Physical activity and memory functions: Are neurotrophins and cerebral gray matter volume the missing link?

Functional neuroplasticity of facilitation and interference effects on inhibitory control following 3-month physical exercise in aging

Preservation of executive function, like inhibition, closely links to the quality of life in senior adults. Although neuroimaging literature has shown enhanced inhibitory function followed by aerobic exercise, current evidence implies inconsistent neuroplasticity patterns along different time durations of exercise. Hence, we conducted a 12-week exercise intervention on 12 young and 14 senior volunteers and repeatedly measured the inhibitory functionality of distinct aspects (facilitation and interference effects) using the numerical Stroop task and functional Magnetic Resonance Imaging. Results showcased improved accuracy and reduced reaction times (RT) after 12-week exercise, attributed to frontoparietal and default mode network effects. In young adults, the first phase (0 to six weeks) exercise increased the activation of the right superior medial frontal gyrus, associated with reduced RT in interference, but in the second intervention phase (six to twelve weeks), the decreased activation of the left superior medial frontal gyrus positively correlated with reduced RT in facilitation. In senior adults, the first six-week intervention led to reduced activations of the inferior frontal gyrus, inferior parietal gyrus, and default mode network regions, associated with the reduced RT in interference. Still, in the second intervention phase, only the visual area exhibited increased activity, associated with reduced RT in interference. Except for the distinctive brain plasticity between the two phases of exercise intervention, the between-group comparison also presented that the old group gained more cognitive benefits within the first six weeks of exercise intervention; however, the cognitive improvements in the young group occurred after six weeks of intervention. Limited by the sample size, these preliminary findings corroborated the benefits of aerobic exercise on the inhibitory functions, implying an age × exercise interaction on the brain plasticity for both facilitation and interference.

Effects of a brief HIIT intervention on cognitive performance in older women

Cardiorespiratory fitness (CRF) mitigates age-related decline in cognition and brain volume. Little is known, however, about the effects of high-intensity interval training (HIIT) on cognitive aging and the relationship between HIIT, cognition, hippocampal subfield volumes, and cerebral oxygen extraction fraction (OEF). Older sedentary women participated in an 8-week HIIT intervention. We conducted cognitive assessments, fitness assessments (VO2max), MRI scans: asymmetric spin echo oxygen extraction fraction (ASE-OEF), high-resolution multiple image co-registration and averaging (HR-MICRA) imaging, and transcranial Doppler ultrasonography before and after the intervention. VO2max increased from baseline (M = 19.36, SD = 2.84) to follow-up (M = 23.25, SD = 3.61), Z =  - 2.93, p < .001, r = 0.63. Composite cognitive (Z =  - 2.05, p = 0.041), language (Z =  - 2.19, p = 0.028), and visuospatial memory (Z =  - 2.22, p = 0.026), z-scores increased significantly. Hippocampal subfield volumes CA1 and CA3 dentate gyrus and subiculum decreased non-significantly (all p > 0.05); whereas a significant decrease in CA2 (Z =  - 2.045, p = 0.041, r = 0.436) from baseline (M = 29.51; SD = 24.50) to follow-up (M = 24.50; SD = 13.38) was observed. Right hemisphere gray matter was correlated with language z-scores (p = 0.025; r = 0.679). The subiculum was correlated with attention (p = 0.047; r = 0.618) and verbal memory (p = 0.020; r = 0.700). The OEF and CBF were unchanged at follow-up (all p > .05). Although we observed cognitive improvements following 8 weeks of our HIIT intervention, they were not explained by hippocampal, OEF, or CBF changes.

Cross-sectional associations between 24-hour time-use composition, grey matter volume and cognitive function in healthy older adults

BACKGROUND

Increasing physical activity (PA) is an effective strategy to slow reductions in cortical volume and maintain cognitive function in older adulthood. However, PA does not exist in isolation, but coexists with sleep and sedentary behaviour to make up the 24-hour day. We investigated how the balance of all three behaviours (24-hour time-use composition) is associated with grey matter volume in healthy older adults, and whether grey matter volume influences the relationship between 24-hour time-use composition and cognitive function.

METHODS

This cross-sectional study included 378 older adults (65.6 ± 3.0 years old, 123 male) from the ACTIVate study across two Australian sites (Adelaide and Newcastle). Time-use composition was captured using 7-day accelerometry, and T1-weighted magnetic resonance imaging was used to measure grey matter volume both globally and across regions of interest (ROI: frontal lobe, temporal lobe, hippocampi, and lateral ventricles). Pairwise correlations were used to explore univariate associations between time-use variables, grey matter volumes and cognitive outcomes. Compositional data analysis linear regression models were used to quantify associations between ROI volumes and time-use composition, and explore potential associations between the interaction between ROI volumes and time-use composition with cognitive outcomes.

RESULTS

After adjusting for covariates (age, sex, education), there were no significant associations between time-use composition and any volumetric outcomes. There were significant interactions between time-use composition and frontal lobe volume for long-term memory (p = 0.018) and executive function (p = 0.018), and between time-use composition and total grey matter volume for executive function (p = 0.028). Spending more time in moderate-vigorous PA was associated with better long-term memory scores, but only for those with smaller frontal lobe volume (below the sample mean). Conversely, spending more time in sleep and less time in sedentary behaviour was associated with better executive function in those with smaller total grey matter volume.

CONCLUSIONS

Although 24-hour time use was not associated with total or regional grey matter independently, total grey matter and frontal lobe grey matter volume moderated the relationship between time-use composition and several cognitive outcomes. Future studies should investigate these relationships longitudinally to assess whether changes in time-use composition correspond to changes in grey matter volume and cognition.

The effect of exercise on cerebral blood flow and executive function among young adults: a double-blinded randomized controlled trial

Studies have demonstrated that exercise benefits executive function. However, it remains unclear which type of exercise is optimal for preserving executive function among young adults and the cerebral blood flow (CBF) mechanisms that underlie exercise-induced cognitive benefits. Therefore, this study aims to compare the intervention effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on executive function and the CBF mechanism. This was a double-blinded, randomized, controlled trial study conducted between October 2020 and January 2021 (ClinicalTrials.gov identifier: NCT04830059). Ninety-three healthy young adults (25.23 ± 2.18 years old; 49.82% male) were randomized into the HIIT (N = 33), MICT (N = 32), and control (N = 28) groups. Participants in exercise groups were guided to perform 40 min of HIIT and MICT three times a week for 12 weeks, while the control group received health education for the same period. The primary outcomes, changes in executive function assessed by the trail-making test (TMT), and CBF measured by transcranial Doppler flow analyzer (EMS-9WA), were evaluated before and after the interventions. The time taken to complete the TMT task improved significantly in the MICT group compared to the control group [β = -10.175, 95%, confidence interval (CI) =  -20.320, -0.031]. Additionally, the MICT group showed significant improvements in the pulsatility index (PI) (β = 0.120, 95% CI = 0.018, 0.222), resistance index (RI) (β = 0.043, 95% CI = 0.005, 0.082), and peak-systolic/end-diastolic velocity (S/D) (β = 0.277, 95% CI = 0.048, 0.507) of CBF compared to the control group. The time taken to complete the TMT was associated with the velocity of peak-systolic (F = 5.414, P = 0.022), PI (F = 4.973, P = 0.012), and RI (F = 5.845, P = 0.006). Furthermore, the accuracy of TMT was associated with PI (F = 4.797, P = 0.036), RI (F = 5.394, P = 0.024), and S/D (F = 4.312, P = 0.05) of CBF. A 12-week MICT intervention improved CBF and executive function more effectively than HIIT among young adults. Furthermore, the findings suggest that CBF was one of the potential mechanisms underlying the cognitive benefits of exercise in young people. These results provide practical evidence supporting the promotion of regular exercise to maintain executive function and improve brain health.

Effects of physical activity interventions on executive function in older adults with dementia: A meta-analysis of randomized controlled trials

BACKGROUND

To date quantitative meta-analysis with large samples to investigate the effects and potential moderators of physical activity (PA) on executive function (EF) in older adults with dementia is insufficient. Therefore, we conducted this meta-analysis.

DESIGN

Meta-analysis of randomized controlled trials (RCTs).

PARTICIPANTS

Old people with Alzheimer's disease (AD) or related dementia of varying types and severity as the primary diagnosis.

METHODS

PubMed, Web of Science, the Cochrane Library and Embase databases were searched for relevant studies published from 01 January, 2010 to 01 March, 2022. The results of executive function were reported in all RCTs. Random-effects meta-analysis was used to calculate the size of effects. Subgroup analyses of three moderators (including the specific sub-domains of EF, exercise prescription variables, and sample characteristics) were performed.

