Exercise training and sympathetic nervous system activity: evidence for physical activity dependent neural plasticity

Sympathetic nervous system activity is associated with choroidal thickness and axial length in school-aged children

BACKGROUND/AIMS

We aim to explore the effect of sympathetic nervous system (SNS) on choroid thickness (ChT) and axial length (AL).

METHODS

Students of grade 2 and 3 from a primary school were included and followed for 1 year. Visual acuity, refraction, AL and ChT were measured. Morning urine samples were collected for determining SNS activity by analysing concentrations of epinephrine, norepinephrine and dopamine using the liquid chromatography-tandem mass spectrometry. The most important factor (factor 1) was calculated using factor analysis to comprehensively indicate the SNS activity.

RESULTS

A total of 273 students were included, with an average age of 7.77±0.69 years, and 150 (54.95%) were boys. Every 1 µg/L increase in epinephrine is associated with 1.60 µm (95% CI 0.30 to 2.90, p=0.02) decrease in average ChT. Every 1 µg/L increase in norepinephrine is associated with 0.53 µm (95% CI 0.08 to 0.98, p=0.02) decrease in the ChT in inner-superior region. The factor 1 was negatively correlated with the ChT in the superior regions. Every 1 µg/L increase in norepinephrine was associated with 0.002 mm (95% CI 0.0004 to 0.004, p=0.016) quicker AL elongation. The factor 1 was positively correlated with AL elongation (coefficient=0.037, 95% CI 0.005 to 0.070, p=0.023).

CONCLUSIONS

We hypothesised that chronic stress characterised by elevated level of the SNS, was associated with significant increase in AL elongation, probably through thinning of the choroid.

Effect of physical activity on the relationship between adiposity and cardiac autonomic modulation in female breast cancer survivors: a longitudinal study

This longitudinal study aimed to analyze the influence of physical activity (PA) on the relationship between body adiposity and cardiac autonomic modulation (CAM) in women survivors of breast cancer. We collected body adiposity through electrical bioimpedance considering body fat percentage (BFP), CAM through heart rate variability (considering RMSSD, SDNN, PNN50, LF (m2), HF (m2), SD1 indexes and SD1/SD2 ratio) and PA through a questionnaire in 64 participants (58.0 ± 9.6 years), recruited through the local association of support for breast cancer and by direct indications from city mastologists. After insertion of PA into the multivariate statistical model, significant attenuation was observed in the relationship between body adiposity and CAM for the indices: SDNN (β = -0.94; 95 percent CI: -1.93; 0.04; p = .060) and SD1/SD2 (β = -0.01;95 percent CI = -0.02; 0.001; p = .065). In conclusion, it was observed that PA was able to mitigate the relationships between BFP and CAM (considering SDNN index and SD1/SD2 ratio) in breast cancer survivors.

Association Between Physical Activity Levels in Different Domains and Cardiac Autonomic Modulation in Breast Cancer Survivors: A Cross-sectional Study

BACKGROUND

Breast cancer survivors frequently present cardiac autonomic dysfunction. Physical activity (PA) has been associated with better cardiac autonomic modulation (CAM) in breast cancer survivors.

OBJECTIVE

This study aimed to analyze the association between CAM and PA levels performed in different domains (work and occupation, sport and exercise, and leisure time and commuting) in breast cancer survivors.

METHODS

This is a cross-sectional study with 99 breast cancer survivors (age, 55.3 ± 10.4 years). Cardiac autonomic modulation was assessed by heart rate variability, and PA levels at work and occupation, sport and exercise, and leisure time and commuting were assessed using the Baecke PA questionnaire. The sum of these 3 domains provided the total PA. The Mann-Whitney test was used to compare CAM between active and inactive women in different domains of PA.

RESULTS

Cardiac autonomic modulation was similar between active and inactive women in the different domains ( P > .05). However, when considering the total PA, active breast cancer survivors presented higher SDNN (average standard deviation of all normal RR intervals) (20.0 ± 13.4 vs 28.8 ± 14.0; P = .008) and SD2 (standard deviation of the long-term intervals between consecutive heartbeats) indices (29.2 ± 17.3 vs 38.7 ± 19.9; P = .005) compared with their inactive counterparts.

CONCLUSION

Breast cancer survivors with higher total PA presented better CAM compared with their less active peers.

IMPLICATIONS FOR PRACTICE

The results of this study are promising and show the importance of increasing PA levels in different domains for the maintenance of cardiovascular health among breast cancer survivors.

Virtual reality facilitated exercise improves pain perception: A crossover study

STUDY OBJECTIVE

Both virtual reality (VR) and exercise are recognized for their analgesic and anxiolytic properties. The purpose of this study is to evaluate the ability of VR-facilitated exercise to modulate pain.

DESIGN

Within-subject cross-over clinical trial.

SETTING

The Stanford Chariot Program conducted this study at Lucile Packard Children's Hospital Stanford (LCPHS).

PATIENTS

Healthy participants meeting inclusion criteria were recruited by volunteer solicitation from LCPHS.

INTERVENTIONS

Participants were randomized by hand dominance and subjected to a standardized cold pressor test with no VR or exercise. After a 5-min wash-out period, participants repeated the test on their other hand while experiencing a VR-facilitated exercise condition. Pain sensitivity, pain tolerance, and sympathetic activation data were collected during both conditions.

MEASUREMENTS

Pain sensitivity was scored 0-10 and collected every 30 s. Pain tolerance was recorded as the duration a participant could endure the painful stimuli. Sympathetic activation was measured by skin conductance response density (SCRD) and recorded in 30 s epochs by a biosensor. In all analyses, data were nested by participant.

MAIN RESULTS

Forty-one participants completed both interventions. Pain sensitivity was reduced in the VR-facilitated exercise condition (p < 0.0001). There was no difference in pain tolerance between conditions. While both conditions resulted in an increase in sympathetic activity, SCRD was higher at all time points in the VR-facilitated exercise condition.

CONCLUSIONS

The reduction in pain sensitivity indicates VR-facilitated exercise results in improved pain perception. VR-facilitated exercise may be especially useful for patients with chronic pain or other conditions requiring physical therapy, where pain may be exacerbated by exercise.

Impact of Yoga as an Add-On Intervention on Neurocognitive Functions Among Adult Athletes: A Pilot Study

BACKGROUND

Athletes are vulnerable to musculoskeletal injuries and psychiatric conditions. Previous studies have reported the benefits of yoga on cognitive functions among healthy children, adults, and the elderly. This pilot study aimed to test the neurocognitive functions among athletes with/without yoga intervention.

METHODS

A non-randomized, two-armed parallel-group, single-blind comparative trial was used. The participants were grouped into (i) yoga with sports activity (YSA, n = 15) and (ii) sports activity alone (SA, n = 14). The subjects were assessed at the baseline and after a one-month intervention using digit span forward (DSF), digit span backward (DSB), Trail Making Test (TMT) A & B, and Rey Auditory Verbal Learning Test (RAVLT). A comprehensive one-hour yoga training three days a week for two months constitutes selected asanas (postures), pranayama (breathing techniques), relaxation techniques, and meditation techniques. The control group constitutes the routine sports activity for the same period.

RESULTS

A paired sample t-test showed a significant improvement in cognitive performance on TMT A & B duration and RAVLT total score in the YSA group compared with the SA group. However, a significant trend was observed for DSF, DSB, and RAVLT immediate recall. Independent sample t-test (pre-post change scores) showed no significant group difference in cognitive performance, except there was a significant trend observed related to DSF (p = 0.053) and RAVLT distraction (p = 0.09), where the yoga group showed better performance in cognitive functions.

CONCLUSION

The results suggest that yoga may be integrated with sports to enhance neurocognitive functions.

