Strengthening the Brain-Is Resistance Training with Blood Flow Restriction an Effective Strategy for Cognitive Improvement?

Acute resistance exercise combined with whole body vibration and blood flow restriction: Molecular and neurocognitive effects in late-middle-aged and older adults

Limited research exists regarding the effects of resistance exercise (RE) combined with whole body vibration (WBV), blood flow restriction (BFR), or both on the neuropsychological performance of working memory (WM) in late-middle-aged and older adults and regarding the physiological mechanisms underlying this effect. This study thus explored the acute molecular and neurophysiological mechanisms underlying WM performance following RE combined with WBV, BFR, or both. Sixty-six participants were randomly assigned into a WBV, BFR, or WBV + BFR group. Before and after the participants engaged in a single bout of isometric RE combined with WBV, BFR, or both, this study gathered data on several neurocognitive measures of WM performance, namely, accuracy rate (AR), reaction time (RT), and brain event-related potential (specifically P3 latency and amplitude), and data on biochemical indices, such as the levels of insulin-like growth factor-1 (IGF-1), norepinephrine (NE), and brain-derived neurotrophic factor (BDNF). Although none of the RE modalities significantly affected RTs and P3 latencies, ARs and P3 amplitudes significantly improved in the WBV and WBV + BFR groups. The WBV + BFR group exhibited greater improvements than the WBV group did. Following acute RE combined with WBV, BFR, or both, IGF-1 and NE levels significantly increased in all groups, whereas BDNF levels did not change. Crucially, only the changes in NE levels were significantly correlated with improvements in ARs in the WBV + BFR and WBV groups. The findings suggest that combining acute RE with WBV, BFR, or both could distinctively mitigate neurocognitive decline in late-middle-aged and older adults.

Move Your Body, Boost Your Brain: The Positive Impact of Physical Activity on Cognition across All Age Groups

While the physical improvements from exercise have been well documented over the years, the impact of physical activity on mental health has recently become an object of interest. Physical exercise improves cognition, particularly attention, memory, and executive functions. However, the mechanisms underlying these effects have yet to be fully understood. Consequently, we conducted a narrative literature review concerning the association between acute and chronic physical activity and cognition to provide an overview of exercise-induced benefits during the lifetime of a person. Most previous papers mainly reported exercise-related greater expression of neurotransmitter and neurotrophic factors. Recently, structural and functional magnetic resonance imaging techniques allowed for the detection of increased grey matter volumes for specific brain regions and substantial modifications in the default mode, frontoparietal, and dorsal attention networks following exercise. Here, we highlighted that physical activity induced significant changes in functional brain activation and cognitive performance in every age group and could counteract psychological disorders and neural decline. No particular age group gained better benefits from exercise, and a specific exercise type could generate better cognitive improvements for a selected target subject. Further research should develop appropriate intervention programs concerning age and comorbidity to achieve the most significant cognitive outcomes.

Neuroplasticity to autophagy cross-talk in a therapeutic effect of physical exercises and irisin in ADHD

Adaptive neuroplasticity is a pivotal mechanism for healthy brain development and maintenance, as well as its restoration in disease- and age-associated decline. Management of mental disorders such as attention deficit hyperactivity disorder (ADHD) needs interventions stimulating adaptive neuroplasticity, beyond conventional psychopharmacological treatments. Physical exercises are proposed for the management of ADHD, and also depression and aging because of evoked brain neuroplasticity. Recent progress in understanding the mechanisms of muscle-brain cross-talk pinpoints the role of the myokine irisin in the mediation of pro-cognitive and antidepressant activity of physical exercises. In this review, we discuss how irisin, which is released in the periphery as well as derived from brain cells, may interact with the mechanisms of cellular autophagy to provide protein recycling and regulation of brain-derived neurotrophic factor (BDNF) signaling via glia-mediated control of BDNF maturation, and, therefore, support neuroplasticity. We propose that the neuroplasticity associated with physical exercises is mediated in part by irisin-triggered autophagy. Since the recent findings give objectives to consider autophagy-stimulating intervention as a prerequisite for successful therapy of psychiatric disorders, irisin appears as a prototypic molecule that can activate autophagy with therapeutic goals.

