Search Results (270)

Background: Elite athletes are frequently subjected to high-intensity training regimens, which can result in cumulative physical stress, overtraining, and potential health risks. Monitoring autonomic responses to such load is essential for optimizing performance and preventing maladaptation. Objective: The present study aimed to assess changes in autonomic regulation immediately and two hours after training in athletes, using an integrated framework (combining time- and frequency-domain HRV indices with nonlinear and recurrence quantification analysis). It was investigated how repeated assessments over a 4-month period can reveal cumulative effects and identify athletes at risk. Special attention was paid to identifying signs of excessive fatigue, autonomic imbalance, and cardiovascular stress. Methods: Holter ECGs of 12 athletes (mean age 21 ± 2.22 years; males, athletes participating in competitions) over a 4-month period were recorded before, immediately after, and two hours after high-intensity training, with HRV calculated from 5-min segments. Metrics included HRV and recurrent quantitative analysis. Statistical comparisons were made between the pre-, post-, and recovery phases to quantify autonomic changes (repeated-measures ANOVA for comparisons across the three states, paired t-tests for direct two-state contrasts, post hoc analyses with Holm–Bonferroni corrections, and effect size estimates η²). Results: Immediately after training, significant decreases in SDNN (↓ 35%), RMSSD (↓ 40%), and pNN50 (↓ 55%), accompanied by increases in LF/HF (↑ 32%), were observed. DFA α1 and Recurrence Rate increased, indicating reduced complexity and more structured patterns of RR intervals. After two hours of recovery, partial normalization was observed; however, RMSSD (−18% vs. baseline) and HF (−21% vs. baseline) remained suppressed, suggesting incomplete recovery of parasympathetic activity. Indications of overtraining and cardiac risk were found in three athletes. Conclusion: High-intensity training in elite athletes induces pronounced acute autonomic changes and incomplete short-term recovery, potentially increasing fatigue and cardiovascular workload. Longitudinal repeated testing highlights differences between well-adapted, fatigued, and at-risk athletes. These findings highlight the need for individualized recovery strategies and ongoing monitoring to optimize adaptation and minimize the risk of overtraining and health complications. Full article

Background/Objectives: Syncope is a common clinical problem often requiring pharmacological treatment, yet evidence-based therapies remain limited. Midodrine, a vasopressor agent, is frequently used, though its autonomic effects over time remain unclear. This study aimed to assess autonomic nervous system changes and blood pressure response in syncope patients treated with Midodrine, placebo, or their combination. Additionally, the structural properties of the Midodrine placebo were analyzed using nanotechnological methods. Methods: A total of 67 patients with syncope were randomized to receive Midodrine, sucrose placebo, or their combination over three weeks. All participants underwent 24 h Holter ECG with heart rate variability (HRV) analysis and ambulatory blood pressure monitoring before and after therapy. Structural analysis of Midodrine tablets, sucrose, and Midodrine placebo was performed using Raman spectroscopy and X-ray diffraction (XRD). Results: Patients receiving the Midodrine–placebo combination showed a significant reduction in HRV markers of parasympathetic activity (RMSSD, pNN50, HF) and an increase in sympathetic dominance (LF/HF ratio) compared to the other groups. Only this group showed a statistically significant rise in average systolic and diastolic blood pressure. Raman and XRD analyses revealed structural alterations in the sucrose-based placebo compared to its original form, indicating subtle changes in crystalline structure. Conclusions: In this exploratory study, the combination of Midodrine and placebo was associated with autonomic imbalance and modest increases in blood pressure, which may indicate a potential effect in patients with hypotensive syncope phenotypes. These preliminary findings should be interpreted with caution, and the structural modifications observed in the placebo formulation are presented as hypotheses requiring further investigation rather than established mechanisms. Full article