Attenuated cardiac autonomic function in humans with high-affinity hemoglobin and compensatory polycythemia

During hypoxic exposure, humans with high-affinity hemoglobin (and compensatory polycythemia) have blunted increases in heart rate compared with healthy humans with typical oxyhemoglobin dissociation curves. This response may be associated with altered autonomic control of heart rate. Our hypothesis-generating study aimed to investigate cardiac baroreflex sensitivity and heart rate variability among nine humans with high-affinity hemoglobin [6 females, O2 partial pressure at 50% [Formula: see text] (P50) = 16 ± 1 mmHg] compared with 12 humans with typical affinity hemoglobin (6 F, P50 = 26 ± 1 mmHg). Participants breathed normal room air for a 10-min baseline, followed by 20 min of isocapnic hypoxic exposure, designed to lower the arterial partial pressure O2 ([Formula: see text]) to ∼50 mmHg. Beat-by-beat heart rate and arterial blood pressure were recorded. Data were averaged in 5-min periods throughout the hypoxia exposure, beginning with the last 5 min of baseline in normoxia. Spontaneous cardiac baroreflex sensitivity and heart rate variability were determined using the sequence method and the time and frequency domain analyses, respectively. Cardiac baroreflex sensitivity was lower in humans with high-affinity hemoglobin than controls at baseline and during isocapnic hypoxic exposure (normoxia: 7 ± 4 vs. 16 ± 10 ms/mmHg, hypoxia minutes 15-20: 4 ± 3 vs. 14 ± 11 ms/mmHg; group effect: P = 0.02, high-affinity hemoglobin vs. control, respectively). Heart rate variability calculated in both the time (standard deviation of the N-N interval) and frequency (low frequency) domains was lower in humans with high-affinity hemoglobin than in controls (all P < 0.05). Our data suggest that humans with high-affinity hemoglobin may have attenuated cardiac autonomic function.

Integration of yoga within exercise and sports science as a preventive and management strategy for musculoskeletal injuries/disorders and mental disorders - A review of the literature

OBJECTIVES

Exercise-induced musculoskeletal injuries/disorders and associated mental disorders are prevalent among athletes. The main objective of this review is to analyze the prospects of Yoga practices as a preventive and management strategy for musculoskeletal injuries/disorders and associated mental disorders often encountered in exercise and sports activities.

METHODS

A review of the literature was performed using electronic databases such as MEDLINE/PubMed and google scholar published between January 1991 and December 2021 which yielded 88 research articles. The keywords used were yoga OR exercise AND musculoskeletal injuries OR disorders, yoga OR exercise AND mental disorders, yoga AND sports injuries, yoga AND stress, yoga OR exercise AND oxidative stress, yoga OR exercise AND inflammation, yoga OR exercise AND diet.

RESULTS

The moderate and regular exercises are beneficial to health. However, high intensity and overtraining physical activities lead to immune suppression, oxidative stress, muscle damage/fatigue, coronary risk, psychiatric disorders and so on due to enormous strain on various physiological functions. Yoga seems to undermine these adverse activities through up-regulating the functions of the parasympathetic nervous system (PNS) and down-regulating the activities of hypothalamohypophysial axis (HPA) which are conducive to healing, recovery, regeneration, reduction in stress, relaxation of mind, better cognitive functions, promotion of mental health, reduction in inflammation and oxidative stress, and so on.

CONCLUSION

Literature suggests that Yoga should be integrated within exercise and sports sciences mainly to prevent & manage musculoskeletal injuries/disorders and associated mental disorders.

Exercise modulates sympathetic and vascular function in chronic kidney disease

BACKGROUNDChronic kidney disease (CKD) is characterized by chronic overactivation of the sympathetic nervous system (SNS), which increases the risk of cardiovascular (CV) disease and mortality. SNS overactivity increases CV risk by multiple mechanisms, including vascular stiffness. We tested the hypothesis that aerobic exercise training would reduce resting SNS activity and vascular stiffness in patients with CKD.METHODSIn this randomized controlled trial, sedentary older adults with CKD underwent 12 weeks of exercise (cycling, n = 32) or stretching (an active control group, n = 26). Exercise and stretching interventions were performed 20-45 minutes/session at 3 days/week and were matched for duration. Primary endpoints include resting muscle sympathetic nerve activity (MSNA) via microneurography, arterial stiffness by central pulse wave velocity (PWV), and aortic wave reflection by augmentation index (AIx).RESULTSThere was a significant group × time interaction in MSNA and AIx with no change in the exercise group but with an increase in the stretching group after 12 weeks. The magnitude of change in MSNA was inversely associated with baseline MSNA in the exercise group. There was no change in PWV in either group over the study period.CONCLUSIONOur data demonstrate that 12 weeks of cycling exercise has beneficial neurovascular effects in patients with CKD. Specifically, exercise training safely and effectively ameliorated the increase in MSNA and AIx observed over time in the control group. This sympathoinhibitory effect of exercise training showed greater magnitude in patients with CKD with higher resting MSNA.TRIAL REGISTRATIONClinicalTrials.gov, NCT02947750.FUNDINGNIH R01HL135183; NIH R61AT10457; NIH NCATS KL2TR002381; and NIH T32 DK00756; NIH F32HL147547; and VA Merit I01CX001065.

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.

Cardiovascular and autonomic dysfunction in long-COVID syndrome and the potential role of non-invasive therapeutic strategies on cardiovascular outcomes

A significant percentage of COVID-19 survivors develop long-lasting cardiovascular sequelae linked to autonomic nervous system dysfunction, including fatigue, arrhythmias, and hypertension. This post-COVID-19 cardiovascular syndrome is one facet of "long-COVID," generally defined as long-term health problems persisting/appearing after the typical recovery period of COVID-19. Despite the fact that this syndrome is not fully understood, it is urgent to develop strategies for diagnosing/managing long-COVID due to the immense potential for future disease burden. New diagnostic/therapeutic tools should provide health personnel with the ability to manage the consequences of long-COVID and preserve/improve patient quality of life. It has been shown that cardiovascular rehabilitation programs (CRPs) stimulate the parasympathetic nervous system, improve cardiorespiratory fitness (CRF), and reduce cardiovascular risk factors, hospitalization rates, and cognitive impairment in patients suffering from cardiovascular diseases. Given their efficacy in improving patient outcomes, CRPs may have salutary potential for the treatment of cardiovascular sequelae of long-COVID. Indeed, there are several public and private initiatives testing the potential of CRPs in treating fatigue and dysautonomia in long-COVID subjects. The application of these established rehabilitation techniques to COVID-19 cardiovascular syndrome represents a promising approach to improving functional capacity and quality of life. In this brief review, we will focus on the long-lasting cardiovascular and autonomic sequelae occurring after COVID-19 infection, as well as exploring the potential of classic and novel CRPs for managing COVID-19 cardiovascular syndrome. Finally, we expect this review will encourage health care professionals and private/public health organizations to evaluate/implement non-invasive techniques for the management of COVID-19 cardiovascular sequalae.

Effects of neuromodulation on cognitive and emotional responses to psychosocial stressors in healthy humans

Physiological and psychological stressors can exert wide-ranging effects on the human brain and behavior. Research has improved understanding of how the sympatho-adreno-medullary (SAM) and hypothalamic-pituitary-adrenocortical (HPA) axes respond to stressors and the differential responses that occur depending on stressor type. Although the physiological function of SAM and HPA responses is to promote survival and safety, exaggerated psychobiological reactivity can occur in psychiatric disorders. Exaggerated reactivity may occur more for certain types of stressors, specifically, psychosocial stressors. Understanding stressor effects and how the body regulates these responses can provide insight into ways that psychobiological reactivity can be modulated. Non-invasive neuromodulation is one way that responding to stressors may be altered; research into these interventions may provide further insights into the brain circuits that modulate stress reactivity. This review focuses on the effects of acute psychosocial stressors and how neuromodulation might be effective in altering stress reactivity. Although considerable research into stress interventions focuses on treating pathology, it is imperative to first understand these mechanisms in non-clinical populations; therefore, this review will emphasize populations with no known pathology and consider how these results may translate to those with psychiatric pathologies.

