Ryan J Dougherty

• PhD
• Assistant Professor at Rutgers, The State University of New Jersey

BACKGROUND Alzheimer's disease (AD) is characterized by the abnormal accumulation of amyloid‐beta (Aβ) and tau that can be quantified in vivo through cerebrospinal fluid (CSF) sampling. Physical activity has emerged as a possible modifier of AD risk; however, its impact on CSF biomarkers and cognitive function is not yet fully understood. We examin...

The purpose of this study was to investigate whether long-term television viewing patterns, a common sedentary behavior, in early to mid-adulthood is associated with gray matter brain volume in midlife and if this is independent of physical activity. We evaluated 599 participants (51% female, 44% black, mean age 30.3 ± 3.5 at baseline and 50.2 ± 3....

Introduction: Higher energetic costs for mobility predict gait speed decline. Slow gait is linked to cognitive decline and Alzheimer's disease (AD). Whether the energetic cost of walking is linked to AD pathology is unknown. We investigated the cross-sectional association between the energetic cost of walking, gait speed, and amyloid beta (Aβ) sta...

Introduction: Cardiorespiratory fitness (CRF) may mitigate Alzheimer's disease (AD) progression. This study examined the longitudinal associations of CRF with brain atrophy and cognitive decline in a late-middle-aged cohort of adults at risk for AD. Methods: One hundred ten cognitively unimpaired adults (66% female, mean age at baseline 64.2 ± 5...

Background: Higher energetic costs for mobility are associated with declining gait speed and slow gait is linked to cognitive decline and Alzheimer's disease. However, the physiological underpinnings of gait and brain health have not been well explored. We examined the associations of the energetic cost of walking with brain volume in cognitively...

Introduction Chronic widespread musculoskeletal pain (CMP) is a primary condition of Veterans who were deployed to the Persian Gulf War. The mechanisms that underlie CMP in these Veterans are unknown and few efficacious treatment options exist. This study tested the effects of 16 weeks of resistance exercise training (RET) on gray matter (GM) volum...

Introduction Physical activity is a modifiable risk factor for dementia. However, the potential reverse effect of adverse cognitive change on physical activity remains underexplored. Methods Cross-sectional analysis of a subset of National Health and Aging Trends Study (NHATS, N = 706) U.S. Medicare beneficiaries. Dementia status (dementia vs. no...

Background Impairments in sensory and motor function are common and have been independently linked with higher risk of dementia in older adults. Yet, there is limited information associated with the increasing number of such impairments and dementia risk. This study investigated longitudinal associations between sensory and motor impairment and dem...

Background Higher levels of physical activity, measured through accelerometry, have shown associations with several indices of brain and cognitive health in middle‐to‐late aged individuals. The association of physical activity and AD‐specific biomarkers measured through positron emission tomography (PET), however, remains unclear. Previous studies...

Motor function impairments reflect physical health status for older adults, which has profound implications for quality of life. However, there is a significant research gap concerning comprehensive, nationally representative data on the prevalence of these impairments, including diminished gait speed, chair stand ability, standing balance, and gri...

Early detection of persons at risk for, or living with, mild cognitive impairment (MCI) is a public health priority. Sensorimotor functioning—the integration of sensory information with motor function signaling to perform tasks and interact with the environment—may be a specific domain intertwined with movement planning and mental ability. However,...

Alzheimer’s disease (AD) is characterized by the abnormal accumulation of amyloid-β (plaques), and tau (neurofibrillary tangles) that can be quantified in vivo through cerebrospinal fluid (CSF) sampling. Physical activity has emerged as a possible modifier of AD risk; however, the influence of physical activity on CSF biomarkers and cognitive funct...

Introduction: Alterations in circadian rest/activity rhythms (RARs) are common among older adults. RARs can be derived from accelerometry data and are routinely used as proxy measures. Evidence suggests that altered (e.g., fragmented, delayed) RARs may be risk factors for dementia. However, results have been mixed. Using data from the ARIC Study, a...

This study examined the association between in vivo skeletal mitochondrial function and digital free-living physical activity patterns—a measure that summarizes biological, phenotypic, functional, and environmental effects on mobility. Among 459 participants (mean age 68 years; 55% women) in the Baltimore Longitudinal Study of Aging, mitochondrial...

Background Daily physical activity patterns differ by Alzheimer’s disease (AD) status and might signal cognitive risk. It is critical to understand whether patterns are disrupted early in the AD pathological process. Yet, whether established AD risk markers (β-amyloid [Aβ] or apolipoprotein E-ε4 [APOE-ε4]) are associated with differences in objecti...