Background: Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by both motor and non-motor symptoms, including autonomic dysfunction. Structural alterations in the vagus nerve (VN) may contribute to PD pathophysiology, though existing data remain inconsistent. Objective: This study aimed to evaluate morphological changes in the VN using high-resolution ultrasound (USVN) and to investigate associations with autonomic symptoms, heart rate variability (HRV), and clinical characteristics in PD patients. Methods: A cross-sectional study was conducted involving 60 PD patients and 60 age- and sex-matched healthy controls. USVN was performed to assess VN cross-sectional area (CSA), echogenicity, and homogeneity bilaterally. Autonomic symptoms were measured using the Composite Autonomic Symptom Scale 31 (COMPASS-31). HRV parameters—SDNN, RMSSD, and pNN50—were obtained via 24 h Holter monitoring. Additional clinical data included Unified Parkinson’s Disease Rating Scale (UPDRS) scores, transcranial sonography findings, and third ventricle width. Results: PD patients showed significantly reduced VN CSA compared to controls (right: 1.90 ± 0.19 mm² vs. 2.07 ± 0.18 mm²; left: 1.74 ± 0.21 mm² vs. 1.87 ± 0.22 mm²; p < 0.001 and p < 0.02). Altered echogenicity and decreased homogeneity were also observed. Right VN CSA correlated with body weight, third ventricle size, and COMPASS-31 scores. Left VN CSA was associated with body size parameters and negatively correlated with RMSSD (p = 0.025, r = −0.21), indicating reduced vagal tone. Conclusions: USVN detects structural VN changes in PD, correlating with autonomic dysfunction. These findings support its potential as a non-invasive biomarker for early autonomic involvement in PD. Full article

This study aimed to investigate the effects of diesel/ethanol/n-butanol mixed fuel on the marine diesel engine combustion and emissions at different ethanol blending ratios, different single injection times, and pre-injection times. In addition, this study takes the injector fault phenomenon as an example, simulates the three fault phenomena of the injector, and uses a variety of algorithms to optimize the probabilistic neural network model to achieve the fault state identification and diagnosis of the injector. The results of research showed that, with the increase in the ethanol blending ratio, the peak cylinder pressure shows a decreasing trend. The ignition delay period is extended, and the peak instantaneous heat release rate increases. Compared with D100, the nitrogen oxide (NO_x) emissions of D50E40B10 mixed fuel are reduced by 12.3%, soot emissions are reduced by 29.18%, and carbon monoxide (CO) emissions are increased by 5.7 times. With the injection time advances, the peak values of cylinder pressure and heat release rate show an increasing trend, soot emissions gradually decrease, and NO_x and CO emissions gradually increase. The peaks of the cylinder pressure and heat release rate in the pilot injection stage gradually decrease as the pilot injection time advances, while the peak heat release rate in the main injection stage increases. In terms of emissions, NO_x emissions first decrease and then increase as the pilot injection time advances, while soot emissions gradually increase. The average accuracy of the PSO-PNN neural network model reaches 90%, and the average accuracy of the WOA-PNN neural network model reaches 95%. Therefore, the WOA-PNN neural network model is determined to be the optimal injector fault diagnosis model, which can be applied to the identification and diagnosis of injector fault states of diesel engines. Full article