RESULTS

Eighteen RCTs were included with a combined sample size of 1366. Overall, PA interventions improved overall EF (standardized mean difference [SMD]=0.23, 95% confidence interval [CI] 0.05 to 0.41, p<0.05). The EF sub-domain "planning" was significant moderator (SMD=0.31, 95%CI 0.11 to 1.51, p<0.01), but inhibitory control, working memory and cognitive flexibility were not significant. Regarding exercise prescription variables, type of resistance training; moderate intensity; total duration ≤24 weeks and short (once or twice a week) frequency improved overall EF performance. Session length may be a moderator. Regarding sample characteristics, old-old, AD and both dementia and AD had significant benefits.

CONCLUSIONS AND IMPLICATIONS

EF in older adults with AD or related dementia benefited from physical activity, and the benefit was affected by the type, intensity, total duration, frequency of exercise. Physical activity can be an alternative intervention in aging patients with dementia, to improve EF performance or prevent or EF decline.

Multisystem physiological perspective of human frailty and its modulation by physical activity

"Frailty" is a term used to refer to a state characterized by enhanced vulnerability to, and impaired recovery from, stressors compared with a nonfrail state, which is increasingly viewed as a loss of resilience. With increasing life expectancy and the associated rise in years spent with physical frailty, there is a need to understand the clinical and physiological features of frailty and the factors driving it. We describe the clinical definitions of age-related frailty and their limitations in allowing us to understand the pathogenesis of this prevalent condition. Given that age-related frailty manifests in the form of functional declines such as poor balance, falls, and immobility, as an alternative we view frailty from a physiological viewpoint and describe what is known of the organ-based components of frailty, including adiposity, the brain, and neuromuscular, skeletal muscle, immune, and cardiovascular systems, as individual systems and as components in multisystem dysregulation. By doing so we aim to highlight current understanding of the physiological phenotype of frailty and reveal key knowledge gaps and potential mechanistic drivers of the trajectory to frailty. We also review the studies in humans that have intervened with exercise to reduce frailty. We conclude that more longitudinal and interventional clinical studies are required in older adults. Such observational studies should interrogate the progression from a nonfrail to a frail state, assessing individual elements of frailty to produce a deep physiological phenotype of the syndrome. The findings will identify mechanistic drivers of frailty and allow targeted interventions to diminish frailty progression.

Correlations between physical activity and quality of life in entrepreneurs from Wrocław, Poland

BACKGROUND

Limited physical activity is one of the main reasons for the rapid increase in the prevalence of diseases of affluence, which can lead to premature deaths in adults. Quality of life may be one of potential determinants of physical activity. The aim of this article is to identify the relationships between physical activity and quality of life in entrepreneurs from Wroclaw, Poland.

METHODS

A cross-sectional study was conducted on a group of 616 entrepreneurs (216 women and 400 men). A diagnostic survey method was used with a direct interview technique. The research tools included the International Physical Activity Questionnaire Short Form and the World Health Organization Quality of Life Questionnaire.

RESULTS

Among the studied entrepreneurs, along with their higher ratings of overall quality of life, the odds of high rather than low levels of physical activity increased nearly fivefold (OR 4.86, CI 3.34-7.07). Entrepreneurs with higher assessment levels of their perceived health condition were nearly twice as likely to report high rather than low physical activity levels (OR 1.92, CI 1.42-2.59). The conditional probability of high rather than low levels of physical activity also increased in the entrepreneurs with higher assessments of quality of life in the physical, psychological, social, and environmental domains, by 34%, 11%, 5%, and 6%, respectively.

CONCLUSION

Programs promoting physical activity among entrepreneurs, which focus on moderate and high intensity exercise, should be considered desirable in the context of the study findings. Activities aimed at improving quality of life in the physical and psychological domains as a potential determinant of the level of physical activity of entrepreneurs are also worth recommending.

Beta-band MEG signal power changes in older adults after physical exercise program with and without additional cognitive training

Physical exercise has been considered to be an efficient mean of preserving cognitive function and it influences both the structural and functional characteristics of the brain. It has especially been shown to increase brain plasticity, the capacity to re-structure brain properties in response to interaction, such as cognitive practice. Studies have also examined the potential additive effect of cognitive training on the documented benefit of physical exercise, commonly, however, not at the neural level. We monitored, using magnetoencephalography (MEG), the brain processes associated with executive functions in older individuals who participated in a 12-month randomized controlled trial including two research arms: physical and cognitive training vs physical training alone. Measurements were conducted at 0 months, 6 months, and 12 months. The addition of cognitive training was associated with better performance in the Stroop test that reflects executive control. The extra benefit of cognitive training was also manifested as decreased modulation of beta frequency band (15-25 Hz) especially to difficult distractors. As beta band activity is associated with attentional control, this indicates fewer resources needed to inhibit irrelevant sensory inputs. These results imply an enhancing role of cognitive elements integrated with physical training in improving or maintaining executive functions in older individuals.

Benefits of Tai Chi Quan on neurodegenerative diseases: A systematic review

BACKGROUND

Neurodegenerative diseases have become an important concern with the accelerated aging process. Tai Chi Quan (TCQ) has positive benefits for brain health and chronic diseases. The aim of this study was to summarize the protective effects of TCQ for motor function, cognition, quality of life, and mood in patients with neurodegenerative diseases.

METHODS

A systematic search was conducted via PubMed database and the Web of Science core collection database until August 20, 2021. The available English systematic reviews, meta-analyses, and clinical trials were included. Two reviewers completed the screening and assessment process independently.

RESULTS

A total of 28 studies on Parkinson's disease, 21 on cognitive impairment, and 9 on multiple sclerosis met the included criteria. The study found that TCQ remarkably improved general motor function and balance, and prevented falls for Parkinson's disease. TCQ significantly improved global cognitive function for cognitive impairment. TCQ was likely safe and beneficial for multiple sclerosis as result of heterogeneous outcomes and small samples.

CONCLUSION

TCQ exercise can effectively improve the motor function, global cognitive function, and falls in patients with neurodegenerative diseases. However, the positive effects of TCQ on the quality of life and mood of patients with neurodegenerative diseases need further evidence.

The physiological mechanism and effect of resistance exercise on cognitive function in the elderly people

Background

As brain function declines and cognitive ability declines, the benefits of resistance exercise to the brain of older people are gradually gaining attention.

Objective

The purpose of this review is to explore the mechanism and relationship between physiological factors such as vascular and neuronal degeneration and cognitive decline, and to categorize the differences in the effects of an acute and chronic resistance exercise intervention on cognitive function in healthy elderly people and the possible regulators of cognitive effects.

Methods

Using PubMed, Elsevier, Web of Science, X-MOL, CNKI, and Taiwan academic literature database, the research papers published in relevant journals at home and abroad until April 2022 were searched with Chinese and English keywords such as Resistance exercise, the elderly, hippocampus, memory performance, neurons, cognitive function. Pedro scale was used to check the quality of various documents, and the relevant research documents were obtained with the resistance exercise elements as the main axis for comprehensive analysis.

Results and conclusion

(1) Resistance exercise can have a beneficial effect on the brain function of the elderly through blood flow changes, stimulate nerve conduction substances and endocrine metabolism, promote cerebrovascular regeneration and gray matter volume of the brain, and prevent or delay the cognitive function degradation such as memory and attention of the elderly; (2) Acute resistance can temporarily stimulate hormone secretion in vivo and significantly improve the effect of short-term memory test, but it has little effect on the cognitive performance of the elderly; (3) Moderate-high intensity resistance exercise (50-80%1RM, 1-3 times/week, 2-3 groups/time) lasting for at least 6 months is more prominent for the improvement of cognitive function of the elderly, while the parameters such as resistance exercise intensity, exercise amount, duration, evaluation test time and differences of subjects may have different degrees of influence on cognitive benefits.

The Effect of Self-Paced Exercise Intensity and Cardiorespiratory Fitness on Frontal Grey Matter Volume in Cognitively Normal Older Adults: A Randomised Controlled Trial

OBJECTIVE

Exercise has been found to be important in maintaining neurocognitive health. However, the effect of exercise intensity level remains relatively underexplored. Thus, to test the hypothesis that self-paced high-intensity exercise and cardiorespiratory fitness (peak aerobic capacity; VO_2peak) increase grey matter (GM) volume, we examined the effect of a 6-month exercise intervention on frontal lobe GM regions that support the executive functions in older adults.

