Cognitive reserve and health-related fitness are associated with favorable cognitive aging, but Black/African American older adults are underrepresented in extant research. Our objective was to explore the relative contributions and predictive value of cognitive reserve and health-related fitness metrics on cognitive performance at baseline and cognitive status at a 4-year follow up in a large sample of Black/African American older adults.

Participants aged 65 years and older from the Health and Retirement Study (HRS) who identified as Black/African American and completed baseline and follow-up interviews (including physical, health, and cognitive assessments) were included in the study. The final sample included 321 Black/African American older adults (mean age = 72.8; sd = 4.8; mean years of education = 12.3; sd = 2.9; mean body mass index (BMI) = 29.1; sd = 5.2; 60.4% identified as female). A cross-sectional analysis of relative importance – a measure of partitioned variance controlling for collinearity and model order – was first used to explore predictor variables and inform the hierarchical model order. Next, hierarchical multiple regression was used to examine cross-sectional relationships between cognitive reserve (years of education), health-related fitness variables (grip strength, lung capacity, gait speed, BMI), and global cognition. Multiple logistic regression was used to examine prospective relationships between predictors and longitudinal cognitive status (maintainers versus decliners). Control variables in all models included age, gender identity, and a chronic disease index score.

Cross-sectional relative importance analyses identified years of education and gait speed as important predictors of global cognition. The cross-sectional hierarchical regression model explained 33% of variance in baseline global cognition. Education was the strongest predictor of cognitive performance (β = 0.48, p < 0.001). Holding all other variables constant, gait speed was significantly associated with baseline cognitive performance and accounted for a significant additional amount of explained variance (ΔR = 0.01, p = 0.032). In a prospective analysis dividing the sample into cognitive maintainers and decliners, a single additional year of formal education increased chances of being classified as a cognitive maintainer (OR = 1.30, 95% CI = 1.17-1.45). There were no significant relationships between rate of change in health-related fitness and rate of change in cognition.

Education, a proxy for cognitive reserve, was a robust predictor of global cognition at baseline and was associated with increased odds of maintaining cognitive ability at 4-year follow up in Black/African American older adults. Of the physical performance metrics, gait speed was associated with cognitive performance at baseline. The lack of observed association between other fitness variables and cognition may be attributable to the brief assessment procedures implemented in this large-scale study.

The current study had two primary objectives: 1) To assess the dose-response relationship between acute bouts of aerobic exercise intensity and performance in multiple cognitive domains (episodic memory, attention, and executive function) and 2) To replicate and extend the literature by examining the dose-response relationship between aerobic exercise intensity and pattern separation.

18 young adults (mean age = 21.6, sd = 2.6; mean education = 13.9, sd = 3.4; 50% female) were recruited from The Ohio State University and surrounding area (Columbus, OH). Participants completed control (no exercise), light intensity, and vigorous intensity exercise conditions across three counterbalanced appointments. For each participant, all three appointments occurred at approximately the same time of day with at least 2 days between appointments. Following the rest or exercise conditions and after an approximately 7 minute delay, participants completed a Mnemonic Similarity Task (MST; Stark et al., 2019) to assess pattern separation. This task was always administered first as we attempted to replicate previous studies and further clarify the relationship between acute bouts of aerobic exercise and pattern separation by implementing an exercise stimulus that varied in intensity. After the MST, three brief cognitive tasks (roughly 5 min each) were administered in a counterbalanced order: a gradual-onset continuous performance task (gradCPT; Esterman et al., 2013), the flanker task from the NIH toolbox, and a face-name episodic memory task. Here we report results from the gradCPT, which assesses sustained attention and inhibitory control. Heart rate and ratings of perceived exertion were collected to validate the rest and exercise conditions. Repeated-measures ANOVAs were used to assess the relationship between exercise condition and dependent measures of sustained attention and inhibitory control and pattern separation.

One-way repeated-measures ANOVAs revealed a main effect of exercise condition on gradCPT task performance for task discrimination ability (d') and commission error rate (p’s < .05). Pairwise comparisons revealed task discrimination ability was significantly higher following the light intensity exercise condition versus the control condition. Commission error rate was significantly lower for both the light and vigorous exercise conditions compared to the control condition. For the MST, two-way repeated-measures ANOVAs revealed an expected significant main effect of lure similarity on task performance; however, there was not a significant main effect of exercise intensity on task performance (or a significant interaction).