Exploring the interplay between mechanisms of neuroplasticity and cardiovascular health in aging adults: A multiple linear regression analysis study

BACKGROUND

Neuroplasticity and cardiovascular health behavior are critically important factors for optimal brain health.

OBJECTIVE

To assess the association between the efficacy of the mechanisms of neuroplasticity and metrics of cardiovascular heath in sedentary aging adults.

METHODS

We included thirty sedentary individuals (age = 60.6 ± 3.8 y; 63 % female). All underwent assessments of neuroplasticity, measured by the change in amplitude of motor evoked potentials elicited by single-pulse Transcranial Magnetic Stimulation (TMS) at baseline and following intermittent Theta-Burst (iTBS) at regular intervals. Cardiovascular health measures were derived from the Incremental Shuttle Walking Test and included Heart Rate Recovery (HRR) at 1-min/2-min after test cessation. We also collected plasma levels of brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and c-reactive protein.

RESULTS

We revealed moderate but significant relationships between TMS-iTBS neuroplasticity, and the predictors of cardiovascular health (|r| = 0.38 to 0.53, p < .05). HRR1 was the best predictor of neuroplasticity (β = 0.019, p = .002). The best fit model (Likelihood ratio = 5.83, p = .016) of the association between neuroplasticity and HRR1 (β = 0.043, p = .002) was selected when controlling for demographics and health status. VEGF and BDNF plasma levels augmented the association between neuroplasticity and HRR1.

CONCLUSIONS

Our findings build on existing data demonstrating that TMS may provide insight into neuroplasticity and the role cardiovascular health have on its mechanisms. These implications serve as theoretical framework for future longitudinal and interventional studies aiming to improve cardiovascular and brain health. HRR1 is a potential prognostic measure of cardiovascular health and a surrogate marker of brain health in aging adults.

Hormetic response to B-type procyanidin ingestion involves stress-related neuromodulation via the gut-brain axis: Preclinical and clinical observations

B-type procyanidins, a series of catechin oligomers, are among the most ingested polyphenols in the human diet. Results of meta-analyses have suggested that intake of B-type procyanidins reduces cardiovascular disease risk. Another recent focus has been on the effects of B-type procyanidins on central nervous system (CNS) function. Although long-term B-type procyanidin ingestion is linked to health benefits, a single oral intake has been reported to cause physiological alterations in circulation, metabolism, and the CNS. Comprehensive analyses of previous reports indicate an optimal mid-range dose for the hemodynamic effects of B-type procyanidins, with null responses at lower or higher doses, suggesting hormesis. Indeed, polyphenols, including B-type procyanidins, elicit hormetic responses in vitro, but animal and clinical studies are limited. Hormesis of hemodynamic and metabolic responses to B-type procyanidins was recently confirmed in animal studies, however, and our work has linked these effects to the CNS. Here, we evaluate the hormetic response elicited by B-type procyanidins, recontextualizing the results of intervention trials. In addition, we discuss the possibility that this hormetic response to B-type procyanidins arises via CNS neurotransmitter receptors. We have verified the direction of future research for B-type procyanidins in this review.

Remembering how to run: a descriptive wheel run analysis in CF1 males and females mice

Physical exercise is known to have beneficial effects on general health and wellbeing in humans and it is also related to neuronal plasticity, increasing neurogenesis and consequently leading to improvements in processes such as learning and memory. In this sense, wheel running performance in mice appears as an extensively used behavioral approach for neurobiological studies. Here, we explored the running patterns in CF1 male and female mice allowing voluntary wheel running for 20 min along three consecutive days. We analyzed differences in the accumulated distance traveled, instant velocity, and latency to run and breaks taken in both males and females, comparing performance between days. Results revealed that after a first experience with the wheel, animals that had learnt how to run on day 1 quickly look forward to stepping into the wheel in subsequent training days, reflected by a significant increase in daily running distance and velocity. Further, no differences were found in the running performance between males and females. In summary, in a first experience with the wheel, animals get familiarized with the wheel and grow accustomed to it.

A Mixed Comparisons of Aerobic Training With Different Volumes and Intensities of Physical Exercise in Patients With Hypertension: A Systematic Review and Network Meta-Analysis

It is essential for patients with hypertension to effectively reduce and maintain appropriate blood pressure levels. As one of the non-pharmacological and invasive methods, physical exercise seems to improve blood pressure of the patients with hypertension. However, different volumes and intensities of physical exercise on the improvement of hypertension are different. To understand the effects of the type of exercise training on blood pressure and the other health status of patients with hypertension, a network meta-analysis was used to compare the mixed effects of different types of exercise training. This systematic review includes all eligible randomized controlled trials of PubMed, Medline, Cochrane Library, and CINAHL. Twelve studies met the inclusion criteria (n = 846 participants at the end of the study). The results show that a medium-intensity training (MIT) is best in improving the blood pressure of patients with hypertension, while a high-volume high-intensity interval training (HVHIIT) is better in reducing body mass and resting heart rate. In addition, the analysis of the exercise capacity shows that HVHIIT has a better effect on the improvement of patients with hypertension. Noticeably, long-term high-volume and appropriate intensity exercise can effectively improve the health status of patients with hypertension. In short, for patients with high blood pressure, MIT seems to be better at lowering blood pressure, while HVHIIT can better improve exercise ability and physical fitness. However, larger randomized controlled trials with a longer duration than those included in this meta-analysis are needed to confirm these results.

The Exercising Brain: An Overlooked Factor Limiting the Tolerance to Physical Exertion in Major Cardiorespiratory Diseases?

“Exercise starts and ends in the brain”: this was the title of a review article authored by Dr. Bengt Kayser back in 2003. In this piece of work, the author highlights that pioneer studies have primarily focused on the cardiorespiratory-muscle axis to set the human limits to whole-body exercise tolerance. In some circumstances, however, exercise cessation may not be solely attributable to these players: the central nervous system is thought to hold a relevant role as the ultimate site of exercise termination. In fact, there has been a growing interest relative to the “brain” response to exercise in chronic cardiorespiratory diseases, and its potential implication in limiting the tolerance to physical exertion in patients. To reach these overarching goals, non-invasive techniques, such as near-infrared spectroscopy and transcranial magnetic stimulation, have been successfully applied to get insights into the underlying mechanisms of exercise limitation in clinical populations. This review provides an up-to-date outline of the rationale for the “brain” as the organ limiting the tolerance to physical exertion in patients with cardiorespiratory diseases. We first outline some key methodological aspects of neuromuscular function and cerebral hemodynamics assessment in response to different exercise paradigms. We then review the most prominent studies, which explored the influence of major cardiorespiratory diseases on these outcomes. After a balanced summary of existing evidence, we finalize by detailing the rationale for investigating the “brain” contribution to exercise limitation in hitherto unexplored cardiorespiratory diseases, an endeavor that might lead to innovative lines of applied physiological research.

Effects of mind-body practice on arterial stiffness, central hemodynamic parameters and cardiac autonomic function of college students

A substantial number of studies have shown the beneficial effects of mind-body practice on physical fitness among both the healthy middle-aged and elderly adults and patients with chronic diseases. However, its positive effects on college students remain poorly understood. This study aimed to systematically investigate the potential efficiency of the Baduanjin exercise on the maintenance of the homeostasis of body composition and the improvement of the cardiovascular function of the college students. The study revealed a promising efficacy of the Baduanjin exercise in the prevention of the loss of water, inorganic salts, protein, and muscle contents and the accumulation of body fat. Furthermore, the present study also demonstrated the positive efficacy of Baduanjin exercise in decreasing of peripheral and central arterial blood pressure and carotid and femoral artery pulse wave velocity (cfPWV) of the college students. Moreover, the heart rate variability (HRV) analysis was also performed using the assessment of time and frequency domain indices. The data showed that all of the time-domain indices and the high-frequency (HF) band of the HRV relatively increased, whereas the low-frequency (LF) band of the HRV relatively decreased after the long-term Baduanjin exercise. Collectively, the present study suggested that a 12-week Baduanjin exercise could maintain the body composition in a relatively healthy and stable range and improve blood pressure, central hemodynamics, and the arterial stiffness of the college students. The underlying mechanism might be due to the improvement of parasympathetic activity and the suppression of sympathetic activity of college students via Baduanjin exercise.

