Sex-dependent effect of the BDNF Val66Met polymorphism on executive functioning and processing speed in older adults: evidence from the health ABC study

Cardiorespiratory fitness is associated with cognitive function in late adulthood: baseline findings from the IGNITE study

OBJECTIVES

To evaluate the association between cardiorespiratory fitness (CRF) and cognition in a large sample of older adults, and to examine clinical and demographic factors that might moderate these associations.

METHODS

CRF was measured with a graded exercise test performed on a motorised treadmill. A confirmatory factor analysis was conducted using data from a comprehensive neuropsychological battery to obtain latent factors reflecting core cognitive domains. Linear regression models evaluated the association between CRF and each of the cognitive composites, and potential moderators including demographic factors (age, sex, education), apolipoprotein E ε4 (APOE4) carriage, beta-blocker use and components of maximal effort criteria during CRF testing.

RESULTS

The sample consisted of 648 adults (mean (SD) age 69.88 (3.75)), including 461 women (71.1%). The highest oxygen consumption obtained during testing (VO2max) was mean (SD) = 21.68 (5.06) mL/kg/min. We derived a five-factor model composed of episodic memory, processing speed, working memory, executive function/attentional control and visuospatial function. Higher CRF was associated with better performance across all five cognitive domains after controlling for covariates. Age and APOE4 carriage did not moderate observed associations. The relationship between CRF and cognitive performance was greater in women, those with fewer years of education and those taking beta-blockers in the domains of processing speed (sex: β=-0.447; p=0.015; education: β=-0.863; p=0.018) and executive function/attentional control (sex: β=-0.417; p=0.022; education β=-0.759; p=0.034; beta-blocker use: β=0.305; p=0.047).

CONCLUSION

Higher CRF in older adulthood is associated with better cognitive performance across multiple domains susceptible to age-related cognitive decline. Sex, education and use of beta-blockers moderated observed associations within select cognitive domains.

Cerebral white matter myelination is associated with longitudinal changes in processing speed across the adult lifespan

Myelin's role in processing speed is pivotal, as it facilitates efficient neural conduction. Its decline could significantly affect cognitive efficiency during ageing. In this work, myelin content was quantified using our advanced MRI method of myelin water fraction mapping. We examined the relationship between myelin water fraction at the time of MRI and retrospective longitudinal change in processing speed among 121 cognitively unimpaired participants, aged 22-94 years, from the Baltimore Longitudinal Study of Aging and the Genetic and Epigenetic Signatures of Translational Aging Laboratory Testing (a mean follow-up duration of 4.3 ± 6.3 years) using linear mixed-effects models, adjusting for demographics. We found that higher myelin water fraction values correlated with longitudinally better-maintained processing speed, with particularly significant associations in several white matter regions. Detailed voxel-wise analysis provided further insight into the specific white matter tracts involved. This research underscores the essential role of myelin in preserving processing speed and highlights its potential as a sensitive biomarker for interventions targeting age-related cognitive decline, thereby offering a foundation for preventative strategies in neurological health.

Various modalities of resistance exercise promote similar acute cognitive improvements and hemodynamic increases in young, healthy adults

The aim was to examine the effects of modalities of acute resistance exercise (RE) on cognition and hemodynamics including internal carotid artery (ICA) blood flow (BF). Twenty adults completed familiarization and experimental visits. One-repetition maximum (1RM) for bilateral leg extension was quantified, and baseline executive functioning was determined from three run-in visits. Subsequent visits included three randomized, volume-equated, acute exercise bouts of 30 %1RM+blood flow restriction (BFR), 30 %1RM, and 70 %1RM. Both 30 %1RM trials completed four sets of exercise (1 × 30, 3 × 15), and the 70 %1RM condition completed four sets of 8 repetitions. BFR was induced with 40 % of the pressure to occlude the femoral arteries. 11 min following each exercise, participants completed the Stroop and Shifting Attention Tests. Baseline and post-exercise values were used to calculate change scores. The resulting mean change scores were evaluated with mixed factorial ANOVAs. A p≤0.05 was considered significant. All measured outcome variables increased in response to exercise. The ANOVAs for cognitive scores indicated no significant (p>0.05) interactions. For cognitive flexibility and executive function index, there were main effects of Sex. Change scores of the females were significantly greater than the males for cognitive flexibility (7.6 ± 5.9 vs. -2.6 ± 8.4 au; p=0.007) and executive function index (7.4 ± 4.6 vs. -2.5 ± 6.5 au; p=0.001). For ICA BF, there was no significant interaction or any main effect. The females exhibited a smaller exercise-induced increase in blood pressure compared to the males (17.7 ± 5.9 vs. 11.0 ± 4.1 mmHg; p=0.010). Each RE modality yielded acute improvements in cognition, but only for females. There were no cognitive improvements related to BFR such that each RE bout yielded similar results.