The current study indicated that acute bouts of exercise improve both sustained attention and inhibitory control as measured with the gradCPT. We did not replicate previous work reporting that acute bouts of exercise improve pattern separation in young adults. Our results further indicate that vigorous exercise did not detrimentally impact or improve pattern separation performance. Our results indicate that light intensity exercise is sufficient to enhance sustained attention and inhibitory control, as there were no significant differences in performance following light versus vigorous exercise.

To identify the relative contributions and importance of modifiable fitness and demographic variables to cognitive performance in a cohort of healthy older adults.

Metrics of modifiable fitness (gait speed, respiratory function, grip strength, and body mass index (BMI)) and cognition (executive function, episodic memory, and processing speed) were assessed in 619 older adults from the Health and Retirement Study 2016 wave (mean age = 74.9, sd = 6.9; mean education = 13.4 years, sd = 2.6; 42% female). General linear models were employed to assess the contribution of modifiable fitness variables in predicting three domains of cognition: executive function, episodic memory, and processing speed. Demographics (age, sex, education, time between appointments, and a chronic disease score) were entered as covariates for each model. Relative importance metrics were computed for all variables in each model using Lindeman, Merenda, and Gold (lmg) analysis, a technique which decomposes a given model’s explained variance to describe the average contribution of each predictor variable, independent of its position in the linear model.

When all variables were entered into the general linear model, demographic and modifiable fitness variables explained 35%, 24%, and 26% of the variance in executive function, episodic memory, and processing speed, respectively (all three models were significant, p <0.001). Age, education, respiratory function, and walking speed had higher relative importance values (all lmgs > 1.8) compared to BMI, grip strength, and other covariates in all three models (all lmgs < 1.3). Gender was also relatively important in the executive function (lmg = 4.2) and episodic memory models (lmg = 5.0). Of the modifiable fitness variables, walking speed and respiratory function had the greatest lmg values (5.8 and 6.4 respectively) in the executive function model, similar to demographic variables age (lmg = 6.0) and education (lmg = 8.9). When demographic variables were entered as covariates, modifiable fitness variables collectively accounted for an additional 9.7%, 6.3%, and 6.0% variance in the executive function, episodic memory, and processing speed models respectively (all three models were significant, p <0.001).

Our findings indicate that walking speed and respiratory function are of similar importance compared to “traditional” demographic variables such as age and education in predicting cognitive performance in a cohort of healthy older adults. Moreover, modifiable fitness variables accounted for unique variance in executive function, episodic memory, and processing speed after accounting for age and education. Modifiable fitness variables explained the most unique variance in executive function. These results extend the current literature by demonstrating that modifiable fitness variables, even when assessed with brief and relatively coarse measures of physical performance, may be useful in predicting cognitive function. Moreover, the results highlight the need to assess metrics of cognitive reserve, such as education, as well as modifiable fitness variables and their respective roles in accounting for cognitive performance. The data further suggest that relative contributions of physical performance metrics may vary by cognitive domain in healthy older adults.

To identify novel associations between modifiable physical and health variables, Alzheimer’s disease (AD) biomarkers, and cognitive function in a cohort of older adults with Mild Cognitive Impairment (MCI).

Metrics of cardiometabolic risk, stress, inflammation, neurotrophic/growth factors, AD, and cognition were assessed in 154 MCI participants (Mean age = 74.1 years) from the Alzheimer’s Disease Neuroimaging Initiative. Partial Least Squares analysis was employed to examine associations among these physiological variables and cognition.

Latent variable 1 revealed a unique combination of AD biomarkers, neurotrophic/growth factors, education, and stress that were significantly associated with specific domains of cognitive function, including episodic memory, executive function, processing speed, and language, representing 45.2% of the cross-block covariance in the data. Age, body mass index, and metrics tapping basic attention or premorbid IQ were not significant.

Our data-driven analysis highlights the significant relationships between metrics associated with AD pathology, neuroprotection, and neuroplasticity, primarily with tasks tapping episodic memory, executive function, processing speed, and verbal fluency rather than more basic tasks that do not require mental manipulation (basic attention and vocabulary). These data also indicate that biological metrics are more strongly associated with episodic memory, executive function, and processing speed than chronological age in older adults with MCI.