The Effect of Blood Flow-Restricted Low Resistance Training on Microvascular Circulation of Myocardium in Spontaneously Hypertensive Rats

Objective: The purpose of this study was to explore the effect of blood flow-restricted low resistance training on microvascular rarefaction in the myocardium of spontaneously hypertensive rats (SHRs).

Methods: Four-week-old male SHRs were randomly divided into the following groups: Wistar-Kyoto (WKY), SHR control (SHR-SED), high-intensity resistance training (HIRT), low-intensity resistance training (LIRT), and blood flow-restricted low resistance training (BFRT). The exercise groups began to receive exercise intervention for 8 weeks at the age of 7 weeks. Blood pressure (BP), heart rate (HR), cardiac function, capillary density, and Vascular endothelial growth factor -Phosphatidylinositol 3-kinase-Protein kinase B-Endothelial nitric oxide synthetase (VEGF-Pi3k-Akt-eNOS) were assessed.

Results: 1) BP and HR of BFRT decreased significantly, Ejection fraction (EF) and Fraction shortening (FS) increased, and the effect of BFRT on lowering BP and HR was better than that of other groups (p < 0.05); 2) The expression of VEGF, VEGFR2, p-VEGFR2, Pi3k, Akt, p-Akt, eNOS and p-eNOS in the myocardium of the BFRT was significantly upregulated, and eNOS expression was significantly higher than other groups (p < 0 05); 3) the expression of VEGF in the blood of the BFRT was significantly upregulated, higher than SHR-SED, lower than HIRT (p < 0.05), and there was no significant difference between BFRT and LIRT(p > 0.05); 4) the capillary density in the myocardium of BFRT was significantly higher than other exercise groups (p < 0 05).

Conclusion: Blood flow-restricted low resistance training can activate the VEGF-Pi3k-Akt-eNOS pathway, upregulate the expression of VEGF in blood, improve microvascular rarefaction, and promote myocardial microvascular circulation, thereby improving cardiac function and lowering blood pressure, achieving the preventive effect of early hypertension.

State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions

For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.

The Influence of Acute Sprint Interval Training on Cognitive Performance of Healthy Younger Adults

There is considerable evidence showing that an acute bout of physical exercises can improve cognitive performance, but the optimal exercise characteristics (e.g., exercise type and exercise intensity) remain elusive. In this regard, there is a gap in the literature to which extent sprint interval training (SIT) can enhance cognitive performance. Thus, this study aimed to investigate the effect of a time-efficient SIT, termed as "shortened-sprint reduced-exertion high-intensity interval training" (SSREHIT), on cognitive performance. Nineteen healthy adults aged 20-28 years were enrolled and assessed for attentional performance (via the d2 test), working memory performance (via Digit Span Forward/Backward), and peripheral blood lactate concentration immediately before and 10 min after an SSREHIT and a cognitive engagement control condition (i.e., reading). We observed that SSREHIT can enhance specific aspects of attentional performance, as it improved the percent error rate (F%) in the d-2 test (t (18) = -2.249, p = 0.037, d = -0.516), which constitutes a qualitative measure of precision and thoroughness. However, SSREHIT did not change other measures of attentional or working memory performance. In addition, we observed that the exercise-induced increase in the peripheral blood lactate levels correlated with changes in attentional performance, i.e., the total number of responses (GZ) (rm = 0.70, p < 0.001), objective measures of concentration (SKL) (rm = 0.73, p < 0.001), and F% (rm = -0.54, p = 0.015). The present study provides initial evidence that a single bout of SSREHIT can improve specific aspects of attentional performance and conforming evidence for a positive link between cognitive improvements and changes in peripheral blood lactate levels.

Comparison of the effects of open vs. closed skill exercise on the acute and chronic BDNF, IGF-1 and IL-6 response in older healthy adults

BACKGROUND

Accumulating evidence shows that physical exercise has a positive effect on the release of neurotrophic factors and myokines. However, evidence regarding the optimal type of physical exercise for these release is still lacking. The aim of this study was to assess the acute and chronic effects of open-skill exercise (OSE) compared to closed-skill exercise (CSE) on serum and plasma levels of brain derived neurotrophic factor (BDNFS, BDNFP), and serum levels of insulin like growth factor 1 (IGF-1), and interleukin 6 (IL-6) in healthy older adults.

