Bedside-to-Bench conference: research agenda for idiopathic fatigue and aging

Role of Walking Energetics and Perceived Fatigability Differs by Gait Speed: The Study of Muscle, Mobility and Aging (SOMMA)

BACKGROUND

Slower gait speed may be driven by greater energy deficits and fatigability among older adults. We examined associations of walking energetics and perceived physical fatigability with gait speed among slower and faster walkers. Additionally, we used statistical mediation to examine the role of fatigability in the associations of walking energetics and gait speed using the Study of Muscle, Mobility and Aging (SOMMA).

METHODS

Perceived physical fatigability was assessed using the Pittsburgh Fatigability Scale (PFS) Physical score (range 0-50, higher = greater). A 3-phase cardiopulmonary exercise treadmill test collected peak oxygen consumption (VO2peak, mL/kg/min), energetic cost of walking (ECW, mL/kg/m), and cost-capacity ratio (VO2/VO2peak*100, %). Slower (<1.01 m/s) versus faster (≥1.01 m/s) walkers were classified using median 4-m gait speed. Linear regressions and statistical mediation analyses were conducted.

RESULTS

Slower walkers had lower VO2peak, higher ECW at preferred walking speed (PWS), and greater PFS Physical score compared to faster walkers (all p < .05; N = 849). One standard deviation (1-SD) higher VO2peak was associated with 0.1 m/s faster gait speed, while 1-SD higher ECW PWS, cost-capacity ratio at PWS and slow walking speed (SWS), and PFS Physical score were associated with 0.02-0.23 m/s slower gait speed. PFS Physical score was a significant statistical mediator in the associations between VO2peak (15.2%), SWS cost-capacity ratio (15.9%), and ECW PWS (10.7%) with gait speed and was stronger among slower walkers.

CONCLUSIONS

Slower walkers may be more influenced by perceptions of fatigue in addition to walking energetics. Our work highlights the importance of targeting both energetics and perceived fatigability to prevent mobility decline.

Combined non-targeted and targeted metabolomics reveals the mechanism of delaying aging of Ginseng fibrous root

Background: The fibrous root of ginseng (GFR) is the dried thin branch root or whisker root of Ginseng (Panax ginseng C. A. Mey). It is known for its properties such as tonifying qi, producing body fluid, and quenching thirst. Clinically, it is used to treat conditions such as cough, hemoptysis, thirst, stomach deficiency, and vomiting. While GFR and Ginseng share similar metabolites, they differ in their metabolites ratios and efficacy. Furthermore, the specific role of GFR in protecting the body remains unclear. Methods: We employed ultra-high performance liquid chromatography-triple quadrupole mass spectrometry to examine alterations in brain neurotransmitters and elucidate the impact of GFR on the central nervous system. Additionally, we analyzed the serum and brain metabolic profiles of rats using ultra-high performance liquid chromatography-quadrupole-orbitrap mass spectrometry to discern the effect and underlying mechanism of GFR in delaying aging in naturally aged rats. Results: The findings of the serum biochemical indicators indicate that the intervention of GFR can enhance cardiovascular, oxidative stress, and energy metabolism related indicators in naturally aging rats. Research on brain neurotransmitters suggests that GFR can augment physiological functions such as learning and memory, while also inhibiting central nervous system excitation to a certain degree by maintaining the equilibrium of central neurotransmitters in aged individuals. Twenty-four abnormal metabolites in serum and seventeen abnormal metabolites in brain could be used as potential biomarkers and were involved in multiple metabolic pathways. Among them, in the brain metabolic pathways, alanine, aspartate and glutamate metabolism, arginine and proline metabolism, histidine metabolism, and tyrosine metabolism were closely related to central neurotransmitters. Butanoate metabolism improves energy supply for life activities in the aging body. Cysteine and methionine metabolism contributes to the production of glutathione and taurine and played an antioxidant role. In serum, the regulation of glycerophospholipid metabolism pathway and proline metabolism demonstrated the antioxidant capacity of GFR decoction. Conclution: In summary, GFR plays a role in delaying aging by regulating central neurotransmitters, cardiovascular function, oxidative stress, energy metabolism, and other aspects of the aging body, which lays a foundation for the application of GFR.

Multidimensional Model of Energy in Patients With Cancer

OBJECTIVES

Evidence suggests that energy is a distinct symptom from fatigue in patients with cancer. The purpose of this paper is to present the Multidimensional Model of Energy in Patients with Cancer (MMEPC) that is based on emerging evidence and to make recommendations for clinical practice and future research.

METHODS

The literature was reviewed to determine various factors associated with variations in energy in patients with cancer. In addition, some of the emerging evidence in the model is supported by studies of energy in the general population and in patients with other chronic conditions.

RESULTS

Based on a review of the literature, specific concepts in the MMEPC include: person factors, clinical factors, cancer-related factors, biological factors, factors associated with energy balance, and co-occurring symptoms. The evidence to support the association between each of these factors and variations in energy levels in patients with cancer is described and synthesized.

CONCLUSION

This article provides emerging evidence on factors that influence variations in energy levels in patients with cancer. While the fundamental biobehavioral and biologic mechanisms that underlie variations in energy levels are not well understood, the model can be used to design pre-clinical and clinical studies of energy in patients with cancer. In addition, while emerging evidence supports the hypothesis that fatigue and energy are distinct symptoms, additional research on common and distinct risk factors and underlying mechanisms is warranted to be able to develop and test precision interventions for one or both symptoms.

IMPLICATIONS FOR NURSING PRACTICE

The risk factors (eg, being female, sleep quality) associated with variations in energy levels in patients with cancer identified in this paper have important clinical implications. Clinicians can use the identified risk factors to guide their assessments; identify high-risk patients with decrements in energy decrement; and develop targeted energy conservation interventions for the patients.

Associations of depression and perceived physical fatigability with white matter integrity in older adults

BACKGROUNDS

Fatigability is prevalent in older adults. However, it is often associated with depressed mood. We aim to investigate these two psychobehavioral constructs by examining their underpinning of white matter structures in the brain and their associations with different medical conditions.

METHODS

Twenty-seven older adults with late-life depression (LLD) and 34 cognitively normal controls (CN) underwent multi-shell diffusion MRI. Fatigability was measured with the Pittsburgh Fatigability Scale. We examined white matter integrity by measuring the quantitative anisotropy (QA), a fiber tracking parameter with better accuracy than the traditional imaging technique.

RESULTS

We found those with LLD had lower QA in the 2nd branch of the left superior longitudinal fasciculus (SLF-II), and those with more physical fatigability had lower QA in more widespread brain regions. In tracts associated with more physical fatigability, the lower QA in left acoustic radiation and left superior thalamic radiation correlated with higher blood glucose (r = - 0.46 and - 0.49). In tracts associated with depression, lower QA in left SLF-II correlated with higher bilirubin level (r = - 0.58).

DISCUSSION

Depression and fatigability were associated with various white matter integrity changes, which correlated with biochemistry biomarkers all related to inflammation.

Health-related quality of life and fatigue in adult rare bone disease patients: A cross-sectional study from Austria

OBJECTIVES

To assess physical and mental health domains of health related quality of life (HRQoL) as well as fatigue in rare bone disease (RBD) patients and to compare to patients with osteoporosis (OPO) and healthy controls (CTRL) without known bone diseases and to study associations of Fatique Severity Scale (FSS) with eight domains of HRQoL.

METHODS

Monocentric, cross-sectional study carried out between 2020 and 2022 in a hospital affiliated with the Vienna Bone and Growth Center (European Reference Network Center for Rare Bone Disease) in Vienna, Austria. The study comprised three types of RBD: Osteogenesis imperfecta, Hypophosphatasia and X-linked Hypophosphatemia. Fatigue was assessed by FSS. The higher score indicates more fatigue severity. HRQoL was assessed by Short-Form Health Survey (SF-36 v2). Physical component (PCS) and mental component summary scores (MCS) were calculated and normalised to a general population. A higher score indicates better HRQoL. Age-adjusted ANCOVA was used to assess differences in PCS and MCS between groups. Spearman correlation was used for associations of FSS with eight domains of HRQoL.

RESULTS

Study comprised 50 RBD patients [Mean age (SD) 48.8 (±15.9), 26 % male], 51 OPO patients [66.6 (±10.0), 9.8 % male] and 52 controls [50.8 (±16.3), 26.9 % male]. RBD patients had significantly higher mean age-adjusted FSS (3.5, 95 % CI 3.1-4.0) than controls (2.6, 95 % CI 2.2-3.0, p = 0.008), but not in comparison to osteoporotic patients 2.6 (95 % CI 2.2-3.0, p = 0.69). Diminished age-adjusted PCS of HRQoL was observed in RBD patients with a mean score of 37.1 (95 % CI 33.4-40.8), whereas their MCS of 50.1 (95 % CI 46.6-53.7) was comparable to controls (52.9, 95 % CI 49.8-56.0) and osteoporotic patients (50.2, 95 % CI 45.4-54.9). FSS score was negatively correlated with physical and mental component in RBD (ρ = -0.37, p < 0.05 and ρ = -0.54, p < 0.01, respectively) and OPO patients (ρ = -0.37, p < 0.05 and ρ = -0.35, p < 0.01, respectively).

CONCLUSIONS

The HRQoL in adult patients with rare bone diseases is lower than compared to osteoporotic and control group in this Austrian population. Fatigue has significant negative impact on HRQoL and it is important to address it when meeting with RBD patients in clinical practice.

Circadian disturbances and frailty risk in older adults

Frailty is characterized by diminished resilience to stressor events. It is associated with adverse future health outcomes and impedes healthy aging. The circadian system orchestrates ~24-h rhythms in bodily functions in synchrony with the day-night cycle, and disturbed circadian regulation plays an important role in many age-related health consequences. We investigated prospective associations of circadian disturbances with incident frailty in over 1000 older adults who had been followed annually for up to 16 years. We found that decreased rhythm strength, reduced stability, or increased variation were associated with a higher risk of incident frailty and faster progress of frailty over time. Perturbed circadian rest-activity rhythms may be an early sign or risk factor for frailty in older adults.