Physical exercise, cognition, and brain health in aging

Exercise training is an important strategy to counteract cognitive and brain health decline during aging. Evidence from systematic reviews and meta-analyses supports the notion of beneficial effects of exercise in cognitively unimpaired and impaired older individuals. However, the effects are often modest, and likely influenced by moderators such as exercise training parameters, sample characteristics, outcome assessments, and control conditions. Here, we discuss evidence on the impact of exercise on cognitive and brain health outcomes in healthy aging and in individuals with or at risk for cognitive impairment and neurodegeneration. We also review neuroplastic adaptations in response to exercise and their potential neurobiological mechanisms. We conclude by highlighting goals for future studies, including addressing unexplored neurobiological mechanisms and the inclusion of under-represented populations.

Potential role of APOE ɛ4 allele as a modifier for the association of BDNF Val66Met polymorphisms and cognitive impairment in community-dwelling older adults

Objective

To determine whether the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is associated with cognitive impairment (CI) in community-dwelling Chinese older adults, and to investigate whether this relationship is modified by the Apolipoprotein E (APOE) ɛ4 allele.

Methods

The study is a secondary analysis of 703 participants aged ≥60 years randomly enrolled from the Beijing Longitudinal Study of Aging II prospective cohort. The education-adjusted Mini-Mental State Examination and the Clinical Dementia Rating Scale were used to measure the cognitive performance of the subjects. The main effects and interactions (additive and multiplicative) of the BDNF Met and the APOE ε4 alleles on CI were estimated by logistic regression models.

Results

In total, 84 out of 703 older adults aged ≥60 years old had CI. No significant difference was observed in the risk of CI between participants with the BDNF Met allele and that of subjects without the BDNF Met allele (p = 0.213; p = 0.164). Individuals carrying both the BDNF Met and APOE ε4 alleles had an almost 1.5-fold increased odds of CI compared with carriers of the BDNF Met allele but without the APOE ε4 allele. The additive association indicated a positive interaction of both BDNF Met and APOE ε4 alleles with wide CIs (p = 0.021; p = 0.018).

Conclusion

The results suggest that the APOE ε4 allele may be a potential modifier for the association of the BDNF Val66Met polymorphism with CI in community-dwelling older adults.

BDNF gene Val66Met polymorphisms as a predictor for clinical presentation in schizophrenia - recent findings

Schizophrenia is a highly heritable, severe psychiatric disorder that involves dysfunctions in thinking, emotions, and behavior, with a profound impact on a person's ability to function normally in their daily life. Research efforts continue to focus on elucidating possible genetic underlying mechanisms of the disorder. Although the genetic loci identified to date to be significantly associated with schizophrenia risk do not represent disease-causing factors, each one of them could be seen as a possible incremental contributor. Considering the importance of finding new and more efficient pharmacological approaches to target the complex symptomatology of this disorder, in this scoping review, we are focusing on the most recent findings in studies aiming to elucidate the contribution of one of the genetic factors involved - the BDNF gene Val66Met polymorphisms. Here we performed a systematic search in Pubmed, Embase, and Web of Science databases with the search terms: (BDNF gene polymorphism) AND (schizophrenia) for articles published in the last 5 years. To be selected for this review, articles had to report on studies where genotyping for the BDNF Val66Met polymorphism was performed in participants diagnosed with schizophrenia (or schizophrenia spectrum disorders or first-episode psychosis). The search provided 35 results from Pubmed, 134 results from Embase, and 118 results from the Web of Science database. Twenty-two articles were selected to be included in this review, all reporting on studies where an implication of the BDNF Val66Met polymorphisms in the disorder's pathophysiology was sought to be elucidated. These studies looked at BDNF gene Val66Met polymorphism variants, their interactions with other genes of interest, and different facets of the illness. The Met/Met genotype was found to be associated with higher PANSS positive scores. Furthermore, Met/Met homozygous individuals appear to present with worse cognitive function and lower levels of serum BDNF. In the Val/Val genotype carriers, increased BDNF levels were found to correlate with weight gain under Risperidone treatment. However, due to heterogeneous results, the diversity in study populations and studies' small sample sizes, generalizations cannot be made. Our findings emphasize the need for further research dedicated to clarifying the role of gene polymorphisms in antipsychotic treatment to enhance specificity and efficacy in the treatment of schizophrenia.