Background: Time-restricted eating (TRE) lowers body weight in many studies. Whether TRE induces weight loss independent of reductions in calorie intake, as seen in rodent studies, is unknown. Objective: To determine the effect of TRE versus a usual eating pattern (UEP) on body weight in the setting of stable caloric intake. Design: Randomized...

INTRODUCTION Age‐related sensory and motor impairment are associated with risk of dementia. No study has examined the joint associations of multiple sensory and motor measures on prevalence of early cognitive impairment (ECI). METHODS Six hundred fifty participants in the Baltimore Longitudinal Study of Aging completed sensory and motor function t...

Background White matter hyperintensities (WMH) increase with advancing age and may contribute to the development of Alzheimer’s Disease. Energy utilization, as defined by walking efficiency, worsens with advancing age and is a prognostic marker of physical and cognitive function in older adults. While both WMH and energy utilization have been assoc...

Poor motor function is associated with brain volume and cognitive impairment. Less is known about the associations among motor domains and brain atrophy and whether associations are affected by cerebrovascular burden and/or physical activity. We analyzed data from 726 Baltimore Longitudinal Study of Aging participants (mean age 70.6±10.1 years, 56%...

Individuals living with dementia exhibit disrupted sleep/wake rhythms; however, whether daily physical activity volume and patterns are worse among those living with dementia is not well established. We examined the cross-sectional association between dementia classification and accelerometry-derived patterns of daily physical activity in NHATS. Wr...

Slower gait speed is linked to dementia risk, but the role muscle strength plays in this relationship is unclear. We examined whether muscle strength measured in the hands and legs is related to dementia risk beyond usual gait speed. We included 3,212 NHATS participants (mean age 75 years, 54% women) followed from 2011-2019 without dementia at base...

INTRODUCTION White matter hyperintensities (WMHs) increase with age and contribute to cognitive and motor function decline. Energy costs for mobility worsen with age, as the energetic cost of walking increases and energetic capacity declines. We examined the cross‐sectional associations of multiple measures of walking energetics with WMHs in mid‐ t...

Background Poor motor function is associated with brain atrophy and cognitive impairment. Less is known about the relationship between motor domains and brain atrophy and whether associations are affected by cerebrovascular burden and/or physical activity. Methods We analyzed data from 726 Baltimore Longitudinal Study of Aging participants (mean a...

Introduction: Beta-amyloid (Aβ) plaque deposition is a biomarker of preclinical Alzheimer's disease (AD). Impairments in sensory function are associated with cognitive decline. We sought to investigate the relationship between PET-indicated Aβ deposition and sensory impairment. Methods: Using data from 174 participants ≥55 years in the Baltimore...

Introduction: Time-restricted eating (TRE) is a dietary pattern that may promote weight loss by limiting caloric intake, but evidence for its effects on physical activity are limited. Objective: To determine the effect of a TRE pattern compared to a usual eating pattern (UEP) on physical activity. Methods: We examined physical activity data from 41...

Wrist-worn accelerometry metrics are not well defined in older adults. Accelerometry data from 720 participants (mean age 70 years, 55% women) were summarized into (a) total activity counts per day, (b) active minutes per day, (c) active bouts per day, and (d) activity fragmentation (the reciprocal of the mean active bout length). Linear regression...

Introduction An active lifestyle with regular exercise is thought to decrease or delay the onset of Alzheimer dementia through increasing blood flow to the brain. We examined the mean flow velocity (MFV) and pulsatility index (PI) in the middle cerebral arteries of individuals randomized into 2 groups—a usual physical activity (UPA) group and an en...

This study compared accelerometer-measured physical activity by body placement to daily total energy expenditure (TEE) and activity energy expenditure (AEE) measured using doubly labeled water (DLW). Forty-nine adult participants wore accelerometers placed on the nondominant wrist, dominant wrist, and chest while also undergoing DLW assessments. In...

Introduction: This study examined the relationship between cardiorespiratory fitness (CRF) and longitudinal cognitive functioning in a cohort enriched with risk factors for Alzheimer's disease (AD). Methods: A total of 155 enrollees in the Wisconsin Registry for Alzheimer's Prevention completed repeat comprehensive neuropsychological evaluations...

Purpose of Review This review assessed recent evidence on the association between objectively measured physical activity from wearable accelerometers and blood pressure (BP) in participants with metabolic syndrome (MetS). Recent Findings Results directly related to BP were mixed, with some studies showing positive associations and others showing n...