METHODS

Ninety-eight cognitively normal participants (age = 69.06 ± 5.2 years; n = 54 female) were randomised into either a self-paced high- or moderate-intensity cycle-based exercise intervention group, or a no-intervention control group. Participants underwent magnetic resonance imaging and fitness assessment pre-intervention, immediately post-intervention, and 12-months post-intervention.

RESULTS

The intervention was found to increase fitness in the exercise groups, as compared with the control group (F = 9.88, p = <0.001). Changes in pre-to-post-intervention fitness were associated with increased volume in the right frontal lobe (β = 0.29, p = 0.036, r = 0.27), right supplementary motor area (β = 0.30, p = 0.031, r = 0.29), and both right (β = 0.32, p = 0.034, r = 0.30) and left gyrus rectus (β = 0.30, p = 0.037, r = 0.29) for intervention, but not control participants. No differences in volume were observed across groups.

CONCLUSIONS

At an aggregate level, six months of self-paced high- or moderate-intensity exercise did not increase frontal GM volume. However, experimentally-induced changes in individual cardiorespiratory fitness was positively associated with frontal GM volume in our sample of older adults. These results provide evidence of individual variability in exercise-induced fitness on brain structure.

Relationship between Physical Activity and Emotional Regulation Strategies in Early Adulthood: Mediating Effects of Cortical Thickness

We investigated the relationship between physical activity (PA) and emotional regulation strategies among college students to establish the mediating role of cortical thickness. A total of 60 university students (18−20 years old) were enrolled in this study. The International Physical Activity Questionnaire (IPAQ-L) was used to estimate PA levels. Based on the International Physical Activity Working Group standards, PA levels were divided into low, medium, and high PA groups; emotional regulation strategies were determined by the Emotion Regulation Questionnaire (ERQ), including the Cognitive Reappraisal Scale (CR) and the Expressive Suppression Scale (ES). Structural magnetic resonance imaging (MRI) was used to measure cortical thickness. Differences in use of the ES strategy among high, medium, and low PA groups were not marked. However, compared to the low PA group, the CR strategy was frequently used in the high PA group, with a thicker right hemisphere rostral anterior cingulate cortex (rrACC). PA levels were positively correlated with thickness of the rrACC cortex (r = 0.398, p = 0.002 < 0.05) and CR strategy (r = 0.398, p = 0.002 < 0.05), and negatively correlated with the ES strategy (r = −0.348, p = 0.007 < 0.05). The rrACC cortical thickness played a partial mediating role in the relationship between PA and CR strategy, accounting for 33.1% of total effect values. These findings indicate that although the negative correlation between PA and ES was not significant, the positive correlation between PA with CR was significant, and rrACC thickness played a partial mediating role in the relationship between PA and CR, providing new evidence toward comprehensively revealing the relationship between PA, rrACC cortical thickness, and emotion regulation strategies.

Effects of different physical activities on brain-derived neurotrophic factor: A systematic review and bayesian network meta-analysis

Background

Emerging evidence suggests that exercise is a simple and effective method for maintaining brain function.

Aims

This review evaluates the effects of five physical exercises, including aerobic training (AT), high-intensity interval training (HIIT), combined training (CT), resistance training (RT), and AT+RT, on the serum level of brain-derived neurotrophic factor (BDNF) in healthy and non-healthy populations.

Methods

We searched CNKI, PubMed, Embase, Scopus, Medline, Web of Science, and Cochrane Library databases to review randomized controlled studies on exercise interventions for BDNF. Quantitative merging analysis of the resulting data using Bayesian network meta-analysis.

Results

The screening and exclusion of the searched literature resulted in the inclusion of 39 randomized controlled trials containing 5 exercise interventions with a total of 2031 subjects. The AT, RT, AT+RT, HIIT, and CT groups (intervention groups) and the CG group (conventional control group) were assigned to 451, 236, 102, 84, 293, and 865 subjects, respectively. The Bayesian network meta-analysis ranked the effect of exercise on BDNF level improvement in healthy and non-healthy subjects as follows: RT > HIIT > CT > AT+RT > AT > CG. Better outcomes were observed in all five intervention groups than in the CG group, with RT having the most significant effect [MD = 3.11 (0.33, 5.76), p < 0.05].

Conclusions

RT at moderate intensity is recommended for children and older adults in the case of exercise tolerance and is effective in maintaining or modulating BDNF levels for promoting brain health.

Systematic Review Registration

https://inplasy.com, INPLASY202250164.

Regular aerobic exercise is positively associated with hippocampal structure and function in young and middle-aged adults

Regular exercise has numerous benefits for brain health, including the structure and function of the hippocampus. The hippocampus plays a critical role in memory function, and is altered in a number of psychiatric disorders associated with memory impairments (e.g., depression and schizophrenia), as well as healthy aging. While many studies have focused on how regular exercise may improve hippocampal integrity in older individuals, less is known about these effects in young to middle-aged adults. Therefore, we assessed the associations of regular exercise and cardiorespiratory fitness with hippocampal structure and function in these age groups. We recruited 40 healthy young to middle-aged adults, comprised of two groups (n = 20) who self-reported either high or low levels of exercise, according to World Health Organization guidelines. We assessed cardiorespiratory fitness using a graded exercise test (VO₂ max) and hippocampal structure via manual tracing of T1-weighted magnetic resonance images. We also assessed hippocampal function using magnetic resonance spectroscopy to derive estimates of N-acetyl-aspartate concentration and hippocampal-dependent associative memory and pattern separation tasks. We observed evidence of increased N-acetyl-aspartate concentration and associative memory performance in individuals engaging in high levels of exercise. However, no differences in hippocampal volume or pattern separation capacity were observed between groups. Cardiorespiratory fitness was positively associated with left and right hippocampal volume and N-acetyl-aspartate concentration. However, no associations were observed between cardiorespiratory fitness and associative memory or pattern separation. Therefore, we provide evidence that higher levels of exercise and cardiorespiratory fitness are associated with improved hippocampal structure and function. Exercise may provide a low-risk, effective method of improving hippocampal integrity in an early-to-mid-life stage.

Free-Living Physical Activity Measured With a Wearable Device Is Associated With Larger Hippocampus Volume and Greater Functional Connectivity in Healthy Older Adults: An Observational, Cross-Sectional Study in Northern Portugal

Several studies using neuroimaging techniques have established a positive relationship between physical activity (PA) and brain structure and function in older populations. However, the use of subjective measures of PA and the lack of multimodal neuroimaging approaches have limited the understanding of this association. This study aims to explore the associations between PA and brain structure and function by objectively evaluating PA. Community-dwelling cognitively healthy older adults (without diagnosed cognitive, neurological or degenerative disease) were recruited from local health centers and local gyms. In a cross-sectional design, participants were evaluated regarding cognitive, clinical, anthropometric, physical performance, and lifestyle characteristics. A 3 T magnetic resonance imaging (MRI) was performed for structural and functional brain measures. PA time and level was assessed via a Xiaomi Mi Band 2^® worn for 15 consecutive days. Participants (n = 110, after inclusion/exclusion criteria and completion of all evaluations) were 58 females (56%), with an average age of 68.42 years old (SD = 3.12), most were active. Multiple regression analysis revealed that higher time spent in vigorous PA associated with larger left parahippocampal gyrus and right hippocampus volumes. Furthermore, the analysis of the functional connectome indicated a greater functional connectivity (FC) between the frontal gyrus, cingulate gyrus, occipital inferior lobe for light, moderate, and total PA time, and sedentary time associated with lower FC in the same networks. Overall, the structural and functional findings may provide evidence on the relevant association between PA and brain health in aging.

Active Life for Brain Health: A Narrative Review of the Mechanism Underlying the Protective Effects of Physical Activity on the Brain

A growing body of evidence clearly indicates the beneficial effects of physical activity (PA) on cognition. The importance of PA is now being reevaluated due to the increase in sedentary behavior in older adults during the COVID-19 pandemic. Although many studies in humans have revealed that PA helps to preserve brain health, the underlying mechanisms have not yet been fully elucidated. In this review, which mainly focuses on studies in humans, we comprehensively summarize the mechanisms underlying the beneficial effects of PA or exercise on brain health, particularly cognition. The most intensively studied mechanisms of the beneficial effects of PA involve an increase in brain-derived neurotrophic factor (BDNF) and preservation of brain volume, especially that of the hippocampus. Nonetheless, the mutual associations between these two factors remain unclear. For example, although BDNF presumably affects brain volume by inhibiting neuronal death and/or increasing neurogenesis, human data on this issue are scarce. It also remains to be determined whether PA modulates amyloid and tau metabolism. However, recent advances in blood-based biomarkers are expected to help elucidate the beneficial effects of PA on the brain. Clinical data suggest that PA functionally modulates cognition independently of neurodegeneration, and the mechanisms involved include modulation of functional connectivity, neuronal compensation, neuronal resource allocation, and neuronal efficiency. However, these mechanisms are as yet not fully understood. A clear understanding of the mechanisms involved could help motivate inactive persons to change their behavior. More accumulation of evidence in this field is awaited.