Spleen tissue changes after restraint stress: effects of aerobic exercise training

Inflammation has been described as a prominent mechanism involved in dysfunctions and diseases evoked by chronic stress. Notably, the spleen is an immune organ controlled by sympathetic and glucocorticoid mechanisms, but the impact of chronic stress in the spleen is not entirely understood. Besides, the impact of aerobic exercise training on the effects of chronic stress in the spleen has never been reported. Therefore, this study aimed to assess the changes caused in the spleen by repeated restraint stress and the effect of aerobic exercise training performed after a period of chronic restraint stress in rats. We identified that daily exposure to restraint stress (120 min per session, for 14 consecutive days) increased corticosterone and noradrenaline content, gene expression of glucocorticoid and β₂-adrenergic receptors, TNF-α and IL-6 levels, and increased pro-oxidant substances in the spleen. Circulating levels of corticosterone were also increased in chronically stressed animals. Exercise training (1 h a day/5 days per week, for 60 days) increased glucocorticoid receptor gene expression, interleukin (IL)-10 and antioxidant mechanisms in the spleen. Exercise also decreased splenic noradrenaline, tumoral necrosis factor (TNF)-α, and IL-6 contents. Lastly, the effects of repeated restraint stress in the spleen were mitigated in animals subjected to aerobic training. Taken together, the results reported in the present study indicate that aerobic exercise training is a relevant non-pharmacological therapeutic approach to dysfunctions in the spleen caused by a period of stress.

Chronic stress induced perivascular adipose tissue impairment of aortic function and the therapeutic effect of exercise

NEW FINDINGS

What is the central question of this study? Thoracic perivascular adipose tissue (tPVAT) is known to, in part, regulate aortic function: what are the effects of unpredictable chronic mild stress (UCMS) on the tPVAT regulation of aortic function and what is the role of exercise training in alleviating the potential negative actions of UCMS on tPVAT? What is the main finding and its importance? UCMS causes tPVAT to disrupt endothelium-dependent dilatation, increases inflammatory cytokine production and diminishes tPVAT-adiponectin. Exercise training proved efficacious in preventing tPVAT-mediated disruption of aortic function. The data support a tPVAT mechanism through which chronic stress negatively impacts vascular health, which adds to our knowledge of how psychological disorders might increase the risk of cardiovascular disease.

ABSTRACT

Chronic stress is a major risk for cardiovascular disease. Perivascular adipose tissue (PVAT) has been shown to regulate vascular function; however, the impact of chronic stress and the comorbidity of metabolic syndrome (MetS) on thoracic (t)PVAT is unknown. Additionally, aerobic exercise training (AET) is known to combat the pathology of MetS and chronic stress, but the role of tPVAT in these actions is also unknown. Therefore, the purpose of this study was to examine the effects of unpredictable chronic mild stress (UCMS) on the tPVAT regulation of aortic function and the preventative effect of AET. Lean (LZR) and obese (OZR) Zucker rats (16-17 weeks old) were exposed to 8 weeks of UCMS with and without treadmill exercise (AET). In LZR, UCMS impaired aortic endothelium-dependent dilatation (EDD) (assessed ex vivo by wire myography) and aortic stiffness (assessed by elastic modulus) with no change in OZR subject to UCMS. However, both LZR and OZR UCMS tPVAT impaired EDD compared to respective controls. LZR and OZR subject to UCMS had higher oxidative stress production, diminished adiponectin and impaired aortic nitric oxide levels. Divergently, UCMS induced greater inflammatory cytokine production in LZR UCMS tPVAT, but not in OZR UCMS tPVAT. AET prevented the tPVAT impairment of aortic relaxation with UCMS in LZR and OZR. Additionally, AET reduced aortic stiffness in both LZR and OZR. These beneficial effects on tPVAT regulation of the aorta are likely due to AET preservation of adiponectin, reduced oxidative stress and inflammation, and enhanced nitric oxide. UCMS impaired tPVAT-regulated aortic function in LZR, and augmented MetS-induced EDD in OZR. Conversely, AET in combination with UCMS largely preserved aortic function and the tPVAT environment, in both groups.

Role of exercise on visceral adiposity after spinal cord injury: a cardiometabolic risk factor

PURPOSE

Visceral adipose tissue (VAT) is associated with cardiometabolic disease risk in able-bodied (AB) populations. However, the underlying mechanisms of VAT-induced disease risk are unknown in persons with spinal cord injury (SCI). Potential mechanisms of VAT-induced cardiometabolic dysfunction in persons with SCI include systemic inflammation, liver adiposity, mitochondrial dysfunction, and anabolic deficiency. Moreover, how exercise interventions impact these mechanisms associated with VAT-induced cardiometabolic dysfunction are still being explored.

METHODS

A search for relevant scientific literature about the effects of exercise on VAT and cardiometabolic health was conducted on the PubMed database. Literature from reference lists was also included when appropriate.

RESULTS

Both aerobic and resistance exercise training beneficially impact health and VAT mass via improving mitochondrial function, glucose effectiveness, and inflammatory signaling in SCI and AB populations. Specifically, aerobic exercise appears to also modulate cellular senescence in AB populations and animal models, while resistance exercise seems to augment anabolic signaling in persons with SCI.

CONCLUSIONS

The current evidence supports regular engagement in exercise to reduce VAT mass and the adverse effects on cardiometabolic health in persons with SCI. Future research is needed to further elucidate the precise mechanisms by which VAT negatively impacts health following SCI. This will likely facilitate the development of rehabilitation protocols that target VAT reduction in persons with SCI.

Does exercise attenuate age- and disease-associated dysfunction in unconventional T cells? Shining a light on overlooked cells in exercise immunology

Unconventional T Cells (UTCs) are a unique population of immune cells that links innate and adaptive immunity. Following activation, UTCs contribute to a host of immunological activities, rapidly responding to microbial and viral infections and playing key roles in tumor suppression. Aging and chronic disease both have been shown to adversely affect UTC numbers and function, with increased inflammation, change in body composition, and physical inactivity potentially contributing to the decline. One possibility to augment circulating UTCs is through increased physical activity. Acute exercise is a potent stimulus leading to the mobilization of immune cells while the benefits of exercise training may include anti-inflammatory effects, reductions in fat mass, and improved fitness. We provide an overview of age-related changes in UTCs, along with chronic diseases that are associated with altered UTC number and function. We summarize how UTCs respond to acute exercise and exercise training and discuss potential mechanisms that may lead to improved frequency and function.

Arterial Stiffness and Hemodynamics in Young Women: The Effects of Oral Contraceptive Intake and Physical Habits

Oral contraceptive (OC) intake seems to be associated with increased central hemodynamics and arterial stiffness. Conversely, physical activity (PA) is known to induce benefits on vascular structure and function, suggesting that the negative effects of the OC pill could be counterbalanced by regular PA. The aim of this cross-sectional study was to determine (1) whether OC intake in young women is associated with higher values of hemodynamic parameters and arterial stiffness and (2) whether these negative effects could be counterbalanced by regular physical activity. Forty-nine young healthy women (21.9 years ± 2.1) were recruited and divided into 4 groups, depending on their hormonal status (OC users: OC+ or non-OC users: OC−) and their physical habits (active/inactive). Assessments of central hemodynamics (central blood pressure, Aix75) and pulse wave velocity (PWV) were performed using applanation tonometry. cBP was higher in OC+ vs. OC−, while PWV was similar between these two groups. No interaction between physical activity and hormonal status was observed for any of these variables. Nevertheless, PWV was lower in young active women compared with age-matched inactive women, suggesting that the positive effect of regular physical exercise on the cardiovascular system is already visible in the first years of women’s adulthood, whatever the hormonal status.

