Exercise and the Aging Brain: Considerations for Sex Differences

Efficacy of exercise rehabilitation for managing patients with Alzheimer's disease

Alzheimer's disease (AD) is a progressive and degenerative neurological disease characterized by the deterioration of cognitive functions. While a definitive cure and optimal medication to impede disease progression are currently unavailable, a plethora of studies have highlighted the potential advantages of exercise rehabilitation for managing this condition. Those studies show that exercise rehabilitation can enhance cognitive function and improve the quality of life for individuals affected by AD. Therefore, exercise rehabilitation has been regarded as one of the most important strategies for managing patients with AD. Herein, we provide a comprehensive analysis of the currently available findings on exercise rehabilitation in patients with AD, with a focus on the exercise types which have shown efficacy when implemented alone or combined with other treatment methods, as well as the potential mechanisms underlying these positive effects. Specifically, we explain how exercise may improve the brain microenvironment and neuronal plasticity. In conclusion, exercise is a cost-effective intervention to enhance cognitive performance and improve quality of life in patients with mild to moderate cognitive dysfunction. Therefore, it can potentially become both a physical activity and a tailored intervention. This review may aid the development of more effective and individualized treatment strategies to address the challenges imposed by this debilitating disease, especially in low- and middle-income countries.

Sex as a Determinant of Age-Related Changes in the Brain

The notion of notable anatomical, biochemical, and behavioral distinctions within male and female brains has been a contentious topic of interest within the scientific community over several decades. Advancements in neuroimaging and molecular biological techniques have increasingly elucidated common mechanisms characterizing brain aging while also revealing disparities between sexes in these processes. Variations in cognitive functions; susceptibility to and progression of neurodegenerative conditions, notably Alzheimer's and Parkinson's diseases; and notable disparities in life expectancy between sexes, underscore the significance of evaluating aging within the framework of gender differences. This comprehensive review surveys contemporary literature on the restructuring of brain structures and fundamental processes unfolding in the aging brain at cellular and molecular levels, with a focus on gender distinctions. Additionally, the review delves into age-related cognitive alterations, exploring factors influencing the acceleration or deceleration of aging, with particular attention to estrogen's hormonal support of the central nervous system.

Does cardiorespiratory fitness mediate or moderate the association between mid-life physical activity frequency and cognitive function? findings from the 1958 British birth cohort study

BACKGROUND

Physical activity (PA) is associated with a lower risk of cognitive decline and all-cause dementia in later life. Pathways underpinning this association are unclear but may involve either mediation and/or moderation by cardiorespiratory fitness (CRF).

METHODS

Data on PA frequency (exposure) at 42y, non-exercise testing CRF (NETCRF, mediator/moderator) at 45y and overall cognitive function (outcome) at 50y were obtained from 9,385 participants (50.8% female) in the 1958 British birth cohort study. We used a four-way decomposition approach to examine the relative contributions of mediation and moderation by NETCRF on the association between PA frequency at 42y and overall cognitive function at 50y.

RESULTS

In males, the estimated overall effect of 42y PA ≥once per week (vs.

CONCLUSION

We present the first evidence from a four-way decomposition analysis of the potential contribution that CRF plays in the relationship between mid-life PA frequency and subsequent cognitive function. Our lack of evidence in support of CRF mediating or moderating the PA frequency-cognitive function association suggests that other pathways underpin this association.

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MESH Headings

• Humans
• Cardiorespiratory Fitness/physiology
• Male
• Female
• Cognition/physiology
• Exercise/physiology
• United Kingdom/epidemiology
• Adult
• Middle Aged
• Birth Cohort
• Cohort Studies

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Grants

• Medical Research Council
• British Heart Foundation

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Affiliation(s)

Tom Norris Faculty of Medical Sciences, Institute of Sport, Division of Surgery and Interventional Science, Exercise and Health, UCL, London, United Kingdom
John J. Mitchell Faculty of Medical Sciences, Institute of Sport, Division of Surgery and Interventional Science, Exercise and Health, UCL, London, United Kingdom
Joanna M. Blodgett Faculty of Medical Sciences, Institute of Sport, Division of Surgery and Interventional Science, Exercise and Health, UCL, London, United Kingdom
Mark Hamer Faculty of Medical Sciences, Institute of Sport, Division of Surgery and Interventional Science, Exercise and Health, UCL, London, United Kingdom
Snehal M. Pinto Pereira Faculty of Medical Sciences, Institute of Sport, Division of Surgery and Interventional Science, Exercise and Health, UCL, London, United Kingdom

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Prevention of Vascular Contributions to Cognitive Impairment and Dementia: The Role of Physical Activity and Exercise

Vascular contributions to cognitive impairment and dementia, specifically cerebral small vessel disease (CSVD), are the second most common cause of dementia. Currently, there are no specific pharmacological treatments for CSVD, and the use of conventional antidementia drugs is not recommended. Exercise has the potential to prevent and mitigate CSVD-related brain damage and improve cognitive function. Mechanistic pathways underlying the neurocognitive benefits of exercise include the control of vascular risk factors, improving endothelial function, and upregulating exerkines. Notably, the therapeutic efficacy of exercise may vary by exercise type (ie, aerobic versus resistance training) and biological sex; thus, studies designed specifically to examine these moderating factors within a CSVD context are needed. Furthermore, future research should prioritize resistance training interventions, given their tremendous therapeutic potential. Addressing these knowledge gaps will help us refine exercise recommendations to maximize their therapeutic impact in the prevention and mitigation of CSVD.

Physical Activity Attenuates Brain Irradiation-Associated Skeletal Muscle Damage in the Rat

PURPOSE

Radiation therapy for brain tumors increases patient survival. Nonetheless, side effects are increasingly reported such as cognitive deficits and fatigue. The etiology of fatigue remains poorly described. Our hypothesis is that the abscopal effects of radiation therapy on skeletal muscle may be involved in fatigue. The present study aims to assess the effect of brain irradiation on skeletal muscles and its relationship with fatigue and to analyze whether physical activity could counteract brain radiation-induced side effects.

METHODS AND MATERIALS

Adult Wistar rats were randomly distributed between 4 groups: control (CTL), irradiated (IR), nonirradiated with physical activity (PA), and irradiated with physical activity (IR+PA). IR rats were exposed to a whole-brain irradiation (WBI) of 30 Gy (3 × 10 Gy). Rats subjected to PA underwent sessions of running on a treadmill, 3 times/week for 6 months. The effects of WBI on muscles were evaluated by complementary approaches: behavioral tests (fatigue, locomotion activity), magnetic resonance imaging, and histologic analyses.

RESULTS

IR rats displayed a significant fatigue and a reduced locomotor activity at short term compared with the CTL group, which were attenuated with PA at 6 months after WBI. The IR rat's gastrocnemius mass decreased compared with CTL rats, which was reversed by physical activity at 14 days after WBI. Multiparametric magnetic resonance imaging of the skeletal muscle highlighted an alteration of the fiber organization in IR rats as demonstrated by a significant decrease of the mean diffusivity in the gastrocnemius at short term. Alteration of fibers was confirmed by histologic analyses: the number of type I fibers was decreased, whereas that of type IIa fibers was increased in IR animals but not in the IR+PA group.

CONCLUSIONS

The data show that WBI induces skeletal muscle damage, which is attenuated by PA. This muscle damage may explain, at least in part, the fatigue of patients treated with radiation therapy.

Investigating female versus male differences in white matter neuroplasticity associated with complex visuo-motor learning

Magnetic resonance imaging (MRI) has increasingly been used to characterize structure-function relationships during white matter neuroplasticity. Biological sex differences may be an important factor that affects patterns of neuroplasticity, and therefore impacts learning and rehabilitation. The current study examined a participant cohort before and after visuo-motor training to characterize sex differences in microstructural measures. The participants (N = 27) completed a 10-session (4 week) complex visuo-motor training task with their non-dominant hand. All participants significantly improved movement speed and their movement speed variability over the training period. White matter neuroplasticity in females and males was examined using fractional anisotropy (FA) and myelin water fraction (MWF) along the cortico-spinal tract (CST) and the corpus callosum (CC). FA values showed significant differences in the middle portion of the CST tract (nodes 38-51) across the training period. MWF showed a similar cluster in the inferior portion of the tract (nodes 18-29) but did not reach significance. Additionally, at baseline, males showed significantly higher levels of MWF measures in the middle body of the CC. Combining data from females and males would have resulted in reduced sensitivity, making it harder to detect differences in neuroplasticity. These findings offer initial insights into possible female versus male differences in white matter neuroplasticity during motor learning. This warrants investigations into specific patterns of white matter neuroplasticity for females versus males across the lifespan. Understanding biological sex-specific differences in white matter neuroplasticity may have significant implications for the interpretation of change associated with learning or rehabilitation.

Changes in cardiovascular health and white matter integrity with aerobic exercise, cognitive and combined training in physically inactive healthy late-middle-aged adults: the "Projecte Moviment" randomized controlled trial

INTRODUCTION

This is a 12-weeks randomized controlled trial examining the effects of aerobic exercise (AE), computerized cognitive training (CCT) and their combination (COMB). We aim to investigate their impact on cardiovascular health and white matter (WM) integrity and how they contribute to the cognitive benefits.