Accelerometer-Measured, Habitual Physical Activity and Circulating Brain-Derived Neurotrophic Factor: A Cross-Sectional Study

BACKGROUND

One of the mechanisms suggested to link physical activity (PA) to favorable brain health is through stimulation of neural growth factors such as brain-derived neurotrophic factor (BDNF). Acute bouts of PA stimulate circulating BDNF levels.

OBJECTIVE

In this investigation, we assessed whether habitual, accelerometer-measured PA levels were related to circulating BDNF levels in a middle-aged cohort.

METHODS

In the Framingham Heart Study Third Generation cohort, 1,769 participants provided reliable accelerometry data and were not missing BDNF measurement and platelet counts. In a cross-sectional analysis, using multivariable regression, we related PA measures to serum BDNF levels, adjusting for age, sex, smoking status, platelet count, depression status, and accelerometer wear time.

RESULTS

Our study participants (mean age 47±9 years, 50.8% women) spent an average of 22.3 mins/day moderate-to-vigorous (MV)PA. Most PA variables (steps, MVPA, light activity, and sedentary time) were not related to BDNF levels (p > 0.05). We observed a non-linear trend, where 15-50 mins/week vigorous activity was associated with lower BDNF compared to those with 0 min vigorous activity (β= -0.049±0.024, p = 0.05), but with no significant associations at lower or higher vigorous activity levels. In smokers, MVPA was also associated with lower BDNF levels (β= -0.216±0.079, p = 0.01).

CONCLUSION

Our study reveals that circulating BDNF is not chronically elevated in individuals with higher levels of habitual PA in middle-aged adults from the community and may even be chronically suppressed with higher PA in subgroups, including current smokers. These results do not contradict previous studies demonstrating that circulating BDNF rises acutely after PA.

Effects of a physical activity intervention on brain atrophy in older adults at risk of dementia: a randomized controlled trial

Lack of physical activity is a risk factor for dementia, however, the utility of interventional physical activity programs as a protective measure against brain atrophy and cognitive decline is uncertain. Here we present the effect of a randomized controlled trial of a 24-month physical activity intervention on global and regional brain atrophy as characterized by longitudinal voxel-based morphometry with T1-weighted MRI images. The study sample consisted of 98 participants at risk of dementia, with mild cognitive impairment or subjective memory complaints, and having at least one vascular risk factor for dementia, randomized into an exercise group and a control group. Between 0 and 24 months, there was no significant difference detected between groups in the rate of change in global, or regional brain volumes.

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.

Physical fitness mediates the association between age and cognition in healthy adults

BACKGROUND

Physical fitness is an important contributor to healthy aging that improves cognition. Older adults who engage in cardiorespiratory fitness activities show less cognitive decline.

AIMS

To examine whether physical fitness acts as a potential protective mechanism shielding against the negative associations between age and cognition. Specifically, we examined whether physical fitness mediates the relationship between age and processing speed.

METHODS

114 (M = 63.80, SD = 10.63) senior executives completed a computerized cognitive battery composed of four processing speed tasks. Level of physical fitness was assessed on a treadmill stress test and reported in metabolic equivalents (METs).

RESULTS

Older age was associated with slower processing speed (r = 0.25, p = 0.007), whereas greater physical fitness was associated with faster processing speed (r = -0.30, p = 0.001). Path analysis indicated that the association between age and processing speed was fully mediated by the level of physical fitness (Indirect effect: β = 0.10, p = 0.008; Direct effect: β = 0.16, p = 0.20).

CONCLUSIONS AND DISCUSSION

The findings indicate that physical fitness is a strong mediator of the relationship between age and processing speed and imply that physical fitness makes a major contribution to cognitive reserve during the aging process. The results may suggest that the decrease in physical fitness during aging may partially account for slower cognitive processing.

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.

When your brain looks older than expected: combined lifestyle risk and BrainAGE

Lifestyle may be one source of unexplained variance in the great interindividual variability of the brain in age-related structural differences. While physical and social activity may protect against structural decline, other lifestyle behaviors may be accelerating factors. We examined whether riskier lifestyle correlates with accelerated brain aging using the BrainAGE score in 622 older adults from the 1000BRAINS cohort. Lifestyle was measured using a combined lifestyle risk score, composed of risk (smoking, alcohol intake) and protective variables (social integration and physical activity). We estimated individual BrainAGE from T1-weighted MRI data indicating accelerated brain atrophy by higher values. Then, the effect of combined lifestyle risk and individual lifestyle variables was regressed against BrainAGE. One unit increase in combined lifestyle risk predicted 5.04 months of additional BrainAGE. This prediction was driven by smoking (0.6 additional months of BrainAGE per pack-year) and physical activity (0.55 less months in BrainAGE per metabolic equivalent). Stratification by sex revealed a stronger association between physical activity and BrainAGE in males than females. Overall, our observations may be helpful with regard to lifestyle-related tailored prevention measures that slow changes in brain structure in older adults.

Exploring the Impact of Modifiable Factors on Serum BDNF in Psychiatric Patients and Community Controls

BACKGROUND

Brain-derived neurotrophic factor (BDNF) has been a focus of psychiatric research for the past two decades. BDNF has been shown to impact neural function and development. Studies have investigated serum BDNF as a biomarker for psychiatric disorders such as depression and schizophrenia. In some studies, investigators attempt to control for variables such as smoking status, exercise, or diet. However, the relationship between these factors and BDNF is not clearly established. Furthermore, some studies have questioned whether a difference in the impact of BDNF exists between psychiatric and healthy populations.

PURPOSE

We aim to examine the association between serum BDNF levels and modifiable risk factors such as body mass index (BMI), smoking, exercise levels, and diet. Subsequently, we aim to examine whether the relationship between these risk factors and serum BDNF is different between psychiatric and control populations.

PATIENTS AND METHODS

We use cross-sectional data from an age- and sex-matched case-control study of participants with psychiatric inpatients and community controls without psychiatric diagnoses. Participants completed comprehensive assessments at study enrolment including sociodemographic information, smoking status, exercise, diet, and BMI. Serum BDNF levels were collected from participants. Linear regression analysis was performed to determine the association between modifiable factors and serum BDNF level.

RESULTS

A significant association was found between sedentary activity level and lower serum BDNF levels (Beta coefficient = -2.49, 95% confidence interval [CI] -4.70, -0.28, p = 0.028). Subgroup analysis demonstrated that this association held for psychiatric inpatients but not for community controls; it also held in females (Beta coefficient = -3.18, 95% CI -6.29, -0.07, p = 0.045) but not in males (Beta coefficient = -1.42, 95% CI -4.61, 1.78, p = 0.383). Antidepressant use had a significantly different association between male (Beta coefficient = 3.20, 95% CI 0.51, 5.88, p = 0.020) and female subgroups (Beta coefficient = -3.10, 95% CI -5.75, -0.46, p = 0.022). No significant association was found between other factors and serum BDNF.

CONCLUSION

Sedentary activity level may lead to lower serum BDNF levels in individuals with psychiatric diagnoses. Our findings support the notion that physical activity can provide a positive impact as part of treatment for psychiatric illness.

Effects of physical activity on brain function and structure in older adults: A systematic review

Despite increasing evidence that physical activity (PA) contributes to brain health in older individuals, both at the level of brain structure and function, this relationship is not yet well established. To explore this potential association, a systematic literature search was performed using PubMed, Scopus, and Web of Science, adhering to PRISMA guidelines. A total of 32 studies met the eligibility criteria: 24 cross-sectional and 8 longitudinal. Results from structural Magnetic Resonance Imaging (MRI) showed that PA associated with larger brain volumes (less brain atrophy) specifically in brain regions vulnerable to dementia, comprising the hippocampus, temporal, and frontal regions. Furthermore, functional MRI (fMRI) showed greater task-relevant activity in brain areas recruited in executive function and memory tasks. However, the dose-response relationship is unclear due to the high variability in PA measures. Further research using objective measures is needed to better understand which PA type, intensity, frequency, and duration, has the greatest protective effect on brain health. Findings highlight the importance of PA in both cognitive decline and dementia prevention.