Chronic musculoskeletal pain (CMP) is a significant burden for Persian Gulf War Veterans (GWV), yet the causes are poorly understood. Brain structure abnormalities are observed in GWV, however relationships with modifiable lifestyle factors such as physical activity (PA) are unknown. We evaluated gray matter volumes and associations with symptoms,...

Background Gradual disengagement from daily physical activity (PA) could signal present or emerging mild cognitive impairment (MCI) or Alzheimer’s disease (AD). Objective This study examined whether accelerometry-derived patterns of everyday movement differ by cognitive diagnosis in participants of the Baltimore Longitudinal Study of Aging (BLSA)....

Background Cardiopulmonary exercise testing has demonstrated clinical utility in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). However, to what extent exercise responses are independent of, or confounded by, aerobic fitness remains unclear. Purpose To characterize and compare exercise responses in ME/CFS and controls with and withou...

Higher level of and greater longitudinal increase in perceived fatigability are linked to cognitive decline and lower brain volumes in older adults. However, it remains unclear whether perceived fatigability is associated with Alzheimer’s disease-related brain pathology. In the BLSA, 163 participants without neurological disease or cognitive impair...

Higher energetic costs for mobility are associated with slow and declining gait speed. Slow gait is linked to cognitive decline and Alzheimer’s disease (AD), but the physiological underpinnings are note well-understood. We investigated the cross-sectional association between the energetic cost of walking and amyloid status (+/-) in 174 cognitively...

Background Cardiorespiratory fitness (CRF) may be a mitigating factor for Alzheimer’s Disease (AD) progression. The purpose of this study was to examine the longitudinal associations of CRF with brain atrophy and cognitive function in a late‐middle‐aged cohort of adults at risk for AD. Method One hundred and ten adults (mean age = 64.2 ± 5.7 years...

Background Cerebral blood flow (CBF) alterations and brain microvascular deficits contribute to progression of Alzheimer’s disease (AD). The aim of this series of studies was to evaluate whether cardiorespiratory fitness (CRF) supports cerebrovascular health among individuals at risk for AD. Methods Four studies were conducted among participants f...

This study examined 5-year changes in cardiorespiratory fitness, physical activity, and sedentary time in mid-to-late aged adults. Fifty-seven participants completed baseline and follow-up treadmill exercise tests and physical activity monitoring. We observed a 14% decline in fitness (p < 0.001), 12% decrease in physical activity (p = 0.010), and n...

Introduction: Arterial stiffness progresses with age and is associated with cardiovascular disease (CVD) events and cognitive decline. Alzheimer’s disease (AD) risk factors like physical inactivity overlap significantly with progression of arterial stiffness. Aerobic exercise training reduces arterial stiffness and may bolster cognition at a time o...

Aims Chronic widespread musculoskeletal pain (CMP) is a primary complaint of Veterans suffering from Gulf War illness. This study evaluated the influence of resistance exercise training (RET) on symptoms, mood, perception of improvement, fitness, and total physical activity in Gulf War Veterans (GWV) with CMP. Main methods Fifty-four GWV with CMP...

Introduction: While it is generally accepted that a physically active lifestyle is important for overall health, sedentary behavior has become a public health focus due to evidence that it may impart unique risk for chronic diseases. The purpose of this study was to examine the association between 20-year television (TV) viewing patterns, as a prox...

Background Low levels of physical activity and aerobic fitness are established modifiable risk factors for Alzheimer’s disease and all‐cause mortality. Work from our group and others has demonstrated significant and positive cross‐sectional relationships between physical activity, aerobic fitness and indicators of brain health (e.g. biomarkers of A...

Objective Investigate whether socioeconomic status (SES) was related to brain volume in aging related regions, and if so, determine whether this relationship was mediated by lifestyle factors that are known to associate with risk of dementia in a population-based sample of community dwelling middle-aged adults. Methods We studied 645 (41% black) p...

Patterns of decreased resting cerebral blood flow (CBF) within the inferior temporal gyri, angular gyri, and posterior cingulate are a feature of aging and Alzheimer’s disease (AD) and have shown to be predictive of cognitive decline among older adults. Fitness and physical activity are both associated with many indices of brain health and may posi...

Introduction: Individuals with Alzheimer's disease (AD) broadly exhibit lower cardiorespiratory fitness (CRF) compared to cognitively healthy older adults. Other factors, such as increasing age and female sex, are also known to track with lower CRF levels. However, it is unclear how these factors together with AD diagnosis and genetic risk (apolip...