Adverse cardiovascular events and increased mortality are associated with cardiac autonomic nervous system dysfunction in the early stages of the systemic sclerosis (SSc), even prior to the development of cardiac fibrosis. The objective of the study was to evaluate the impact of a three-month exercise training regimen and a subsequent comparable period of detraining on the activity of the cardiac autonomic nervous system in patients with SSc. A total of forty patients with SSc were randomized to either the control group (Group COΝ) or the exercise training group (Group ET). Cardiopulmonary exercise testing was performed at baseline, three months later, and six months later to assess peak oxygen uptake (VO₂peak). They also had 24 h electrocardiogram monitoring for heart rate variability (HRV) and heart rate turbulence analysis. The following time-domain indices were evaluated in the context of HRV analysis: the standard deviation of NN intervals (SDNN), the root mean square of successive RR interval differences (rMSSD), and the percentage of successive RR intervals that differ by more than 50 ms (pNN50). Additionally, regarding the frequency-domain indicators, the low-frequency (LF) and high-frequency (HF) components, as well as the LF/HF ratio, were evaluated. Independent t-tests and Chi-square tests were used for baseline comparisons, while two-way repeated measures ANOVA with Bonferroni post hoc tests assessed changes over time and between groups. Linear and multiple regression analyses were conducted to explore relationships among variables and identify predictors of HRV indices and VO₂peak. Group ET implemented a three-month mixed-type exercise training program, while Group COΝ received standard care. Group ET improved indices of vagal activity [rMSSD by 32.6% (p = 0.017), pNN50 by 57.1% (p = 0.01) and HF by 20.1% (p = 0.01)] and sympathovagal activity [SDNN by 15.5% (p = 0.002) and LF/HF by 12.03% (p = 0.004)] after three months. Exercising patients also increased their VO₂peak by 20.8% (p = 0.001). A robust positive correlation was observed between ΔVO₂peak and ΔSDNN (r = 0.754, p < 0.001). After three months, there was no statistically significant difference in the VO₂peak or any HRV index in the group COΝ. Compared to the baseline values, there was no statistically significant difference in group ET at 6 months, whereas the control group exhibited a decline. In summary, a three-month mixed-type exercise training program can enhance the cardiorespiratory efficiency and cardiac autonomic nervous system function of patients with SSc, as well as alleviate the deterioration that arises following the detraining period. Full article

Background: This study aimed to examine changes in heart rate variability (HRV) across three match-related time points (pre-match, during the match, and post-match) and to explore whether these physiological responses differed between winners and losers in competitive padel. Methods: Twelve matches were analyzed, involving 11 high-level Finnish padel players ranked within the national top 24. HRV was recorded before, during, and immediately after each match, with each measurement lasting a minimum of five min. Time-domain (e.g., SDNN, RMSSD, pNN50), frequency-domain (e.g., LF, HF), and non-linear (e.g., SD1, SD2) HRV metrics were extracted for analysis. All matches took place in Tampere, Finland, under controlled conditions. Results: Results revealed significant intra-match fluctuations in HRV across all domains. Moreover, losing players exhibited consistently higher relative heart rate during the match, suggesting greater physiological strain. Conclusions: This study contributes novel evidence on the dynamic nature of autonomic responses in padel and supports the integration of HRV monitoring in performance and recovery management protocols for high-level athletes. Full article

Background: Chronic pain is closely associated with dysregulation of the autonomic nervous system, often reflected by reduced heart rate variability (HRV). While observational studies have demonstrated this association, the extent to which pain interventions modulate HRV and the impact of individual factors on HRV changes remain unclear. Objective: To evaluate the impact of pain interventions on HRV parameters through meta-analysis of randomized controlled trials (RCTs), and to examine whether intervention type and individual factors such as body mass index (BMI) moderate HRV responses. Methods: We conducted a systematic review of 23 RCTs and a meta-analysis of 21 RCTs (1262 subjects) involving patients with acute and chronic pain. HRV outcomes were extracted pre- and post-intervention. Both between-group (active vs. sham/control) and one-group (pre-post within active group) analyses were performed for time-domain indices—standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD), and percentage of successive normal-to-normal intervals > 50 ms (pNN50)—and frequency-domain indices—high-frequency (HF) and low-frequency (LF) components. Meta-regressions tested moderators including BMI, age, and pain phenotype. The protocol was registered in PROSPERO (CRD42023448264). Results: Twenty-three RCTs involving 1262 participants with a wide range of pain conditions were included. Meta-analysis of time-domain HRV parameters showed a trend toward improvement: SDNN (g = 0.435, p = 0.059) approached significance, while RMSSD (g = 0.361, p = 0.099) and pNN50 (g = 0.222, p = 0.548) showed smaller, non-significant effects. Frequency-domain analysis revealed a significant moderate reduction in the LF/HF ratio (g = −0.378, p = 0.003), suggesting a shift toward parasympathetic dominance. HF and LF showed small, non-significant changes. One-group meta-analysis confirmed significant improvements in vagally mediated HRV, with large effects for RMSSD (g = 1.084, p < 0.001) and HF (g = 0.622, p < 0.001), and a moderate effect for SDNN (g = 0.455, p = 0.004). Meta-regression identified BMI as a significant moderator: higher BMI was associated with attenuated improvements in HF and RMSSD and a slight shift toward sympathetic predominance. Conclusions: Pain interventions can significantly modulate autonomic function, as reflected in HRV improvements, particularly in vagally mediated indices. These effects are influenced by patient characteristics such as BMI. HRV may serve as a valuable biomarker for both treatment efficacy and autonomic recovery in pain management. In this context, HRV highlights its role as a biomarker for pain dysregulation and compensatory failure, reflecting shared top-down modulation between nociception and autonomic regulation. Full article

