Cognitive function in elderly marathon runners: cross-sectional data from the marathon trial (APSOEM)

Deducing the Impact of Physical Activity, Sedentary Behavior, and Physical Performance on Cognitive Function in Healthy Older Adults

Objectives: Participating in physical activity and maintaining physical performance as well as reducing sedentary behavior are discussed to be beneficially associated with cognitive function in older adults. The purpose of this cross-sectional analysis was to differentiate the relevance of objectively measured physical activity, physical performance, and sedentary behavior on cognitive function in healthy older adults (n = 56, age = 76 ± 7 yrs, gender = 30 female).

Methods: Accelerometer based physical activity and sedentary behavior were analyzed as minutes per week spent sedentary and physically active with light or moderate to vigorous intensity. Participants' physical performance was assessed via cardiopulmonary exercise testing and analyzed as maximal workload and heart rate, heart rate reserve and peak oxygen uptake. The assessment of cognitive function included working memory, attention, executive function, and verbal memory. Data was analyzed with Spearman and partial correlations. Trial registration: NCT02343029.

Results: Light physical activity was moderately associated with executive function (r = −0.339, p = 0.015). Attention was significantly associated with maximal workload (r = −0.286, p = 0.042) and peak oxygen uptake (r = −0.337, p = 0.015). Working memory was associated with maximal workload (r = 0.329, p = 0.017).

Conclusion: Whereas a broad range of cognitive function were beneficially linked to physical performance, light intensity activities in particular showed an impact on executive function. Our research underlines the need to separate the impact of physical performance and physical activity on cognitive function and highlights the relevance of light physical activity.

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.

Decreased Serum Brain-Derived Neurotrophic Factor Concentrations 72 Hours Following Marathon Running

Background: Physical exercise has been linked to beneficial effects on brain plasticity. One potential key mechanism for this relationship is an exercise-induced increase of brain-derived neurotrophic factor (BDNF). However, the kinetics of BDNF in athletes during training phase, extreme exercise competition, and recovery period have not been investigated so far.

Methods: We assessed serum BDNF concentrations in 51 marathon runners (23% female, mean age 43 years) in a longitudinal study design over a period of 6 months. Assessments were conducted during the training period before the marathon and after the marathon race during short-term (24 to 72 h) and long-term (3 months) follow-ups. Potential confounders (fitness level, sex, and platelet count) were included in subsequent linear-model analyses.

Results: Linear mixed-model analyses revealed a main effect of time for BDNF concentrations over the study period (F_(4,89.389) = 4.296, p = 0.003). Values decreased significantly with the lowest values at 72 h after the marathon compared to baseline (p = 0.025), a finding that was more pronounced in the larger male cohort.

Conclusion: Prolonged exercise induces a significant decrease in serum BDNF concentration 72 h post-exercise. We assume that this observation is mainly driven by regenerative mechanisms and a higher muscular utilization.

Systematic Review of Psychological and Behavioral Correlates of Recreational Running

Introduction: The aim of this review was to systematically synthesize the published literature describing the psychological and behavioral correlates of recreational running in adults, defined as running for leisure, with or without a competitive component. Methods: Quantitative research published in peer-reviewed journals until January 2021 were included. Studies were identified through MEDLINE, PsycINFO, SPORTDiscus, and Web of Science and were included in this review if they (1) were aimed at recreational running, (2) included general adult samples (18 years or older, without a diagnosed medical condition or metabolic disorder), and (3) assessed psychological or behavioral correlates of recreational running. Results: Fifty-six articles reporting 58 studies met the eligibility criteria and were included. There were 27 cross-sectional studies, 12 longitudinal studies, and 19 trials (8 non-controlled trials, 5 controlled trials, and 6 randomized controlled trials) (n = 37,501, 1877 years old, 43% women). Twenty-eight studies assessed antecedents of running behavior, and 25 studies used running behavior as treatment or predictor of a given effect or outcome. Four studies examined both predictors and outcomes of running. Thirty-one studies showed poor quality, while 20 had fair and 7 good quality. Motives were the most frequently studied antecedent of running behavior (k = 19), and results suggest that the highest-ranked or more prevalent motives were physical health, psychological motives, and personal achievement. Additionally, perceived control, attitude toward running, intention and subjective norms, self-efficacy, and social support may have also played a role in the adoption of recreational running. Moreover, improvements in mood (k = 10) and well-being (k = 10) were the most frequently reported positive outcomes of running. Reductions in depression, anxiety, and stress were also reported in included studies. Discussion: To our knowledge, this is the first systematic review on this topic. The identification of behavioral and psychological correlates of recreational running across populations can contribute to inform and guide a public policy agenda, focused on helping people sustain regular physical activity, through a modality they have chosen and appear to enjoy. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=68954, identifier: CRD42017068954.