METHODS

To investigate acute effects, thirty-eight participants were randomly assigned to either an intervention (badminton (aOSE) and bicycling (aCSE), n  = 24, 65.83 ± 5.98 years) or control group (reading (CG), n  = 14, 67.07 ± 2.37 years). Blood samples were taken immediately before and 5 min after each condition. During each condition, heart rate was monitored. The mean heart rate of aOSE and aCSE were equivalent (65 ± 5% of heart rate reserve). In a subsequent 12-week training-intervention, twenty-two participants were randomly assigned to either a sport-games (cOSE, n  = 6, 64.50 ± 6.32) or a strength-endurance training (cCSE, n  = 9, 64.89 ± 3.51) group to assess for chronic effects. Training intensity for both groups was adjusted to a subjective perceived exertion using the CR-10 scale (value 7). Blood samples were taken within one day after the training-intervention.

RESULTS

BDNFS, BDNFP, IGF-1, and IL-6 levels increased after a single exercise session of 30 min. After 12 weeks of training BDNFS and IL-6 levels were elevated, whereas IGF-1 levels were reduced in both groups. However, only in the cOSE group these changes were significant. We could not find any significant differences between the exercise types.

CONCLUSION

Our results indicate that both exercise types are efficient to acutely increase BDNFS, BDNFP, IGF-1 and IL-6 serum levels in healthy older adults. Additionally, our results tend to support that OSE is more effective for improving basal BDNFS levels after 12 weeks of training.

Current Techniques Used for Practical Blood Flow Restriction Training: A Systematic Review

ABSTRACT

Bielitzki, R, Behrendt, T, Behrens, M, and Schega, L. Current techniques used for practical blood flow restriction training: a systematic review. J Strength Cond Res 35(10): 2936-2951, 2021-The purpose of this article was to systematically review the available scientific evidence on current methods used for practical blood flow restriction (pBFR) training together with application characteristics as well as advantages and disadvantages of each technique. A literature search was conducted in different databases (PubMed, Web of Science, Scopus, and Cochrane Library) for the period from January 2000 to December 2020. Inclusion criteria for this review were (a) original research involving humans, (b) the use of elastic wraps or nonpneumatic cuffs, and (c) articles written in English. Of 26 studies included and reviewed, 15 were conducted using an acute intervention (11 in the lower body and 4 in the upper body), and 11 were performed with a chronic intervention (8 in the lower body, 1 in the upper body, and 2 in both the upper and the lower body). Three pBFR techniques could be identified: (a) based on the perceptual response (perceived pressure technique), (b) based on the overlap of the cuff (absolute and relative overlap technique), and (c) based on the cuffs' maximal tensile strength (maximal cuff elasticity technique). In conclusion, the perceived pressure technique is simple, valid for the first application, and can be used independently of the cuffs' material properties, but is less reliable within a person over time. The absolute and relative overlap technique as well as the maximal cuff elasticity technique might be applied more reliably due to markings, but require a cuff with constant material properties over time.

Time to Save Time: Beneficial Effects of Blood Flow Restriction Training and the Need to Quantify the Time Potentially Saved by Its Application During Musculoskeletal Rehabilitation

The main goal of musculoskeletal rehabilitation is to achieve the pre-injury and/or pre-surgery physical function level with a low risk of re-injury. Blood flow restriction (BFR) training is a promising alternative to conventional therapy approaches during musculoskeletal rehabilitation because various studies support its beneficial effects on muscle mass, strength, aerobic capacity, and pain perception. In this perspective article, we used an evidence-based progressive model of a rehabilitative program that integrated BFR in 4 rehabilitation phases: (1) passive BFR, (2) BFR combined with aerobic training, (3) BFR combined with low-load resistance training, and (4) BFR combined with low-load resistance training and traditional high-load resistance training. Considering the current research, we propose that a BFR-assisted rehabilitation has the potential to shorten the time course of therapy to reach the stage where the patient is able to tolerate resistance training with high loads. The information and arguments presented are intended to stimulate future research, which compares the time to achieve rehabilitative milestones and their physiological bases in each stage of the musculoskeletal rehabilitation process. This requires the quantification of BFR training-induced adaptations (eg, muscle mass, strength, capillary-to-muscle-area ratio, hypoalgesia, molecular changes) and the associated changes in performance with a high measurement frequency (≤1 week) to test our hypothesis. This information will help to quantify the time saved by BFR-assisted musculoskeletal rehabilitation. This is of particular importance for patients, because the potentially accelerated recovery of physical functioning would allow them to return to their work and/or social life earlier. Furthermore, other stakeholders in the health care system (eg, physicians, nurses, physical therapists, insurance companies) might benefit from that with regard to work and financial burden.