Does dance counteract age-related cognitive and brain declines in middle-aged and older adults? A systematic review

BACKGROUND

Dance is a multidomain activity that combines aerobic, coordination and cognitive exercise. This music-associated physical and cognitive exercise is a leisure activity that motivates people, elicits emotions, and avoids boredom, promoting adherence to practice. Continuing physical activity is of paramount importance, since cognitive benefits tend to disappear or even reverse when training ceases.

OBJECTIVE

The question we addressed in this systematic review is what influence dance has on the brain and cognition of healthy middle-aged and older adults.

LITERATURE SURVEY

We systematically reviewed the effects of dance on brain and cognition in older adults using MEDLINE, Psyc-Info, PubMed and Scopus databases.

METHODOLOGY

After screening 1051 studies, thirty-five met the eligibility inclusion criteria. These studies showed that dance improves brain structure and function as well as physical and cognitive functions.

CONCLUSIONS

The protective effect of dance training on cognition in older adults, together with the possibility of adapting intensity and style to suit possible physical limitations makes this activity very suitable for older adults.

Assessment of Leisure Time Physical Activity and Brain Health in a Multiethnic Cohort of Older Adults

IMPORTANCE

Results from longitudinal studies suggest that regular leisure time physical activity (LTPA) is associated with reduced risk of dementia or Alzheimer disease. Data on the association between LTPA and brain magnetic resonance imaging (MRI) measures remain scarce and inconsistent.

OBJECTIVE

To examine the association of LTPA and MRI-assessed brain aging measures in a multiethnic elderly population.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included 1443 older (≥65 years) adults without dementia who were participants of the Washington/Hamilton Heights-Inwood Columbia Aging Project study. LTPA, from self-reported questionnaire, was calculated as metabolic equivalent of energy expenditure. Both moderate to vigorous LTPA, assessed as meeting Physical Activity Guidelines for Americans (≥150 minutes/week) or not, and light-intensity LTPA were also examined.

EXPOSURES

LTPA.

MAIN OUTCOMES AND MEASURES

Primary outcomes included total brain volume (TBV), cortical thickness, and white matter hyperintensity volume, all derived from MRI scans with established methods and adjusted for intracranial volume when necessary. We examined the association of LTPA with these imaging markers using regression models adjusted for demographic, clinical, and vascular risk factors.

RESULTS

The 1443 participants of the study had a mean (SD) age of 77.2 (6.4) years; 921 (63.8%) were women; 27.0%, 34.4%, and 36.3% were non-Hispanic White, non-Hispanic African American, and Hispanic individuals, respectively; and 27.3% carried the apolipoprotein E (APOE) ɛ4 allele. Compared with the LTPA of nonactive older adults, those with the most LTPA had larger (in cm3) TBV (β [SE], 13.17 [4.42] cm3; P = .003; P for trend = .006) and greater cortical thickness (β [SE], 0.016 [0.008] mm; P = .05; P for trend = .03). The effect size comparing the highest LTPA level with the nonactive group was equivalent to approximately 3 to 4 years of aging (β for 1 year older, -3.06 and -0.005 for TBV and cortical thickness, respectively). A dose-response association was found and even the lowest LTPA level had benefits (eg, TBV: β [SE], 9.03 [4.26] cm3; P = .03) compared with the nonactive group. Meeting Physical Activity Guidelines for Americans (TBV: β [SE], 18.82 [5.14] cm3; P < .001) and light-intensity LTPA (TBV: β [SE], 9.26 [4.29] cm3; P = .03) were also associated with larger brain measures. The association between LTPA and TBV was moderated by race/ethnicity, sex, and APOE status, but generally existed in all subgroups. The results remained similar after excluding participants with mild cognitive impairment.

CONCLUSIONS AND RELEVANCE

In this study, more physical activity was associated with larger brain volume in older adults. Longitudinal studies are warranted to explore the potential role of physical activity in brain health among older individuals.

A neural mechanism for affective well-being: Subgenual cingulate cortex mediates real-life effects of nonexercise activity on energy

Physical activity substantially improves well-being and mental health, but the underlying brain processes remain unclear. Most research concerns exercise, although the majority of everyday human behaviors, such as walking or stair climbing, are nonexercise activities. Combining neuroimaging with ecological assessment of activity and GPS-triggered smartphone diaries, we show a specific association of nonexercise activity with energy in two independent samples mediated by the subgenual part of the anterior cingulate cortex (sgACC), a key emotion regulatory site. Furthermore, energy predicted a range of mental health metrics. sgACC volume moderated humans' emotional gain from nonexercise activity in real life: Individuals with low sgACC volume, a risk factor for depression, felt less energized when inactive but benefited more from periods of high nonexercise activity. This suggests an everyday life mechanism affecting affective well-being in the general population and, if substantiated in patient samples, a risk and resilience process for mood disorders.

[Prevention of dementia in patients with mild cognitive impairment]

Cognitive impairment is one of the most common consequences of brain dysfunction. Nowadays, there is an increasing interest in the diagnosis and treatment of cognitive impairment without dementia, as a stage of cognitive deficit spectrum that could be controlled. The article discusses the current approaches to the management of patients with mild cognitive impairment including non-pharmacological strategies as well as medical antioxidant treatment.

White Matter Changes on Diffusion Tensor Imaging in the FINGER Randomized Controlled Trial

Background:

Early pathological changes in white matter microstructure can be studied using the diffusion tensor imaging (DTI). It is not only important to study these subtle pathological changes leading to cognitive decline, but also to ascertain how an intervention would impact the white matter microstructure and cognition in persons at-risk of dementia.

Objectives:

To study the impact of a multidomain lifestyle intervention on white matter and cognitive changes during the 2-year Finnish Geriatric Intervention Study to prevent Cognitive Impairment and Disability (FINGER), a randomized controlled trial in at-risk older individuals (age 60–77 years) from the general population.

Methods:

This exploratory study consisted of a subsample of 60 FINGER participants. Participants were randomized to either a multidomain intervention (diet, exercise, cognitive training, and vascular risk management, n = 34) or control group (general health advice, n = 26). All underwent baseline and 2-year brain DTI. Changes in fractional anisotropy (FA), diffusivity along domain (F1) and non-domain (F2) diffusion orientations, mean diffusivity (MD), axial diffusivity (AxD), radial diffusivity (RD), and their correlations with cognitive changes during the 2-year multidomain intervention were analyzed.

Results:

FA decreased, and cognition improved more in the intervention group compared to the control group (p < 0.05), with no significant intergroup differences for changes in F1, F2, MD, AxD, or RD. The cognitive changes were significantly positively related to FA change, and negatively related to RD change in the control group, but not in the intervention group.

Conclusion:

The 2-year multidomain FINGER intervention may modulate white matter microstructural alterations.

Larger Volume and Different Activation of the Brain in Response to Threat in Military Officers

Introduction:

Military missions involve stressful and life-threatening situations; however, soldiers should have a healthy cognition on the battlefield despite their high-stress levels. This is an ability that should be gained during prior military training. Successful and influential training is suggested to be associated with structural and functional improvements of the brain.

Methods:

This study investigated the pattern of brain activation while observing videos relevant to life-threatening situations, in addition to brain structure. Accordingly, the obtained data were compared between 20 military members and 26 healthy controls. The study participants were all male, aged between 19 to 24 years, right-handed, studying BSc, and from the same socioeconomic status.

Results:

The obtained data presented a larger volume in a total number of 1103 voxels of the brain (in 5 brain areas) in the military group. Furthermore, the military group suggested higher brain activation in the visual processing areas of the brain when observing real combat videos; however, this increment was mostly in the areas associated with motor processing and executive functions in the controls.

Conclusion:

This study indicated that military training is associated with positive structural changes in the brain. Besides, it provided a different brain activation in response to stressful situations. These findings highlighted the importance of qualified military training.