Basal myokine levels are associated with quality of life and depressed mood in older adults

In an aging society, late-life depression has become an increasing problem. There is evidence that physical activity ameliorates depressive symptoms and increases the quality of life (QoL). However, the underlying mechanisms are still poorly understood. Myokines are molecules secreted in response to muscle contraction. Some of them can cross the blood-brain barrier, making them promising candidates for mediating the beneficial effects of physical activity on mood. The present study aims to compare circulating myokine levels to depression/QoL in older athletes and controls. 55 athletes, 57 controls >59 years were enrolled. The assessment included ergometry, magnetic resonance imaging, blood withdrawal, and neuropsychological testing. Serum interleukin-6 (IL-6), irisin, brain-derived neurotrophic factor (BDNF), kynurenine, and cathepsin B were analyzed and compared to surrogates of depression and quality of life. Athletes presented with higher levels of Cathepsin B. Among controls, all myokines but irisin were associated with age. Also, among controls, kynurenine and IL-6 correlated inversely with specific dimensions of quality of life questionnaires, and IL-6 further with depressive symptoms and decreased physical performance. No such associations could be found among athletes. Irisin levels were inversely associated with mild depression and low-grade white matter-lesions in the brain and predicted impaired QoL. The circulating levels of several myokines/muscle activity-related factors appear to be associated with depressive symptoms and impaired QoL among older adults. However, in athletes, some of these connections seem ameliorated, suggesting additional stressors (as f.e. age) or a different pathomechanism among athletes.

Changes of Mood and Cognitive Performance before and after a 100 km Nighttime Ultramarathon Run

Ultramarathons are becoming an increasingly popular endurance sport. Year after year, the demands on athletes’ skills and endurance increase. Ultramarathons are particularly taxing on athletes’ psychological functioning. This study assessed the relationships between taking part in a nighttime ultramarathon and changes in mood and cognitive functioning. The study included 20 experienced runners aged 26–57 (M = 37.29; SD = 7.94) who had M = 7.08, SD = 5.41 (range 3–44) years of experience running. There were 18 men and 2 women. The mood states were measured twice, just before the start of the run and shortly after crossing the finish line, using the Polish version of the UMACL UWIST Mood Adjective Checklist by Mathews, Chamberlain, and Jones. To assess cognitive functioning, the Stroop Color and Word Test and “Forward digit span” subtest from the Wechsler Adult Intelligence Scale were used. We observed statistically significant changes in the mood of the runners: tense arousal, associated with the experienced stress, was significantly higher before the run than immediately after the finish. Moreover, we observed an improvement in cognitive functioning after finishing the 100 km run on both of the trials on the Stroop color word test and on the forward digit span test.

(Neuro) Peptides, Physical Activity, and Cognition

Regular physical activity (PA) improves cognitive functions, prevents brain atrophy, and delays the onset of cognitive decline, dementia, and Alzheimer’s disease. Presently, there are no specific recommendations for PA producing positive effects on brain health and little is known on its mediators. PA affects production and release of several peptides secreted from peripheral and central tissues, targeting receptors located in the central nervous system (CNS). This review will provide a summary of the current knowledge on the association between PA and cognition with a focus on the role of (neuro)peptides. For the review we define peptides as molecules with less than 100 amino acids and exclude myokines. Tachykinins, somatostatin, and opioid peptides were excluded from this review since they were not affected by PA. There is evidence suggesting that PA increases peripheral insulin growth factor 1 (IGF-1) levels and elevated serum IGF-1 levels are associated with improved cognitive performance. It is therefore likely that IGF-1 plays a role in PA induced improvement of cognition. Other neuropeptides such as neuropeptide Y (NPY), ghrelin, galanin, and vasoactive intestinal peptide (VIP) could mediate the beneficial effects of PA on cognition, but the current literature regarding these (neuro)peptides is limited.

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.