METHODS

109 participants were recruited and 82 (62% female; age = 58.38 ± 5.47) finished the intervention with > 80% adherence. We report changes in cardiovascular risk factors and WM integrity (fractional anisotropy (FA); mean diffusivity (MD)), how they might be related to changes in physical activity, age and sex, and their potential role as mediators in cognitive improvements.

RESULTS

A decrease in BMI (SMD = - 0.32, p = 0.039), waist circumference (SMD = - 0.42, p = 0.003) and diastolic blood pressure (DBP) (SMD = - 0.42, p = 0.006) in the AE group and a decrease in BMI (SMD = - 0.34, p = 0.031) and DBP (SMD = - 0.32, p = 0.034) in the COMB group compared to the waitlist control group was observed. We also found decreased global MD in the CCT group (SMD = - 0.34; p = 0.032) and significant intervention-related changes in FA and MD in the frontal and temporal lobes in the COMB group.

CONCLUSIONS

We found changes in anthropometric measures that suggest initial benefits on cardiovascular health after only 12 weeks of AE and changes in WM microstructure in the CCT and COMB groups. These results add evidence of the clinical relevance of lifestyle interventions and the potential benefits when combining them.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT031123900.

A case for seeking sex-specific treatments in Alzheimer's disease

There is no satisfactory explanation for the sex-related differences in the incidence of many diseases and this is also true of Alzheimer's disease (AD), where females have a higher lifetime risk of developing the disease and make up about two thirds of the AD patient population. The importance of understanding the cause(s) that account for this disproportionate distribution cannot be overestimated, and is likely to be a significant factor in the search for therapeutic strategies that will combat the disease and, furthermore, potentially point to a sex-targeted approach to treatment. This review considers the literature in the context of what is known about the impact of sex on processes targeted by drugs that are in clinical trial for AD, and existing knowledge on differing responses of males and females to these drugs. Current knowledge strongly supports the view that trials should make assessing sex-related difference in responses a priority with a focus on exploring the sex-stratified treatments.

Intrinsic functional brain connectivity changes following aerobic exercise, computerized cognitive training, and their combination in physically inactive healthy late-middle-aged adults: the Projecte Moviment

Lifestyle interventions have positive neuroprotective effects in aging. However, there are still open questions about how changes in resting-state functional connectivity (rsFC) contribute to cognitive improvements. The Projecte Moviment is a 12-week randomized controlled trial of a multimodal data acquisition protocol that investigated the effects of aerobic exercise (AE), computerized cognitive training (CCT), and their combination (COMB). An initial list of 109 participants was recruited from which a total of 82 participants (62% female; age = 58.38 ± 5.47) finished the intervention with a level of adherence > 80%. Only in the COMB group, we revealed an extended network of 33 connections that involved an increased and decreased rsFC within and between the aDMN/pDMN and a reduced rsFC between the bilateral supplementary motor areas and the right thalamus. No global and especially local rsFC changes due to any intervention mediated the cognitive benefits detected in the AE and COMB groups. Projecte Moviment provides evidence of the clinical relevance of lifestyle interventions and the potential benefits when combining them.

Basal forebrain functional connectivity as a mediator of associations between cardiorespiratory fitness and cognition in healthy older women

Age-related cholinergic dysfunction within the basal forebrain (BF) is one of the key hallmarks for age-related cognitive decline. Given that higher cardiorespiratory fitness (CRF) induces neuroprotective effects that may differ by sex, we investigated the moderating effects of sex on the associations between CRF, BF cholinergic function, and cognitive function in older adults. 176 older adults (68.5 years) were included from the Nathan Kline Institute Rockland Sample. Functional connectivity (rsFC) of the BF subregions including the medial septal nucleus/diagonal band of Broca (MS/DB) and nucleus basalis of Meynert (NBM) were computed from resting-sate functional MRI. Modified Astrand-Ryhming submaximal cycle ergometer protocol was used to estimate CRF. Trail making task and inhibition performance during the color word interference test from the Delis-Kaplan Executive Function System and Rey Auditory Verbal Learning Test were used to examine cognitive function. Linear regression models were used to assess the associations between CRF, BF rsFC, and cognitive performance after controlling for age, sex, and years of education. Subsequently, we measured the associations between the variables in men and women separately to investigate the sex differences. There was an association between higher CRF and greater rsFC between the NBM and right middle frontal gyrus in older men and women. There were significant associations between CRF, NBM rsFC, and trail making task number-letter switching performance only in women. In women, greater NBM rsFC mediated the association between higher CRF and better trail making task number-letter switching performance. These findings provide evidence that greater NBM rsFC, particularly in older women, may be an underlying neural mechanism for the relationship between higher CRF and better executive function.

Examining sex differences in the association between sedentary behavior and cognitive function in bariatric surgery patients

BACKGROUND

Obesity is associated with cognitive impairment. A potential contributor to these deficits is sedentary behavior (SB), which is linked to poorer cognitive functioning in other populations. Little is known about the association between SB and cognitive function in bariatric surgery populations.

OBJECTIVES

This cross-sectional study examined the association between SB and cognitive function in preoperative bariatric surgery patients, as well as possible sex differences in this relationship.

SETTING

Data were collected at 2 health centers in the United States.

METHODS

A total of 121 participants (43.2 ± 10.3 yr of age) scheduled for Roux-en-Y gastric bypass or sleeve gastrectomy completed the National Institute of Health (NIH) Toolbox for the Assessment of Neurological and Behavioral Function Cognition Domain, a computerized neuropsychological assessment battery. Participants wore a waist-mounted accelerometer for 7 consecutive days to measure SB and light-intensity physical activity (LPA).

RESULTS

Pearson and partial correlations found no significant relationships between cognitive function and SB or LPA in the full sample. However, partial correlations controlling for LPA found that greater SB was associated with poorer performance on List Sorting Working Memory Test in women (r = -.28; P = .006), whereas there was a positive relationship between SB and Dimensional Change Card Sort for men (r = .51; P = .015; 95% CI [.25, .73]).

CONCLUSIONS

These results showed that greater SB, independent of LPA, is associated with poorer working memory in women and better set shifting ability in men. Future studies should examine the possibility of domain-specific cognitive effects associated with SB in bariatric surgery samples and clarify possible sex differences.

Neurophysiology, Neuropsychology, Epilepsy, 2022: Hills We Have Climbed and the Hills Ahead. Cognition and Sensory Systems in Healthy and Diseased Subjects

This article summarizes selected presentations from a session titled "Cognition and Sensory Systems in Healthy and Diseased Subjects", held to highlight and honor the work of Dr. Marilyn Jones-Gotman. The session was part of a two-day symposium, "Neurophysiology, Neuropsychology, Epilepsy, 2022: Hills We Have Climbed and the Hills Ahead". The session presented research on epilepsy and sensory systems by colleagues and former trainees of Dr. Jones-Gotman. The extended summaries provide an overview of historical and current work in the neuropsychology of epilepsy, neuropsychological and neuroimaging approaches to understanding brain organization, sex differences in brain mechanisms underlying neurological disorders, dietary influences on brain function and cognition, and expertise in olfactory training and language experiences and their implications for brain organization and structure.

Walking for Cognitive Health: Previous Parity Moderates the Relationship Between Self-Reported Walking and Cognition

BACKGROUND

Older females show greater cognitive gains from physical activity (PA) than males, which may be related to long-term consequences of female-specific reproductive events (eg, pregnancy) on cognitive health.

METHODS

To determine whether previous parity could moderate the relationship between PA and cognitive decline in older women, we conducted secondary analyses of data from the Health, Aging, and Body Composition Study. We tested whether the association between average PA over 10 years and cognition (Modified Mini-Mental State Examination [3MS]) and executive functioning (digit symbol substitution test [DSST]) over 10 years varied by previous parity (nulliparity, low parity, medium parity, and grand multiparity). An analysis of covariance was performed with cognition (average and change over 10 years) as the dependent variables, parity as a categorical predictor, average PA as a continuous predictor, and a set of relevant covariates.

RESULTS

Significant interactions were found between PA and parity group for all 4 comparisons: average 3MS (p = .014), average DSST (p = .032), change in 3MS (p = .016), and change in DSST (p = .017). Simple slope analyses indicated the positive relationship between PA and average 3MS and DSST was only significant in the nulliparity and grand multiparity groups, and the positive relationship between PA and change in 3MS and DSST was only significant in the grand multiparity group.

CONCLUSION

The findings suggest the relationship between self-reported walking and cognitive performance was strongest in the groups at risk for cognitive decline and dementia, the nulliparous and grand multiparous groups.

Grip strength, gait speed, and trajectories of cognitive function in community-dwelling older adults: A prospective study

Introduction

This study investigated whether grip strength and gait speed predict cognitive aging trajectories and examined potential sex-specific associations.

Methods

Community-dwelling older adults (n = 19,114) were followed for up to 7 years, with regular assessment of global function, episodic memory, psychomotor speed, and executive function. Group-based multi-trajectory modeling identified joint cognitive trajectories. Multinomial logistic regression examined the association of grip strength and gait speed at baseline with cognitive trajectories.

Results

High performers (14.3%, n = 2298) and low performers (4.0%, n = 642) were compared to the average performers (21.8%, n = 3492). Grip strength and gait speed were positively associated with high performance and negatively with low performance (P-values < 0.01). The association between grip strength and high performance was stronger in women (interaction P < 0.001), while gait speed was a stronger predictor of low performance in men (interaction P < 0.05).