Exercise benefits on Alzheimer's disease: State-of-the-science

Although there is no unanimity, growing evidence supports the value of regular physical exercise to prevent Alzheimer's disease as well as cognitive decline in affected patients. Together with an introductory summary on epidemiological evidence, the aim of this review is to summarize the current knowledge on the potential biological mechanisms underlying exercise benefits in this condition. Regular physical exercise has proven to be beneficial for traditional cardiovascular risk factors (e.g., reduced vascular flow, diabetes) involved in the pathogenesis of Alzheimer's disease. Exercise also promotes neurogenesis via increases in exercise-induced metabolic factors (e.g., ketone bodies, lactate) and muscle-derived myokines (cathepsin-B, irisin), which in turn stimulate the production of neurotrophins such as brain-derived neurotrophic factor. Finally, regular exercise exerts anti-inflammatory effects and improves the brain redox status, thereby ameliorating the pathophysiological hallmarks of Alzheimer's disease (e.g., amyloid-β deposition). In summary, physical exercise might provide numerous benefits through different pathways that might, in turn, help prevent risk and progression of Alzheimer's disease. More evidence is needed, however, based on human studies.

Physical Activity as a Moderator of Alzheimer Pathology: A Systematic Review of Observational Studies

INTRODUCTION

Observational studies have found that physical activity is associated with a reduced risk of cognitive decline and dementia. Whether physical activity may also reduce the level of AD pathology, remains undetermined.

OBJECTIVE

To examine the relationship between physical activity and AD biomarkers (beta-amyloid1- 42, total tau and phosphorylated tau in CSF, amyloid PET, hippocampal atrophy on MRI and parietotemporal hypometabolism on brain 18F-FDG-PET).

METHODS

We carried out a systematic review of the observational studies of physical activity and AD biomarkers in healthy subjects, subjective cognitive complaints, mild cognitive impairment (MCI) and AD dementia.

RESULTS

We identified a total of 40 papers, which were eligible for inclusion. Thirty-four studies were conducted on healthy subjects, 3 on MCI and healthy subjects, 1 on MCI, and 2 on AD and healthy controls. Six studies reported on CSF biomarkers, 9 on amyloid PET, 29 on MRI and 4 on brain 18FFDG- PET. The majority of studies did not find a significant association between physical activity and AD biomarkers.

CONCLUSION

The quality of included studies with only a few longitudinal studies, limits the conclusions which may be drawn from the present findings especially regarding the biomarkers other than hippocampal volume. However, the majority of the identified studies did not find a significant association.

Objectively measured physical activity is associated with dorsolateral prefrontal cortex volume in older adults

BACKGROUND

Epidemiological studies suggest physical activity (PA) can slow or prevent both cognitive decline and age-related atrophy in frontal and hippocampal gray matter volumes. However, much of this evidence is based on self-reported measures of PA.

METHODS

PA was measured objectively with a SenseWear™ Armband to examine the cross-sectional associations between the duration of light, moderate and vigorous intensity PA with gray matter volume in the dorsolateral prefrontal cortex (DLPFC) and hippocampus in 167 (female: 43%) cognitively healthy older adults aged 73 to 78.

RESULTS

The duration of objective moderate to vigorous intensity physical activity (MVPA) was associated with a greater volume of the right DLPFC (β ​= ​0.16; p ​= ​0.04). In addition, objective moderate-intensity PA alone was also associated with greater volume of the left (β ​= ​0.17; p ​= ​0.03) and right (β ​= ​0.19; p ​= ​0.01) DLPFC after controlling for covariates and adjustment for multiple comparisons. In contrast, there were no significant associations between light- or vigorous-intensity PA and gray matter volumes (all p ​> ​0.05). No associations between PA and cognitive performance were detected, and self-reported PA was not associated with any of the outcomes investigated.

CONCLUSIONS

These findings suggest that an intensity-dependent relationship may exist, whereby a greater duration of MVPA, perhaps driven by moderate-intensity PA, is associated with preserved gray matter volume in frontal regions of the brain. Future research should investigate the mechanisms of this dose-effect and determine whether greater brain volumes associated with objective PA convey protective effects against cognitive decline.

Effects of aquatic physical intervention on fall risk, working memory and hazard-perception as pedestrians in older people: a pilot trial

BACKGROUND

Normal aging is associated with balance, mobility and working memory decline that increase fall risk and influence activity of daily living functions. Mounting evidence suggests that physical activity is beneficial for decreasing aging effects. Previous studies have focused on land-based physical activity. Research concerning the aquatic environment is scarce. The primary objectives of this three arm intervention pilot study were to examine the effects of an aquatic physical intervention program on balance, gait, fall risk and working memory among community-dwelling older individuals. The secondary objective was to examine the effects of an aquatic physical intervention program on safety of street-crossing among community-dwelling older individuals.

METHODS

Forty-two healthy participants aged 65 or older were enrolled into one of three intervention groups: aquatic physical intervention (API) (N = 13), on-land physical intervention (OLPI) (N = 14) or non-physical intervention (NPI) (N = 15). The intervention took place from 2018 until 2019 at Tel-Aviv University, Sheba medical center and Reich Center. The protocol included 30-min sessions twice a week for 12 weeks. Balance, gait and fall risk were assessed by the Tinneti test, working memory abilities were assessed by digit span and Corsi blocks tests and simulated safe streets-crossing was assessed by the hazard perception test for pedestrians. Testing and data collection was conducted at baseline, after six weeks and 12 weeks of intervention. All members of the professional team involved in evaluating participants were blind to the intervention group to which participants were allocated.

RESULTS

The differences in Tinetti balance (F (2, 39)=10.03, p < 0.01), fall risk (F (2, 39)=5.62, p0 > .05), digit span forward (F (2, 39)=8.85, p < 0.01) and Corsi blocks forward (F (2, 39)=3.54, p < 0.05) and backward (F (2, 39)=6.50, p < 0.05) scores after 12 weeks between the groups were significant. The API group showed improved scores. The differences in hazard perception test for pedestrians scores after 12 weeks of intervention between the groups were marginally significant (F (2, 39)=3.13, p = 0.055). The API group showed improved scores.

CONCLUSIONS

These findings may affect experts working with the elderly population when making decisions concerning therapeutic prevention interventions for the deficiencies of elderly patients. Older adults practicing aquatic physical activity could contribute to their increased safety.

TRIAL REGISTRATION

Trial registration number: ClinicalTrials.gov Registry NCT03510377. Date of registration: 10/31/2017.

Brain-Derived Neurotrophic Factor and Diabetes

Diabetes and its chronic complications still represent a great clinical problem, despite improvements made in the diagnosis and treatment of the disease. People with diabetes have a much higher risk of impaired brain function and psychiatric disorders. Neurotrophins are factors that protect neuronal tissue and improve the function of the central nervous system, and among them is brain-derived neurotrophic factor (BDNF). The level and function of BDNF in diabetes seems to be disturbed by and connected with the presence of insulin resistance. On the other hand, there is evidence for the highly beneficial impact of physical activity on brain function and BDNF level. However, it is not clear if this protective phenomenon works in the presence of diabetes. In this review, we summarize the current available research on this topic and find that the results of published studies are ambiguous.

Exercise and Dementia

Several experimental and human studies documented the preventive and therapeutic effects of exercise on various diseases as well as the normal physiological function of different systems during aging. The findings of several basic animal studies and clinical investigations identified the advantageous effects of exercise as non-pharmaceutical intervention on dementia and Alzheimer's disease (AD). The main positive effects suggested for exercise are less cognitive and behavioral impairment or decline, development of health-associated conditions (stress, sleep), reduction of dementia risk factors including chronic non-communicable disease (diabetes, cardiovascular disease), increase in neurotrophins, enhancement of brain blood flow, angiogenesis, neurogenesis, synaptogenesis and synaptic plasticity in the brain memory-related region (e.g., hippocampus), and reduction of neuroinflammation and apoptosis. However, regarding the controversial evidence in literature, designing standard clinical and experimental studies to reveal the correlation between physical activity and dementia sign and symptom including biomarker alternation, brain supramolecular and molecular changes, and neuropsychological manifestation is necessary for preparation of effective guidelines and recommendations.

The role of exercise in the reversal of IGF-1 deficiencies in microvascular rarefaction and hypertension

Hypertension has been linked with peripheral and central reductions in vascular density, and with devastating effects on brain function. However, the underlying mechanisms in the relationship between blood pressure and cognitive impairment have yet to be fully elucidated. Here, we review compelling evidence from two lines of inquiry: one that links microvascular rarefaction with insulin-like growth factor 1 (IGF-1) deficiencies, and another which posits that vascular dysfunction precedes hypertension. Based on the findings from experimental and clinical studies, we propose that these lines of evidence converge, and suggest that age-related declines in IGF-1 concentrations precede microvascular rarefaction, initiate an increase in vascular resistance, and therefore are causally linked to onset of hypertension. Physical exercise provides a relevant model for supporting our premise, given the well-established effects of exercise in attenuating vascular dysfunction, hypertension, IGF-1 deficiency, and cognitive decline. We highlight here the role of exercise-induced increases in blood flow in improving vascular integrity and enhancing angiogenesis via the actions of IGF-1, resulting in reversal of rarefaction and hypertension, and enhancement of cerebral blood flow and cognition.