High intensity endurance training is associated with better quality of life, but not with improved cognitive functions in elderly marathon runners

Impairment of cognitive functions in advanced age leads to a reduced quality of life and impaired ability to perform everyday tasks. The positive impact of physical exercise on the quality of life and well-being, also at a later age, is well established. However, the effect of endurance exercises, including long distance running and cycling, on cognitive function and mental health within the elderly population has still to be elucidated. To this end, elderly active marathoners (N = 50) aged over 60 years and non-athlete controls (N = 49) were followed for four years. Cognitive function was assessed using the CERAD test battery. In addition, the Short Form Health Survey (SF-36) was applied to assess self-reported physical, mental, and emotional health. Except for age, sex and education-corrected z-values of the test “Word list recall”, with marathon runners showing a decline compared to an improvement in controls (p < 0.05), there was no statistically significant difference in time trend between groups. In contrast, concerning self-reported health, scores in all eight domains of the SF-36 remained stable over time and, in nearly all of them, marathon runners showed higher self-reported health than controls. The results indicated that extensive endurance exercise is associated with improved subjective health but does not lead to better scores in cognitive performance tests in elderly persons.

An investigation into the relationship between cardiorespiratory fitness, cognition and BDNF in young healthy males

BACKGROUND

Recent investigations demonstrate that cardiorespiratory fitness may benefit brain health and plasticity with concurrent enhancements in cognitive performance; possibly via a brain-derived neurotrophic factor (BDNF)-regulated mechanism. While a number of studies have demonstrated an increase in BDNF concentration post exercise the relationship between BDNF, cardiorespiratory fitness and cognitive function requires further investigation.

OBJECTIVE

The present cross-sectional study assessed the association between cardiorespiratory fitness (VO₂max), cognitive performance and circulating BDNF concentration.

METHODS

Thirty-nine healthy male volunteers (mean age 21.7 ± 0.5 years) participated. Cognitive performance was measured by reaction time on a standard detection task and accuracy in a n-back and Continuous Paired Associative Learning (CPAL) task. Cardiorespiratory fitness was assessed using a standardised graded exercise test. Plasma and serum BDNF concentrations were assayed by ELISA.

RESULTS

A significant negative correlation between VO₂max and reaction time was demonstrated (p < 0.05). However VO₂max was not associated with circulating BDNF concentration, or performance in the n-back and CPAL tasks (p > 0.05).

CONCLUSIONS

Enhanced psychomotor speed was associated with higher cardiorespiratory fitness. In contrast to previous research no significant association between cardiorespiratory fitness and BDNF concentration was observed.

Association of Brain-Derived Neurotrophic Factor and Vitamin D with Depression and Obesity: A Population-Based Study

BACKGROUND

Depression and obesity are widespread and closely linked. Brain-derived neurotrophic factor (BDNF) and vitamin D are both assumed to be associated with depression and obesity. Little is known about the interplay between vitamin D and BDNF. We explored the putative associations and interactions between serum BDNF and vitamin D levels with depressive symptoms and abdominal obesity in a large population-based cohort.

METHODS

Data were obtained from the population-based Study of Health in Pomerania (SHIP)-Trend (n = 3,926). The associations of serum BDNF and vitamin D levels with depressive symptoms (measured using the Patient Health Questionnaire) were assessed with binary and multinomial logistic regression models. The associations of serum BDNF and vitamin D levels with obesity (measured by the waist-to-hip ratio [WHR]) were assessed with binary logistic and linear regression models with restricted cubic splines.

RESULTS

Logistic regression models revealed inverse associations of vitamin D with depression (OR = 0.966; 95% CI 0.951-0.981) and obesity (OR = 0.976; 95% CI 0.967-0.985). No linear association of serum BDNF with depression or obesity was found. However, linear regression models revealed a U-shaped association of BDNF with WHR (p < 0.001).

CONCLUSION

Vitamin D was inversely associated with depression and obesity. BDNF was associated with abdominal obesity, but not with depression. At the population level, our results support the relevant roles of vitamin D and BDNF in mental and physical health-related outcomes.