Acute exercise and cognition: A review with testable questions for future research into cognitive enhancement with blood flow restriction

Blood flow restriction, in combination with low load/intensity exercise, has consistently been shown to increase both muscle size and strength. In contrast, the effects of blood flow restricted exercise on cognition have not been well studied. Therefore, the purpose of this paper is 1) to review the currently available literature investigating the impact of blood flow restricted exercise on cognition and 2) to provide some hypotheses for how blood flow restriction might provide an additive stimulus for augmenting specific cognitive domains above exercise alone. Given the lack of research in this area, the effects of blood flow restricted exercise on cognition are still unclear. We hypothesize that blood flow restricted exercise could potentially enhance several cognitive domains (such as attention, executive functioning, and memory) through increases in lactate production, catecholamine concentration, and PGC-1α expression. We review work that suggests that blood flow restriction is not only a beneficial strategy to improve musculoskeletal function but could also be a favorable method for enhancing multiple domains of cognition. Nonetheless, it must be emphasized this is a hypothesis that currently has only minimal experimental support, and further investigations in the future are necessary to test the hypothesis.

The Contribution of Functional Magnetic Resonance Imaging to the Understanding of the Effects of Acute Physical Exercise on Cognition

The fact that a single bout of acute physical exercise has a positive impact on cognition is well-established in the literature, but the neural correlates that underlie these cognitive improvements are not well understood. Here, the use of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), offers great potential, which is just starting to be recognized. This review aims at providing an overview of those studies that used fMRI to investigate the effects of acute physical exercises on cerebral hemodynamics and cognition. To this end, a systematic literature survey was conducted by two independent reviewers across five electronic databases. The search returned 668 studies, of which 14 studies met the inclusion criteria and were analyzed in this systematic review. Although the findings of the reviewed studies suggest that acute physical exercise (e.g., cycling) leads to profound changes in functional brain activation, the small number of available studies and the great variability in the study protocols limits the conclusions that can be drawn with certainty. In order to overcome these limitations, new, more well-designed trials are needed that (i) use a more rigorous study design, (ii) apply more sophisticated filter methods in fMRI data analysis, (iii) describe the applied processing steps of fMRI data analysis in more detail, and (iv) provide a more precise exercise prescription.

Does squatting need attention?-A dual-task study on cognitive resources in resistance exercise

INTRODUCTION

Accumulating evidence shows that acute resistance exercises and long-term resistance training positively influence cognitive functions, but the underlying mechanisms have been rarely investigated. One explanatory approach assumes that the execution of resistance exercises requires higher cognitive processes which, in turn, lead to an 'indirect' training of higher cognitive functions. However, current knowledge on the engagement of higher cognitive functions during the execution of resistance exercises is relatively sparse. Hence, the purpose of this study was to examine to what extent cognitive resources are needed to perform a resistance exercise in the form of barbell back squatting.

METHODS

Twenty-four young adults performed a cognitive task (serial subtraction of 7's) during standing and during barbell back squatting on a Smith machine. The total number and the number of correct responses were analyzed and taken as indicators of the cognitive load imposed by the experimental condition (squatting) and the control condition (standing). Additionally, participants' perceived exertion, mean heart rate, and the number of squats they were able to perform were assessed.

RESULTS

While accuracy scores were found not to be significantly different between conditions, the numbers of total and of correct responses were significantly lower during squatting than during standing. Additionally, during squatting a higher number of total answers was given in the fifth set compared to the first set. We attribute this phenomenon to a learning effect. Furthermore, there was no statistically significant correlation between cognitive measures and perceived exertion.

CONCLUSION

Results suggest that perceived exertion cannot explain the higher dual-task costs observed during squatting. They rather reflect that more cognitive resources are needed to perform low-load barbell back squats than during standing. However, further research is necessary to confirm and generalize these findings.