Sympathetic neural responses in heart failure during exercise and after exercise training

The sympathetic nervous system coordinates the cardiovascular response to exercise. This regulation is impaired in both experimental and human heart failure with reduced ejection fraction (HFrEF), resulting in a state of sympathoexcitation which limits exercise capacity and contributes to adverse outcome. Exercise training can moderate sympathetic excess at rest. Recording sympathetic nerve firing during exercise is more challenging. Hence, data acquired during exercise are scant and results vary according to exercise modality. In this review we will: (1) describe sympathetic activity during various exercise modes in both experimental and human HFrEF and consider factors which influence these responses; and (2) summarise the effect of exercise training on sympathetic outflow both at rest and during exercise in both animal models and human HFrEF. We will particularly highlight studies in humans which report direct measurements of efferent sympathetic nerve traffic using intraneural recordings. Future research is required to clarify the neural afferent mechanisms which contribute to efferent sympathetic activation during exercise in HFrEF, how this may be altered by exercise training, and the impact of such attenuation on cardiac and renal function.

Parasympathetic Nervous Activity Associated with Discoordination Between Physical Acceleration and Heart Rate Variability in Patients with Sleep Apnea

Sleep apnea syndrome (SAS) often accompanies alterations in heart rate variability (HRV). The severity of SAS is sometimes evaluated using the oxygen desaturation index (ODI). We hypothesized that effects of the autonomic nervous system could be involved in the coordination between HRV and physical acceleration during free movement in patients with SAS. Among 33 women aged 60 years or older, 19 had a high ODI (>5). Their HRV and physical acceleration were simultaneously obtained every minute for 24 hours. The low frequency/high frequency (LF/HF) ratio and the high frequency in normalized units (HFnu) were used as HRV indices. Low levels of %Lag0, defined as the percentage of the lag = 0 min in 1 h, indicated coordination between physical acceleration and HRV. Nineteen participants were divided into group A (high %Lag0 before sleep [n = 9]) or group B (low %Lag0 [n = 10]). In group B participants with a high ODI and low %Lag0 in the hour after waking, HFnu was significantly increased compared to that in group A participants with high ODI and high %Lag0 in the hour after waking (p < 0.05). These results suggest that close associations between high ODI and discoordination between HRV and physical acceleration may be due to higher parasympathetic nervous system activity after waking.

Cardiac adaptations to 60 day head-down-tilt bed rest deconditioning. Findings from the AGBRESA study

Aims

Reduced physical activity increases the risk of heart failure; however, non‐invasive methodologies detecting subclinical changes in myocardial function are not available. We hypothesized that myocardial, left ventricular, systolic strain measurements could capture subtle abnormalities in myocardial function secondary to physical inactivity.

Methods and results

In the AGBRESA study, which assessed artificial gravity through centrifugation as potential countermeasure for space travel, 24 healthy persons (eight women) were submitted to 60 day strict −6° head‐down‐tilt bed rest. Participants were assigned to three groups of eight subjects: a control group, continuous artificial gravity training on a short‐arm centrifuge (30 min/day), or intermittent centrifugation (6 × 5 min/day). We assessed cardiac morphology, function, strain, and haemodynamics by cardiac magnetic resonance imaging (MRI) and echocardiography. We observed no differences between groups and, therefore, conducted a pooled analysis. Consistent with deconditioning, resting heart rate (∆8.3 ± 6.3 b.p.m., P < 0.0001), orthostatic heart rate responses (∆22.8 ± 19.7 b.p.m., P < 0.0001), and diastolic blood pressure (∆8.8 ± 6.6 mmHg, P < 0.0001) increased, whereas cardiac output (∆−0.56 ± 0.94 L/min, P = 0.0096) decreased during bed rest. Left ventricular mass index obtained by MRI did not change. Echocardiographic left ventricular, systolic, global longitudinal strain (∆1.8 ± 1.83%, P < 0.0001) decreased, whereas left ventricular, systolic, global MRI circumferential strain increased not significantly (∆−0.68 ± 1.85%, P = 0.0843). MRI values rapidly returned to baseline during recovery.

Conclusion

Prolonged head‐down‐tilt bed rest provokes changes in cardiac function, particularly strain measurements, that appear functional rather than mediated through cardiac remodelling. Thus, strain measurements are of limited utility in assessing influences of physical deconditioning or exercise interventions on cardiac function.

Parasympathetic and sympathetic nervous systems interactively predict change in cognitive functioning in midlife adults

The two branches of the autonomic nervous system (ANS) have been individually linked to changes in cognitive functioning: The parasympathetic nervous system (PNS) has been associated with healthy cognitive aging, whereas excessive sympathetic nervous system (SNS) activity has been linked to heightened cognitive decline. Despite these separate findings and despite the integrative nature of the ANS, little work has examined the two branches simultaneously to better understand their interactive effects on changes in cognitive functioning in midlife adults. We examined cognitive change in two waves of the Midlife in the United States (MIDUS) study cognitive project and indexed PNS and SNS activity from heart rate variability and epinephrine levels, respectively, from the MIDUS biomarker project (minimum n = 843, 57.9% female, mean age at first wave = 53.8 years). Our findings indicate that greater PNS responsivity (i.e., greater withdrawal and greater recovery) in response to cognitive challenge is associated with attenuated cognitive decline, but only among individuals with low SNS levels; at higher SNS levels, the effects of the PNS on cognitive decline are attenuated. These results suggest that future research targeting the ANS and cognitive aging should consider both ANS branch's effects simultaneously.

Activity-Dependent Neuroplastic Changes in Autonomic Circuitry Modulating Cardiovascular Control: The Essential Role of Baroreceptors and Chemoreceptors Signaling

Aerobic exercise training improves the autonomic control of the circulation. Emerging evidence has shown that exercise induces neuroplastic adaptive changes in preautonomic circuitry controlling sympathetic/parasympathetic outflow to heart and vessels. The mechanisms underlying neuronal plasticity are, however, incompletely understood. Knowing that sinoaortic denervation blocks training-induced cardiovascular benefits, we investigate whether baroreceptors’ and chemoreceptors’ signaling are able to drive neuronal plasticity within medullary and supramedullary pathways controlling autonomic outflow. Male Wistar rats submitted to sinoaortic denervation (SAD) or dopamine β-hydroxylase-saporin lesion (DBHx) and respective controls (SHAM) were allocated to training (T) or sedentary (S) protocols for 8 weeks. After hemodynamic measurements at rest, rats were deeply anesthetized for brain harvesting. The density of DBH and oxytocin (OT) cell bodies and terminals were analyzed in brainstem and hypothalamic brain areas (double immunofluorescence reactions, optic and confocal microscopy). In SHAM rats training augmented the density of DBH+ neurons in the nucleus of solitary tract, increased the density of ascending NORergic projections and the number of DBH+ boutons contacting preautonomic OT+ neurons into paraventricular hypothalamic preautonomic nuclei, augmented the density of local OTergic neurons and enhanced the density of OT+ terminals targeting brainstem autonomic areas. These plastic changes occurred simultaneously with reduced sympathetic/increased parasympathetic activity, augmented baroreflex sensitivity and reduced resting heart rate. SAD reduced the density of both DBH+ fibers ascending from brainstem to paraventricular nucleus of hypothalamus and preautonomic OT+ neurons projecting to the brainstem, abrogated training-induced plastic changes and autonomic adaptive responses without changing the treadmill performance. Minor neuroplastic changes with preserved baroreflex sensitivity were observed in trained rats after partial selective disruption of ascending NORergic projections. Our data indicated that afferent inputs conveyed by arterial baroreceptors and chemoreceptors are the main stimuli to drive both inactivity-induced and activity-dependent neuroplasticity within the autonomic circuitry.

