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BackgroundPhysical activity (PA) is a promising strategy for the promotion of brain health, although substantial variation exists in the effects of PA at the individual level. Given the greater prevalence and faster progression of Alzheimer's disease in women compared to men, and known sex differences in brain architecture, analysis of sex differences in the relationship between PA, cognition, and brain region volumes is warranted.MethodsTo address this, we conducted secondary analyses of data from the Health, Aging, and Body Composition study. To determine whether longitudinal changes in PA over 10 years predicted declines in global cognitive functioning and executive functions and processing speed differently in males and females, latent growth curve modeling was utilized. Magnetic resonance imaging was performed at year 10, and the hippocampus and dorsolateral prefrontal cortex were identified as regions of interest.ResultsMaintaining PA over 10 years predicted less declines in executive functions and processing speed in females but not males. Maintaining PA over 10 years was significantly associated with greater volume of the left dorsolateral prefrontal cortex, a brain region involved in executive functions, in year 10 in females only. Maintaining physical activity was associated with better global cognitive function in both males and females, and also predicted volume of the left hippocampus, albeit in different directions with females showing a negative relationship and males showing a positive relationship.ConclusionsThese findings suggest that the relationship of PA with cognition and its neurobiological correlates differ by sex, with females apparently benefiting from PA to a greater extent than males. Development of personalized, tailored exercise recommendations to promote healthy brain aging should account for sex differences.

Background: Sex differences for subsequent falls and falls risk factors in community-dwelling older adults who have fallen are unknown. Our aim was to: (1) compare the number of falls between sexes, (2) identify modifiable falls risk factors, and (3) explore the interaction of sex on falls risk factors in older adults who fall. Methods: Four hundred sixty-two community dwellers seeking medical attention after an index fall were recruited from the Vancouver Falls Prevention Clinic and participated in this 12-month prospective cohort study. Ninety-six participants were part of a randomized controlled trial of exercise. Falls were tracked with monthly falls calendars. Demographics, falls risk measures, and the number of subsequent falls were compared between sexes. A principal component analysis (PCA) was employed to reduce the falls risk measures to a smaller set of factors. The PCA factors were used in negative binomial regression models to predict the number of subsequent falls. Age, exposure time (i.e., number of falls monitoring days), and prescribed exercise (yes/no) were used as covariates, and sex (male/female) and PCA factors were used as main effects. The interaction of sex by PCA factor was then included. Results: Males fell more over 12 months (males: 2.80 ± 6.86 falls; females: 1.25 ± 2.63 falls) than females, and poorer executive function predicted falls in males. Four PCA factors were defined – impaired cognition and mobility, low mood and self-efficacy, mobility resilience, and perceived poor health – each predicted the number of falls. The sex by mobility resilience interaction suggested that mobility resilience was less protective of falls in males. Conclusion: Modifiable risk factors related to cognition, physical function, psychological wellbeing, and health status predicted subsequent falls. In males, better mobility was not as protective of falls compared with females. This may be due to males' poorer executive function, contributing to decreased judgement or slowed decision-making during mobility. These results may inform efficacious sex-specific falls prevention strategies. [ABSTRACT FROM AUTHOR]

The number of older people worldwide living with cognitive impairment and neurodegenerative diseases is growing at an unprecedented rate. Despite accumulating evidence that engaging in physical activity is a promising primary behavioral strategy to delay or avert the deleterious effects of aging on brain health, a large degree of variation exists in study findings. Thus, before physical activity and exercise can be prescribed as "medicine" for promoting brain health, it is imperative to understand how different biological factors can attenuate or amplify the effects of physical activity on cognition at the individual level. In this review article, we briefly discuss the current state of the literature, examining the relationship between physical activity and brain health in older adults and we present the argument that biological sex is a potent moderator of this relationship. Additionally, we highlight some of the potential neurobiological mechanisms underlying this sex difference for this relatively new and rapidly expanding line of research. [ABSTRACT FROM AUTHOR]

Exercise is a non-pharmacological strategy to mitigate the deleterious effects of aging on brain health. However, a large amount of variation exists in its efficacy. Sex of participants and exercise type are two possible factors contributing to this variation. To better understand this, we conducted a concurrent systematic review and meta-analysis of cognitively healthy older adults. Executive functions, episodic memory, visuospatial function, word fluency, processing speed and global cognitive function were examined for exercise- and sex-dependent effects. For executive functions, three types of exercise interventions – aerobic training, resistance training, and multimodal training (i.e., both aerobic and resistance training) – were associated with larger effect sizes in studies comprised of a higher percentage of women compared to studies with a lower percentage of women. This suggests that women’s executive processes may benefit more from exercise than men. Regardless of sex, compared to control, all three exercise training approaches enhanced visuospatial function, but only multimodal training enhanced episodic memory. Overall, aerobic training led to greater benefits than resistance training in global cognitive function and executive functions, while multimodal combined training led to greater benefits than aerobic training for global cognitive function, episodic memory, and word fluency. Possible underlying mechanisms, including brain-derived neurotrophic factor and sex steroid hormones, are discussed. [ABSTRACT FROM AUTHOR]

Research in humans indicates that women may show greater cognitive benefits from aerobic training (AT) than men. To determine whether this sex difference extends to rodents, we conducted a systematic review and meta-analysis of studies in healthy, older rodents. Results indicate that compared to controls, AT improved hippocampus-dependent and -independent learning and memory. A sex difference was found with males showing larger benefits from AT on conditioned-avoidance and non-spatial memory tasks. AT also increased brain-derived neurotrophic factor compared to controls, with larger effects in females. As an exploratory analysis, sex differences in voluntary AT were examined separately from forced AT. Voluntary AT enhanced non-spatial memory to a greater extent in males. Forced AT enhanced hippocampus-dependent learning and memory more so in females. These findings suggest that sex is an important factor to consider, and studies directly assessing sex differences in the ability of exercise to improve brain function are needed. [ABSTRACT FROM AUTHOR]