Discussion

Grip strength and gait speed are associated with cognitive trajectories in older age, but with sex differences.

Highlights

There is inter-individual variability in late-life cognitive trajectories.Grip strength and gait speed predicted cognitive trajectories in older age.However, sex-specific associations were identified.In women, grip strength strongly predicted high, compared to average, trajectory.In men, gait speed was a stronger predictor of low cognitive performance trajectory.

Estimation of blood-based biomarkers of glial activation related to neuroinflammation

Background

Neuroinflammation is a well-known feature of Alzheimer’s disease (AD), and a blood-based test for estimating the levels of neuroinflammation would be expected. In this study, we examined and validated a model using blood-based biomarkers to predict the level of glial activation due to neuroinflammation, as estimated by ¹¹C-DPA-713 positron emission tomography (PET) imaging.

Methods

We included 15 patients with AD and 10 cognitively normal (CN) subjects. Stepwise backward deletion multiple regression analysis was used to determine the predictors of the TSPO-binding potential (BP_ND) estimated by PET imaging. The independent variables were age, sex, diagnosis, apolipoprotein E4 positivity, body mass index and the serum concentration of blood-based biomarkers, including monocyte chemotactic protein 1 (MCP-1), fractalkine, chitinase 3-like protein-1 (CHI3L1), soluble triggering receptor expressed on myeloid cells 2 (sTREM2), and clusterin.

Results

Sex, diagnosis, and serum concentrations of MCP1 and sTREM2 were determined as predictors of TSPO-BP_ND in the Braak1-3 area. The serum concentrations of MCP1 and sTREM2 correlated positively with TSPO-BP_ND. In a leave one out (LOO) cross-validation (CV) analysis, the model gave a LOO CV R² of 0.424, which indicated that this model can account for approximately 42.4% of the variance of brain TSPO-BP_ND.

Conclusions

We found that the model including serum MCP-1 and sTREM2 concentration and covariates of sex and diagnosis was the best for predicting brain TSPO-BP_ND. The detection of neuroinflammation in AD patients by blood-based biomarkers should be a sensitive and useful tool for making an early diagnosis and monitoring disease progression and treatment effectiveness.

The Influence of the BDNF Val66Met Variant on the Association Between Physical Activity/Grip Strength and Depressive Symptoms in Persons With Diabetes

The rs6265 in the brain-derived neurotrophic factor (BDNF) is associated with depression in people with diabetes. Both physical activity (PA) and grip strength are negatively associated with depression. We conducted cross-sectional analyses of the wave 10 survey data for a nationally representative sample of 1,051 diabetes participants of the Health and Retirement Study. Both greater PA (β = -.15) and stronger grip strength (β = -.02) were independently associated with depression. Although the interaction between BDNF rs6265 and PA on depressive symptoms was not significant, the negative PA-depression association was stronger among female non-Met carriers (β = -.19) and male Met carriers (β = -.14). Meanwhile, grip strength was associated with depression only in Met carriers (β = -.04), and similar association was observed in both males and females. In conclusion, female non-Met carriers and male Met carriers may benefit from PA.

Peer-supported exercise intervention for persons with mild cognitive impairment: a waitlist randomised controlled trial (the BRAin Vitality Enhancement trial)

BACKGROUND

motivating older people with cognitive impairment to remain physically active is challenging.

OBJECTIVE

this study aimed to examine the effects of a peer-supported exercise intervention on the cognitive function and health-related quality of life (HRQoL) of persons with mild cognitive impairment (MCI).

DESIGN

a two-arm randomised controlled trial.

SETTING AND PARTICIPANTS

community-dwelling persons with MCI were recruited from community centres for older adults in Hong Kong.

METHODS

participants randomised to the intervention group received an 8-week group-based peer-supported multicomponent exercise intervention, while the waitlist control group received usual care. A battery of neuropsychological tests and the Short Form-36 were administered at baseline, immediately post-intervention and 3 months post-intervention.

RESULTS

two hundred and twenty-nine participants were randomised to the intervention (n = 116) or control (n = 113) group. Compared with the control group, participants in the intervention group showed significantly greater improvements in processing speed and attention measured by the Colour Trails Test 1 (β = 7.213, 95% confidence interval [CI] = 2.870-11.557, P = 0.001) and working memory measured by the Digit Span Backward Test (β = 0.540, 95% CI = 0.199-0.881, P = 0.002) immediately post-intervention. The effects were sustained at 3 months post-intervention. Similarly, significantly greater improvements in sequencing and mental flexibility measured by the Colour Trails Test 2 were observed in the intervention group 3 months post-intervention (β = 6.979, 95% CI = 3.375-10.584, P < 0.001). Changes in global cognition, short-term memory and HRQoL were not significant.

CONCLUSION

the peer-supported exercise intervention was effective at sustaining improvements in executive function, attention and working memory in persons with MCI.

Effect of isometric handgrip exercise on cognitive function: Current evidence, methodology, and safety considerations

Cognitive function is essential for most behaviors of daily living and is a critical component in assessing the quality of life. Mounting prospective evidence supports the use of isometric handgrip exercise (IHE) as a small muscle mass practice to promote health-related outcomes in clinical and healthy populations. The aim of the present review was to systematically investigate whether IHE is effective in improving the cognitive function of adults (aged ≥18 years). Studies were identified by searching five databases (CINAHL, MEDLINE, SPORTDiscus, PsychINFO, and Web of Science). Eight out of 767 studies met the inclusion criteria, including three types of studies: 1) acute effect for IHE with various intensity protocols (n = 4); 2) acute effect for IHE with one set exhaustion protocol (n = 2); and 3) chronic effect of IHE on cognitive function (n = 2). To assess the methodological quality of studies, the PEDro scale was used (mean score = 6.75). The evidence on whether IHE exerts acute positive effects on cognitive performance is currently rather inconclusive. However, a trend was discernible that implementing IHE can generate a beneficial chronic effect on cognitive function, although the results should be interpreted with caution. The clinical relevance of IHE as a time-efficient type of physical exercise to improve cognitive function warrants further investigation. Methodology and safety considerations were discussed.

Systematic Review Registration: (https://osf.io/gbzp9).

Effects of Sex, APOE4, and Lifestyle Activities on Cognitive Reserve in Older Adults

BACKGROUND AND OBJECTIVES

Lifestyle activities, such as physical activity and cognitive stimulation, may mitigate age-associated cognitive decline, delay dementia onset, and increase cognitive reserve. Whether the association between lifestyle activities and cognitive reserve differs by sex and APOE4 status is an understudied yet critical component for informing targeted prevention strategies. The current study examined interactions between sex and physical or cognitive activities on cognitive reserve for speed and memory in older adults.

METHODS

Research participants with unimpaired cognition, mild cognitive impairment, or dementia from the Washington Heights-Inwood Columbia Aging Cohort were included in this study. Cognitive reserve scores for speed and memory were calculated by regressing out hippocampal volume, total gray matter volume, and white matter hyperintensity volume from composite cognitive scores for speed and memory, respectively. Self-reported physical activity was assessed using the Godin Leisure Time Exercise Questionnaire, converted to metabolic equivalents (METS). Self-reported cognitive activity (COGACT) was calculated as the sum of 3 yes/no questions. Sex by activity interactions and sex-stratified analyses were conducted using multivariable linear regression models, including a secondary analysis with APOE4 as a moderating factor.

RESULTS

Seven hundred fifty-eight participants (mean age = 76.11 ± 6.31 years, 62% women) were included in this study. Higher METS was associated with greater speed reserve in women (β = 0.04, CI 0.0-08) but not in men (β = 0.004, CI -0.04 to 0.05). METS was not associated with memory reserve in women or men. More COGACT was associated with greater speed reserve in the cohort (β = 0.13, CI 0.05-0.21). More COGACT had a trend for greater memory reserve in women (β = 0.06, CI -0.02 to 0.14) but not in men (β = -0.04, CI -0.16 to 0.08). Only among women, APOE4 carrier status attenuated relationships between METS and speed reserve (β = -0.09, CI -0.22 to 0.04) and between COGACT and both speed (β = -0.26, CI -0.63 to 0.11) and memory reserves (β = -0.20, CI -0.50.0 to 093).

DISCUSSION

The associations of self-reported physical and cognitive activities with cognitive reserve are more pronounced in women, although APOE4 attenuates these associations. Future studies are needed to understand the causal relationship among sex, lifestyle activities, and genetic factors on cognitive reserve in older adults to best understand which lifestyle activities may be most beneficial and for whom.

Exercise Effects on Cognition in Older African Americans: A Pilot Randomized Trial

Introduction

Regular physical activity lowers risk for cognitive decline and neurodegenerative disorders. Older African Americans (AAs) have been underrepresented in trials that increased physical activity to improve cognitive outcomes.

Methods

56 sedentary, older, cognitively healthy AAs (avg. 69.2 ± 3.4 yrs. old) were randomized in 1:1 ratio into either a 12-week successful aging group (SAG) or a 12-week physical activity group (PAG). Participants in SAG attended weekly 60-min educational sessions in which healthy aging topics were discussed. Participants in PAG attended supervised physical activity sessions twice per week at local YMCAs (90–120 min/week) and were prescribed 2–3 days per week of home-based activity. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) assessed cognitive function. ANCOVA models compared mean 12-week change in global cognition and subdomain scores between groups with secondary analyses for sex differences. Effect sizes for RBANS were calculated.