The brain-derived neurotrophic factor Val66met polymorphism is associated with better attention and working memory performance and resilience to mild chronic stress

The val66met polymorphism of the brain-derived neurotrophic factor (BDNF) gene has been identified as a potential moderator for the relationship between chronic stress and executive functioning. However, whether the presence of the met allele increases cognitive vulnerability or resilience to stress has yet to be determined. Given the established effects of autonomic activity and psychological arousal on executive functioning, in the present study, 56 healthy university students completed self-report measures of chronic stress, positive arousal (vigour) and negative arousal (anxiety) and measured heart-rate variability to quantify autonomic activity. Participants then completed a cognitive test battery that measured attention, decision-making, visual learning and working memory. Regression analyses demonstrated that Val/met participants performed better on attention and working memory tasks than Val/val participants, but no differences were seen in decision-making and visual learning. Further, Val/met participants were protected from stress-related differences in attention seen in Val/val participants. Val66met was not associated with physiological or psychological arousal. This study demonstrates that val66met plays an important but selective role in cognitive performance.

Aerobic exercise improves executive functions in females, but not males, without the BDNF Val66Met polymorphism

BACKGROUND

Aerobic exercise promotes cognitive function in older adults; however, variability exists in the degree of benefit. The brain-derived neurotropic factor (BDNF) Val66Met polymorphism and biological sex are biological factors that have been proposed as important modifiers of exercise efficacy. Therefore, we assessed whether the effect of aerobic exercise on executive functions was dependent on the BDNFval66met genotype and biological sex.

METHODS

We used data from a single-blind randomized controlled trial in older adults with subcortical ischemic vascular cognitive impairment (NCT01027858). Fifty-eight older adults were randomly assigned to either the 6 months, three times per week progressive aerobic training (AT) group or the usual care plus education control (CON) group. The secondary aim of the parent study included executive functions which were assessed with the Trail Making Test (B-A) and the Digit Symbol Substitution Test at baseline and trial completion at 6 months.

RESULTS

Analysis of covariance, controlling for baseline global cognition and baseline executive functions performance (Trail Making Test or Digit Symbol Substitution Test), tested the three-way interaction between experimental group (AT, CON), BDNFval66met genotype (Val/Val carrier, Met carrier), and biological sex (female, male). Significant three-way interactions were found for the Trail Making Test (F(1,48) = 4.412, p < 0.04) and Digit Symbol Substitution Test (F(1,47) = 10.833, p < 0.002). Posthoc analyses showed female Val/Val carriers benefited the most from 6 months of AT compared with CON for Trail Making Test and Digit Symbol Substitution Test performance. Compared with CON, AT did not improve Trail Making Test performance in male Val/Val carriers or Digit Symbol Substitution Test performance in female Met carriers.

CONCLUSIONS

These results suggest that future randomized controlled trials should take into consideration BDNF genotype and biological sex to better understand the beneficial effects of AT on cognitive function in vascular cognitive impairment to maximize the beneficial effects of exercise and help establish exercise as medicine for cognitive health.

Sedentary behavior, brain-derived neurotrophic factor and brain structure in midlife: A longitudinal brain MRI sub-study of the coronary artery risk development in young adults study

Background

Brain-derived neurotrophic factor levels are higher in those who are physically active and lower in people with cognitive dysfunction. This study investigated whether brain-derived neurotrophic factor mediated or modified the association of sedentary time to MRI-estimated brain volumes in midlife.