The effects of stress on cardiovascular disease and Alzheimer's disease: Physical exercise as a counteract measure

AD is a complicated multi-systemic neurological disorder that involves different biological pathways. Several risk factors have been identified, including chronic stress. Chronic stress produces an alteration in the activity of the hypothalamic pituitary adrenal (HPA) system, and the autonomic nervous system (ANS), which over time increase the risk of AD and also the incidence of cardiovascular disease (CVD) and risk factors, such as hypertension, obesity and type 2 diabetes, associated with cognitive impairment and AD. Considering the multi-factorial etiology of AD, understanding the complex interrelationships between different risk factors is of potential interest for designing adequate strategies for preventing, delaying the onset or slowing down the progression of this devastating disease. Thus, in this review we will explore the general mechanisms and evidence linking stress, cardiovascular disease and AD, and discuss the potential benefits of physical activity for AD by counteracting the negative effects of chronic stress, CVD and risk factors.

Atrial Fibrillation – An Orchestra of Classic and Modern Risk Factors

Over the past years, prevention and control of risk factors has begun to play an important role in the management of patients prone to develop atrial fibrillation (AF). A considerable number of risk factors that contribute to the creation of a predisposing substrate for AF has been identified over the years. Although certain AF risk factors such as age, gender, genetic predisposition, or race are unmodifiable, controlling modifiable risk factors may represent an invaluable tool in the management of AF patients. In the recent decades, numerous studies have evaluated the mechanisms linking different risk factors to AF, but the exact degree of atrial remodeling induced by each factor remains unknown. Elucidating these mechanisms is essential for initiating personalized therapies in patients prone to develop AF. The present review aims to provide an overview of the most relevant modifiable risk factors involved in AF occurrence, with a focus on the mechanisms by which these factors lead to AF initiation and perpetuation.

Exercise training upregulates Nrf2 protein in the rostral ventrolateral medulla of mice with heart failure

Chronic heart failure (CHF) is associated with global oxidative stress, which contributes to sympathoexcitation. Increased reactive oxygen species in the brain accumulate within neurons and lead to enhanced neuronal excitability. Exercise training (ExT) is associated with a reduction of oxidative stress by upregulation of antioxidant enzymes. The link between ExT and antioxidant enzyme expression in the brain of animals with CHF is not clear. We hypothesized that ExT enhances transcription and translation of the nuclear factor erythroid 2-related factor 2 (Nrf2) gene, a master transcription factor that modulates antioxidant enzyme gene expression, in the rostral ventrolateral medulla (RVLM) of mice with CHF. Mice were divided into the following groups: Sham sedentary (Sham-Sed), Sham-ExT, CHF-Sed, and CHF-ExT. After 8 wk of ExT, we measured Nrf2 and NAD(P)H dehydrogenase [quinone] 1 (NQO-1) message and protein expression along with maximal exercise tolerance and urinary norepinephrine (NE) excretion. We found that Nrf2 and NQO-1 mRNA and protein expression in the RVLM were lower in CHF-Sed mice compared with Sham-Sed. ExT attenuated the CHF-induced reduction of Nrf2 and NQO-1 mRNA and protein expression in the RVLM. NE excretion was higher in CHF-Sed mice compared with Sham-Sed (666.8 ± 79.3 ng/24 h, n = 6 vs. 397.8 ± 43.7 ng/24 h, P = 0.04). CHF-ExT mice exhibited reduced urinary NE excretion compared with CHF-Sed (360.7 ± 41.7 ng, n = 4 vs. 666.8 ± 79.3 ng, n = 6; P = 0.03). We conclude that ExT-induced upregulation of Nrf2 in the RVLM contributes to the beneficial effects of ExT on sympathetic function in the heart failure state.NEW & NOTEWORTHY This study provide evidence for an important role for exercise training in the modulation of antioxidant enzyme production in the rostral ventrolateral medulla (RVLM) in the heart failure state. We show here a correlation between exercise training and the expression of the antioxidant transcription factor Nrf2 in the RVLM. Exercise training reduced sympathetic function (norepinephrine excretion) and upregulated both Nrf2 and the antioxidant enzyme NQO-1. We conclude that Nrf2 in the RVLM may be an important target for controlling sympathetic outflow in heart failure.

Effects of 6 Months of Exercise-Based Cardiac Rehabilitation on Autonomic Function and Neuro-Cardiovascular Stress Reactivity in Coronary Artery Disease Patients

Background Autonomic dysregulation represents a hallmark of coronary artery disease (CAD). Therefore, we investigated the effects of exercise-based cardiac rehabilitation (CR) on autonomic function and neuro-cardiovascular stress reactivity in CAD patients. Methods and Results Twenty-two CAD patients (4 women; 62±8 years) were studied before and following 6 months of aerobic- and resistance-training-based CR. Twenty-two similarly aged, healthy individuals (CTRL; 7 women; 62±11 years) served as controls. We measured blood pressure, muscle sympathetic nerve activity, heart rate, heart rate variability (linear and nonlinear), and cardiovagal (sequence method) and sympathetic (linear relationship between burst incidence and diastolic blood pressure) baroreflex sensitivity during supine rest. Furthermore, neuro-cardiovascular reactivity during short-duration static handgrip (20s) at 40% maximal effort was evaluated. Six months of CR lowered resting blood pressure (P<0.05), as well as muscle sympathetic nerve activity burst frequency (48±8 to 39±11 bursts/min; P<0.001) and burst incidence (81±7 to 66±17 bursts/100 heartbeats; P<0.001), to levels that matched CTRL and improved sympathetic baroreflex sensitivity in CAD patients (P<0.01). Heart rate variability (all P>0.05) and cardiovagal baroreflex sensitivity (P=0.11) were unchanged following CR, yet values were not different pre-CR from CTRL (all P>0.05). Furthermore, before CR, CAD patients displayed greater blood pressure and muscle sympathetic nerve activity reactivity to static handgrip versus CTRL (all P<0.05); yet, responses were reduced following CR (all P<0.05) to levels observed in CTRL. Conclusions Six months of exercise-based CR was associated with marked improvement in baseline autonomic function and neuro-cardiovascular stress reactivity in CAD patients, which may play a role in the reduced cardiac risk and improved survival observed in patients following exercise training.

Combined effects of obesity and objectively-measured daily physical activity on the risk of hypertension in middle-aged Japanese men: A 4-year prospective cohort study

BACKGROUND

The combined effects of physical inactivity and obesity on hypertension have been recognized; however, previous studies evaluated physical activity using questionnaires. We aimed to examine the effects of physical activity, measured using an accelerometer, and obesity on hypertension onset.

METHODS

At baseline, 426 middle-aged Japanese men who were not on antihypertensive medications were included. Physical activity was measured for 7 consecutive days using an accelerometer. Mean daily moderate to vigorous physical activity (MVPA) and step count (SC) were calculated. Low MVPA and low SC were each defined as the first tertile. Obesity was defined as ≥25 kg/m2 of body mass index. The onset of hypertension was defined as receiving antihypertensive agents during the 4-year follow-up. The combined effects of obesity and physical inactivity on hypertension were examined using Cox regression analysis. Potential confounders included age, smoking, alcohol consumption, daily salt intake, dyslipidemia, diabetes mellitus, and systolic and diastolic blood pressures.