Usual-Paced 400m Long Distance Corridor Walk Estimates Cardiorespiratory Fitness among Older Adults: The Study of Muscle, Mobility and Aging (SOMMA)

Background

Cardiopulmonary exercise testing (CPET), the gold-standard method to quantify cardiorespiratory fitness (CRF), is not always feasible due to cost, access, and burden. The usual-paced 400m long-distance corridor walk (LDCW), a measure of mobility among older adults, may provide an alternate method to assess CRF among populations unable to complete maximal intensity testing. The purpose of this study was to develop and validate an estimating equation to estimate VO 2 peak from average 400m walking speed (WS) among participants in the Study of Muscle, Mobility and Aging (SOMMA).

Methods

At baseline, participants (N=820, 76.2±4.9 years, 58% Women, 86% Non-Hispanic White) completed a 400m LDCW (400m WS=400m/completion time in seconds) and symptom-limited maximal CPET (Modified Balke Protocol). VO 2 peak (mL/kg/min) was considered the highest 30-second average oxygen consumption during CPET. Other covariates included: age, sex, race, physical activity (7-day wrist-worn accelerometer), physical function (Short Physical Performance Battery, range 0-12), perceived physical fatigability (Pittsburgh Fatigability Scale, range 0-50), and Borg Rating of Perceived Exertion (RPE, range 6-20) at completion of the 400m LDCW. Stepwise linear regression was used. Internal validation was completed using data-splitting method (70%; 30%).

Results

Mean VO 2 peak was 20.2±4.8 mL/kg/min and mean 400m WS was 1.06±0.2 m/s. Each 0.05 m/s increment in 400m WS was associated with a 0.40 mL/kg/min higher VO 2 peak after adjustment for covariates. An estimating equation including 400m WS, age, sex, race, and RPE was developed. Internal validation showed low overall bias (-0.26) and strong correlation (r = 0.71) between predicted and measured VO 2 peak values. Bland-Altman plot and regression analyses indicated predicted VO 2 peak was an acceptable alternative, despite mean underestimation of 4.53 mL/kg/min among those with CPET VO 2 peak ≥25 mL/kg/min.

Conclusions

Usual-paced 400m LDCW strongly correlates with direct measures of cardiorespiratory fitness during CPET in older adults with lower fitness and can be used to test both fitness and function.

Age-related differences in symptom distress among patients with cancer

INTRODUCTION

Differences in symptom distress among older (age 65-74) and very old (age 75+) patients with cancer, compared to younger patients, remain to be well explored. These differences are important to understand given the heterogeneity of older populations and may have implications for age-appropriate symptom detection and management.

MATERIALS AND METHODS

We examined routinely collected Edmonton Symptom Assessment System Revised (ESAS-r) scores from 9,143 patients age 40+ initiating chemotherapy for solid malignancies at a single academic cancer centre, between September 2011 and May 2019. We used multivariable logistic regression models to determine associations between the most common symptoms and age group (ages 40-64, 65-74, 75-84, and 85+), cancer site, clinical stage, sex, and income levels. We focused our findings on patients with the five most common cancers, breast (n = 1,532), prostate (n = 923), lung (n = 889), pancreatic (n = 429), and colorectal (n = 368), prior to receiving treatment.

RESULTS

Within our sample, 58.0% were age 40-64, 27.3% age 65-74, 11.8% age 75-84, and 2.9% age 85+. Among the nine symptoms in the ESAS-r (anxiety, depression, tiredness, wellbeing, nausea, pain, drowsiness, appetite, and shortness of breath), the most common symptoms overall were anxiety (moderate-severe scores [ESAS-r 4 or higher] were reported by 33.8% of patients), lack of well-being (38.3%), and tiredness (38.3%). Older age was associated with lower odds of moderate/severe anxiety (odds ratio [OR] 0.81, 95% confidence interval [CI] 0.73-0.90 for age 65-74; OR 0.81, 95%CI 0.70-0.93 for age 75-84; OR 0.62, 95%CI 0.47-0.82 for age 85+; referent is 40-64-year-olds for all analyses), and increased odds of tiredness (OR 1.00, 95%CI 0.90-1.11 for age 65-74; OR 1.19, 95%CI 1.04-1.37 for age 75-84; and OR 1.34, 95%CI 1.04-1.72 for age 85+). Advanced stage, female sex, and lower income levels were associated with higher odds of moderate/severe tiredness, anxiety, and lack of well-being in adjusted models. Patients with pancreatic and lung cancers reported worse scores for these three symptoms than patients with other cancers.

DISCUSSION

Older age was associated with differences in symptom experiences such as increased tiredness and reduced anxiety. Supportive care interventions and future research should focus on addressing these symptoms to improve patient quality of life.

Fatigue in Alzheimer's disease: biological basis and clinical management-a narrative review

BACKGROUND

Fatigue is a common symptom in neurodegenerative diseases and is associated with decreased cognitive performances. A full knowledge of the causes and physiopathological pathways leading to fatigue in Alzheimer's disease could help treating this symptom and obtain positive effects on cognitive functions.

OBJECTIVES

To provide an overview of the clinical conditions and the biological mechanisms leading to fatigue in Alzheimer's disease patients. To review the recent advances on fatigue management and describe the landscape of future possibilities.

METHODS

We performed a narrative review including all type of studies (e.g. cross-sectional and longitudinal analysis, reviews, clinical trials).

RESULTS

We found very few studies considering the symptom fatigue in Alzheimer's disease patients. Populations, designs, and objectives varied across studies rendering comparability across studies difficult to perform. Results from cross-sectional and longitudinal analysis suggest that the amyloid cascade may be involved in the pathogenesis of fatigue and that fatigue may be a prodromal manifestation of Alzheimer's disease. Fatigue and neurodegeneration of Alzheimer's disease could share common brain signatures (i.e. hippocampal atrophy and periventricular leukoaraiosis). Some mechanisms of aging (i.e. inflammation, mitochondrial dysfunction, telomere shortening) may be proposed to play a common underlying role in Alzheimer's disease neurodegeneration and muscle fatigability. Considering treatments, donepezil has been found to reduce cognitive fatigue in a 6-week randomized controlled study. Fatigue is frequently reported as an adverse event in patients treated by anti-amyloid agents in clinical trials.

CONCLUSION

The literature is actually inconclusive about the main causes of fatigue in Alzheimer's disease individuals and its potential treatments. Further research is needed to disentangle the role of several components such as comorbidities, depressive symptoms, iatrogenic factors, physical decline and neurodegeneration itself. Given the clinical relevance of this symptom, it seems to be important to systematically assess fatigue by validated tools in Alzheimer's disease clinical trials.

Measuring and Understanding the Health Impact of Greater Fatigability in Older Adults: A Call to Action and Opportunities

Different from fatigue, an instantaneous state of tiredness, weakness and lack of energy, fatigability is a trait that contextualizes whole-body fatigue to the level of activity (i.e., intensity and duration) with which the fatigue is associated. Fatigability can be perceived or performance-related. Measuring fatigability improves upon traditional fatigue measures by accounting for self-pacing as older adults likely slow down or limit their daily activity to maintain fatigue in a tolerable range. Anchoring fatigue to activities/tasks improves sensitivity and allows for meaningful comparisons across individuals/between studies, as well as evaluating change over time and treatment effects. Two well-validated approaches are utilized to measure perceived fatigability: 1) a 5-minute slow-paced (1.5 mph/0.67 m/s, 0% grade) treadmill walk immediately followed by Borg rating of perceived exertion; and 2) a self-administered 10-item questionnaire, Pittsburgh Fatigability Scale, with both physical and mental subscales. Many walking-based performance fatigability measures are based on certain lap time or distance, while the Pittsburgh Performance Fatigability Index uses raw accelerometry data to quantify percent of cadence decline over the entire long distance walking tasks. Perceived fatigability prevalence ranges from 20-90% in older adults varying by assessment tool, and is higher with advancing age and in women compared to men. Fatigability is associated with physical and cognitive function, fall risk, mobility decline, and mortality. Unfortunately, the available research lacks representativeness in terms of racial and ethnic diversity. The time is now to incorporate our established sensitive and validated fatigability measures into global research and clinical practice to better understand mechanistic underpinnings and reveal intervention effects to reduce the burden and lessen the consequences of greater fatigability worldwide.

Dual Roles of Cardiorespiratory Fitness and Fatigability in the Life-Space Mobility of Older Adults: The Study of Muscle, Mobility and Aging (SOMMA)

BACKGROUND

Cardiorespiratory fitness and perceived fatigability are interrelated components of physical capacity that may jointly influence movement within one's living environment (life-space mobility). We examined whether fitness and fatigability were associated with life-space mobility in community-dwelling older adults, and whether the association of fitness with life-space varied by the level of perceived fatigability.

METHODS

Participants were from the Study of Muscle, Mobility and Aging (SOMMA) baseline cohort (N = 775, mean age 76.1 years). Life Space Assessment scores incorporated level, frequency, and assistance used (personal, devices) for life-space mobility. Fitness was measured as VO2peak from symptom-limited treadmill testing. Fatigability cut-points included: (i) Borg Rating of Perceived Exertion (RPE) ≥ 10 after a fixed-speed (1.5 mph) treadmill test, (ii) the Pittsburgh Fatigability Scale (PFS) Physical ≥ 15, and (iii) PFS Mental ≥ 13. The total count of cut-points was used as a composite fatigability measure (range: 0-3). Linear regressions were adjusted for demographic, lifestyle, and health confounders.