Results

The RBANS global cognition score (SAG Est. 5.6 ± 1.8, effect size = 0.37, p = 0.003) and several subdomain scores (one-sample T tests, all p < 0.05) increased significantly within the SAG. Scores for global cognition increased more in SAG than in PAG (Change Estimate, PAG minus SAG: –4.6 ± 2.5 points, effect size = 0.31) at a trend level (p = 0.072). SAG females increased their global cognition score more than PAG females and more than males in either PAG or SAG (all p < 0.035).

Discussion

A 12-week physical activity intervention (PAG) did not improve cognitive functioning among older AAs but a comparator healthy aging education program did. Inadequate physical activity dosage or duration, SAG members acting on health-related information from educational sessions, and/or social stimulation within the SAG may have contributed to these results. Future studies should combine socially engaging activities with vigorous physical activity for cognitive enhancement among cognitively healthy older African Americans.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT03474302.

Precision Exercise Medicine: Sex Specific Differences in Immune and CNS Responses to Physical Activity

Physical activity is a powerful lifestyle factor capable of improving cognitive function, modifying the risk for dementia associated with neurodegeneration and possibly slowing neurodegenerative disease progression in both men and women. However, men and women show differences in the biological responses to physical activity and in the vulnerabilities to the onset, progression and outcome of neurodegenerative diseases, prompting the question of whether sex-specific regulatory mechanisms might differentially modulate the benefits of exercise on the brain. Mechanistic studies aimed to better understand how physical activity improves brain health and function suggest that the brain responds to physical exercise by overall reducing neuroinflammation and increasing neuroplasticity. Here, we review the emerging literature considering sex-specific differences in the immune system response to exercise as a potential mechanism by which physical activity affects the brain. Although the literature addressing sex differences in this light is limited, the initial findings suggest a potential influence of biological sex in the brain benefits of exercise, and lay out a scientific foundation to support very much needed studies investigating the potential effects of sex-differences on exercise neurobiology. Considering biological sex and sex-differences in the neurobiological hallmarks of exercise will help to enhance our understanding of the mechanisms by which physical activity benefits the brain and also improve the development of treatments and interventions for diseases of the central nervous system.

Molecular and Brain Volume Changes Following Aerobic Exercise, Cognitive and Combined Training in Physically Inactive Healthy Late-Middle-Aged Adults: The Projecte Moviment Randomized Controlled Trial

Behavioral interventions have shown promising neuroprotective effects, but the cascade of molecular, brain and behavioral changes involved in these benefits remains poorly understood. Projecte Moviment is a 12-week (5 days per week—45 min per day) multi-domain, single-blind, proof-of-concept randomized controlled trial examining the cognitive effect and underlying mechanisms of an aerobic exercise (AE), computerized cognitive training (CCT) and a combined (COMB) groups compared to a waitlist control group. Adherence was > 80% for 82/109 participants recruited (62% female; age = 58.38 ± 5.47). In this study we report intervention-related changes in plasma biomarkers (BDNF, TNF-α, HGF, ICAM-1, SDF1-α) and structural-MRI (brain volume) and how they related to changes in physical activity and individual variables (age and sex) and their potential role as mediators in the cognitive changes. Our results show that although there were no significant changes in molecular biomarker concentrations in any intervention group, changes in ICAM-1 and SDF1-α were negatively associated with changes in physical activity outcomes in AE and COMB groups. Brain volume changes were found in the CCT showing a significant increase in precuneus volume. Sex moderated the brain volume change in the AE and COMB groups, suggesting that men may benefit more than women. Changes in molecular biomarkers and brain volumes did not significantly mediate the cognitive-related benefits found previously for any group. This study shows crucial initial molecular and brain volume changes related to lifestyle interventions at early stages and highlights the value of examining activity parameters, individual difference characteristics and using a multi-level analysis approach to address these questions.

COVID-19 Quarantine Impact on Wellbeing and Cognitive Functioning During a 10-Week High-Intensity Functional Training Program in Young University Students

Physical exercise can improve cognitive functioning and wellbeing; however, the degree of change in either of these two variables seems to be related to the exercise intensity or type. Therefore, new physical training (PT) programs have been developed to increase exercise efficiency. One such example is high-intensity functional training (HIFT), which has proven to be a time-efficient and highly effective strategy to improve physical fitness. This study analyzed whether HIFT can affect reaction time (RT) and vitality, as well as positive and negative affect. Forty-two college students participated in the study, 21 in the experimental group and 21 in the control group. The experimental group completed 10 weeks of training, five of which were supervised, and the remainder consisted of online training during the COVID-19 quarantine. Participants were evaluated at the beginning, at the end of the 5 weeks of supervised training, and after the 5 weeks of online training. HIFT improved RT without changes in psychological wellbeing during the entire period of training supervised and online. Therefore, during the HIFT program, the quarantine situation did not adversely affect this population’s wellbeing, but it did negatively affect adherence to the training program.

Optimal dose and type of exercise to improve cognitive function in older adults: A systematic review and bayesian model-based network meta-analysis of RCTs

OBJECTIVE

To examine the dose-response relationship between overall and specific types of exercise with cognitive function in older adults.

DESIGN

Systematic Review and Bayesian Model-Based Network Meta-Analysis.

DATA SOURCES

Systematic search of MEDLINE, Web of Science, Scopus, PsycINFO and SPORTDiscus.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomized controlled trials of exercise interventions in participants aged 50 years or over, and that reported on at least one global cognition outcome.

RESULTS

The search returned 1998 records, of which 44 studies (4793 participants; 102 different effect sizes) were included in this review with meta-analysis. There was a non-linear, dose-response association between overall exercise and cognition. We found no minimal threshold for the beneficial effect of exercise on cognition. The estimated minimal exercise dose associated with clinically relevant changes in cognition was 724 METs-min per week, and doses beyond 1200 METs-min per week provided less clear benefits. We also found that the dose-response association was exercise type dependent, and our results show that clinically important effects may occur at lower doses for many types of exercise. Our findings also highlighted the superior effects of resistance exercises over other modalities.

CONCLUSIONS

If provided with the most potent modalities, older adults can get clinical meaningful benefits with lower doses than the WHO guidelines. Findings support the WHO recommendations to emphasise resistance training as a critical component of interventions for older adults.

Exploring Sex-Related Differences in Microglia May Be a Game-Changer in Precision Medicine

One area of microglial biology that has been relatively neglected until recently is sex differences and this is in spite of the fact that sex is a risk factor in several diseases that are characterized by neuroinflammation and, by extension, microglial activation. Why these sex differences exist is not known but the panoply of differences extend to microglial number, genotype and phenotype. Significantly, several of these sex-related differences are also evident in health and change during life emphasizing the dynamic and plastic nature of microglia. This review will consider how age impacts on sex-related differences in microglia and ask whether the advancement of personalized medicine demands that a greater focus is placed on studying sex-related differences in microglia in Alzheimer's disease, Parkinson's disease and models of inflammatory stress and trauma in order to make true progress in dealing with these conditions.

Prefrontal cortex hemodynamic response to acute high intensity intermittent exercise during executive function processing

We investigated prefrontal cortex (PFC) hemodynamic response, through functional near infrared spectroscopy (fNIRS) during executive function (EF) processing in response to acute high intensity intermittent exercise (HIIE) in young adults. We also assessed the associated sex differences in the cognitive scores and related PFC hemodynamic functions in response to HIIE. 49 young healthy adult participants (32 women, 17 men) were randomly assigned to either control or HIIE intervention groups. HIIE group participants performed 4 × 4 minutes of HIIE on cycle ergometer with 3 minutes of active recovery between the bouts; control group relaxed for the time equivalent to intervention. fNIRS data was collected during the performance of the EF tests including Color Word Stroop Test (CWST) and Trail Making Test (TMT) in pre and post sessions in both the groups. Results indicated a significant change in the hemodynamic response in the form of increased oxygenated and decreased deoxygenated hemoglobin in the PFC areas specific to the EF tasks, with improved CWST and TMT scores in response to HIIE intervention. PFC activation was different in men and women in response to HIIE, however similar scores of task performance were observed in men and women during the performance of executive functions in response to HIIE. The study concludes that an acute HIIE session improves executive function which is associated with an increase activation of PFC. Sex differences exist in the activation of PFC in response to HIIE during EF processing. Our study adds to the current evidence regarding exercise and cognition.