Assessment of brain-derived neurotrophic factor and osteopontin in a healthy pediatric population

Biomarkers are routinely used for noninvasive identification or monitoring of disease processes in clinical practice, as well as surrogate end points for drug development. There is a significant lack of data regarding biomarkers in children. An understanding of biomarker levels in a healthy pediatric cohort is essential as more studies begin to apply noninvasive biomarkers to pediatric populations. Brain-derived neurotrophic factor (BDNF) functions in neuronal survival and plasticity and is associated with exercise capacity and inflammatory disease processes. Osteopontin (OPN) plays a regulatory role in inflammation and may be a clinically useful biomarker of cardiovascular disease processes, ventricular remodeling, and skeletal muscle regeneration. This study describes our initial experience with a cohort of healthy pediatric patients and seeks to provide normal values of BDNF and OPN with correlation to age, gender, and cardiovascular and fitness measures. Serum BDNF and plasma OPN were measured using enzyme-linked immunosorbent assay in 33 healthy pediatric subjects. Subjects underwent complete cardiac evaluation, including echocardiography, exercise stress testing, and health risk assessment. The 5th-95th percentile was 5.63-37.86 ng/ml for serum BDNF and 4.9-164.9 ng/ml for plasma OPN. Plasma OPN correlated with number of days of exercise per week (r = 0.46, p = 0.008). No other correlations were significant. This study provides the initial data on serum BDNF and plasma OPN in children and begins to explore the relationships of BDNF and OPN to cardiovascular health and fitness in the pediatric population.

Objectively Measured Physical Activity and Cognitive Function in Older Adults

PURPOSE

Emerging evidence suggests physical activity (PA) is associated with cognitive function. To overcome limitations of self-report PA measures, this study investigated the association of accelerometer-measured PA with incident cognitive impairment and longitudinal cognition among older adults.

METHODS

Participants were recruited from the cohort study Reasons for Geographic and Racial Differences in Stroke in the United States. Accelerometers provided PA measures, including the percentage of total accelerometer wearing time spent in moderate-to-vigorous-intensity PA (MVPA%), light-intensity PA, and sedentary time for four to seven consecutive days at baseline. Cognitive impairment was defined by the Six-Item Screener. Letter fluency, animal fluency, word list learning, and Montreal Cognitive Assessment (orientation and recall) were conducted to assess executive function and memory.

RESULTS

Participants (N = 6452, 69.7 ± 8.5 yr, 55.3% women, 30.5% Black) with usable accelerometer and cognition measures spent extremely limited time in MVPA (1.5% ± 1.9% of accelerometer wearing time). During an average of 3 yr of follow-up, 346 cases of incident cognitive impairment were observed. After adjustments, participants in higher MVPA% quartiles had a lower risk of cognitive impairment (i.e., quartile 2: odds ratio = 0.64, 95% confidence interval = 0.48-0.84) and better maintenance in executive function (≥0.03 z-score units) and memory (≥0.12 z-score units) compared with quartile 1 (P < 0.05). Stratified analyses showed the same association among White adults, but higher MVPA% was associated with better maintenance of only memory among Black adults. No significance was found for light-intensity PA or sedentary time.

CONCLUSION

There was a dose-response relationship between MVPA% and cognitive function in older adults, with higher levels associated with a 36% or lower risk of cognitive impairment and better maintenance of memory and executive function over time, particularly in White adults.

A combination of routine blood analytes predicts fitness decrement in elderly endurance athletes

Endurance sports are enjoying greater popularity, particularly among new target groups such as the elderly. Predictors of future physical capacities providing a basis for training adaptations are in high demand. We therefore aimed to estimate the future physical performance of elderly marathoners (runners/bicyclists) using a set of easily accessible standard laboratory parameters. To this end, 47 elderly marathon athletes underwent physical examinations including bicycle ergometry and a blood draw at baseline and after a three-year follow-up period. In order to compile a statistical model containing baseline laboratory results allowing prediction of follow-up ergometry performance, the cohort was subgrouped into a model training (n = 25) and a test sample (n = 22). The model containing significant predictors in univariate analysis (alanine aminotransferase, urea, folic acid, myeloperoxidase and total cholesterol) presented with high statistical significance and excellent goodness of fit (R2 = 0.789, ROC-AUC = 0.951±0.050) in the model training sample and was validated in the test sample (ROC-AUC = 0.786±0.098). Our results suggest that standard laboratory parameters could be particularly useful for predicting future physical capacity in elderly marathoners. It hence merits further research whether these conclusions can be translated to other disciplines or age groups.