RESULTS

Better fitness was associated with greater life-space, but the association plateaued at higher fitness levels (VO2peak > 18). Life-space was significantly lower for individuals meeting ≥2 fatigability criteria (vs none), attributable mainly to more severe physical, but not mental, fatigability. In moderation analyses, the fitness-life-space association was significant only for those with RPE ≥ 10 but did not differ by PFS.

CONCLUSION

Fitness below a critically low threshold was associated with limited life-space mobility, suggesting that certain older individuals may need to operate close to their maximum aerobic capacity to traverse daily environments; these associations were driven by those with more severe physical fatigability.

Depressive and Biopsychosocial Frailty Phenotypes: Impact on Late-life Cognitive Disorders

 In older age, frailty is a detrimental transitional status of the aging process featuring an increased susceptibility to stressors defined by a clinical reduction of homoeostatic reserves. Multidimensional frailty phenotypes have been associated with all-cause dementia, mild cognitive impairment (MCI), Alzheimer's disease (AD), AD neuropathology, vascular dementia, and non-AD dementias. In the present article, we reviewed current evidence on the existing links among depressive and biopsychosocial frailty phenotypes and late-life cognitive disorders, also examining common pathways and mechanisms underlying these links. The depressive frailty phenotype suggested by the construct of late-life depression (LLD) plus physical frailty is poorly operationalized. The biopsychosocial frailty phenotype, with its coexistent biological/physical and psychosocial dimensions, defines a biological aging status and includes motivational, emotional, and socioeconomic domains. Shared biological pathways/substrates among depressive and biopsychosocial frailty phenotypes and late-life cognitive disorders are hypothesized to be inflammatory and cardiometabolic processes, together with multimorbidity, loneliness, mitochondrial dysfunction, dopaminergic neurotransmission, specific personality traits, lack of subjective/objective social support, and neuroendocrine dysregulation. The cognitive frailty phenotype, combining frailty and cognitive impairment, may be a risk factor for LLD and vice versa, and a construct of depressive frailty linking physical frailty and LLD may be a good dementia predictor. Frailty assessment may enable clinicians to better target the pharmacological and psychological treatment of LLD. Given the epidemiological links of biopsychosocial frailty with dementia and MCI, multidomain interventions might contribute to delay the onset of late-life cognitive disorders and other adverse health-related outcomes, such as institutionalization, more frequent hospitalization, disability, and mortality.

Effects of an individualised exercise programme plus Behavioural Change Enhancement (BCE) strategies for managing fatigue in frail older adults: a cluster randomised controlled trial

BACKGROUND

To the best of our knowledge, although ageing-induced fatigue could cause adverse outcomes such as frailty, there is currently no intervention for it. This study evaluated the effects of an individualised exercise programme with/without BCE strategies on reducing fatigue in older adults.

METHODS

A three-armed cluster-randomised controlled trial (RCT) was conducted with 184 participants (mean age: 79.1 ± 6.4; mean frailty score: 2.8 + 0.8) from 21 community centres (ClinicalTrials.gov: NCT03394495). They were randomised into either: the COMB group (n = 64), receiving 16 weeks of exercise training plus the BCE programme; the EXER group (n = 65), receiving exercise training and health talks; or the control group (n = 55), receiving only health talks. Fatigue was assessed using the Multi-dimensional Fatigue Inventory (range: 20 to 100, with higher scores indicating higher fatigue levels) at baseline, and immediately, 6 months, and 12 months post-intervention.

RESULTS

The GEE analyses showed significant interaction (time x group) between the COMB and control groups immediately (p < 0.001), 6 months (p < 0.001), and 12 months (p < 0.001) post-intervention. Comparing the COMB and EXER groups, there was a significant interaction immediately (p = 0.013) and at 12 months post-intervention (p = 0.007). However, no significant difference was seen between the EXER group and control group at any time point.

CONCLUSIONS

The COMB intervention showed better immediate and sustainable effects (i.e., 12 months after the intervention) on reducing fatigue in frail older adults than exercise training or health education alone.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03394495), registered on 09/01/2018.

Maladaptive Immune Activation in Age-Related Decline of Muscle Function

Age-related changes in immune competency and inflammation play a role in the decline of physical function. In this review of the conference on Function-Promoting Therapies held in March 2022, we discuss the biology of aging and geroscience with an emphasis on decline in physical function and the role of age-related changes in immune competence and inflammation. More recent studies in skeletal muscle and aging highlighting a crosstalk between skeletal muscle, neuromuscular feedback, and immune cell subsets are also discussed. The value of strategies targeting specific pathways that affect skeletal muscle and more systems-wide approaches that provide benefits in muscle homeostasis with aging are underscored. Goals in clinical trial design and the need for incorporating differences in life history when interpreting results from these intervention strategies are important. Where applicable, references are made to papers presented at the conference. We conclude by underscoring the need to incorporate age-related immune competency and inflammation when interpreting results from interventions that target specific pathways predicted to promote skeletal muscle function and tissue homeostasis.

A real-world evidence study evaluating consumer experience of Supradyn Recharge or Supradyn Magnesium and Potassium during demanding periods

Background

Challenging periods and/or mild micronutrient deficiencies may result in a lack of energy and general fatigue, frequently occurring in the general population. Supradyn Recharge and Supradyn Magnesium and Potassium (Mg/K) are multimineral/vitamin supplements formulated to ensure adequate daily intake of micronutrients. We conducted an observational study addressing consumption behaviour, reasons for intake, frequency of intake, and consumer experiences, satisfaction and characteristics under real-life conditions.

Methods

This was a retrospective, observational study carried out with two computer-aided web quantitative interviews.

Results

A total of 606 respondents (almost equally split between men and women; median age 40 years) completed the questionnaires. The majority indicated having a family, a job and a good level of education; they stated to be long-time and daily users, reporting an average daily intake of 6 days a week. More than 90% of consumers claimed they were satisfied, would use the products again and recommend them; over two-thirds felt the value for money was good. Supradyn Recharge has been mainly used to support lifestyle change and mental resilience, seasonal changes, and post-illness recovery. Supradyn Mg/K has been used to sustain or regain energy levels during hot weather or physical activity and as a support against stress. Users claimed a positive impact on quality of life.

Conclusion

Overall, the perception of benefit by consumers was extremely positive as reflected in their consumption behaviour, the majority of whom stated to be long-time users and daily consumers, with an average daily intake of 6 days for both products. These data complement and add up to the results of Supradyn clinical trials.

Quasi-passive lower limbs exosuit: an in-depth assessment of fatigue, kinematic and muscular patterns while comparing assistive strategies on an expert subject's gait analysis

Wearable robots are becoming a valuable solution that helps injured, and elderly people regain mobility and improve clinical outcomes by speeding up the rehabilitation process. The XoSoft exosuit identified several benefits, including improvement of assistance, usability, and acceptance with a soft, modular, bio-mimetic, and quasi-passive exoskeleton. This study compares two assistive configurations: (i) a bilateral hip flexion (HA, hips-assistance) and (ii) a bilateral hip flexion combined with ankle plantarflexion (HAA, hips-ankles-assistance) with the main goal of evaluating compensatory actions and synergetic effects generated by the human- exoskeleton interaction. A complete description of this complex interaction scenario with this actuated exosuit is evaluated during a treadmill walking task, using several indices to quantify the human-robot interaction in terms of muscular activation and fatigue, metabolic expenditure, and kinematic motion patterns. Evidence shows that the HAA biomimetic controller is synergetic with the musculature and performs better concerning the other control strategy. The experimentation demonstrated a metabolic expenditure reduction of 8% of Metabolic Equivalent of Task (MET), effective assistance of the muscular activation of 12.5%, a decrease of the muscular fatigue of 0.6% of the mean frequency, and a significant reduction of the compensatory actions, as discussed in this work. Compensatory effects are present in both assistive configurations, but the HAA modality provides a 47% reduction of compensatory effects when considering muscle activation.

Age-related changes in gait biomechanics and their impact on the metabolic cost of walking: Report from a National Institute on Aging workshop

Changes in old age that contribute to the complex issue of an increased metabolic cost of walking (mass-specific energy cost per unit distance traveled) in older adults appear to center at least in part on changes in gait biomechanics. However, age-related changes in energy metabolism, neuromuscular function and connective tissue properties also likely contribute to this problem, of which the consequences are poor mobility and increased risk of inactivity-related disease and disability. The U.S. National Institute on Aging convened a workshop in September 2021 with an interdisciplinary group of scientists to address the gaps in research related to the mechanisms and consequences of changes in mobility in old age. The goal of the workshop was to identify promising ways to move the field forward toward improving gait performance, decreasing energy cost, and enhancing mobility for older adults. This report summarizes the workshop and brings multidisciplinary insight into the known and potential causes and consequences of age-related changes in gait biomechanics. We highlight how gait mechanics and energy cost change with aging, the potential neuromuscular mechanisms and role of connective tissue in these changes, and cutting-edge interventions and technologies that may be used to measure and improve gait and mobility in older adults. Key gaps in the literature that warrant targeted research in the future are identified and discussed.

A Multi-Dimensional Model of Fatigue in Old Age: Implications for Brain Aging

As the most reported symptom in old age, fatigue is understudied in terms of both mechanisms and measures. Population heterogeneity and methodological inconsistency makes understanding the relationship between fatigue and brain aging challenging. The present article comprehensively reviews existing conceptual and operational frameworks of fatigue, as well as mechanistic heterogeneities of fatigue that exist in the aging literature. Then, I propose a Multi-Dimensional Model of fatigue to provide theoretical cohesion to the study of fatigue in old age, along with a "fatigue circuit" addressing brain profiles across dimensions of fatigue. The potential relationships between fatigue dimensions, the fatigue circuit, and brain aging are discussed to inform the direction of future research.

Changes in Objectively Measured Physical Activity Are Associated With Perceived Physical and Mental Fatigability in Older Men

BACKGROUND

Lower physical activity (PA) is associated with greater perceived fatigability, a person-centered outcome. The association between change in PA and fatigability with advanced age has yet to be established.