RESULTS

Cox regression analysis revealed that both obesity and low MVPA predicted hypertension in patients, independent of confounders (hazard ratio [HR]: 2.64, 95% confidence interval [CI]: 1.08-6.42, p = 0.033), unlike obesity alone (HR: 1.50, 95% CI: 0.50-3.26, p = 0.590). Stratification by obesity and SC revealed similar hypertension risks among the two groups (Obesity with low SC [HR: 2.10, 95% CI 0.88-5.24, p = 0.089]; Obesity without low SC [HR: 1.72, 95% CI 0.93-4.01, p = 0.082]).

CONCLUSIONS

Here, findings suggest that the coexistence of obesity and decreased MVPA may increase the risk of hypertension onset.

Physical Exercise for Individuals with Hypertension: It Is Time to Emphasize its Benefits on the Brain and Cognition

Hypertension affects more than 40% of adults worldwide and is associated with stroke, myocardial infarction, heart failure, and other cardiovascular diseases. It has also been shown to cause severe functional and structural damage to the brain, leading to cognitive impairment and dementia. Furthermore, it is believed that these cognitive impairments affect the mental ability to maintain productivity at work, ultimately causing social and economic problems. Because hypertension is a chronic condition that requires clinical treatment, strategies with fewer side effects and less-invasive procedures are needed. Physical exercise (PE) has proven to be an efficient and complementary tool for hypertension management, and its peripheral benefits have been widely supported by related studies. However, few studies have specifically examined the potential positive effects of PE on the brain in hypertensive individuals. This narrative review discusses the pathophysiological mechanisms that hypertension promotes in the brain, and suggests PE as an important tool to prevent and reduce cognitive damage caused by hypertension. We also provide PE recommendations for hypertensive individuals, as well as suggestions for promoting PE as a method for increasing cognitive abilities in the brain, particularly for hypertensive individuals.

The influence of angiotensin I-converting enzyme (ACE) I/D gene polymorphism on cardiovascular and muscular adaptations following 8 weeks of isometric handgrip training (IHG) in untrained normotensive males

We examined the association between the angiotensin I-converting enzyme (ACE) I/D gene polymorphism and isometric handgrip (IHG) training on cardiovascular and muscular responses among normotensive males. Thirty (II = 10, ID = 10, and DD = 10) normotensive untrained males underwent IHG training at 30% of their maximal voluntary contraction 3 days per week for 8 weeks. Cardiovascular and muscular variables were measured before IHG, after a session of IHG and after 8 weeks of IHG. No significant interaction effect was found between ACE I/D genotype and IHG training session on all dependent variables (all p > 0.05). There was a significant main effect of IHG training session on systolic blood pressure (SBP) (p = 0.002), mean arterial pressure (MAP) (p = 0.015) and handgrip strength (HGS) (p = 0.001) scores, while no difference in diastolic blood pressure (DBP), pulse pressure, or heart rate scores was found. A greater improvement in cardiovascular parameters following 8 weeks of IHG training was observed in participants with the D allele than the I allele (SBP reduction: ID+DD genotype group (-5.53 ± 6.2 mmHg) vs. II genotype group (-1.52 ± 5.3 mmHg)); MAP reduction: ID + DD genotype group (-2.80 ± 4.5 mmHg) vs. II genotype group (-1.45 ± 3.5 mmHg). Eight weeks of IHG training improved cardiovascular and muscular performances of normotensive men. Reduction in SBP and MAP scores in D allele carriers compared to I allele carriers indicates that the ACE I/D polymorphism may have an influence on IHG training adaptation in a normotensive population.

Aerobic exercise regulates synaptic transmission and reactive oxygen species production in the paraventricular nucleus of spontaneously hypertensive rats

Aerobic exercise lowers blood pressure in patients with hypertension, but the underlying mechanisms remain incompletely understood. The hypothalamic paraventricular nucleus (PVN) plays a key role in the control of sympathetic outflow and cardiovascular tone. We examined whether chronic aerobic exercise altered synaptic transmission and reactive oxygen species (ROS) production in the PVN. In the present study, spontaneously hypertensive rats (SHRs) were subjected to exercise training for 8 weeks, five times per week, with Wistar Kyoto (WKY) rats as the cohort control. Miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs) were recorded from the PVN in ex vivo hypothalamic slice preparations obtained after the last training, and biomarkers of oxidative stress and physical indexes were observed. The mean frequency and amplitude, as well as the rise time and the decay time constant of mIPSCs, significantly decreased in 20-wk-old SHRs compared to WKY 20-wk-old controls. In contrast to mIPSCs, only the mean mEPSC frequency was higher, and there were no other changes in mEPSCs in comparison to the control group. SHRs exhibited higher ROS, 8-OHdG, and MDA; and lower SOD1, SOD2, CAT, Ogg1, and SOD and CAT activity in the PVN. These SHRs also had a significant increase in heart rate, blood pressure and sympathetic nerve activity, and higher levels of norepinephrine (NE). Exercise training ameliorated all these abnormalities, resulting in an increase in the mean frequency, amplitude and kinetics of mIPSCs, accompanied by a decrease in the mean frequency of mEPSCs in the PVN. This study demonstrates that moderate intensity, high frequency exercise training induces a selective enhancement of inhibitory synaptic transmission in the PVN, which may dampen sympathetic activity and reduce blood pressure in hypertension. These changes may be due to antioxidant-related adaptations in the PVNs of SHRs.

Central nervous system neuroplasticity and the sensitization of hypertension

The causes of essential hypertension remain an enigma. Interactions between genetic and external factors are generally recognized to act as aetiological mechanisms that trigger the pathogenesis of high blood pressure. However, the questions of which genes and factors are involved, and when and where such interactions occur, remain unresolved. Emerging evidence indicates that the hypertensive response to pressor stimuli, like many other physiological and behavioural adaptations, can become sensitized to particular stimuli. Studies in animal models show that, similarly to other response systems controlled by the brain, hypertensive response sensitization (HTRS) is mediated by neuroplasticity. The brain circuitry involved in HTRS controls the sympathetic nervous system. This Review outlines evidence supporting the phenomenon of HTRS and describes the range of physiological and psychosocial stressors that can produce a sensitized hypertensive state. Also discussed are the cellular and molecular changes in the brain neural network controlling sympathetic tone involved in long-term storage of information relating to stressors, which could serve to maintain a sensitized state. Finally, this Review concludes with a discussion of why a sensitized hypertensive response might previously have been beneficial and increased biological fitness under some environmental conditions and why today it has become a health-related liability.

The role of nervous system in adaptive response of bone to mechanical loading

Bone tissue is remodeled through the catabolic function of the osteoclasts and the anabolic function of the osteoblasts. The process of bone homeostasis and metabolism has been identified to be co-ordinated with several local and systemic factors, of which mechanical stimulation acts as an important regulator. Very recent studies have shown a mutual effect between bone and other organs, which means bone influences the activity of other organs and is also influenced by other organs and systems of the body, especially the nervous system. With the discovery of neuropeptide (calcitonin gene-related peptide, vasoactive intestinal peptide, substance P, and neuropeptide Y) and neurotransmitter in bone and the adrenergic receptor observed in osteoclasts and osteoblasts, the function of peripheral nervous system including sympathetic and sensor nerves in bone resorption and its reaction to on osteoclasts and osteoblasts under mechanical stimulus cannot be ignored. Taken together, bone tissue is not only the mechanical transmitter, but as well the receptor of neural system under mechanical loading. This review aims to summarize the relationship among bone, nervous system, and mechanotransduction.

The effects of aerobic exercise on eGFR, blood pressure and VO2peak in patients with chronic kidney disease stages 3-4: A systematic review and meta-analysis

BACKGROUND

CKD is associated with several comorbidities, cardiovascular disease being the most significant. Aerobic training has a beneficial effect on cardiovascular health in healthy and some well-defined non-healthy populations. However, the effect of aerobic training on glomerular filtration rate in patients with CKD stages 3-4 is unclear.