A growing body of evidence supports that aerobic exercise can decrease the risk of future cognitive impairment and Alzheimer’s disease (AD). There is a pressing need to rigorously determine whether cognitively normal yet at-risk individuals stand to benefit from the protective effects of exercise. The present study will test the feasibility of an a...

Aerobic exercise has been associated with reduced burden of brain and cognitive changes related to Alzheimer's disease (AD). However, it is unknown whether exercise training in asymptomatic individuals harboring risk for AD improves outcomes associated with AD. We investigated the effect of 26 weeks of supervised aerobic treadmill exercise training...

Post-exertional malaise (PEM) is a potentially debilitating aspect of Gulf War Illness (GWI) that has received limited research attention. The purpose of the present investigation was to determine symptom severity changes following exercise in Veterans with GWI compared to control Veterans without GWI (CO). Sixty-seven Veterans (n = 39 GWI; n = 28...

Anticipation of a painful experience can influence brain activity and increase sensitivity to experimental somatosensory stimuli in healthy adults, but this response is poorly understood among individuals with chronic musculoskeletal pain (CMP). Studies of brain and perceptual responses to somatosensory stimuli are used to make inferences about cen...

Background Previous studies indicate that cardiorespiratory fitness (CRF) and sleep are each favorably associated with Alzheimer’s disease (AD) pathophysiology, including reduced amyloid-β (Aβ) and tau pathology. However, few studies have examined CRF and sleep in the same analysis. Objective To examine the relationship between sleep and core AD c...

Background: Age is the cardinal risk factor for Alzheimer's disease (AD), and white matter hyperintensities (WMH), which are more prevalent with increasing age, may contribute to AD. Higher cardiorespiratory fitness (CRF) has been shown to be associated with cognitive health and decreased burden of AD-related brain alterations in older adults. Acc...

Introduction Alzheimer's disease (AD) is characterized by the presence of amyloid β (Aβ) plaques, neurofibrillary tangles, and neurodegeneration, evidence of which may be detected in vivo via cerebrospinal fluid (CSF) sampling. Physical activity (PA) has emerged as a possible modifier of these AD-related pathological changes. Consequently, the aim...

Cardiorespiratory fitness (CRF) is routinely investigated in older adults; however, the most appropriate CRF measure to use for this population has received inadequate attention. This study aimed to 1) evaluate the reliability and validity of the oxygen uptake efficiency slope (OUES) as a sub-maximal measurement of CRF; 2) examine demographic, risk...

Chronic musculoskeletal pain (CMP) affects ∼25% of the 700,000 Veterans deployed during the Persian Gulf War (1990-91). The cause of their pain is unknown and there are no efficacious treatments. A small body of literature suggests that brain abnormalities exist in Gulf War Veterans (GVs), yet relationships between brain abnormalities and disease s...

The objective of this study was to investigate the relationship between accelerometer-measured physical activity (PA) and glucose metabolism in asymptomatic late-middle-aged adults. Ninety-three cognitively healthy late-middle-aged adults from the Wisconsin Registry for Alzheimer’s Prevention participated in this cross-sectional study. They underwe...

Background: Consensus for an operational definition of post-exertion malaise (PEM) and which symptoms best characterize PEM has not been established and may be due to variability within and between studies. Purpose: Determine the magnitude of the effect of maximal and submaximal physical exertion on multiple myalgic encephalomyelitis/chronic fatigu...

Introduction Cardiorespiratory fitness (CRF) has been shown to be related to brain health in older adults. In individuals at risk for developing Alzheimer's disease (AD), CRF may be a modifiable risk factor that could attenuate anticipated declines in brain volume and episodic memory. The objective of this study was to determine the association bet...

Post exertion malaise is one of the most debilitating aspects of Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome, yet the neurobiological consequences are largely unexplored. The objective of the study was to determine the neural consequences of acute exercise using functional brain imaging. Fifteen female Myalgic Encephalomyelitis/Chronic Fati...

The objective of this study was to examine the association of chronotropic response (CR) and heart rate (HR) recovery— two indices of cardiovascular function within the context of a graded exercise test— with cognitive performance in a cognitively healthy, late-middle-aged cohort at risk for Alzheimer’s disease (AD). Ninety participants (age = 63.5...

Introduction: Physical activity (PA) is associated with brain health in older adults. However, it is unknown whether the current physical activity recommendations (PAR) impart substantive benefit. The objective of this study was to compare temporal lobe volumes between older adults who met PAR and those who did not. Methods: Ninety-one enrollees...