METHODS

Community-dwelling older men (N = 1 113, age = 84.1 ± 3.9 years at Year 14) had free-living PA assessed using SenseWear Armband prospectively at Year 7 (2007-2009) and Year 14 (2014-2016) of Osteoporotic Fractures in Men Study, a longitudinal cohort established in 2000 (baseline). We categorized percent changes in PA into groups (large decline → large increase) for 4 metrics: step count, light intensity PA (LIPA, metabolic equivalents [METs] >1.5 to <3.0), moderate-to-vigorous PA (MVPA, METs ≥ 3.0), and sedentary behavior (SB, METs ≤ 1.5, excluding sleep). Perceived physical and mental fatigability were measured (Year 14) with the Pittsburgh Fatigability Scale (PFS, higher score = greater fatigability; range = 0-50). Associations between each metric of percent changes in PA and fatigability were examined using linear regression, adjusted for demographics, change in health conditions, and Year 7 step count or total PA (METs > 1.5).

RESULTS

Men declined 2 336 ± 2 546 (34%) steps/d, 24 ± 31 (25%) LIPA min/d, 33 ± 58 (19%) MVPA min/d, and increased 40 ± 107 (6%) SB min/d over 7.2 ± 0.7 years. Compared to large decline (% change less than -50%), those that maintained or increased step count had 3-8 points lower PFS Physical scores; those who maintained or increased LIPA and MVPA had 2-3 and 2-4 points lower PFS Physical scores, respectively (all p ≤ .01). Associations were similar, but smaller, for PFS Mental scores.

CONCLUSION

Older men who maintained or increased PA had lower fatigability, independent of initial PA. Our findings inform the types and doses of PA that should be targeted to reduce fatigability in older adults.

Prospective Associations Between Physical Activity and Perceived Fatigability in Older Men: Differences by Activity Type and Baseline Marital Status

BACKGROUND

Lower physical activity has been cross-sectionally associated with greater perceived fatigability, defined as self-reported fatigue anchored to activity intensity and duration. The temporality of this relationship, and whether it differs by activity type or marital status, remains unclear.

METHODS

In the Osteoporotic Fractures in Men Study (N = 1 759), self-reported total, exercise, and household activity were assessed using the Physical Activity Scale for the Elderly across 7 visits (2000-2016). The Pittsburgh Fatigability Scale (range: 0-50; higher scores = greater fatigability) measured physical (mean = 16.6 ± 9.7) and mental (mean = 7.8 ± 8.3) fatigability at Year 14. Least absolute deviation and linear regression were used to examine associations between baseline and change in activity over 14 years with subsequent fatigability. Models were adjusted for demographic, health, and lifestyle factors.

RESULTS

After adjustment, lower baseline (β= -0.08, 95% confidence interval [CI]: -0.12, -0.04) and greater annual declines in total activity (β = -0.09, 95% CI: -0.14, -0.05) were prospectively associated with higher Pittsburgh Fatigability Scale (PFS) Physical scores. Associations were similar for mental fatigability (both p < .05). Lower baseline leisure exercise, but not baseline household activity, predicted higher PFS Physical scores (β = -0.10 vs -0.001). In contrast, greater declines in household activity, but not declines in exercise, were associated with higher PFS Physical scores (β = -0.09 vs -0.03). Lower baseline household activity predicted higher PFS Mental scores only for unmarried men (β = -0.15, 95% CI: -0.29, -0.01, interaction p = .019).

CONCLUSIONS

Baseline total activity and leisure exercise, and declines in total and household activity, were associated with higher subsequent perceived fatigability in older men. Marital status may mitigate the contribution of household activity to subsequent fatigability.

Fatigue Effect on Minimal Toe Clearance and Toe Activity during Walking

This study investigates the effects of fatigue on the process of walking in young adults using the developed clog-integrated sensor system. The developed sensor can simultaneously measure the forefoot activity (FA) and minimum toe clearance (MTC). The FA was evaluated through the change in the contact area captured by a camera using a method based on a light conductive plate. The MTC was derived from the distance between the bottom surface of the clog and ground obtained using a time of flight (TOF) sensor, and the clog posture was obtained using an acceleration sensor. The induced fatigue was achieved by walking on a treadmill at the fastest walking speed. We evaluated the FA and MTC before and after fatigue in both feet for 14 participants. The effects of fatigue manifested in either the FA or MTC of either foot when the results were evaluated by considering the participants individually, although individual variances in the effects of fatigue were observed. In the dominant foot, a significant increase in either the FA or MTC was observed in 13 of the 14 participants. The mean MTC in the dominant foot increased significantly (p = 0.038) when the results were evaluated by considering the participants as a group.

Structural Basal Ganglia Correlates of Subjective Fatigue in Middle-Aged and Older Adults

OBJECTIVE

Fatigue is among the most common complaints in community-dwelling older adults, yet its etiology is poorly understood. Based on models implicating frontostriatal pathways in fatigue pathogenesis, we hypothesized that smaller basal ganglia volume would be associated with higher levels of subjective fatigue and reduced set-shifting in middle-aged and older adults without dementia or other neurologic conditions.

METHODS

Forty-eight non-demented middle-aged and older adults (M_age = 68.1, SD = 9.4; M_MMSE = 27.3, SD = 1.9) completed the Fatigue Symptom Inventory, set-shifting measures, and structural MRI as part of a clinical evaluation for subjective cognitive complaints. Associations were examined cross-sectionally.

RESULTS

Linear regression analyses showed that smaller normalized basal ganglia volumes were associated with more severe fatigue (β = -.29, P = .041) and poorer Trail Making Test B-A (TMT B-A) performance (β = .30, P = .033) controlling for depression, sleep quality, vascular risk factors, and global cognitive status. Putamen emerged as a key structure linked with both fatigue (r = -.43, P = .003) and TMT B-A (β = .35, P = .021). The link between total basal ganglia volume and reduced TMT B-A was particularly strong in clinically fatigued patients.

CONCLUSION

This study is among the first to show that reduced basal ganglia volume is an important neurostructural correlate of subjective fatigue in physically able middle-aged and older adults without neurological conditions. Findings suggest that fatigue and rapid set-shifting deficits may share common neural underpinnings involving the basal ganglia, and provide a framework for studying the neuropathogenesis and treatment of subjective fatigue.

Development of a Novel Accelerometry-Based Performance Fatigability Measure for Older Adults

INTRODUCTION

Efforts to study performance fatigability have been limited because of measurement constrains. Accelerometry and advanced statistical methods may enable us to quantify performance fatigability more granularly via objective detection of performance decline. Thus, we developed the Pittsburgh Performance Fatigability Index (PPFI) using triaxial raw accelerations from wrist-worn accelerometer from two in-laboratory 400-m walks.

METHODS

Sixty-three older adults from our cross-sectional study (mean age, 78 yr; 56% women; 88% White) completed fast-paced ( n = 59) and/or usual-paced 400-m walks ( n = 56) with valid accelerometer data. Participants wore ActiGraph GT3X+ accelerometers (The ActiGraph LLC, Pensacola, FL) on nondominant wrist during the walking task. Triaxial raw accelerations from accelerometers were used to compute PPFI, which quantifies percentage of area under the observed gait cadence-versus-time trajectory during a 400-m walk to a hypothetical area that would be produced if the participant sustained maximal cadence throughout the entire walk.

RESULTS

Higher PPFI scores (higher score = greater fatigability) correlated with worse physical function, slower chair stands speed and gait speed, worse cardiorespiratory fitness and mobility, and lower leg peak power (| ρ | = 0.36-0.61 from fast-paced and | ρ | = 0.28-0.67 from usual-paced walks, all P < 0.05). PPFI scores from both walks remained associated with chair stands speed, gait speed, fitness, and mobility, after adjustment for sex, age, race, weight, height, and smoking status; PPFI scores from the fast-paced walk were associated with leg peak power.

CONCLUSIONS

Our findings revealed that the objective PPFI is a sensitive measure of performance fatigability for older adults and can serve as a risk assessment tool or outcome measure in future studies and clinical practice.

Neuroimaging correlates of persistent fatigue in older adults: A secondary analysis from the Multidomain Alzheimer Preventive Trial (MAPT) trial

OBJECTIVES

Fatigue has been suggested as a marker of biological aging. It seems plausible that this symptom might be associated with changes in brain health. The objective of this study was to examine the associations between persistent fatigue and neuroimaging correlates in a non-disease-specific population of community-dwelling older adults.

METHODS

We performed a cross-sectional analysis using data from The Multidomain Alzheimer Preventive Trial (MAPT). We included 458 subjects. Persistent fatigue was defined as meeting exhaustion criterion of Fried frailty phenotype in two consecutive clinical visits six months apart between study baseline and one year. Brain imaging correlates, assessed by magnetic resonance imaging (MRI), were the outcomes. The associations between persistent fatigue and brain correlates were explored using mixed model linear regressions with random effect at the center level.

RESULTS

The mean age of the participants was 74.8 ± 4 years old, and 63% of the subjects were women. Forty-seven participants (10%) exhibited a persistent fatigue profile. People with persistent fatigue were older compared to subjects without persistent fatigue (76.2 years ± 4.3 vs.74.7 ± 3.9 p = 0.009). Persistent fatigue was associated with higher white matter hyperintensity volume in the fully adjusted analysis. We did not find any cross-sectional association between persistent fatigue and sub-cortical volumes and global and regional cortical thickness.

CONCLUSION

Persistent fatigue was cross-sectionnally associated with higher white matter hyperintensity volume in older adults. Further longitudinal studies, using an assessment tool specifically designed and validated for measuring fatigue, are needed to confirm our findings.

Association of fatigue, inflammation, and physical activity on gait speed: the Long Life Family Study

BACKGROUND

Fatigue, inflammation, and physical activity (PA) are all independently associated with gait speed, but their directionality is not fully elucidated.