Decreased peripheral brain-derived neurotrophic factor levels in Alzheimer's disease: a meta-analysis study (N=7277)

Studies suggest that dysfunction of brain-derived neurotrophic factor (BDNF) is a possible contributor to the pathology and symptoms of Alzheimer's disease (AD). Several studies report reduced peripheral blood levels of BDNF in AD, but findings are inconsistent. This study sought to quantitatively summarize the clinical BDNF data in patients with AD and mild cognitive impairment (MCI, a prodromal stage of AD) with a meta-analytical technique. A systematic search of Pubmed, PsycINFO and the Cochrane Library identified 29 articles for inclusion in the meta-analysis. Random-effects meta-analysis showed that patients with AD had significantly decreased baseline peripheral blood levels of BDNF compared with healthy control (HC) subjects (24 studies, Hedges' g=-0.339, 95% confidence interval (CI)=-0.572 to -0.106, P=0.004). MCI subjects showed a trend for decreased BDNF levels compared with HC subjects (14 studies, Hedges' g=-0.201, 95% CI=-0.413 to 0.010, P=0.062). No differences were found between AD and MCI subjects in BDNF levels (11 studies, Hedges' g=0.058, 95% CI=-0.120 to 0.236, P=0.522). Interestingly, the effective sizes and statistical significance improved after excluding studies with reported medication in patients (between AD and HC: 18 studies, Hedges' g=-0.492, P<0.001; between MCI and HC: 11 studies, Hedges' g=-0.339, P=0.003). These results strengthen the clinical evidence that AD or MCI is accompanied by reduced peripheral blood BDNF levels, supporting an association between the decreasing levels of BDNF and the progression of AD.

Physical Activity Is Associated with Reduced Implicit Learning but Enhanced Relational Memory and Executive Functioning in Young Adults

Accumulating evidence suggests that physical activity improves explicit memory and executive cognitive functioning at the extreme ends of the lifespan (i.e., in older adults and children). However, it is unknown whether these associations hold for younger adults who are considered to be in their cognitive prime, or for implicit cognitive functions that do not depend on motor sequencing. Here we report the results of a study in which we examine the relationship between objectively measured physical activity and (1) explicit relational memory, (2) executive control, and (3) implicit probabilistic sequence learning in a sample of healthy, college-aged adults. The main finding was that physical activity was positively associated with explicit relational memory and executive control (replicating previous research), but negatively associated with implicit learning, particularly in females. These results raise the intriguing possibility that physical activity upregulates some cognitive processes, but downregulates others. Possible implications of this pattern of results for physical health and health habits are discussed.

Low Vitamin D Levels Do Not Predict Hyperglycemia in Elderly Endurance Athletes (but in Controls)

BACKGROUND AND AIM

Recent studies revealed a link between hypovitaminosis D3 and the risk for hyperglycemia. Further mechanistic and interventional investigations suggested a common reason for both conditions rather than a causal relationship. Exposure to sunlight is the most relevant source of vitamin D3 (25(OH)D), whereas adipose tissue is able to store relevant amounts of the lipophilic vitamin. Since running/bicycling leads to increased out-door time and alters physiological response mechanisms, it can be hypothesized that the correlation between hypovitaminosis D3 and hyperglycemia might be disturbed in outdoor athletes.

METHODS

47 elderly marathoners/bicyclists and 47 age/sex matched controls were studied in a longitudinal setting at baseline and after three years. HbA1c as a surrogate for (pre-)diabetic states was quantified via HPLC, 25(OH)D levels were measured by means of chemiluminescent assays. Physical performance was assessed by ergometry.

RESULTS

When adjusted for seasonal variations, 25(OH)D was significantly higher in athletes than in controls. 25(OH)D levels inversely correlated with triglycerides in both groups, whereas only in controls an association between high BMI or low physical performance with hypovitaminosis D3 had been found. Likewise, the presence of hypovitaminosis D3 at baseline successfully predicted hyperglycemia at the follow up examinations within the control group (AUC = 0.85, 95% CI [0.74, 0.96], p < .001, statistically independent from BMI), but not in athletes.

CONCLUSION

Our data suggest that mechanisms of HbA1c elevation might differ between athletes and controls. Thus, intense physical activity must be taken into account as a potential pre-analytic confounder when it is aimed to predict metabolic risk by vitamin D3 levels.

