had ended, participants who were originally in the PA group continued to engage in more minutes of moderate PA and tended to have better SPPB and walking speed than those in the SA group (effect sizes [ES]: SPPB = 0.40, walking speed = 0.37). Seven (12.7%) participants in the PA group failed the 400-m walk at the 36-month follow-up assessment, whereas this number was 11 (21.6%) in the SA group.
Older adults who have compromised physical function are able to sustain some of the benefits derived from participating in structured PA 2 years after supervised treatment has been terminated.
Aging; Disability; Mobility; SPPB; 400-m walk
Literature has shown that exercise is beneficial for cognitive function in older adults and that aerobic fitness is associated with increased hippocampal tissue and blood volumes. The current study used novel network science methods to shed light on the neurophysiological implications of exercise-induced changes in the hippocampus of older adults. Participants represented a volunteer subgroup of older adults that were part of either the exercise training (ET) or healthy aging educational control (HAC) treatment arms from the Seniors Health and Activity Research Program Pilot (SHARP-P) trial. Following the 4-month interventions, MRI measures of resting brain blood flow and connectivity were performed. The ET group's hippocampal cerebral blood flow (CBF) exhibited statistically significant increases compared to the HAC group. Novel whole-brain network connectivity analyses showed greater connectivity in the hippocampi of the ET participants compared to HAC. Furthermore, the hippocampus was consistently shown to be within the same network neighborhood (module) as the anterior cingulate cortex only within the ET group. Thus, within the ET group, the hippocampus and anterior cingulate were highly interconnected and localized to the same network neighborhood. This project shows the power of network science to investigate potential mechanisms for exercise-induced benefits to the brain in older adults. We show a link between neurological network features and CBF, and it is possible that this alteration of functional brain networks may lead to the known improvement in cognitive function among older adults following exercise.
hippocampus; exercise; fitness; aging; perfusion; networks; small-world; fMRI
It has been suggested that lower extremity muscle power is more important for physical function in older adults compared to strength, and that there is a nonlinear relationship between power or strength and physical function that might be indicative of a threshold above which the association between muscle function and physical function is no longer evident. This study examined the association between lower extremity strength or power with the time to complete a 400-meter walk, and attempted to identify thresholds within the relationship.
A cross-sectional analysis of a sample of 384 females and 336 males aged ≥ 65 years from the InCHIANTI study (“Invecchiare in Chianti,” i.e., Aging in the Chianti Area) was conducted. Measures included 400-meter walk time, lower extremity strength and power, comorbidities, and sociodemographic variables (age, gender, height, education, cognitive function, depression).
Linear regression models showed that both lower extremity strength and power were significant predictors of 400-meter walk time, although power explained marginally more of the variance in 400-meter walk time. Quadratic models of lower extremity strength and power fit the data slightly better than the linear models. Regardless of gender, comorbidities, or normalization scheme for strength and power, the curvilinear form of the relationship between strength or power and 400-meter walk time remained the same.
Lower extremity muscle strength and power are both important predictors of the 400-meter walk time. Although curvilinear relationships existed between muscle strength and power and the 400-meter walk time, the data do not indicate a clear threshold for either strength or power above which the performance in the 400-meter walk test plateaus.
The number of older adults living in the U.S. continues to increase, and recent research has begun to target interventions to older adults who have mobility limitations and are at risk for disability. The objective of this study is to describe and examine correlates of health-related quality of life in this population subgroup using baseline data from a larger intervention study.
The Lifestyle Interventions and Independence for Elders–Pilot study (LIFE–P) was a randomized, controlled trial that compared a physical activity intervention to a non-exercise educational intervention with 424 older adults at risk for disability. Baseline data (collected April–December 2004; analyzed in 2006) included demographics, medical history, the Quality of Well-Being Scale (QWB-SA), a timed 400 m walk, and the Short Physical Performance Battery (SPPB). Descriptive HRQOL data are presented. Hierarchical linear regression models were used to examine correlates of HRQOL.
The mean QWB-SA score for the sample was 0.630 on an interval scale ranging from 0.0 (death) to 1.0 (asymptomatic, optimal functioning). The mean of 0.630 is 0.070 lower than a comparison group of healthy older adults. The variables associated with lower HRQOL included white ethnicity, more comorbid conditions, slower 400-m walk times, and lower SPPB balance and chair stand scores.
Older adults who are at risk for disability had reduced HRQOL. Surprisingly, however, mobility was a stronger correlate of HRQOL than an index of comorbidity, suggesting that interventions addressing mobility limitations may provide significant health benefits to this population.