AIMS

Evaluate the bidirectional associations amongst fatigue, inflammation, and PA on gait speed.

METHODS

This cross sectional study included probands (n = 1280, aged 49-105) and offspring (n = 2772, aged 24-88) in the Long Life Family Study. We assessed gait speed, fatigue with the question "I could not get going", inflammation using fasting interleukin-6 (IL-6) and high sensitivity C-reactive protein (CRP), and self-reported PA as walking frequency in the past two weeks. The two generations were examined separately using linear mixed modeling.

RESULTS

Lower fatigue, lower IL-6, and greater PA were all associated with faster gait speed in both generations (all p < 0.05); lower CRP was only associated with faster gait speed in the offspring. PA explained the association of fatigue and gait speed via a 16.1% (95% CI 9.7%, 26.7%) attenuation of the direct associations for the probands and 9.9% (95% CI 6.3%, 18.8%) in the offspring. In addition, IL-6 explained more of the association of fatigue and gait speed than the association between PA and gait speed, via a 14.9% (95% CI 9.2%, 23.4%) attenuation of the direct association in the offspring only.

DISCUSSION

Results revealed a potential directionality from fatigue to IL-6 to PA that may lead to faster gait speed. Future work should examine these relationships longitudinally to establish temporality and causality.

CONCLUSIONS

Our findings support a signal that lowering fatigue and inflammation and increasing physical activity may delay functional decline.

Fatigue in community-dwelling older adults: A review of definitions, measures, and related factors

Fatigue is a common age-related symptom among community-dwelling adults aged 65 years and older. Yet, a systematic approach has rarely been applied to review definitions, measures, related factors, and consequences of fatigue in this population. A scoping review was conducted in December 2020 to fill the gap, and 36 articles met the inclusion criteria. Definitions, albeit diverse, included at least one of the following attributes: an early indicator of disablement, subjective, a lack of energy, multidimensional, impaired daily activities, and temporal. A summary of fatigue measures used in this population was provided, including a brief overview, number of items, reliability, and validity. In general, different measures were used with considerable variability in the content. Additionally, most measures had limited information on test-retest reliability and validity. Fatigue-related factors mapped into biological, psychological, social, and behavioral factors. Fatigue consequences were primarily declines in physical and cognitive functions. (100-150 words).

Evaluation of the Bidirectional Relations of Perceived Physical Fatigability and Physical Activity on Slower Gait Speed

BACKGROUND

Lower physical activity levels and greater fatigability contribute independently to slower gait speed in older adults. To fully understand the bidirectional relations between physical activity and fatigability, and to inform potential intervention strategies, we examined whether physical activity or fatigability explains more of the other factor's association on slower gait speed.

METHODS

Two generations (probands and offspring) of older adults (N = 2079, mean age 73.0 ± 10.0 years, 54.2% women, 99.7% White) enrolled in the Long Life Family Study were assessed at Visit 2 (2014-2017). Self-reported physical activity was measured with the Framingham Physical Activity Index and perceived physical fatigability using the Pittsburgh Fatigability Scale. Statistical mediation analyses were conducted separately by generation with linear mixed-effect models accounting for family relatedness and adjusted for demographics, health conditions, and field center.

RESULTS

Greater perceived physical fatigability explained the association of lower physical activity on slower gait speed via a 22.5% attenuation of the direct association (95% confidence interval [CI]: 15.0%-35.2%) for the probands and 39.5% (95% CI: 22.8%-62.6%) for the offspring. Whereas lower physical activity explained the association of greater perceived fatigability on slower gait speed via a 22.5% attenuation of the direct association (95% CI: 13.4%-32.8%) for the probands and 6.7% (95% CI: 3.8%-15.4%) for the offspring.

CONCLUSIONS

Our findings suggest that the impact of greater perceived physical fatigability on the association between lower physical activity and slower gait speed differs between younger-old and middle-to-oldest-old adults, indicating perceived physical fatigability as a potential mediator in the disablement pathway.

Evaluating Test-Retest Reliability of Fatigability in Chronic Stroke

OBJECTIVES

The subjective nature of fatigue may contribute to inconsistencies in prevalence rates for post-stroke fatigue. More objective performance fatigue measures may offer a more reliable construct of fatigue. Our goal was to establish test-retest reliability of fatigability in stroke during 6-minute walk (6MW) testing. Relationships between post-stoke fatigability and other constructs were assessed.

MATERIALS AND METHODS

Twenty-three hemiparetic stroke survivors underwent two 6MW tests with portable metabolic monitoring performed at least 48 hours apart. Fatigability was defined as ratio of change in walking speed to distance covered during the 6MW. 6MW oxygen consumption (VO2), peak aerobic capacity (VO2peak), walking speed over-ground, dynamic gait index, fatigue, falls efficacy, and BMI were measured.

RESULTS

Fatigability was highly correlated between both 6MW trials (ICC = 0.99, p < 0.001) with no significant difference between trials (0.08, p = 0.48). The strongest correlation was between fatigability and 6MW VO2 trial 1 and 2 (r = 0.92, p < 0.001 and r = 0.95, p < 0.001, respectively). Moderate-to-strong relationships were observed between fatigability for 6MW and fastest-comfortable walking speed (r = -0.82 and -0.77), self-selected walking speed (r = -7.8 and -0.78), 6MW walking speed (r = -0.80 and 0.80, VO2peak (r = -0.47 and -0.48) (p < 0.001), and DGI (r = -0.70 and -0.68, p < 0.001).

CONCLUSION

This study establishes test-retest reliability for an objective measure of fatigue in stroke-related disability. The strong correlations between fatigability and other functional measures also provides insight into the contributors underlying fatigability in this population.

REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01322607.

Slowing: A Vascular Geriatric Syndrome?

OBJECTIVES

This study aimed to investigate the interrelation between slowing in walking, thinking and mood, and their relationship with cerebral small vessel disease (CSVD) in a geriatric population.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

566 geriatric outpatients from the Amsterdam Aging Cohort (49% female; age 79 ±6 years), who visited the Amsterdam UMC geriatric outpatient memory clinic.

METHODS

Patients underwent a comprehensive geriatric assessment, brain imaging, and a neuropsychological assessment as part of medical care. Three slowing aspects were investigated: gait speed, processing speed, and apathy symptoms (higher scores indicating more advanced slowing). We visually rated CSVD [white matter hyperintensities (WMHs), strategic lacunes, and microbleeds] on brain imaging.

RESULTS

Regression analyses showed that slowing in walking (gait speed) was associated with slowing in thinking [processing speed; β = 0.35, 95% confidence interval (CI) 0.22, 0.48] and slowing in mood (apathy symptoms; β = 0.21, 95% CI 0.13, 0.30), independent of important confounders. Large confluent areas of WMH (Fazekas 3) were associated with all slowing aspects: gait speed (β = 0.49, 95% CI 0.28, 0.71), processing speed (β = 0.36, 95% CI 0.19, 0.52) and apathy symptoms (β = 0.30, 95% CI 0.09, 0.51). In addition, in patients with more slowing aspects below predefined cutoffs, severe WMH was more common. Presence of ≥3 microbleeds was associated with apathy symptoms (β = 0.39, 95% CI 0.12, 0.66), whereas lacunes were not associated with slowing.

CONCLUSIONS AND IMPLICATIONS

This study provides evidence that slowing in walking, thinking, and mood are closely related and associated with CSVD. This phenotype or geriatric syndrome could be helpful to identify and characterize patients with CSVD.

Lack of energy is associated with malnutrition in nursing home residents: Results from the INCUR study

Background

Lack of energy is a symptom frequently complained by older people, leading to the inability to continue functioning at the expected level of activity. This study aimed to investigate whether nutritional status was associated with lack of energy in nursing home (NH) residents.

Methods

This was a cross‐sectional study. A total of 570 NH residents (72.1% women) in 13 French NHs from the Incidence of pNeumonia and related ConseqUences in nursing home Residents study cohort were included in the study. Lack of energy was measured by the question “Did you feel full of energy during the past week?” from the geriatric depression scale. Nutritional status was evaluated according to Mini Nutritional Assessment Short‐Form (MNA‐SF). Unadjusted and adjusted logistic regression models were performed to test the association of nutritional status with lack of energy.

Results

The mean age of participants was 86.5 (SD 7.5) years. A total of 246 NH residents (43.2%) reported a lack of energy. Overall, 71 (12.5%) residents were malnourished and 323 (56.7%) residents were at risk of malnutrition. Malnutrition was significantly associated with lack of energy (OR = 3.42, 95% CI = 1.92–6.08, P < 0.001), even after adjustment for potential confounders (OR = 2.41, 95% CI = 1.29–4.52, P = 0.006). Among the single items of the MNA‐SF, decrease in food intake, low mobility, and psychological stress or acute disease were individually associated with lack of energy, independently of potential confounders (OR = 1.85, 95% CI = 1.24–2.77, P = 0.003; OR = 1.43, 95% CI = 1.10–1.86, P = 0.008; OR = 1.48, 95% CI = 1.19–1.84, P < 0.001; for each point respectively).

Conclusions

Lack of energy and malnutrition were closely associated. The reporting of lack of energy should lead to a comprehensive assessment of the aging individual (as happening for malnutrition) in order to preventively/promptly act on potentially reversible causes.

Perceived physical fatigability improves after an exercise intervention among breast cancer survivors: a randomized clinical trial

BACKGROUND

Among breast cancer populations, exercise interventions resulted in positive but relatively small improvements on fatigue, which may be due to insensitive measures of global fatigue. Perceived fatigability-whole-body tiredness anchored to standardized tasks/activities of a specific intensity and duration-may help to detect effective exercise interventions reducing fatigue in oncology. We examined whether perceived physical fatigability improved after an exercise intervention.