Neuroimaging Biomarkers Predicting the Efficacy of Multimodal Rehabilitative Intervention in the Alzheimer's Dementia Continuum Pathology

In this work we aimed to identify neural predictors of the efficacy of multimodal rehabilitative interventions in AD-continuum patients in the attempt to identify ideal candidates to improve the treatment outcome. Subjects in the AD continuum who participated in a multimodal rehabilitative treatment were included in the analysis [n = 82, 38 Males, mean age = 76 ± 5.30, mean education years = 9.09 ± 3.81, Mini Mental State Examination (MMSE) mean score = 23.31 ± 3.81]. All subjects underwent an MRI acquisition (1.5T) at baseline (T0) and a neuropsychological evaluation before (T0) and after intervention (T1). All subjects underwent an intensive multimodal cognitive rehabilitation (8–10 weeks). The MMSE and Neuropsychiatric Inventory (NPI) scores were considered as the main cognitive and behavioral outcome measures, and Delta change scores (T1–T0) were categorized in Improved (ΔMMSE > 0; ΔNPI < 0) and Not Improved (ΔMMSE ≤ 0; ΔNPI ≥ 0). Logistic Regression (LR) and Random Forest classification models were performed including neural markers (Medial Temporal Brain; Posterior Brain (PB); Frontal Brain (FB), Subcortical Brain indexes), neuropsychological (MMSE, NPI, verbal fluencies), and demographical variables (sex, age, education) at baseline. More than 50% of patients showed a positive effect of the treatment (ΔMMSE > 0: 51%, ΔNPI < 0: 52%). LR model on ΔMMSE (Improved vs. Not Improved) indicate a predictive role for MMSE score (p = 0.003) and PB index (p = 0.005), especially the right PB (p = 0.002) at baseline. The Random Forest analysis correctly classified 77% of cognitively improved and not improved AD patients. Concerning the NPI, LR model on ΔNPI (Improved vs. Not Improved) showed a predictive role of sex (p = 0.002), NPI (p = 0.005), PB index (p = 0.006), and FB index (p = 0.039) at baseline. The Random Forest reported a classification accuracy of 86%. Our data indicate that cognitive and behavioral status alone are not sufficient to identify best responders to a multidomain rehabilitation treatment. Increased neural reserve, especially in the parietal areas, is also relevant for the compensatory mechanisms activated by rehabilitative treatment. These data are relevant to support clinical decision by identifying target patients with high probability of success after rehabilitative programs on cognitive and behavioral functioning.

Effects of 5 Years Aerobic Exercise on Cognition in Older Adults: The Generation 100 Study: A Randomized Controlled Trial

Objective

The objective of this study was to investigate whether a 5-year exercise intervention and change in peak oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V{\text{O}}_{{2{\text{peak}}}}$$\end{document}VO2peak) is associated with cognitive function in older adults.

Methods

Nine hundred and forty-five participants (48% women, mean age at study end 78.2 ± 2.02 years) from the Generation 100 Study were randomized 2:1:1 to a control group, moderate-intensity continuous training or high-intensity interval training twice weekly for 5 years. Peak oxygen uptake was measured using ergospirometry at baseline and after 5 years. Global cognition and mild cognitive impairment (MCI) were assessed with the Montreal Cognitive Assessment scale (MoCA) after 5 years.

Results

Compared to the control group, the combined moderate-intensity continuous training plus high-intensity interval training (ExComb) group did not have significantly different cognitive scores (beta value 0.26, 95% confidence interval [CI] − 0.17, 0.69) or odds of MCI (odds ratio 0.86, 95% CI 0.66, 1.13). Men in the ExComb group had 0.80 points higher MoCA (95% CI 0.21, 1.40) and 32% lower odds of MCI compared with male controls (95% CI 0.47, 0.99), with no such findings in women. In the total sample, each 1 metabolic equivalent of task increase in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V{\text{O}}_{{2{\text{peak}}}}$$\end{document}VO2peak corresponded to 0.46 points higher MoCA (95% CI 0.25, 0.67) and 27% lower odds of MCI (95% CI 0.63, 0.85). Compared to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V{\text{O}}_{{2{\text{peak}}}}$$\end{document}VO2peak stable, participants whose \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V{\text{O}}_{{2{\text{peak}}}}$$\end{document}VO2peak increased did not have significantly different cognitive scores (beta value 0.24, CI − 0.68, 1.15) or odds of MCI (odds ratio 0.70, 95% CI 0.36, 1.34), whereas participants whose \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V{\text{O}}_{{2{\text{peak}}}}$$\end{document}VO2peak decreased had 0.64 points lower MoCA (95% CI − 1.15, − 0.14) and 35% higher odds of MCI (95% CI 0.98, 1.87).

Conclusions

Overall, exercise was not significantly associated with cognition among older adults. However, maintaining or increasing \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V{\text{O}}_{{2{\text{peak}}}}$$\end{document}VO2peak appeared to benefit cognition.

Clinical Trial Registration

ClinicalTrials.gov NCT01666340.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01608-5.

Intranasal administration of DHED protects against exhaustive exercise-induced brain injury in rats

DHED (10β,17β-dihydroxyestra-1,4-dien-3-one) is a brain-selective prodrug of 17β-estradiol and has been reported to have a strong neuroprotective effect. In this study, the exhaustive swimming rat model was used to investigate the therapeutic effects and mechanisms of intranasal DHED treatment. Male eight-week-old healthy Sprague Dawley rats were randomly divided into three groups: control group (Cont), exhaustive swimming (ES), and DHED + exhaustive swimming (DHED). The open-field test and beam-walking test were performed to measure exploratory behavior and general activity in rats. Immunofluorescence staining, western blotting, ELISA analysis and related assay kits were applied to measure brain damage, inflammatory cytokines, and apoptosis pathways. Behavioral data shows that DHED intranasal administration can prevent neurobehavioral impairment caused by exhaustive swimming. Using a series of bioanalytical assays, we demonstrated that DHED markedly abated neuronal injury compared to the exhaustive swimming group, as evidenced by the reduced expression of apoptosis-regulated proteins, the improvement of neural survival, and the prevention of myelin loss. In addition, mitochondrial fission was attenuated distinctly, and a dynamic equilibrium was restored. Intranasal administration of DHED likewise significantly suppressed reactive gliosis and the release of inflammatory cytokines in the rat cerebral motor cortex. Consistent with previous reports, DHED treatment ameliorated changes of excitatory neurotransmitters. These results provide strong support for the promising therapeutic effects of DHED on neuroprotection during exhaustive swimming. The underlying mechanisms may rely on mitochondrial dynamics, neuroinflammation, and the balance of neurotransmitters.

Association of gait with global cognitive function and cognitive domains detected by MoCA-J among community-dwelling older adults: a cross-sectional study

BACKGROUND

Gait was proved to be strongly associated with global cognitive function and multiple cognitive domains; however, previous research usually concentrated on individual gait parameters. This study used wearable sensors to measure gait parameters in different aspects and comprehensively explored the association of gait with global cognitive function and cognitive domains.

METHODS

The data of this cross-sectional study were obtained from 236 community-dwelling Japanese older adults (125 men and 111 women) aged 70-81 years. Gait was measured by asking participants to walk a 6-m course and back using the Physilog® sensors (GaiUp®, Switzerland). Global cognitive function and cognitive domains were evaluated by face-to-face interviews using the Japanese version of the Montreal Cognitive Assessment. Twenty gait parameters were summarized as independent gait factors using factor analysis. A generalized linear model and linear regression model were used to explore the relationship of gait with global cognitive function and cognitive domains adjusted for several confounding factors.

RESULTS

Factor analysis yielded four gait factors: general cycle, initial contact, propulsion, and mid-swing. Among them, general cycle factor was significantly associated with global cognitive function (β = - 0.487, [- 0.890, - 0.085]) and executive function (P = 0.049); initial contact was associated with executive function (P = 0.017).

CONCLUSION

General cycle of gait might be the better marker of global cognitive function and gait is most strongly associated with executive function. The longitudinal relationships should be examined in future cohort studies.

Effects of a Brief Stair-Climbing Intervention on Cognitive Functioning and Mood States in Older Adults: A Randomized Controlled Trial

Despite an abundance of evidence that exercise benefits cognition and mood, physical activity levels among older adults remain low, with time and inaccessibility posing major barriers. Interval stair climbing is an accessible time-efficient form of physical activity demonstrated to benefit cognition and mood in young adults, but effectiveness in older adults remains unknown. To address this, 28 older adults (Mage = 69.78 years, 16 females) undertook cognitive and mood assessments twice, 1 week apart, once preceded by interval stair climbing. A fairly large, albeit only marginally significant, effect size (ηp2=.12) indicated improved cognition following the moderate- to high-intensity intervention; however, rather than improving mood, older adults reported feeling more tired (g = 0.51). These outcomes provide initial indications that this mode of exercise that can easily translate to naturalistic settings offers promise as an intervention strategy, but more research is needed to optimize the protocol to suit aged populations (ACTRN1261900169014).

Sex differences in the incidence and prevalence of young-onset Alzheimer's disease: A meta-analysis

OBJECTIVES

The lifetime incidence of Alzheimer's disease is higher in women than in men, but it remains unclear if similar sex differences exist in young-onset Alzheimer's disease (YOAD). This systematic review test the hypothesis that women have a higher prevalence and incidence of YOAD than men.

METHODS

We searched Pubmed and Embase (inception to 11 June 2020) for original publications of population-based observational studies with data on the prevalence and/or incidence of YOAD, defined as a medical diagnosis of Alzheimer's disease before the age of 65 years. Data on cross-sectional and/or prospective numbers, percentages, incidences, and incidence rates (in person-years) were derived from included studies. Quality assessment was done using the Nottingham Ottawa Scale. Meta-analyses were done to test the hypothesis that women have a higher prevalence and incidence of YOAD than men.

RESULTS

After screening of 3252 titles, 12 articles were included. The pooled prevalence was 0.4% (confidence interval [CI] = 0.1-2.1) in women and 0.2% (CI = 0-1.2) in men (six studies, relative risk [RR] = 1.54, CI = 0.69-3.44, I2  = 38%). The pooled incidence was 0.02% (CI = 0.01-0.08) in women and 0.01% (CI = 0-0.05) in men (five studies, RR = 1.50, CI = 0.91-2.48, I2  = 0%). The incidence rates per 100,000 person-years ranged from 0 to 132 in women and from 0 to 42 in men.