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.

Functional and/or structural brain changes in response to resistance exercises and resistance training lead to cognitive improvements - a systematic review

BACKGROUND

During the aging process, physical capabilities (e.g., muscular strength) and cognitive functions (e.g., memory) gradually decrease. Regarding cognitive functions, substantial functional (e.g., compensatory brain activity) and structural changes (e.g., shrinking of the hippocampus) in the brain cause this decline. Notably, growing evidence points towards a relationship between cognition and measures of muscular strength and muscle mass. Based on this emerging evidence, resistance exercises and/or resistance training, which contributes to the preservation and augmentation of muscular strength and muscle mass, may trigger beneficial neurobiological processes and could be crucial for healthy aging that includes preservation of the brain and cognition. Compared with the multitude of studies that have investigated the influence of endurance exercises and/or endurance training on cognitive performance and brain structure, considerably less work has focused on the effects of resistance exercises and/or resistance training. While the available evidence regarding resistance exercise-induced changes in cognitive functions is pooled, the underlying neurobiological processes, such as functional and structural brain changes, have yet to be summarized. Hence, the purpose of this systematic review is to provide an overview of resistance exercise-induced functional and/or structural brain changes that are related to cognitive functions.

METHODS AND RESULTS

A systematic literature search was conducted by two independent researchers across six electronic databases; 5957 records were returned, of which 18 were considered relevant and were analyzed.

SHORT CONCLUSION

Based on our analyses, resistance exercises and resistance training evoked substantial functional brain changes, especially in the frontal lobe, which were accompanied by improvements in executive functions. Furthermore, resistance training led to lower white matter atrophy and smaller white matter lesion volumes. However, based on the relatively small number of studies available, the findings should be interpreted cautiously. Hence, future studies are required to investigate the underlying neurobiological mechanisms and to verify whether the positive findings can be confirmed and transferred to other needy cohorts, such as older adults with dementia, sarcopenia and/or dynapenia.

Beneficial Effect of Exercise on Cognitive Function during Peripheral Arterial Disease: Potential Involvement of Myokines and Microglial Anti-Inflammatory Phenotype Enhancement

Peripheral arterial disease (PAD), leading to intermittent claudication, critical ischemia with rest pain, and/or tissue damage, is a public health issue associated with significant morbidity and mortality. Little is known about the link between PAD, cognitive function, and whether exercise might reduce cognitive dysfunction in PAD patients, as previously observed concerning both quality of life and prognosis. This review highlights the fact that patients suffering from PAD often demonstrate cognitive dysfunction characterized by reduced performance in nonverbal reasoning, reduced verbal fluency, and decreased information processing speed and a greater risk for progression toward dementia. Further, the data presented support that physical exercise, likely through myokine secretion and microglial anti-inflammatory phenotype enhancement, might participate in the cognition protection in common clinical settings.

Applications of Functional Near-Infrared Spectroscopy (fNIRS) Neuroimaging in Exercise⁻Cognition Science: A Systematic, Methodology-Focused Review

For cognitive processes to function well, it is essential that the brain is optimally supplied with oxygen and blood. In recent years, evidence has emerged suggesting that cerebral oxygenation and hemodynamics can be modified with physical activity. To better understand the relationship between cerebral oxygenation/hemodynamics, physical activity, and cognition, the application of state-of-the art neuroimaging tools is essential. Functional near-infrared spectroscopy (fNIRS) is such a neuroimaging tool especially suitable to investigate the effects of physical activity/exercises on cerebral oxygenation and hemodynamics due to its capability to quantify changes in the concentration of oxygenated hemoglobin (oxyHb) and deoxygenated hemoglobin (deoxyHb) non-invasively in the human brain. However, currently there is no clear standardized procedure regarding the application, data processing, and data analysis of fNIRS, and there is a large heterogeneity regarding how fNIRS is applied in the field of exercise⁻cognition science. Therefore, this review aims to summarize the current methodological knowledge about fNIRS application in studies measuring the cortical hemodynamic responses during cognitive testing (i) prior and after different physical activities interventions, and (ii) in cross-sectional studies accounting for the physical fitness level of their participants. Based on the review of the methodology of 35 as relevant considered publications, we outline recommendations for future fNIRS studies in the field of exercise⁻cognition science.