METHODS

This single center randomized clinical trial of 49 breast cancer survivors was conducted from 2015 to 2017, among which 41 participants (22 = exercise, 19 = control) completed the trial and reported their perceived physical fatigability at the first (Visit 1) and the last visit (Visit 3) over 6-14 weeks. Perceived physical fatigability was measured using the 10-item, self-administered Pittsburgh Fatigability Scale (PFS) scored 0-50. The mean differences of perceived physical fatigability between Visit 3 and Visit 1 were computed and compared by intervention groups using two sample t test.

RESULTS

Among the 41 women in the study (mean age 54.9 ± 9.8 years; 80% white), sociodemographic, clinical characteristics and baseline fatigue level were similar by intervention groups, except for antiestrogen use. Post-intervention changes (mean ∆ ± SE) of PFS Physical scores were greater in the exercise group (- 4.4 ± 1.4; - 22.5%) than the control group (0.2 ± 1.4; + 1.0%) (p = .022).

CONCLUSION

The PFS captured a reduction in fatigue after the exercise intervention among breast cancer survivors. These findings aid mounting efforts to reduce fatigue in oncology by introducing a more sensitive instrument to measure perceived physical fatigability to better evaluate patient-reported outcomes in future cancer trials.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02770781.

Validation of perceived physical fatigability using the simplified-Chinese version of the Pittsburgh Fatigability Scale

BACKGROUND

The Pittsburgh Fatigability Scale (PFS) was developed to capture fatigue and demand in a single tool, filling a gap that no validated questionnaire existed to measure perceived fatigability. Since fatigability is a more sensitive measure of a person's susceptibility to fatigue, we validated the simplified-Chinese version of the PFS among Chinese community-dwelling older adults.

METHODS

This cross-sectional study was conducted in an urban community in Beijing between November 2018 and July 2019. The PFS was translated into simplified-Chinese by the translation, retro-translation method. Internal consistency of the Physical subscale of the PFS was evaluated by Cronbach's alpha. Convergent validity and discriminant validity were evaluated against physical performance measures (i.e., Short Physical Performance Battery & Timed Up and Go Test) and daily living performance (i.e., Barthel Index & Instrumental activity of daily living).

RESULTS

Our study included 457 participants, including 182 men (39.8%) and 275 women (60.2%). The age range of the included participants was 61-96 years (mean = 84.8 years, SD = 5.8 years). The simplified-Chinese version of PFS Physical scores showed strong internal consistency (Cronbach's alpha = 0.81). Higher PFS Physical scores were associated with worse physical performance, and daily living performance (|correlation coefficient| range: 0.36-0.56, p < .001). Age- and sex-adjusted PFS Physical scores had moderate to good overall discrimination for correctly classifying people by their physical performance and daily living performance (AUCs range 0.70-0.87, p < .001).

CONCLUSIONS

The PFS simplified-Chinese version is a valid instrument to assess perceived physical fatigability in Chinese-speaking older adults with good convergent validity. Thus, the PFS, with low cost and greater feasibility, is a desired tool to measure fatigability in large population studies.

Is Skeletal Muscle Dysfunction a Limiting Factor of Exercise Functional Capacity in Patients with Sickle Cell Disease?

Patients with sickle cell disease (SCD) have reduced functional capacity due to anemia and cardio-respiratory abnormalities. Recent studies also suggest the presence of muscle dysfunction. However, the interaction between exercise capacity and muscle function is currently unknown in SCD. The aim of this study was to explore how muscle dysfunction may explain the reduced functional capacity. Nineteen African healthy subjects (AA), and 24 sickle cell anemia (SS) and 18 sickle cell hemoglobin C (SC) patients were recruited. Maximal isometric torque (Tmax) was measured before and after a self-paced 6-min walk test (6-MWT). Electromyographic activity of the Vastus Lateralis was recorded. The 6-MWT distance was reduced in SS (p < 0.05) and SC (p < 0.01) patients compared to AA subjects. However, Tmax and root mean square value were not modified by the 6-MWT, showing no skeletal muscle fatigue in all groups. In a multiple linear regression model, genotype, step frequency and hematocrit were independent predictors of the 6-MWT distance in SCD patients. Our results suggest that the 6-MWT performance might be primarily explained by anemia and the self-paced step frequency in SCD patients attempting to limit metabolic cost and fatigue, which could explain the absence of muscle fatigue.

Association between walking energetics and fragmented physical activity in mid-to-late life

BACKGROUND

Physical activity becomes increasingly fragmented with age, which may be an early marker of functional decline. Energetic cost of walking and energy capacity are also linked with functional decline, but their associations with activity fragmentation, and the potential modifying roles of total daily physical activity and age, remains unclear.

METHODS

493 participants (50-93 years) from the Baltimore Longitudinal Study of Aging underwent measures of: energetic cost of usual-paced overground walking (ml/kg/m), energy demand during slow walking (ml/kg/min) on a treadmill (0.67 m/s, 0% grade),m/s, 0% grade), and average peak walking energy expenditure (ml/kg/min) during a fast-paced 400-m walk. A ratio of slow walking to peak walking energy expenditure ("cost-to-capacity ratio") was calculated. Activity fragmentation was quantified as an active-to-sedentary transition probability (ASTP) using Actiheart accelerometer data. Linear regression models with ASTP as the dependent variable were used to test whether poorer energy cost and capacity were associated with higher ASTP and whether the associations differed by daily physical activity or age.

RESULTS

After adjusting for demographics, body composition, comorbidities and daily physical activity, every 10% higher cost-to-capacity ratio was associated with 0.4% greater ASTP (p=0.005). This association was primarily driven by the least active participants (pinteraction=0.023). Peak walking energy expenditure was only associated with ASTP among participants aged ≥70 years.

CONCLUSIONS

Higher cost-to-capacity ratio and lower energy capacity may manifest as more fragmented physical activity, especially among those less active or aged ≥70 years. Future studies should examine whether an increasing cost-to-capacity ratio or declining energy capacity predicts subsequent activity fragmentation.

Validation of Perceived Mental Fatigability Using the Pittsburgh Fatigability Scale

OBJECTIVES

Establish reliability, concurrent and convergent validity of the Pittsburgh Fatigability Scale (PFS) Mental subscale.

DESIGN

Cross-sectional.

SETTING

Older adults from two University of Pittsburgh registries, Baltimore Longitudinal Study of Aging (BLSA), and Long Life Family Study (LLFS).

PARTICIPANTS

PFS Mental subscale validation was conducted using three cohorts: (1) Development Sample (N = 664, 59.1% women, age 74.8 ± 6.4 years, PFS Mental scores 10.3 ± 9.1), (2) Validation Sample I-BLSA (N = 430, 51.9% women, age 74.5 ± 8.2 years, PFS Mental scores 9.4 ± 7.9), and (3) Validation Sample II-LLFS (N = 1,917, 54.5% women, age 72.2 ± 9.3 years, PFS Mental scores 7.5 ± 8.2).

MEASUREMENTS

Development Sample, Validation Sample I-BLSA, and Validation Sample II-LLFS participants self-administered the 10-item Pittsburgh Fatigability Scale. Validation Sample II-LLFS completed cognition measures (Trail Making Tests A and B), depressive symptomatology (Center for Epidemiologic Studies-Depression Scale, CES-D), and global fatigue from two CES-D items.

RESULTS

In the Development Sample and Validation Sample I-BLSA, confirmatory factor analysis showed all 10 items loaded on two factors: social and physical activities (fit indices: SRMSR = 0.064, RMSEA = 0.095, CFI = 0.91). PFS Mental scores had strong internal consistency (Cronbach's α = 0.85) and good test-retest reliability (ICC = 0.78). Validation Sample II-LLFS PFS Mental scores demonstrated moderate concurrent and construct validity using Pearson (r) or Spearman (ρ) correlations against measures of cognition (Trail Making Tests A (r = 0.14) and B (r = 0.17) time), depressive symptoms (r = 0.31), and global fatigue (ρ = 0.21). Additionally, the PFS Mental subscale had strong convergent validity, discriminating according to established clinical or cognitive testing cut points, with differences in PFS Mental scores ranging from 3.9 to 7.6 points (all P < .001). All analyses were adjusted for family relatedness, field center, age, sex, and education.

CONCLUSIONS

The validated PFS Mental subscale may be used in clinical and research settings as a sensitive, one-page self-administered tool of perceived mental fatigability in older adults.

The Associations of Activity Fragmentation With Physical and Mental Fatigability Among Community-Dwelling 75-, 80-, and 85-Year-Old People

BACKGROUND

Fatigue related to task standardized by duration and intensity, termed fatigability, could manifest as shortening of activity bouts throughout the day causing daily activity to accumulate in a more fragmented pattern. Our purpose was to study the association of activity fragmentation with physical and mental dimensions of fatigability.

METHODS

A cross-sectional study of 485 community-dwelling 75-, 80-, and 85-year-old people using a thigh-worn accelerometer for 3-7 days. Activity fragmentation was studied as Active-to-Sedentary Transition Probability for 2 operational definitions of physical activity: accelerations equivalent to at least light physical activity and for upright posture. Physical fatigability was assessed as perceived exertion fatigability, performance fatigability severity, and with the Physical Fatigue Subscale of the Situational Fatigue Scale. Mental fatigability was assessed with the Mental Fatigue Subscale of the Situational Fatigue Scale and as a decrease in perceived mental alertness after a 6-minute walk test.

RESULTS

Higher activity fragmentation was associated with higher self-reported physical fatigability, perceived exertion fatigability, and performance fatigability severity, independent of total activity minutes (β = 0.13-0.33, p < .05 for all). Higher activity fragmentation was not associated with mental fatigability in the fully adjusted models. The associations with fatigability indices were similar for both activity fragmentation indicators. Associations of activity fragmentation and performance fatigability severity were similar also among those with the highest intensity-based physical activity volume.

CONCLUSIONS

The findings provide support that studying fragmented activity patterns can be useful in identifying those at risk for high fatigability, even among those with relatively high physical activity level.