Physical exercise counteracts genetic susceptibility to depression

BACKGROUND/AIMS

Depression is a highly prevalent disorder in elderly individuals. A genetic variant (rs6265) of the brain-derived neurotrophic factor (BDNF) impacting on emotion processing is known to increase the risk for depression. We aim to investigate whether intensive endurance sports might attenuate this genetic susceptibility in a cohort of elderly marathon athletes.

METHODS

Fifty-five athletes and 58 controls were included. rs6265 of the BDNF gene was genotyped by the TaqMan method. Depressive symptoms were assessed by standardized self-rating tests (BDI = Beck Depression Inventory, GDS = Geriatric Depression Scale).

RESULTS

In multivariable analysis of BDI and GDS scores, the interaction between group (athletes vs. controls) and genotypes ([C];[C] vs. [C];[T] + [T];[T]) was found to be statistically significant (BDI: p = 0.027, GDS: p = 0.013). Among [C];[C] carriers, merely controls had an increased relative risk of 3.537 (95% CI = 1.276-9.802) of achieving a subclinical depression score ≥10 on the BDI. There was no such effect in carriers of the [T] allele. In a multivariable binary logistic regression, genetic information, group (athletes/controls), but no information on rs6265 allele carrier status presented as a significant predictor of BDI scores ≥10.

CONCLUSION

Physical exercise positively affects BDNF effects on mood. Since 66Met BDNF secretion is impaired, this effect seems to be much stronger in [C];[C] homozygous individuals expressing the 66Val variant. This confirms that genetic susceptibility to depressive symptoms can indeed be influenced by endurance sports in elderly people.

SOD2 in mitochondrial dysfunction and neurodegeneration

The brain is a highly metabolically active tissue that critically relies on oxidative phosphorylation as a means for maintaining energy. One result of this process is the production of potentially damaging radicals such as the superoxide anion (O2(-)). Superoxide has the capacity to damage components of the electron transport chain and other cellular constituents. Eukaryotic systems have evolved defenses against such damaging moieties, the chief member of which is superoxide dismutase (SOD2), an enzyme that efficiently converts superoxide to the less reactive hydrogen peroxide (H2O2), which can freely diffuse across the mitochondrial membrane. Loss of SOD2 activity can result in numerous pathological phenotypes in metabolically active tissues, particularly within the central nervous system. We review SOD2's potential involvement in the progression of neurodegenerative diseases such as stroke and Alzheimer and Parkinson diseases, as well as its potential role in "normal" age-related cognitive decline. We also examine in vivo models of endogenous oxidative damage based upon the loss of SOD2 and associated neurological phenotypes in relation to human neurodegenerative disorders.

The effects of physical activity and exercise on brain-derived neurotrophic factor in healthy humans: A review

The purpose of this study was to summarize the effects of physical activity and exercise on peripheral brain-derived neurotrophic factor (BDNF) in healthy humans. Experimental and observational studies were identified from PubMed, Web of Knowledge, Scopus, and SPORT Discus. A total of 32 articles met the inclusion criteria. Evidence from experimental studies suggested that peripheral BDNF concentrations were elevated by acute and chronic aerobic exercise. The majority of the studies suggested that strength training had no influence on peripheral BDNF. The results from most observational studies suggested an inverse relationship between the peripheral BDNF level and habitual physical activity or cardiorespiratory fitness. More research is needed to confirm the findings from the observational studies.

Physical activity, cognitive function, and brain health: what is the role of exercise training in the prevention of dementia?

Tor preventive measures are necessary to attenuate the increased economic and social burden of dementia. This review will focus on the potential for physical activity and exercise training to promote brain health and improve cognitive function via neurophysiological changes. We will review pertinent animal and human research examining the effects of physical activity on cognitive function and neurophysiology. We will discuss cross-sectional and longitudinal studies addressing the relationship between neurocognitive health and cardiorespiratory fitness or habitual activity level. We will then present and discuss longitudinal investigations examining the effects of exercise training on cognitive function and neurophysiology. We will conclude by summarizing our current understanding of the relationship between physical activity and brain health, and present areas for future research given the current gaps in our understanding of this issue.