Methods

Baseline (n = 612) and five-year follow-up (n = 418) data were drawn from the multicenter Coronary Artery Risk Development in Young Adults Brain MRI sub-study, including Black and White participants (aged 50.3 years, 51.6% females, 38.6% Black). Sedentary time (hours per day) was categorized into quartiles with low ≤ 4.3 (reference) and high > 8.4. Outcomes of the study were total brain, white matter, gray matter, hippocampal volumes, and white matter fractional anisotropy at baseline and 5-year percent change from baseline. The study used general linear regression models to examine the mediation and moderation effects of brain-derived neurotrophic factor (natural log transformed) on the associations of sedentary time to brain outcomes. The authors adjusted the regression model for age, sex, race, intracranial volume, education, and vascular factors.

Results

Cross-sectionally, baseline participants with the highest sedentary time had a lower total brain (-12.2 cc; 95%CI: -20.7, -3.7), gray matter (-7.8 cc; 95%CI: -14.3, -1.3), and hippocampal volume (-0.2 cc; 95%CI: -0.3, 0.0) compared with populations with the lowest sedentary time. The brain-derived neurotrophic factor levels did not mediate the associations between brain measures and sedentary time. Brain-derived neurotrophic factor was found to moderate associations of sedentary time to total brain and white matter volume such that the brain volume difference between high and low sedentary time decreased as brain-derived neurotrophic factor levels increased. Longitudinally, higher baseline brain-derived neurotrophic factor level was associated with less brain volume decline. The longitudinal associations did not differ by sedentary time, and brain-derived neurotrophic factor did not mediate or moderate the association of sedentary time to brain measure changes.

Conclusions

Higher brain-derived neurotrophic factor levels may buffer the negative effects of sedentary time on the brain.

Sex and BDNF Val66Met polymorphism matter for exercise-induced increase in neurogenesis and cognition in middle-aged mice

Females show greater benefits of exercise on cognition in both humans and rodents, which may be related to brain-derived neurotrophic factor (BDNF). A single nucleotide polymorphism (SNP), the Val66Met polymorphism, within the human BDNF gene, causes impaired activity-dependent secretion of neuronal BDNF and impairments to some forms of memory. We evaluated whether sex and BDNF genotype (Val66Met polymorphism (Met/Met) versus wild-type (Val/Val)) influenced the ability of voluntary running to enhance cognition and hippocampal neurogenesis in mice. Middle-aged C57BL/6J (13 months) mice were randomly assigned to either a control or an aerobic training (AT) group (running disk access). Mice were trained on the visual discrimination and reversal paradigm in a touchscreen-based technology to evaluate cognitive flexibility. BDNF Met/Met mice had fewer correct responses compared to BDNF Val/Val mice on both cognitive tasks. Female BDNF Val/Val mice showed greater cognitive flexibility compared to male mice regardless of AT. Despite running less than BDNF Val/Val mice, AT improved performance in both cognitive tasks in BDNF Met/Met mice. AT increased neurogenesis in the ventral hippocampus of BDNF Val/Val mice of both sexes and increased the proportion of mature type 3 doublecortin-expressing cells in the dorsal hippocampus of female mice only. Our results indicate AT improved cognitive performance in BDNF Met/Met mice and increased hippocampal neurogenesis in BDNF Val/Val mice in middle age. Furthermore, middle-aged female mice may benefit more from AT than males in terms of neuroplasticity, an effect that was influenced by the BDNF Val66Met polymorphism.

Brain-derived neurotrophic factor rs6265 (Val66Met) single nucleotide polymorphism as a master modifier of human pathophysiology

Brain-derived neurotrophic factor is the most prevalent member of the nerve growth factor family. Since its discovery in 1978, this enigmatic molecule has spawned more than 27,000 publications, most of which are focused on neurological disorders. Brain-derived neurotrophic factor is indispensable during embryogenesis and postnatally for the normal development and function of both the central and peripheral nervous systems. It is becoming increasingly clear, however, that brain-derived neurotrophic factor likewise plays crucial roles in a variety of other biological functions independently of sympathetic or parasympathetic involvement. Brain-derived neurotrophic factor is also increasingly recognized as a sophisticated environmental sensor and master coordinator of whole organismal physiology. To that point, we recently found that a common nonsynonymous (Val66→Met) single nucleotide polymorphism in the brain-derived neurotrophic factor gene (rs6265) not only substantially alters basal cardiac transcriptomics in mice but subtly influences heart gene expression and function differentially in males and females. In addition to a short description of recent results from associative neuropsychiatric studies, this review provides an eclectic assortment of research reports that support a modulatory role for rs6265 including and beyond the central nervous system.