Associations of Actigraphic Sleep Parameters With Fatigability in Older Adults

BACKGROUND

Poor sleep may increase the likelihood of fatigue, and both are common in later life. However, prior studies of the sleep-fatigue relationship used subjective measures or were conducted in clinical populations; thus, the nature of this association in healthier community-dwelling older adults remains unclear. We studied the association of actigraphic sleep parameters with perceived fatigability-fatigue in response to a standardized task-and with conventional fatigue symptoms of low energy or tiredness.

METHODS

We studied 382 cognitively normal participants in the Baltimore Longitudinal Study of Aging (aged 73.1 ± 10.3 years, 53.1% women) who completed 6.7 ± 0.9 days of wrist actigraphy and a perceived fatigability assessment, including rating of perceived exertion (RPE) after a 5-minute treadmill walk or the Pittsburgh Fatigability Scale (PFS). Participants also reported non-standardized symptoms of fatigue.

RESULTS

After adjustment for age, sex, race, height, weight, comorbidity index, and depressive symptoms, shorter total sleep time (TST; <6.3 hours vs intermediate TST ≥6.3 to 7.2 hours) was associated with high RPE fatigability (odds ratio [OR] = 2.56, 95% confidence interval [CI] = 1.29, 5.06, p = .007), high PFS physical (OR = 1.88, 95% CI = 1.04, 3.38, p = .035), and high mental fatigability (OR = 2.15, 95% CI = 1.02, 4.50, p = .044), whereas longer TST was also associated with high mental fatigability (OR = 2.19, 95% CI = 1.02, 4.71, p = .043). Additionally, longer wake bout length was associated with high RPE fatigability (OR = 1.53, 95% CI = 1.14, 2.07, p = .005), and greater wake after sleep onset was associated with high mental fatigability (OR = 1.14, 95% CI = 1.01, 1.28, p = .036).

CONCLUSION

Among well-functioning older adults, abnormal sleep duration and sleep fragmentation are associated with greater perceived fatigability.

Longitudinal Association Between Energy Regulation and Fatigability in Mid-to-Late Life

BACKGROUND

Deficits in energy production and utilization have been linked to higher fatigue and functional decline with aging. Lesser known is whether individuals with a combination of low peak energy capacity and high energy costs for mobility (eg, impaired energy regulation) are more likely to experience the onset and progression of high fatigability with aging.

METHODS

Participants in the Baltimore Longitudinal Study of Aging (n = 651, 49.0% male, mean age 71.9, range 50-94) with ≥2 visits who completed fatigability (Borg rating of perceived exertion [RPE] after a 5-minute 1.5 mph treadmill walk), slow walking energy expenditure (VO2 mL/kg/min), and peak walking energy expenditure (VO2 mL/kg/min), testing between 2007 and 2018. The longitudinal association between each measure of energy expenditure, a ratio of energy cost-to-capacity, and perceived fatigability was modeled using mixed effects models adjusted for age, body composition, and comorbidities. Time to higher perceived fatigability (RPE ≥ 10) was modeled using Cox proportional hazards models.

RESULTS

In continuous analyses, higher slow walking energy expenditure (p < .05) and a higher cost ratio (p ≤ .001) were associated with greater perceived fatigability over time. Cox proportional hazards models using tertiles of the cost ratio suggest that, compared to those in the lowest tertile, those in the middle and highest tertiles had 1.89 (95% confidence interval [CI]: 1.57-5.16) and 2.85 (95% CI: 1.05-3.40) times greater risk of developing higher fatigability, respectively.

CONCLUSION

Findings suggest that strategies to prevent fatigability should consider methods to improve energy regulation by targeting both the independent and combined effects of declining peak capacity and rising energy costs for mobility with aging.

Effect of Thyroid Hormone Therapy on Fatigability in Older Adults With Subclinical Hypothyroidism: A Nested Study Within a Randomized Placebo-Controlled Trial

Background

Fatigue often triggers screening for and treatment of subclinical hypothyroidism. However, data on the impact of levothyroxine on fatigue is limited and previous studies might not have captured all aspects of fatigue.

Method

This study is nested within the randomized, placebo-controlled, multicenter TRUST trial, including community-dwelling participants aged ≥65 and older, with persistent subclinical hypothyroidism (TSH 4.60–19.99 mIU/L, normal free thyroxine levels) from Switzerland and Ireland. Interventions consisted of daily levothyroxine starting with 50 μg (25 μg if weight <50 kg or known coronary heart diseases) together with dose adjustments to achieve a normal TSH and mock titration in the placebo group. Main outcome was the change in physical and mental fatigability using the Pittsburgh Fatigability Scale over 1 year, assessed through multivariable linear regression with adjustment for country, sex, and levothyroxine starting dose.

Results

Among 230 participants, the mean ± standard deviation (SD) TSH was 6.2 ± 1.9 mIU/L at baseline and decreased to 3.1 ± 1.3 with LT4 (n = 119) versus 5.3 ± 2.3 with placebo (n = 111, p < .001) after 1 year. After adjustment we found no between-group difference at 1 year on perceived physical (0.2; 95% CI −1.8 to 2.1; p = .88), or mental fatigability (−1.0; 95% CI −2.8 to 0.8; p = .26). In participants with higher fatigability at baseline (≥15 points for the physical score [n = 88] or ≥13 points for the mental score [n = 41]), the adjusted between-group differences at 1 year were 0.4 (95% CI −3.6 to 2.8, p = .79) and −2.2 (95% CI −8.8 to 4.5, p = .51).

Conclusions

Levothyroxine in older adults with mild subclinical hypothyroidism provides no change in physical or mental fatigability.

Longitudinal Association Between Perceived Fatigability and Cognitive Function in Older Adults: Results from the Baltimore Longitudinal Study of Aging

BACKGROUND

Cognitive decline is consistently associated with diminished life satisfaction and inability to live independently. Identifying early, novel markers of cognitive decline is imperative for improving clinical detection and promoting long-term quality of life. Fatigability, one's perceived exertion after a standardized walking task, has been associated with declines in physical function; however, it remains unclear as to whether these effects may also extend to cognitive function.

METHODS

We examined whether perceived fatigability, assessed as the rating of perceived exertion (RPE) after a 5 min slow-paced treadmill walk (0.67 m/s, 0% grade), is longitudinally associated with cognitive performance in the domains of memory, executive functions, language, and attention among 934 cognitively intact individuals aged at least 50 years participating in the Baltimore Longitudinal Study of Aging (BLSA); Mage = 69.6 ± 10.1, 51.9% female participants. Continuous associations between RPE and each domain (individual test and composite scores) were assessed using linear mixed-effect models adjusted for demographics and comorbid conditions.

RESULTS

In fully adjusted models, higher fatigability at baseline was associated with declines in all cognitive domains over an average 2.2 years of follow-up (p < .04 for all). Longitudinally, increased fatigability over time was associated with worsened executive functions (β= -0.01, p = .002).

CONCLUSIONS

These findings suggest that perceived fatigability after a standardized walking task may aid in identification of individuals at a higher risk of future cognitive decline. Future research should examine underlying biological mechanisms contributing to this relationship as well as whether future interventions may target fatigability in midlife to attenuate age-related cognitive decline.

Depressive Symptoms, Fatigue and Social Relationships Influenced Physical Activity in Frail Older Community-Dwellers during the Spanish Lockdown due to the COVID-19 Pandemic

Due to the dramatic impact of the COVID-19 pandemic, Spain underwent a strict lockdown (March-May 2020). How the lockdown modified older adults' physical activity (PA) has been poorly described. This research assesses the effect of the lockdown on PA levels and identifies predictors of sufficient/insufficient PA in frail older community-dwellers. Community-dwelling participants from the +ÀGIL Barcelona frailty intervention program, suspended during the pandemic, underwent a phone-assessment during the lockdown. PA was measured before and after the lockdown using the Brief Physical Activity Assessment Tool (BPAAT). We included 98 frail older adults free of COVID-19 (mean age = 82.7 years, 66.3% women, mean Short Physical Performance Battery = 8.1 points). About one third of participants (32.2%) were not meeting sufficient PA levels at the end of the lockdown. Depressive symptoms (OR = 0.12, CI95% = 0.02-0.55) and fatigue (OR = 0.11, CI95% = 0.03-0.44) decreased the odds of maintaining sufficient PA, whereas maintaining social networks (OR = 5.07, CI95% = 1.60-16.08) and reading (OR = 6.29, CI95% = 1.66-23.90) increased it. Living alone was associated with the reduction of PA levels (b = -1.30, CI95% = -2.14--0.46). In our sample, pre-lockdown mental health, frailty-related symptoms and social relationships were consistently associated with both PA levels during-lockdown and pre-post change. These data suggest considering specific plans to maintain PA levels in frail older community-dwellers.

Carbon Dioxide Expiration and Performance Fatigability Following Aerobic Exercise Training: A Longitudinal, Observational, Pilot Study

Purpose

This study examined the influence of aerobic exercise training (AET) on components of carbon dioxide expiration (VCO2), cardiorespiratory function, and fatigability.

Methods

Twenty healthy adults completed peak cardiopulmonary exercise (CPX) and submaximal tests before and after a vigorous, 4-week AET regimen. Each test was followed by a 10-min recovery and endurance test at 70% of peak wattage attained during CPX. Fatigability was assessed using testing durations and power output. Respiratory buffering (excess VCO2) and non-buffering (metabolic VCO2) were calculated. Data were analyzed for significance (p<0.05) using regressions and paired t-tests.

Results

Significant improvements in all measures of fatigability were observed after AET. A significant increase in excess VCO2 was observed, though not in metabolic VCO2. Excess VCO2 was strongly predictive of fatigability measures.