OBJECTIVE

To review the effects of aerobic exercise training on kidney and cardiovascular function in patients with chronic kidney disease (CKD) stages 3-4.

METHODS

A random-effects meta-analysis was performed to analyse published randomized controlled trials through February 2018 on the effect of aerobic training on estimated glomerular filtration rate, blood pressure and exercise tolerance in patients with CKD stages 3-4. Web of Science, PubMed and Embase databases were searched for eligible studies.

RESULTS

11 randomized controlled trials were selected including 362 participants in total. Favourable effects were observed on estimated glomerular filtration rate (+2.16 ml/min per 1.73m2; [0.18; 4.13]) and exercise tolerance (+2.39 ml/kg/min; [0.99; 3.79]) following an on average 35-week aerobic training program when compared to standard care. No difference in change in blood pressure was found.

CONCLUSIONS

There is a small beneficial effect of aerobic training on estimated glomerular filtration rate and exercise tolerance, but not on blood pressure, in patients with CKD stages 3-4. However, data are limited and pooled findings were rated as of low to moderate quality.

Exercise, the diurnal cycle of cortisol and cognitive impairment in older adults

Exercise has been shown to reduce the risk of developing Mild Cognitive Impairment and Alzheimer's disease as well as to improve cognition in healthy and cognitively impaired individuals. However, the mechanisms of these benefits are not well understood. The stress hypothesis suggests that the cognitive benefits attributed to exercise may partially be mediated by changes in the cortisol secretion pattern. Chronic stress may increase the risk of AD and exacerbate the cognitive deficits and brain pathology characteristic of the condition while physical activity has been shown to attenuate most of stress consequences and risk factors for AD. Initially, research on the effects of cortisol on cognition and physical activity focused on cortisol levels at one time point but the circadian pattern of cortisol secretion is complex and it is still unclear which aspects are most closely associated with cognitive function. Thus, the aim of this review was to analyze the exercise/stress/cognition hypothesis focusing on the effects of the diurnal cycle of cortisol on cognitive function and physical activity in older adults with and without cognitive impairment.

Neurobiology of substance use in adolescents and potential therapeutic effects of exercise for prevention and treatment of substance use disorders

Substance use (e.g., alcohol, marijuana, opioids, cocaine., etc,) use often initiates during adolescence, a critical period of physiological and social development marked by an increase in risk-taking due, in part, to heightened motivation to obtain arousal from rewards. Substance use during adolescence has been associated with a greater risk of substance use disorders (SUD) in adulthood. Although use rates for most substances have remained relatively stable, the frequency of marijuana use and the perception that regular marijuana use is not harmful has increased in adolescents. Furthermore, the nonmedical use of opioids has increased, particularly in the South, Midwest, and rural low-income communities. Substance use in adolescence has been associated with adverse structural and functional brain changes and, may exacerbate the natural "imbalance" between frontal/regulatory and cortical-subcortical circuits, leading to further heightened impulsive and reward-driven behaviors. Exercise increases growth and brain-derived neurotrophic factors that stimulate endogenous dopaminergic systems that, in turn, enhance general plasticity, learning, and memory. Exercise may help to reinforce the "naïve" or underdeveloped connections between neurological reward and regulatory processes in adolescence from the "bottom up" and "offset" reward seeking from substances, while concomitantly improving cardiovascular health, as well as academic and social achievement. In this review, we provide an overview of the current state of substance use in adolescents and rationale for the utilization of exercise, particularly "assisted" exercise, which we have shown increases neural activity in cortical-subcortical regions and may modulate brain dopamine levels during adolescence, a unique window of heightened reward sensitivity and neural plasticity, for the prevention and adjunctive treatment of SUD.

The introduction of IMITATE-R and its comparison with the IMITATE treatment method in the naming ability of two Persian speaking aphasic patients

Mirror neurons that have properties of audio/visual-acuity play a key role in imitation of movement performance. Since speech is a collection of coordinated movements in the producing organs, observing and imitation of speech movements can stimulate these neurons. In addition, observing hand movements trigger some actions related to the verbal cortex in the network of mirror neurons. According to the hypothesis of mirror neurons, new therapeutic approaches, including IMITATE, have been proposed for patients with aphasia. In the present study, using the IMITATE programme, a new therapeutic approach called IMITATE-R was planned based on observation of oral movements, hand gestures, and imitation of oral movements. Afterward, the IMITATE and IMITATE-R methods were compared with each other on naming skills of two Persian people with aphasia. The results showed that the rate of benefit from each treatment in each client was proportional to its individual and linguistic characteristics; however, in both patients, the IMITATE-R method was more effective in improving the naming skill. The results of this study were aimed at confirming the hypothesis of mirror neurons and the use of methods are based on action-observation for the treatment of patients with aphasia.

Exercise as a therapeutic intervention to optimize fetal weight

The Developmental Origins of Health and Disease suggest the in utero environment programs offspring obesity and cardiovascular disease. Therefore, there is a need to implement safe therapeutic interventions that do not involve the intake of medications or biological products during pregnancy that can improve maternal and fetal health. Prenatal exercise is established to promote maternal and fetal health. It is generally recommended that women accumulate at least 150 min per week of moderate-intensity exercise. It has been demonstrated that prenatal exercise maintains healthy weight gain and improves maternal glucose control, maternal cardiac autonomic control, placental efficiency (increases angiogenesis, downregulates genes involved in fatty acid transport and insulin transport across the placenta, and upregulates genes involved in amino acid transport across the placenta), and oxidative stress. These adaptations following exercise improve maternal metabolism and provide adequate uteroplacental perfusion. In this review, we will focus on exercise as a therapeutic intervention to optimize fetal weight. It has been established that prenatal exercise does not increase the risk of having a small for gestational age baby. To the contrary, prenatal exercise has been associated with the prevention of excessive fat accumulation in the newborn and the maintenance of fetal muscle mass.

Autonomic cardiac control response to walking and executive cognitive task in adolescents with acquired brain injury and typically developed controls

INTRODUCTION

Adolescents with acquired brain injury (ABI) present a range of physical and cognitive as well as cardiac autonomic control system (CACS) dysfunctions.

AIM

To examine the CACS response to an executive task, a physical task and a combined physical and executive task, in adolescents with ABI and typically developed (TD) controls.

METHODS

Included were two groups: The first group consisted of 17 adolescents (11-18 years) with ABI, during the in-patient or out-patient rehabilitation period. All were independent walkers. The second group consisted of 18-year-olds age and gender-matched TD adolescents. A Polar RS800CX device was used to assess heart rate (HR) and heart rate variability (HRV). Walking velocity was assessed by average speed on the 6-Minute Walk Test, and executive cognitive function was assessed by the Behavior Rating Inventory of Executive Function (BRIEF) questionnaire. The physical task was walking for 5 minutes on a treadmill. The cognitive task was the Digit Span Backward test. The study included four stages divided into rest state with and without cognitive task and walking state with and without cognitive task.

RESULTS

Adolescents with ABI presented higher HR and lower HRV measures at rest (p-value < 0.01). A significant 'group' and 'activity' interaction effect on HRV was found; change in the activity level had significantly smaller effects on HRV parameters in adolescents with ABI as compared to controls. An interaction effect of 'cognitive' and 'activity' on HR and HRV was noted, with no significant difference between groups; at rest, performing a cognitive task was associated with reduced HRV, while during walking HRV increased.

CONCLUSIONS

While ABI was associated with a reduced HRV at rest and less adaptive cardiac autonomic system to activity, ABI adolescent's response to a cognitive demand during an activity task such as walking was similar to the response of TD adolescents. Accordingly, we may say that adding a cognitive task to a walking task can improve the CACS function of ABI adolescents.