Elevated Peripheral Brain-Derived Neurotrophic Factor Level Associated With Decreasing Insulin Secretion May Forecast Memory Dysfunction in Patients With Long-Term Type 2 Diabetes

Background

With the progressive course of diabetes and the decline in islet function, the cognitive dysfunction of patients aggravated.

Objective

We aimed to investigate the roles of brain-derived neurotrophic factor (BDNF) and the Val66Met polymorphism in mild cognitive impairment (MCI) in patients with type 2 diabetes mellitus (T2DM).

Methods

A total of 169 Chinese patients with T2DM were involved and divided into long-term (diabetes duration >10 years) and short-term (diabetes duration ≤10 years) diabetes, and in each group, the patients were separated as MCI and the control. Demographic characteristics, clinical variables, and cognitive performances were assessed. The plasma BDNF level was measured via enzyme-linked immunosorbent assay. The Val66Met polymorphisms were analyzed.

Results

Long-term T2DM have lower 2 h postprandial C-peptide (p < 0.05). The BDNF level was slightly higher in patients with MCI than in the controls in each duration group without statistical significance. The relationship of BDNF to Montreal Cognitive Assessment was not proven either. However, in the long-term diabetes group, BDNF concentration remained as an independent factor of logical memory test (β = −0.27; p < 0.05), and they were negatively correlated (r = −0.267; p = 0.022); BDNF was also negatively correlated with fasting C-peptide (r = −0.260; p = 0.022), 2 h postprandial C-peptide (r = −0.251; p = 0.028), and homeostasis model assessment of insulin resistance (r = −0.312; p = 0.006). In genotypic groups, BDNF Val/Val performed better in logical memory test than Met/Met and Val/Met.

Conclusion

Elevated peripheral BDNF level associated with declined islet function, when combined with its Val66Met polymorphism, may forecast memory dysfunction in patients with long-term T2DM.

Female specific risk factors for the development of Alzheimer's disease neuropathology and cognitive impairment: Call for a precision medicine approach

Alzheimer's disease (AD) includes a long asymptomatic stage, which precedes the formal diagnosis of dementia. AD biomarker models provide a framework for precision medicine approaches during this stage. However, such approaches have ignored the possible influence of sex on cognition and brain health, despite female sex noted as a major risk factor. Since AD-related changes may emerge in midlife, intervention efforts are being redirected around this period. Midlife coincides with several endocrinological changes, such as the menopausal transition experienced by women. In this narrative review, we discuss evidence for sex-differences in AD neuropathological burden and outline key endocrinological mechanisms for both sexes, focussing on hormonal events throughout the lifespan that may influence female susceptibility to AD neuropathology and dementia onset. We further consider common non-modifiable (genetic) and modifiable (lifestyle and health) risk factors, highlighting possible sex-dependent differential effects for the AD disease course. Finally, we evaluate the studies selected for this review demonstrating sex-differences in cognitive, pathological and health factors, summarising the state of sex differences in AD risk factors. We further provide recommendations for targeted research on female-specific risk factors, to inform personalised strategies for AD-prevention and the promotion of female brain health.

Met carriers of the BDNF Val66Met polymorphism show reduced Glx/NAA in the pregenual ACC in two independent cohorts

The Met allele of the Val66Met SNP of the BDNF gene (rs6265) is associated with impaired activity-dependent release of brain-derived neurotrophic factor (BDNF), resulting in reduced synaptic plasticity, impaired glutamatergic neurotransmission, and morphological changes. While previous work has demonstrated Val66Met effects on magnetic resonance spectroscopy (MRS) markers of either glutamatergic metabolism (Glx) or neuronal integrity (NAA), no study has investigated Val66Met effects on these related processes simultaneously. As these metabolites share a metabolic pathway, the Glx/NAA ratio may be a more sensitive marker of changes associated with the Val66Met SNP. This ratio is increased in psychiatric disorders linked to decreased functioning in the anterior cingulate cortex (ACC). In this study, we investigated the correlation of the Val66Met polymorphism of the BDNF gene with Glx/NAA in the pregenual anterior cingulate cortex (pgACC) using MRS at 3 Tesla (T) (n = 30, all males) and 7 T (n = 98, 40 females). In both cohorts, Met carriers had lower Glx/NAA compared to Val homozygotes. Follow-up analyses using absolute quantification revealed that the Met carriers do not show decreased pgACC glutamate or glutamine levels, but instead show increased NAA compared to the Val homozygotes. This finding may in part explain conflicting evidence for Val66Met as a risk factor for developing psychiatric illnesses.