Conclusion

Significant decreases in fatigability are often observed in clinical populations such as obstructive or restrictive lung disease or pulmonary hypertension following AET, even when peak cardiorespiratory function does not appear to adapt. Decreases in fatigability appear to predict longevity with no yet identified mechanism. These results suggest that respiratory buffering and metabolic components of VCO2 may adapt independently to AET, introducing foundational plausibility for an influence of respiratory buffering adaptation to AET on fatigability status.

Higher Fatigue Prospectively Increases the Risk of Falls in Older Men

Background and Objectives

Fatigue is a common complaint and shares many risk factors with falls, yet the independent contribution of fatigue on fall risk is unclear. This study’s primary aim was to assess the association between fatigue and prospective fall risk in 5642 men aged 64–100 enrolled in the Osteoporotic Fractures in Men Study (MrOS). The secondary aim was to examine the association between fatigue and recurrent fall risk.

Research Design and Methods

Fatigue was measured at baseline using the Medical Outcomes Study (short form) single-item question “During the past four weeks, how much of the time did you feel energetic?” Responses were then classified: higher fatigue = “none,” “a little,” or “some” of the time and lower fatigue = “a good bit,” “most,” or “all” of the time. We assessed falls using triannual questionnaires. Fall risk was examined prospectively over 3 years; recurrent falling was defined as at least 2 falls within the first year. Generalized estimating equations and multinomial logistic regression modeled prospective and recurrent fall risk as a function of baseline fatigue status, adjusted for demographics, medications, physical activity, and gait speed.

Results

Men with higher (26%) versus lower baseline fatigue were older (75.1 ± 6.2 vs 73.2 ± 5.7 years), 24% less active, and had worse physical function (gait speed = 1.09 ± 0.24 vs 1.24 ± 0.21 m/s), all p < .0001. Within 1 year, 25.4% (n = 1409) had fallen at least once, of which 47.4% (n = 668) were recurrent fallers. Men with higher versus lower fatigue had 25% increased fall risk (relative risk = 1.25, 95% CI: 1.14–1.36) over 3 years follow-up, but had 50% increased odds of recurrent falling (odds ratio = 1.50, 95% CI: 1.22–1.85) within the first year.

Discussion and Implications

Fatigue is an important risk factor of falling independent of established risk factors. Reductions in fatigue (ie, increased energy) may lessen the burden of falls in older men and provide a novel avenue for fall risk intervention.

The effect of red blood cell transfusion on fatigability after hospital discharge

In patients with anemia, there is interest in understanding the impact of red blood cell (RBC) transfusion on patient-reported outcomes such as fatigue. However, data from previous studies are mixed as to whether transfusion improves fatigue. One explanation for this is that prior studies have not examined whether changes in fatigue from transfusion may also affect patient activity levels. This is important because if transfusion reduces fatigue, patients may become more active, which could increase their fatigue. Thus, testing whether transfusion affects patients' fatigability, a measure of fatigue in the context of activity, may be more useful than testing the effect of transfusion on fatigue alone. The objective of this study was to test the effect of transfusion during hospitalization on patients' fatigability 7 days postdischarge. This prospective observational study included hospitalized general medicine patients with hemoglobin levels <10 g/dL. Patient-reported fatigability was collected during hospitalization and by telephone 7 days after discharge. Multivariable linear regression was used to test the association between receipt of a transfusion and fatigability 7 days postdischarge. Among the 350 patients participating, larger reductions in fatigability were observed with more transfused RBCs. Receipt of 1 U of RBCs was associated with a smaller reduction in fatigability, whereas receipt of 2 to 3 U of RBCs was associated with reductions in fatigability nearly 1 standard deviation from baseline and 3 times greater than patients receiving 1 U of RBCs. In hospitalized patients with anemia, receipt of a transfusion is associated with reductions in fatigability 7 days after hospital discharge.

Exercise intolerance and rapid skeletal muscle energetic decline in human age-associated frailty

BACKGROUND

Physical frailty in older individuals is characterized by subjective symptoms of fatigue and exercise intolerance (EI). Objective abnormalities in skeletal muscle (SM) mitochondrial high-energy phosphate (HEP) metabolism contribute to EI in inherited myopathies; however, their presence or link to EI in the frail older adult is unknown.

METHODS

Here, we studied 3 groups of ambulatory, community-dwelling adults with no history of significant coronary disease: frail older (FO) individuals (81 ± 2.7 years, mean ± SEM), nonfrail older (NFO) individuals (79 ± 2.0 years), and healthy middle-aged individuals, who served as controls (CONT, 51 ± 2.1 years). Lower extremity SM HEP levels and mitochondrial function were measured with ³¹P magnetic resonance (MR) techniques during graded multistage plantar flexion exercise (PFE). EI was quantified by a 6-minute walk (6MW) and peak oxygen consumption during cardiopulmonary testing (peak VO₂).

RESULTS

During graded exercise, FO, NFO, and CONT individuals all fatigued at similar SM HEP levels, as measured by ³¹P-MR. However, FO individuals fatigued fastest, with several-fold higher rates of PFE-induced HEP decline that correlated closely with shorter exercise duration in the MR scanner and with 6MW distance and lower peak oxygen consumption on cardiopulmonary testing (P < 0.001 for all). SM mitochondrial oxidative capacity was lower in older individuals and correlated with rapid HEP decline but less closely with EI.

CONCLUSION

Several-fold faster SM energetic decline during exercise occurs in FO individuals and correlates closely with multiple measures of EI. Rapid energetic decline represents an objective, functional measure of SM metabolic changes and a potential new target for mitigating frailty-associated physical limitations.

FUNDING

This work was supported by NIH R21 AG045634, R01 AG063661, R01 HL61912, the Johns Hopkins University Claude D. Pepper Older Americans Independence Center P30AG021334, and the Clarence Doodeman Endowment in Cardiology at Johns Hopkins.

Rapid exercise-induced skeletal muscle high-energy phosphate decline occurs in frail, older individuals and is closely linked to exercise intolerance and fatigue.

Fatigability as a Predictor of Subclinical and Clinical Anemia in Well-Functioning Older Adults

BACKGROUND/OBJECTIVES

Anemia is a common condition in older adults for which fatigue, the primary symptom, often goes unrecognized as individuals typically equilibrate their activity to avoid fatigue. Whether assessing fatigability (i.e., susceptibility to fatigue) facilitates identification of anemia is unknown. This study examines the association between fatigability and prevalent, incident, and persistent subclinical and clinical anemia in well-functioning older adults.

DESIGN, SETTING, PARTICIPANTS

Longitudinal analysis of 905 well-functioning men and women aged 60 to 89 years and followed for 1 to 5 years from the Baltimore Longitudinal Study of Aging conducted at the National Institute on Aging, Clinical Research Unit, Baltimore, MD.

MEASUREMENTS

Perceived fatigability was assessed as a rating of perceived exertion (RPE) from 6 to 20 following a 5-minute treadmill walk at 1.5 mph (.67 m/s); fatigue was assessed as reported unusual tiredness in the past month. Clinical anemia was defined using World Health Organization hemoglobin cutpoints of below 13 g/dL and below 12 g/dL for men and women, respectively, and subclinical anemia was defined as 13.0 to 13.9 g/dL and 12.0 to 12.9 g/dL, respectively.

RESULTS

Overall, 14% of participants had clinical and 30% had subclinical anemia at baseline. Each increment (1 RPE) of fatigability was associated after covariate adjustment with 14% (95% confidence interval [CI] = 5-25%, P = .005) and 8% (CI = 1-17%; P = .031), respectively, greater likelihood of prevalent clinical and subclinical anemia. An average of 2.2 years later, each 1 RPE increment in baseline fatigability predicted an 11% (CI = 2-20%; P = .016) higher likelihood of incident and/or persistent subclinical and clinical anemia. Reports of unusual tiredness were associated with prevalent subclinical anemia only.

CONCLUSION

This study provides evidence that perceived fatigability may help identify well-functioning older adults with borderline to clinical anemia who are on a trajectory of persistently suboptimal or worsening hemoglobin status. Assessing fatigability may facilitate earlier diagnosis of health conditions that underlie persistent suboptimal hemoglobin status. J Am Geriatr Soc 68:2297-2302, 2020.

Epidemiology of Perceived Physical Fatigability in Older Adults: The Long Life Family Study

BACKGROUND

Fatigability is a construct that measures whole-body tiredness anchored to activities of a fixed intensity and duration; little is known about its epidemiology and heritability.

METHODS

Two generations of family members enriched for exceptional longevity and their spouses were enrolled (2006-2009) in the Long Life Family Study (LLFS). At Visit 2 (2014-2017, N = 2,355) perceived physical fatigability was measured using the 10-item self-administered Pittsburgh Fatigability Scale (PFS), along with demographic, medical, behavioral, physical, and cognitive risk factors.

RESULTS

Residual genetic heritability of fatigability was 0.263 (p = 6.6 × 10-9) after adjustment for age, sex, and field center. PFS physical scores (mean ± SD) and higher physical fatigability prevalence (% PFS ≥ 15) were greater with each age strata: 60-69 (n = 1,009, 11.0 ± 7.6, 28%), 70-79 (n = 847, 12.5 ± 8.1, 37%), 80-89 (n = 253, 19.3 ± 9.9, 65.2%), and 90-108 (n = 266, 28.6 ± 9.8, 89.5%), p < .0001, adjusted for sex, field center, and family relatedness. Women had a higher prevalence of perceived physical fatigability compared to men, with the largest difference in the 80-89 age strata, 74.8% versus 53.5%, p < .0001. Those with greater body mass index, worse physical and cognitive function, and lower physical activity had significantly higher perceived physical fatigability.

CONCLUSIONS

Perceived physical fatigability is highly prevalent in older adults and strongly associated with age. The family design of LLFS allowed us to estimate the genetic heritability of perceived physical fatigability. Identifying risk factors associated with higher perceived physical fatigability can inform the development of targeted interventions for those most at risk, including older women, older adults with depression, and those who are less physically active.