Running exercise protects oligodendrocytes in the medial prefrontal cortex in chronic unpredictable stress rat model

Previous postmortem and animal studies have shown decreases in the prefrontal cortex (PFC) volume and the number of glial cells in the PFC of depression. Running exercise has been shown to alleviate depressive symptoms. However, the effects of running exercise on the medial prefrontal cortex (mPFC) volume and oligodendrocytes in the mPFC of depressed patients and animals have not been investigated. To address these issues, adult male rats were subjected to chronic unpredictable stress (CUS) for 5 weeks, followed by treadmill running for 6 weeks. Then, the mPFC volume and the mPFC oligodendrocytes were investigated using stereology, immunohistochemistry, immunofluorescence and western blotting. Using a CUS paradigm that allowed for the analysis of anhedonia, we found that running exercise alleviated the deficits in sucrose preference, as well as the decrease in the mPFC volume. Meanwhile, we found that running exercise significantly increased the number of CNPase⁺ oligodendrocytes and Olig2⁺ oligodendrocytes, reduced the ratio between Olig2⁺/NG2⁺ oligodendrocytes and Olig2⁺ oligodendrocytes and increased myelin basic protein (MBP), CNPase and Olig2 protein expression in the mPFC of the CUS rat model. However, running exercise did not change NG2⁺ oligodendrocyte number in the mPFC in these rats. These results indicated that running exercise promoted the differentiation of oligodendrocytes and myelin-forming ability in the mPFC in the context of depression. These findings suggest that the beneficial effects of running exercise on mPFC volume and oligodendrocytes in mPFC might be an important structural basis for the antidepressant effects of running exercise.

Does brain-derived neurotrophic factor mediate the effects of exercise on memory?

Objective: Brain-derived neurotrophic factor (BDNF) has been hypothesized as a potential mechanism through which exercise may subserve memory function. The present review specifically evaluates this hypothesis.Methods: Studies were identified using electronic databases, including PubMed, PsychInfo, Sports Discus and Google Scholar.Results: In total, 52 articles met the study criteria, and among these, 36 were conducted in an animal model and 16 among humans. Among the animal experiments, 100% of them demonstrated that chronic exercise improved memory function; 97% demonstrated an exercise-induced increase in BDNF; and among the eight evaluating BDNF as a mediator, 100% provided evidence that BDNF mediated the relationship between exercise and memory. The findings in the human studies were mixed. Among the human studies, 44% demonstrated that varying exercise protocols improved memory and increased BDNF levels, and among the studies evaluating BDNF as a mediator, 40% provided evidence that BDNF mediated the relationship between exercise and memory.Conclusion: In animal models, chronic exercise training robustly increases BDNF and improves memory performance, with reasonable evidence to also suggest that BDNF may mediate the exercise-memory interaction. These interrelationships, however, are less clear among humans. Future research among humans, in particular, is needed to evaluate the extent to which BDNF may mediate the relationship between exercise and memory.

Physical activity and depression: Towards understanding the antidepressant mechanisms of physical activity

Physical activity can treat and prevent depressive symptoms, but its antidepressant mechanisms are yet to be established. In this review, we comprehensively assess key biological and psychosocial mechanisms through which physical activity exerts antidepressant effects, with a particular focus on exercise. Exercise, a subset of physical activity, influences a range of biological and psychosocial processes also implicated in the pathophysiology of depression. We focus on the capacity for exercise to elicit changes in neuroplasticity, inflammation, oxidative stress, the endocrine system, self-esteem, social support and self-efficacy. We also discuss how a better understanding of these mechanisms can inform the way we design and implement exercise-based interventions to maximise their antidepressant effects on an individual basis. We conclude by presenting a conceptual framework of the key biological and psychosocial mechanisms underlying the relationship between physical activity and depressive symptoms, and the moderators and confounders that may influence it.

Associations of Physical Activity and β-Amyloid With Longitudinal Cognition and Neurodegeneration in Clinically Normal Older Adults

Importance

In the absence of disease-modifying therapies for Alzheimer disease, there is a critical need to identify modifiable risk factors that may delay the progression of Alzheimer disease.

Objective

To examine whether physical activity moderates the association of β-amyloid (Aβ) burden with longitudinal cognitive decline and neurodegeneration in clinically normal individuals and to examine whether these associations are independent of vascular risk.

Design, Setting, and Participants

This longitudinal observational study included clinically normal participants from the Harvard Aging Brain Study. Participants were required to have baseline Aβ positron emission tomography data, baseline medical data to quantify vascular risk, and longitudinal neuropsychological and structural magnetic resonance imaging data. Data were collected from April 2010 to June 2018. Data were analyzed from August to December 2018.

Main Outcomes and Measures

Baseline physical activity was quantified with a pedometer (mean steps per day). Baseline Aβ burden was measured with carbon 11-labeled Pittsburgh Compound B positron emission tomography. Cognition was measured annually with the Preclinical Alzheimer Cognitive Composite (PACC; median [interquartile range] follow-up, 6.0 [4.3-6.3] years). Neurodegeneration was assessed with longitudinal structural magnetic resonance imaging (2 to 5 scans per participant; median [interquartile range] follow-up, 4.5 [3.0-5.0] years), with a focus on total gray matter volume and regional cortical thickness. Physical activity and Aβ burden were examined as interactive predictors of PACC decline and volume loss in separate linear mixed models, adjusting for age, sex, education, apolipoprotein E ε4 status, and, where appropriate, intracranial volume. Secondary models adjusted for vascular risk and its interaction with Aβ burden.

Results

Of the 182 included participants, 103 (56.6%) were female, and the mean (SD) age was 73.4 (6.2) years. In models examining PACC decline and volume loss, there was a significant interaction of physical activity with Aβ burden, such that greater physical activity was associated with slower Aβ-related cognitive decline (β, 0.03; 95% CI, 0.02-0.05; P < .001) and volume loss (β, 482.07; 95% CI, 189.40-774.74; P = .002). Adjusting for vascular risk did not alter these associations. In these models, lower vascular risk was independently associated with slower Aβ-related PACC decline (β, -0.04; 95% CI, -0.06 to -0.02; P < .001) and volume loss (β, -483.41; 95% CI, -855.63 to -111.20; P = .01).

Conclusions and Relevance

Greater physical activity and lower vascular risk independently attenuated the negative association of Aβ burden with cognitive decline and neurodegeneration in asymptomatic individuals. These findings suggest that engaging in physical activity and lowering vascular risk may have additive protective effects on delaying the progression of Alzheimer disease.

Modulation of inhibitory function in the primary somatosensory cortex and temporal discrimination threshold induced by acute aerobic exercise

Acute aerobic exercise beneficially affects brain function. The effect of acute aerobic exercise on the inhibitory mechanism of the primary somatosensory cortex (S1) and somatosensory function remains unclear. We investigated whether acute aerobic exercise modulates S1 inhibitory function and somatosensory function. In Experiment 1, we measured somatosensory evoked potentials (SEP) and paired-pulse inhibition (PPI) in 15 healthy right-handed participants. The right median nerve underwent electrical stimulation (ES). Interstimulus intervals were 5 ms, 30 ms, and 100 ms. In Experiment 2, we assessed the somatosensory function by using a somatosensory temporal discrimination task. Single or paired ES was applied to the distal phalanx of the right index finger. Both the experiments involved three sessions: 20 min of moderate-intensity exercise, 30 min of low-intensity exercise, and 30 min of seated rest. Before and after each session, PPI and somatosensory temporal discrimination task performance were measured. The N20 latency was significantly shortened immediately after moderate exercise. The SEP amplitude was not modulated in any session. The PPI at 30 ms (PPI_30ms) significantly decreased 20 min after moderate exercise, whereas the PPI at 5 ms (PPI_5ms) and PPI at 100 ms (PPI_100ms) did not change. The 50% and 75% thresholds and reaction time did not improve in any session. We found negative relationships between the change in PPI_5ms and the change in the 75% threshold under low-intensity exercise condition. Thus, acute aerobic exercise modulated S1 inhibitory function depending on exercise intensity. The exercise-induced change in PPI was associated with the change in temporal discrimination.