Neurophysiological Effects of Whole Coffee Cherry Extract in Older Adults with Subjective Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled, Cross-Over Pilot Study

Bioactive plant-based compounds have shown promise as protective agents across multiple domains including improvements in neurological and psychological measures. Methodological challenges have limited our understanding of the neurophysiological changes associated with polyphenol-rich supplements such as whole coffee cherry extract (WCCE). In the current study, we (1) compared 100 mg of WCCE to a placebo using an acute, randomized, double-blind, within-subject, cross-over design, and we (2) conducted a phytochemical analysis of WCCE. The primary objective of the study was to determine the neurophysiological and behavioral changes that resulted from the acute administration of WCCE. We hypothesized that WCCE would increase brain-derived neurotrophic factor (BDNF) and glutamate levels while also increasing neurofunctional measures in cognitive brain regions. Furthermore, we expected there to be increased behavioral performance associated with WCCE, as measured by reaction time and accuracy. Participants underwent four neuroimaging scans (pre- and post-WCCE and placebo) to assess neurofunctional/metabolic outcomes using functional magnetic resonance imaging and magnetic resonance spectroscopy. The results suggest that polyphenol-rich WCCE is associated with decreased reaction time and may protect against cognitive errors on tasks of working memory and response inhibition. Behavioral findings were concomitant with neurofunctional changes in structures involved in decision-making and attention. Specifically, we found increased functional connectivity between the anterior cingulate and regions involved in sensory and decision-making networks. Additionally, we observed increased BDNF and an increased glutamate/gamma-aminobutyric acid (GABA) ratio following WCCE administration. These results suggest that WCCE is associated with acute neurophysiological changes supportive of faster reaction times and increased, sustained attention.

The implication of BDNF Val66Met polymorphism in progression from subjective cognitive decline to mild cognitive impairment and Alzheimer's disease: a 9-year follow-up study

Brain-derived natriuretic factor (BDNF) Val66Met polymorphism has been frequently reported to be associated with Alzheimer's disease (AD) with contrasting results. Numerous studies showed that Met allele increased the risk of AD only in women, while other studies have found worse cognitive performance in Val/Val carriers. We aimed to inquire the effects of Val66Met polymorphism on the progression from subjective cognitive decline (SCD) to mild cognitive impairment (MCI) and from MCI to AD and to ascertain if this effect is modulated by demographic and cognitive variables. For this purpose, we followed up 74 subjects (48 SCD, 26 MCI) for a mean time of 9 years. All participants underwent extensive neuropsychological assessment, cognitive reserve estimation, BDNF and apolipoprotein E (ApoE) genotype analysis at baseline. Personality traits and leisure activities were assessed in a subgroup. Each patient underwent clinical-neuropsychological follow-up, during which 18 out of 48 SCD subjects progressed to MCI and 14 out of 26 MCI subjects progressed to AD. We found that Val66Met increased the risk of progression from SCD to MCI and from MCI to AD only in women. Nevertheless, Val/Val carriers who progressed from SCD to MCI had a shorter conversion time compared to Met carriers. We concluded that Val66Met polymorphism might play different roles depending on sex and stage of the disease.

Dose-Response Matters! - A Perspective on the Exercise Prescription in Exercise-Cognition Research

In general, it is well recognized that both acute physical exercises and regular physical training influence brain plasticity and cognitive functions positively. However, growing evidence shows that the same physical exercises induce very heterogeneous outcomes across individuals. In an attempt to better understand this interindividual heterogeneity in response to acute and regular physical exercising, most research, so far, has focused on non-modifiable factors such as sex and different genotypes, while relatively little attention has been paid to exercise prescription as a modifiable factor. With an adapted exercise prescription, dosage can be made comparable across individuals, a procedure that is necessary to better understand the dose-response relationship in exercise-cognition research. This improved understanding of dose-response relationships could help to design more efficient physical training approaches against, for instance, cognitive decline.