CONCLUSIONS

Given the low prevalence and wide CIs, no firm conclusions can be drawn. Large-scale studies are required to verify that women are more likely than men to develop YOAD.

Higher Handgrip Strength Is Linked to Better Cognitive Performance in Chinese Adults with Hypertension

Objective: There is growing evidence that in adults, higher levels of handgrip strength (HGS) are linked to better cognitive performance. However, the relationship between HGS and cognitive performance has not been sufficiently investigated in special cohorts, such as individuals with hypertension who have an intrinsically higher risk of cognitive decline. Thus, the purpose of this study was to examine the relationship between HGS and cognitive performance in adults with hypertension using data from the Global Ageing and Adult Health Survey (SAGE). Methods: A total of 4486 Chinese adults with hypertension from the SAGE were included in this study. Absolute handgrip strength (aHGS in kilograms) was measured using a handheld electronic dynamometer, and cognitive performance was assessed in the domains of short-term memory, delayed memory, and language ability. Multiple linear regression models were fitted to examine the association between relative handgrip strength (rHGS; aHGS divided by body mass index) and measures of cognitive performance. Results: Overall, higher levels of rHGS were associated with higher scores in short-term memory (β = 0.20) and language (β = 0.63) compared with the lowest tertiles of rHGS. In male participants, higher HGS was associated with higher scores in short-term memory (β = 0.31), language (β = 0.64), and delayed memory (β = 0.22). There were no associations between rHGS and cognitive performance measures in females. Conclusion: We observed that a higher level of rHGS was associated with better cognitive performance among hypertensive male individuals. Further studies are needed to investigate the neurobiological mechanisms, including sex-specific differences driving the relationship between measures of HGS and cognitive performance in individuals with hypertension.

Causes and Consequences of Interindividual Response Variability: A Call to Apply a More Rigorous Research Design in Acute Exercise-Cognition Studies

The different responses of humans to an apparently equivalent stimulus are called interindividual response variability. This phenomenon has gained more and more attention in research in recent years. The research field of exercise-cognition has also taken up this topic, as shown by a growing number of studies published in the past decade. In this perspective article, we aim to prompt the progress of this research field by (i) discussing the causes and consequences of interindividual variability, (ii) critically examining published studies that have investigated interindividual variability of neurocognitive outcome parameters in response to acute physical exercises, and (iii) providing recommendations for future studies, based on our critical examination. The provided recommendations, which advocate for a more rigorous study design, are intended to help researchers in the field to design studies allowing them to draw robust conclusions. This, in turn, is very likely to foster the development of this research field and the practical application of the findings.

Impact of various intensities and frequencies of non-occupational physical activity on the risk of dementia among physically independent older adults: the Japan Gerontological Evaluation Study

OBJECTIVES

The aim of this study was to investigate the association between different intensities and frequencies of non-occupational physical activity (PA) and the risk of dementia among Japanese older adults.

STUDY DESIGN

This was a prospective cohort study.

METHODS

A total of 2194 participants aged ≥65 years from the Japan Gerontological Evaluation Study were followed up between 2010 and 2016. The standardised dementia scale of the long-term care insurance system was used to identify incident dementia, whereas non-occupational PA (<2 or ≥2 times/week on each intensity: light, moderate and vigorous) was assessed using a questionnaire. Cox regression was used to compute the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident dementia.

RESULTS

After adjustment for sociodemographic and medical characteristics, the following frequencies and intensities of non-occupational PA, compared with no non-occupational PA at all, were associated with a reduced risk of dementia: light PA ≥2 times/week (HR = 0.61, 95% CI: 0.38-0.97), moderate PA <2 times/week (HR = 0.46, 95% CI: 0.28-0.76), moderate PA ≥2 times/week (HR = 0.57, 95% CI: 0.36-0.91), vigorous PA <2 times/week (HR = 0.40, 95% CI: 0.21-0.74) and vigorous PA ≥2 times/week (HR = 0.29, 95% CI: 0.15-0.57). In the sex-specific analysis, moderate PA <2 times/week and vigorous PA ≥2 times/week were associated with a reduced risk of dementia in men, whereas light and moderate PA ≥2 times/week and all frequencies of vigorous PA were associated with a reduced risk of dementia in women.

CONCLUSIONS

Practicing non-occupational PA was associated with a reduced risk of dementia among Japanese older adults.

New Horizon: Exercise and a Focus on Tissue-Brain Crosstalk

The world population is aging, leading to increased rates of neurodegenerative disorders. Exercise has countless health benefits and has consistently been shown to improve brain health and cognitive function. The purpose of this review is to provide an overview of exercise-induced adaptations in the brain with a focus on crosstalk between peripheral tissues and the brain. We highlight recent investigations into exercise-induced circulating factors, or exerkines, including irisin, cathepsin B, GPLD1, and ketones and the mechanisms mediating their effects in the brain.

Sex Matters in the Association between Physical Activity and Fitness with Cognition

PURPOSE

The benefits from physical activity (PA) and cardiorespiratory fitness (CRF) on normal age-related cognitive decline might be sex dependent. Our aim was to explore the relationship between different types of PA, CRF, and cognition and to identify the mediating effects of CRF in the association between PA and cognition in women and men.

METHODS

We recruited 115 healthy adults 50-70 yr of age. We obtained demographic, cognitive, and PA status data based on the Projecte Moviment protocol. We calculated cognitive domains by grouping z-sample scores. We obtained self-reported total energy expenditure during the last month and grouped it into sportive PA (S-PA) and nonsportive PA (NS-PA). CRF was estimated using the Rockport 1-Mile Walk Test. We applied regression models and mediation analyses in a final sample of 104 individuals (65 women and 39 men).

RESULTS

In the total sample, CRF was positively associated with executive function, verbal memory, and attention-speed. S-PA was positively related to executive function and attention-speed, whereas NS-PA was unrelated to cognitive domains. Greater amounts of S-PA were associated with executive function and attention-speed for both women and men. Higher CRF was associated with executive function, memory, language, and attention-speed only in men. Mediation analyses showed that CRF was a significant mediator of the positive effects of S-PA on executive function and attention-speed in men but not in women.

CONCLUSIONS

Both women and men show cognitive benefits from greater S-PA, but not from NS-PA. However, there were sex differences in the mediating effects of CRF in this relationship, showing that CRF was mediating these benefits only in men.

Effects of cardiorespiratory fitness and exercise training on cerebrovascular blood flow and reactivity: a systematic review with meta-analyses

We address two aims: Aim 1 (Fitness Review) compares the effect of higher cardiorespiratory fitness (CRF) (e.g., endurance athletes) with lower CRF (e.g., sedentary adults) on cerebrovascular outcomes, including middle cerebral artery velocity (MCAv), cerebrovascular reactivity and resistance, and global cerebral blood flow, as assessed by transcranial Doppler (TCD) or magnetic resonance imaging (MRI). Aim 2 (Exercise Training Review) determines the effect of exercise training on cerebrovascular outcomes. Systematic review of studies with meta-analyses where appropriate. Certainty of evidence was assessed by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Twenty studies (18 using TCD) met the eligibility criteria for Aim 1, and 14 studies (8 by TCD) were included for Aim 2. There was a significant effect of higher CRF compared with lower CRF on cerebrovascular resistance (effect size = -0.54, 95% confidence interval = -0.91 to -0.16) and cerebrovascular reactivity (0.98, 0.41-1.55). Studies including males only demonstrated a greater effect of higher CRF on cerebrovascular resistance than mixed or female studies (male only: -0.69, -1.06 to -0.32; mixed and female studies: 0.10, -0.28 to 0.49). Exercise training did not increase MCAv (0.05, -0.21 to 0.31) but showed a small nonsignificant improvement in cerebrovascular reactivity (0.60, -0.08 to 1.28; P = 0.09). Exercise training showed heterogeneous effects on regional but little effect on global cerebral blood flow as measured by MRI. High CRF positively effects cerebrovascular function, including decreased cerebrovascular resistance and increased cerebrovascular reactivity; however, global cerebral blood flow and MCAv are primarily unchanged following an exercise intervention in healthy and clinical populations.NEW & NOTEWORTHY Higher cardiorespiratory fitness is associated with lower cerebrovascular resistance and elevated cerebrovascular reactivity at rest. Only adults with a true-high fitness based on normative data exhibited elevated middle cerebral artery velocity. The positive effect of higher compared with lower cardiorespiratory fitness on resting cerebrovascular resistance was more evident in male-only studies when compared with mixed or female-only studies. A period of exercise training resulted in negligible changes in middle cerebral artery velocity and global cerebral blood flow, with potential for improvements in cerebrovascular reactivity.