Cerebral changes improved by physical activity during cognitive decline: A systematic review on MRI studies

Current treatment in late-life cognitive impairment and dementia is still limited, and there is no cure for brain tissue degeneration or reversal of cognitive decline. Physical activity represents a promising non-pharmacological interventional approach in many diseases causing cognitive impairment, but its effect on brain integrity is still largely unknown. Especially research of cerebral alterations in disease state that goes beyond observations of clinical improvement is crucial to understand disease processes and possible effective treatments. In this systematic review, we address the question how physical activity and fitness in mild cognitive impairment (MCI) and Alzheimer's disease (AD) influences brain architecture compared to cognitively healthy elderly. We review both interventional studies comprising aerobic, coordinative and resistance exercises and observational studies on fitness and physical activity combined with Magnetic Resonance imaging (MRI). Different MRI approaches were included such as volumetric and structural analyses, Diffusion Tensor Imaging (DTI), functional MRI and Cerebral Blood Flow (CBF). We evaluate MRI results for different exercise modalities and performed a methodological evaluation of interventional studies in cognitive decline compared to normal aging. According to our results, among 12 interventions in AD/MCI, aerobic exercise is most frequently applied (9 studies). Interventions in AD/MCI altogether reveal a higher methodological quality compared to interventions in healthy elderly (8.33 ± 2.19 vs. 6.25 ± 2.36 out of 13 points), with most frequent missing aspects related to descriptions of complications, lack of intention-to-treat and statistical power analyses. Effects of aerobic exercise and fitness seem to mainly impact brain structures sensitive to neurodegeneration, which especially comprise frontal, temporal and parietal regions, such as the hippocampal/parahippocampal region, precuneus, anterior cingulate and prefrontal cortex, which are reported by several studies. General fitness measured via an objective fitness assessment and questionnaires seems to have a more global cerebral effect, probably due to its long-term application, whereas distinct intervention effects of durations between 3 and 6 months seem to concentrate on more local brain regions as the hippocampus, which can also be influenced by region of interest analyses. There is still a lack of evidence on other or combined types of intervention modalities, such as resistance, coordinative as well as multicomponent exercise during cognitive decline, and complex interventions as dancing. Future research should examine their beneficial effect on brain integrity, since several non-MRI studies already point to their advantageous impact. As a further future prospect, combination and application of newly developed imaging methods such as metabolic imaging should be envisaged to understand physical activity and its cerebral influence under its many-sided facets.

Lifespan leisure physical activity profile, brain plasticity and cognitive function in old age

OBJECTIVES

Despite the evidence suggesting physical activity (PA) as a major factor for the prevention of age-related cognitive decline, only a few studies have systematically investigated the impact of leisure PA during the lifespan (LLPA). This study investigates the effects of LLPA on cognitive function (CF) and brain plasticity (BP) in old age.

METHOD

Participants' (n = 50, 72 ± 5 yrs, 27 females) LLPA energy expenditure and volume was assessed via a validated questionnaire investigating five epochs (14-80 yrs). Using current WHO PA recommendations as reference, participants were stratified into energy expenditure and volume groups. CF outcomes were attention, executive functions, working memory and memory. BP was assessed using magnetic resonance spectroscopy (MRSI) and brain derived neurotropic factor (BDNF).

RESULTS

Correlation analysis revealed associations of mean LLPA energy expenditure with attention (CF) and N-acetylaspartate to choline ratios (NAA/Cho) (MRSI). ANOVA revealed higher interference control performance (CF) and NAA/Cho in participants complying with current PA recommendations (2-3 h per week) compared to non-compliers. Further CF and BP outcomes including BDNF were not associated with LLPA.

CONCLUSION

Lifelong adherence to minimum recommended PA seems to be associated with markers of cognitive function and neuronal integrity in old age.

Associations between cardiorespiratory fitness, physical activity, intraindividual variability in behavior, and cingulate cortex in younger adults

BACKGROUND

Higher levels of cardiorespiratory fitness (CRF) and greater amounts of physical activity have been associated with lower intraindividual variability (IIV) in executive function in children and older adults. In the present study, we examined whether CRF, measured as maximal oxygen uptake (VO_2max), and daily volume of moderate-to-vigorous intensity physical activity (MVPA) were associated with IIV of reaction time during performance of the incongruent condition of the Stroop task in younger adults. Further, we examined whether the thickness of the cingulate cortex was associated with regulating variability in reaction time performance in the context of CRF or physical activity.

METHODS

CRF (measured as VO_2max), accelerometry-measured MVPA, Stroop performance, and thickness of the rostral anterior cingulate cortex (rACC) derived from magnetic resonance imaging data were collected in 48 younger adults (age = 24.58 ± 4.95 years, mean ± SD). Multiple regression was used to test associations between IIV during the Stroop task and CRF, MVPA, and rACC thickness. Mediation was tested using maximum likelihood estimation with bootstrapping.

RESULTS

Consistent with our predictions, higher VO_2max was associated with greater rACC thickness for the right hemisphere and greater daily amounts of MVPA were associated with greater rACC thickness for both the left and right hemispheres. Greater thickness of the right rACC was associated with lower IIV for the incongruent condition of the Stroop task. CRF and MVPA were not directly associated with IIV. However, we did find that IIV and both CRF and MVPA were indirectly associated via the thickness of the right rACC.

CONCLUSION

These results indicate that higher CRF and greater daily volume of MVPA may be associated with lower IIV during the Stroop task via structural integrity of the rACC. Randomized controlled trials of MVPA would provide crucial information about the causal relations between these variables.

Motives for Exercising and Associations with Body Composition in Icelandic Adolescents

The aim of this study is to identify and analyze the motives that lead Icelandic teenagers to engage in physical exercise and the possible associations with variables of their body composition. For this purpose, the Self-Report of Reasons for the Practice of Physical Exercise questionnaire (AMPEF) was administered to 387 students (54% boys and 46% girls, M_age = 13.38 years) from Reykjavik (Iceland). The results reveal the subscales Revitalization and Enjoyment, Strength and Endurance, Challenge and Competition as the main motives for exercising among the participants. Boys score higher in all subscales than girls except for Revitalization and Enjoyment. Associations between the motive Weight Management and Appearance, and BMI and Fat % levels were found. It can be concluded that the participants’ physical exercise practice is based on the feelings and experiences they perceive in the sports practice process.

Voluntary wheel running delays brain atrophy in aged mice

BACKGROUND:

Physical exercises have been shown to be a surprisingly effective strategy to take advantage of the brain’s natural capacity for plasticity, and prevent brain degeneration in mouse histological studies. In vivo magnetic resonance microscopy (MRM) provides highly resolved anatomical images and allows quantitative assessment of brain atrophy in the aged mouse model.

OBJECTIVE:

The aim of the present study was to investigate, through the effects of 10 weeks voluntary wheel running, the mouse’s brain atrophy.

METHODS:

Sixteen C57BL/6J mice, aged 21 months, were randomized to the exercise or sedentary group. Each mouse was scanned in a 7.0-T MRM scanner at two time points: 22 months old baseline and a follow-up three months later. Multi-atlas based brain segmentation approach was used to obtain volumes of 39 brain regions.

RESULTS:

The results showed that mice in the exercise group had less brain atrophy compared with the mice in the sedentary group.

CONCLUSIONS:

The results provide new insights into exercise induced brain plasticity in aged animals.

Association between use of internet and the cognitive function in older adults, populational longitudinal study EpiFloripa Idoso

OBJECTIVE

To estimate the association between the internet and the gain or loss cognite along of four years in older adults.

METHODS

Longitudinal study, a population-based, with older adults residents in a capital of southern Brazil (≥ 60 years) surveyed in 2009-10 (baseline) and in 2013-14 (follow-up). The outcome was assessed by clinically significant gain or loss of four or more points in the score of the Mini Mental State Examination between the two interviews. The use of internet was measured longitudinally (maintained or not internet usage, stop use of internet, started using the internet, retained the use of internet). Odds Ratios (OR) were estimated adjusted for sex, age, household income, education level and cognitive screening at baseline.

RESULTS

Respondents were 1.705 older adults in 2009-10 and 1.197 in 2013-14. There was a significant association between keep using internet and cognitive performance, with greater chance of cognitive gain (OR= 3.3; 95%CI 1.1 - 9.8) and lower cognitive impairment (OR = 0.39; 95%CI 0.17 - 0.88) for older adults who kept using the internet.

CONCLUSION

Older adults who continue using the internet were more likely to gain significant cognitive and lower cognitive loss. Topromote the internet use in older adults can help a strategy for cognitive stimulation in older adults.