Physical activity for the prevention of cognitive decline: current evidence from observational and controlled studies

A sedentary life style has been associated with different types of dementia in several cross sectional, longitudinal, and case-controlled studies. However, randomized controlled trials that support this relationship are rare, have rather few participants, and mainly focus on physical (usually aerobic) exercise. The benefit of an increased physical activity (PA) has been mainly demonstrated for the prevention of Alzheimer's disease and vascular dementia, less so for other dementia types such as Lewy body dementia or frontotemporal dementia. The clinical evidence builds on a significant amount of animal research pointing to potential mechanisms as to how PA relates to cognitive function. While most studies have investigated singular interventions, others have studied the combination of both mental and physical activity to improve cognition or delay decline. However, questions remain such as what type and how much PA is beneficial? This review gives an overview of the current evidence on the clinical and epidemiological level and tries to answer these questions.

Systemic and cerebral hemodynamics during cognitive testing

OBJECTIVE

Cognitive deficits are reported in 10-60% of individuals with SCI, the primary etiology of these deficits is believed to be concomitant traumatic brain injury (TBI). We recently documented diminished memory and marginally deficient attention and processing speed in individuals with SCI discordant for hypotension but matched for TBI.

METHODS

Twenty-nine individuals participated: 16 non-SCI controls, 6 paraplegic (T2-T10) and 7 tetraplegic (C4-C8). The Stroop test was used to measure cognitive function and transcranial Doppler ultrasound was used to measure cerebral blood flow (CBF) while resting (5 min) and continuously during cognitive testing. Mean arterial pressure (MAP) was calculated from three brachial blood pressures and cerebral vascular resistance index was calculated as: CVRi = MAP/CBF.

RESULTS

The paraplegia group (54 ± 6) was marginally older than the non-SCI (42 ± 15; p = 0.06) and tetraplegic (42 ± 11; p = 0.09) groups. Compared to non-SCI group, normalized t-score on the Stroop Color (SC) task was significantly lower in the paraplegic group (p < 0.05). In the tetraplegic group, MAP was significantly lower (p < 0.05) than the non-SCI and paraplegic groups, and related to SC t-score (r (2) = 0.873; p < 0.01). In the paraplegic group, CBF was reduced (p < 0.05) and CVRi increased (p < 0.05) compared to the non-SCI group, and CVRi was increased compared to the tetraplegic group (p < 0.05). A significant inverse relationship was noted between change in CVRi and SC t-score in the non-SCI group.

CONCLUSION

Asymptomatic hypotension relates to cognitive performance in persons with tetraplegia; therefore, BP normalization should be considered. The inappropriate cerebral vascular response to cognitive testing and poor test performance should be investigated in persons with paraplegia.

Association of cardio-ankle vascular index with physical fitness and cognitive symptoms in aging Finnish firefighters

PURPOSE

Monitoring cardiovascular risk factors is important in health promotion among firefighters. The assessment of arterial stiffness (AS) may help to detect early signs of atherosclerosis. The aim of this study was to analyze associations between aerobic fitness, cognitive symptoms and cardio-ankle vascular index (CAVI) as a measure for AS among Finnish firefighters.

METHODS

The data are one part of a large 13-year follow-up study of the health and physical and mental capacity of Finnish professional firefighters. The subjects in this substudy comprised 65 male firefighters of a mean age of 48.0 (42-58) years in 2009. Their maximal oxygen uptake was successfully measured in two cross-sectional studies in 1996 and 2009, and they responded to questionnaires at both sessions, and their CAVI was measured in 2009. CAVI was calculated from the pulse waveform signal and pulse wave velocity. The lifestyle habits and subjective cognitive stress-related symptoms were collected via a standardized questionnaire. Muscular fitness was measured by the routine test battery used for Finnish firefighters.

RESULTS

CAVI was related to age. About one-fifth of the firefighters had a CAVI of >8. Aerobic fitness was the main physiological factor correlating with increased CAVI. Interestingly, VO(2)max and the accelerated decrease in VO(2)max during a 13-year follow-up were associated with signs of impaired vascular function. The cognitive symptoms derived from the Profile of Mood States questionnaire (POMS) were mainly associated with stress and sleeping difficulties. No clear association with physical fitness was found in this population of fit firefighters.

CONCLUSIONS

Among firefighters, the decrease in aerobic fitness predicts increased arterial stiffness. The speed of the age-related decline in maximal oxygen consumption is as important as absolute level. Against expectations, the cognitive function did not correlate with vascular health parameters. The cognitive symptoms, however, were only mild.