Middle aged turn point in parameters of oxidative stress and glucose catabolism in mouse cerebellum during lifespan: minor effects of every-other-day fasting

The cerebellum is considered to develop aging markers more slowly than other parts of the brain. Intensification of free radical processes and compromised bioenergetics, critical hallmarks of normal brain aging, may be slowed down by caloric restriction. This study aimed to evaluate the intensity of oxidative stress and the enzymatic potential to utilize glucose via glycolysis or the pentose phosphate pathway (PPP) in the cerebellum of mice under ad libitum versus every-other-day fasting (EODF) feeding regimens. Levels of lipid peroxides, activities of antioxidant and key glycolytic and PPP enzymes were measured in young (6-month), middle-aged (12-month) and old (18-month) C57BL/6J mice. The cerebellum showed the most dramatic increase in lipid peroxide levels, antioxidant capacity and PPP key enzyme activities and the sharpest decline in the activities of key glycolytic enzymes under transition from young to middle age but these changes slowed when transiting from middle to old age. A decrease in the activity of the key glycolytic enzyme phosphofructokinase was accompanied by a concomitant increase in the activities of hexokinase and glucose-6-phosphate dehydrogenase (G6PDH), which may suggest that during normal cerebellar aging glucose metabolism shifts from glycolysis to the pentose phosphate pathway. The data indicate that intensification of free radical processes in the cerebellum occurred by middle age and that activation of the PPP together with increased antioxidant capacity can help to resist these changes into old age. However, the EODF regime did not significantly modulate or alleviate any of the metabolic processes studied in this analysis of the aging cerebellum.

Exercise and Fitness Neuroprotective Effects: Molecular, Brain Volume and Psychological Correlates and Their Mediating Role in Healthy Late-Middle-Aged Women and Men

Background: Although exercise is known to have a neuroprotective effect in aging, the mediators underlying the exercise-cognition association remain poorly understood. In this paper we aimed to study the molecular, brain, and behavioral changes related to physical activity and their potential role as mediators. Methods: We obtained demographic, physical activity outcomes [sportive physical activity and cardiorespiratory fitness (CRF)], plasma biomarkers (TNF-α, ICAM-1, HGF, SDF1-α, and BDNF), structural-MRI (brain volume areas), psychological and sleep health (mood, depressive and distress symptoms, and sleep quality), and multi-domain cognitive data from 115 adults aged 50-70 years. We conducted linear regression models and mediation analyses stratifying results by sex in a final sample of 104 individuals [65 women (age = 56.75 ± 4.96) and 39 men (age = 58.59 ± 5.86)]. Results: Women engaging in greater amounts of exercising showed lower TNF-α levels and greater dorsolateral prefrontal cortex and temporal lobe volumes. Men engaging in greater amounts of exercise showed greater temporal lobe volumes. CRF levels were not related to any of the analyzed outcomes in women but in men higher CRF was associated with lower TNF-α, HGF and ventricle volumes, greater volume of temporal and parietal lobes and fewer depressive symptoms and better mood. In men, reduced TNF-α and HGF levels mediated brain and cognitive CRF-related benefits. Conclusion: Our results show that exercise is a promising approach for influencing inflammation and brain volume and also contributes to ongoing discussions about the physiological mediators for the association between CRF and cognition in men.

Longitudinal Associations of Midlife Accelerometer Determined Sedentary Behavior and Physical Activity With Cognitive Function: The CARDIA Study

Background To determine if accelerometer measured sedentary behavior (SED), light-intensity physical activity (LPA), and moderate-to-vigorous-intensity physical activity (MVPA) in midlife is prospectively associated with cognitive function. Methods and Results Participants were 1970 adults enrolled in the CARDIA (Coronary Artery Risk Development in Young Adults) study who wore an accelerometer in 2005 to 2006 (ages 38-50 years) and had cognitive function assessments completed 5 and/or 10 years later. SED, LPA, and MVPA were measured by an ActiGraph 7164 accelerometer. Cognitive function tests included the Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, and Stroop Test. Compositional isotemporal substitution analysis examined associations of SED, LPA, and MVPA with repeated measures of the cognitive function standardized scores. In men, statistical reallocation of 30 minutes of LPA with 30 minutes of MVPA resulted in an estimated difference of SD 0.07 (95% CI, 0.01-0.14), SD 0.09 (95% CI, 0.02-0.17), and SD -0.11 (95% CI, -0.19 to -0.04) in the Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, and Stroop scores, respectively, indicating better performance. Associations were similar when reallocating time in SED with MVPA, but results were less robust. Reallocation of time in SED with LPA resulted in an estimated difference of SD -0.05 (95% CI, -0.06 to -0.03), SD -0.03 (95% CI, -0.05 to -0.01), and SD 0.05 (95% CI, 0.03- 0.07) in the Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, and Stroop scores, respectively, indicating worse performance. Associations were largely nonsignificant among women. Conclusions Our findings support the idea that for men, higher-intensity activities (MVPA) may be necessary in midlife to observe beneficial associations with cognition.

The role of physical exercise in modulating peripheral inflammatory and neurotrophic biomarkers in older adults: A systematic review and meta-analysis

BACKGROUND

Physiological cascades of neurotrophic factors and inflammatory cytokines may mediate the exercise-induced amelioration of cognition in older adults. However, there is limited understanding on how different exercise modalities improving cognition alter biomarkers. Our aim was to evaluate the effects of different exercise modalities on blood biomarker concentrations in cognitive clinical trials of older adults.

METHODS

A systematic review (SR) and meta-analysis (MA) were performed using the databases PubMed, EMBASE, and SCOPUS. After exclusions, 17 trials with 18 distinct exercise interventions were included.

RESULTS

Aerobic training increased (n = 2) or did not significantly change BDNF (n = 5), and resistance training increased (n = 2) or did not significantly change (n = 2) IGF-1. Multimodal training significantly increased (n = 1) or did not change (n = 3) BDNF. Interventions that recruited sex-specific cohorts showed an advantage in males for blood marker concentrations and cognitive performance outcomes (n = 3) compared to females (n = 3). Only one of three interventions decreased concentrations of CRP. Eight studies examining BDNF changes were suited for MA and showed that higher BDNF concentrations were reached post intervention, although not reaching statistical significance (p = .26, I² = 44 %).

DISCUSSION

Our results suggest that exercise has potential to ameliorate cognitive decline in older adults with divergent, modality-specific, neurotrophic mechanisms.

Physical Activity and Trajectory of Cognitive Change in Older Persons: Mayo Clinic Study of Aging

BACKGROUND

Little is known about the association between physical activity (PA) and cognitive trajectories in older adults.

OBJECTIVE

To examine the association between PA and change in memory, language, attention, visuospatial skills, and global cognition, and a potential impact of sex or Apolipoprotein E (APOE) ɛ4 status.

METHODS

Longitudinal study derived from the population-based Mayo Clinic Study of Aging, including 2,060 cognitively unimpaired males and females aged ≥70 years. Engagement in midlife (ages 50-65) and late-life (last year) PA was assessed using a questionnaire. Neuropsychological testing was done every 15 months (mean follow-up 5.8 years). We ran linear mixed-effect models to examine whether mid- or late-life PA at three intensities (mild, moderate, vigorous) was associated with cognitive z-scores.

RESULTS

Light intensity midlife PA was associated with less decline in memory function compared to the no-PA reference group (time x light PA; estimate [standard error] 0.047 [0.016], p = 0.004). Vigorous late-life PA was associated with less decline in language (0.033 [0.015], p = 0.030), attention (0.032 [0.017], p = 0.050), and global cognition (0.039 [0.016], p = 0.012). Females who were physically inactive in midlife experienced more pronounced cognitive decline than females physically active in midlife and males regardless of PA (p-values for time interaction terms with midlife PA levels and sex were all p < 0.05 for global cognition). APOE ɛ4 carriership did not moderate the association between PA and cognition.

CONCLUSION

Engaging in PA, particularly of vigorous intensity in late-life, was associated with less pronounced decline in global and domain-specific cognition. This association may differ by sex.

Association between brain morphometry and aerobic fitness level and sex in healthy emerging adults

OBJECTIVE

Aerobic fitness may be beneficial for neuroanatomical structure. However, few have investigated this in emerging adults while also accounting for potential sex differences. Here we examine aerobic fitness level, sex, and their interaction in relation to cortical thickness, surface area, and volume.

METHOD

Sixty-three young adults between the ages of 16-26 were balanced for sex and demonstrated a wide range of aerobic fitness levels. Exclusion criteria included left-handedness, past-year independent Axis-I disorders, major medical/neurologic disorders, prenatal medical issues, prenatal alcohol/illicit drug exposure, or excessive substance use. Participants completed an MRI scan and a graded exercise test to volitional fatigue (VO2 max). Data analyses were run in Freesurfer and data was corrected for multiple comparisons with Monte Carlo simulations at .05.

RESULTS

Males demonstrated higher VO2 values. Higher VO2 values were statistically independently related to thinner lateral occipital, superior parietal, cuneus, precuneus, and inferior parietal regions, smaller lateral occipital volume, and larger inferior parietal surface area. Compared to females, males had larger volume in rostral anterior cingulate, lateral occipital, and superior frontal regions, and greater surface area in fusiform, inferior parietal, rostral and caudal anterior cingulate, and superior parietal regions. VO2*Sex interactions revealed higher-fit females had higher inferior parietal, paracentral, and supramarginal surface area, while lower-fit males showed larger surface area in these same regions.

CONCLUSIONS

Individuals with higher aerobic fitness performance had thinner cortices, lower volume, and larger surface area in sensorimotor regions than lower fit individuals, perhaps suggesting earlier neuromaturation in higher fit individuals. Larger surface area was associated with higher-fit females and lower-fit males. Thus both sex and aerobic fitness are important in shaping brain health in emerging adults.

Objective aerobic fitness level and neuropsychological functioning in healthy adolescents and emerging adults: Unique sex effects

Objective

Research suggests positive relationships between aerobic fitness and cognition in older adults; however, limited research has adequately investigated the relationship between objectively measured aerobic fitness and broad cognitive functioning in healthy adolescents and young adults without psychiatric or physical health disorders. Further, studies to date have disproportionately examined males and failed to examine sex differences. Here we examine the relationship between aerobic fitness and neuropsychological functioning in physically healthy youth and whether sex moderates these findings.

Design

Sixty-four healthy emerging adults (16-25 years-old; 32 female) underwent measurement of objective aerobic fitness (VO2 max) and neuropsychological assessment. Exclusion criteria included: left-handedness, prenatal medical issues or alcohol/illicit drug exposure, Axis-I psychiatric disorders, major medical disorders including metabolic conditions such as diabetes, hypertension, hyperlipidemia, major neurologic disorders, LOS greater than 2 min, intellectual disability or learning disability, regular substance use (e.g., greater than biweekly use of cannabis) or positive drug toxicology testing.

Method

Multiple regressions examined VO2 max, sex, sex*VO2interaction in relation to neurocognition, controlling for objectively measured body fat percentage.

Results

Prior to including body fat percentage, higher VO2 max related to improved working memory (Letter-Number Sequencing; p = .03) and selective attention (CPT-II hit response time standard error; p = .03). Aerobic fitness significantly interacted with sex, as higher-fit males had better performance on two sustained attention tasks while females did not demonstrate this pattern (CPT-II variability standard error, p = .047; Ruff 2&7 Total Speed, p = .02). Body fat percentage was positively slower cognitive flexibility (D-KEFS color-word switching/inhibition, p = .046).

Conclusions

VO2 independently predicted better working memory and selective attention. Increased aerobic fitness level related to increased performance on sustained attention tasks in males but not females. Therefore, aerobic fitness may be positively related to better cognitive functioning in physically healthy adolescents and emerging adults without metabolic conditions. Further research into factors (e.g., intensity or type of activity) that may relate to beneficial outcomes by sex are needed.

Effects of Aerobic Exercise, Cognitive and Combined Training on Cognition in Physically Inactive Healthy Late-Middle-Aged Adults: The Projecte Moviment Randomized Controlled Trial

Background

Lifestyle interventions are promising strategies to promote cognitive health in aging. Projecte Moviment examines if aerobic exercise (AE), computerized cognitive training (CCT), and their combination (COMB) improves cognition, psychological health, and physical status compared to a control group. We assessed the moderating role of age and sex and the mediating effects of cardiorespiratory fitness (CRF), physical activity (PA), and psychological health on intervention-related cognitive benefits.

Methods

This was a 12-week multi-domain, single-blind, proof-of-concept randomized controlled trial (RCT). 96 healthy adults aged 50-70 years were assigned to AE, CCT, COMB, and a wait-list control group. The per protocol sample, which completed the intervention with a level of adherence > 80%, consisted of 82 participants (62% female; age = 58.38 ± 5.47). We assessed cognition, psychological health, CRF, and energy expenditure in PA at baseline and after the intervention. We regressed change in each outcome on the treatment variables, baseline score, sex, age, and education. We used PROCESS Macro to perform the mediation and moderation analyses.

Results

AE benefited Working Memory (SMD = 0.29, p = 0.037) and Attention (SMD = 0.33, p = 0.028) including the Attention-Speed (SMD = 0.31, p = 0.042) domain, compared to Control. COMB improved Attention (SMD = 0.30, p = 0.043), Speed (SMD = 0.30, p = 0.044), and the Attention-Speed (SMD = 0.30, p = 0.041) domain. CTT group did not show any cognitive change compared to Control. Sportive PA (S-PA) and CRF increased in AE and COMB. Age and sex did not moderate intervention-related cognitive benefits. Change in S-PA, but not in CRF, significantly mediated improvements on Attention-Speed in AE.

Conclusion

A 12-week AE program improved Executive Function and Attention-Speed in healthy late-middle-aged adults. Combining it with CCT did not provide further benefits. Our results add support to the clinical relevance of even short-term AE as an intervention to enhance cognition and highlight the mediating role of change in S-PA in these benefits.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT03123900.

The Influence of the BDNF Val66Met Polymorphism on the Association of Regular Physical Activity With Cognition Among Individuals With Diabetes

INTRODUCTION

Diabetes is associated with cognitive dysfunction that comes with substantial lifetime consequences, such as interference with diabetes self-management and reduced quality of life. Although regular physical activity has been consistently shown to enhance cognitive function among healthy subjects, significant interpersonal differences in exercise-induced cognitive outcomes have been reported among brain-derived neurotrophic factor (BDNF) Val/Val vs. Met carriers. However, the evidence on how the BDNF Val66Met variant influences the relationship between regular physical activity and cognition among individuals with diabetes is currently lacking.

METHODS

A total of 3,040 individuals with diabetes were included in this analysis using data from the Health and Retirement Study. Associations among moderate and vigorous physical activities (MVPA) and measures of cognitive function were evaluated using multivariable linear regression models within each stratum of the Val66Met genotypes.

RESULTS

MVPA was more strongly associated with total cognitive score, mental status, and words recall among Met/Met carriers, compared to Val/Val and Val/Met carriers.

CONCLUSIONS

This study provided preliminary findings on how BDNF variants may modulate the exercise-induced cognitive benefits among mid-aged and older adults with diabetes. Given the limitations of the current study, it is necessary for randomized controlled trials to stratify by BDNF genotypes to more conclusively determine whether Met carriers benefit more from increased physical activity. In addition, future research is needed to examine how the interplay of BDNF Val66Met variants, DNA methylation, and physical activity may have an impact on cognitive function among adults with diabetes.

Sex differences in exercise efficacy: Is midlife a critical window for promoting healthy cognitive aging?

Dementia is one of the most pressing health care issues of this century. As no curative treatment for dementia exists, research efforts are growing to identify effective lifestyle interventions to prevent or delay onset. One such promising strategy that promotes cognitive and brain health is engaging in physical exercise. However, current exercise recommendations are imprecise. To advance the potential of exercise as a preventative and treatment strategy, important questions regarding moderators (ie, biological sex and age) are being addressed in the literature. Biological sex is recognized as an important variable to consider in exercise efficacy on brain health, with females showing greater cognitive gains. This may be related to sex differences in underlying mechanisms. Here, we argue to better understand the sex differences in exercise efficacy, the timing of exercise intervention should also be considered. Specifically, we present the hypothesis that midlife in females is a critical window for the implementation of exercise as an early intervention to promote brain health and prevent dementia. Further, we speculate that exercise interventions targeting midlife will be of critical importance for the female brain, as females exit this period of the lifespan at greater risk for cognitive impairment. Given the potential sex differences in dementia risk and prevalence, it is imperative to assess potential sex differences in exercise efficacy as an early intervention during midlife.

Sexual dimorphism of physical activity on cognitive aging: Role of immune functioning

OBJECTIVE

Exercise is one of the most potent strategies available to support cognitive health with age, yet substantial variability exists. Sexual dimorphism is evident for brain and immune functioning, the latter being implicated as important pathway for exercise. We examined the moderating role of sex on the relationship between physical activity and systemic inflammatory and brain health outcomes in support of more personalized approaches to behavioral interventions.

METHODS

Our discovery cohort included 45 typically aging women matched on age (±5y) and education (±2y) to 45 men (mean age = 72.5; Clinical Dementia Rating = 0) who completed self-reported current physical activity (Physical Activity Scale for Elderly), blood draw, neuropsychological evaluation, and brain MRI. An independent sample of 45 typically aging women and 36 men who completed the same measures comprised a replication cohort. Plasma was analyzed for 11 proinflammatory cytokine and chemokine markers via MesoScale Discovery.

RESULTS

Discovery cohort: Reported physical activity did not differ between sexes (150 vs. 157, p = 0.72). There was a significant interaction between sex and physical activity on chemokine markers MDC, MIP-1b, MCP-4, and eotaxin-3 (ps < 0.03), with a similar trend for MCP-1 and INFγ (ps < 0.09). Men who reported greater activity demonstrated lower inflammatory markers, an effect attenuated-to-absent in women. An interaction between sex and physical activity was also observed for parahippocampal volumes (p = 0.02) and cognition (processing speed and visual memory; ps < 0.04). Again, the beneficial effect of physical activity on outcomes was present in men, but not women. Replication cohort analyses conferred a consistent effect of sex on the relationship between physical activity and immune markers; models examining neurobehavioral outcomes did not strongly replicate. Across cohorts, post-hoc models demonstrated an interaction between sex and activity-related inflammatory markers on total gray matter volume and visual memory. Men with higher inflammatory markers demonstrated poorer brain structure and function, whereas inflammatory markers did not strongly relate to neurobehavioral outcomes in women.

CONCLUSIONS

Greater physical activity was associated with lower markers of inflammation in clinically normal older men, but not women - an effect consistently replicated across cohorts. Additionally, men appeared disproportionately vulnerable to the adverse effects of peripheral inflammatory markers on brain structure and function compared to women. Immune activation may be a male-specific pathway through which exercise confers neurobehavioral benefit.