In recent years, the application of virtual reality (VR) for spatial evaluation has gained traction in the fields of architecture and interior design. However, for VR to serve as a viable substitute for real-world environments, it is essential that experiences within VR elicit emotional responses comparable to those evoked by actual spaces. Despite this prerequisite, there remains a paucity of studies that objectively compare and evaluate the emotional responses elicited by VR and real-world environments. Consequently, it is not yet fully understood whether VR can reliably replicate the emotional experiences induced by physical spaces. This study aims to investigate the influence of presentation modality on emotional responses by comparing a VR space and a real-world space with identical designs. The comparison was conducted using both subjective evaluations (Semantic Differential method) and physiological indices (electroencephalography and heart rate variability). The results indicated that the real-world environment was associated with impressions of comfort and preference, whereas the VR environment evoked impressions characterized by heightened arousal. Additionally, elevated beta wave activity and increased beta/alpha ratios were observed in the VR condition, suggesting a state of high arousal, as further supported by positioning on the Emotion Map. Moreover, analysis of pNN50 revealed a transient increase in parasympathetic nervous activity during the VR experience. This study is positioned as a pilot investigation to explore physiological and emotional differences between VR and real spaces. Full article

The physiological capabilities of horses begin to decline after they reach 15 years of age. However, some exceptionally talented horses can continue their sports careers beyond this age, raising concerns about their welfare. This study investigated animal welfare by observing resting heart rate (HR) and heart rate variability (HRV) metrics in geriatric horses participating in similar training or physical activities compared to younger adult horses over 30 min periods. Forty-six horses of varying ages and activity levels were divided into four groups, including horses under 15 years practising structured training for dressage (AL-1; N = 13) and school riding (AL-2; N = 13) and horses aged between 15 and 20 years participating in AL-1 (N = 10) and AL-2 (N = 10). In adult horses, the HR decreased in those performing AL-1, which was observed alongside an increased RR interval compared to those participating in AL-2 (p < 0.05 for both). Meanwhile, HRV increased in adult horses (measured by pNN50) but decreased in geriatric horses (measured by SDANN, SDNNI, DC, and SD2) participating in AL-1 when compared to their counterparts in AL-2 (p < 0.05 for all). Adult horses exhibited better autonomic regulation while engaged in structured dressage training than geriatric horses. These findings underscore the necessity for the careful management of physical activities to ensure the well-being of all horses, particularly older ones. Full article

Background/Objectives: Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent condition etiologically related to suboptimal levels of dopamine (DA) and norepinephrine (NE) that is typically treated with psychostimulant medication. In individuals with ADHD, divergent thinking abilities have been shown to improve with the use of psychostimulants. Furthermore, psychostimulants affect autonomic nervous system (ANS) functioning, which can impact creative cognition. However, it is not known how DA and NE affect creative cognition in this setting and how this effect is related to autonomic activity in ADHD. Therefore, our objective was to elucidate ANS function and its relationship with divergent creativity gains related to psychostimulant treatment in ADHD. Method: Seventeen individuals diagnosed with ADHD (age 27.9 ± 6.7 sd) participated in two counterbalanced sessions—one while on their prescribed stimulant medication and another after abstaining for at least 24 h. During each session, participants completed convergent (anagrams) and divergent (Torrance Test of Creative Thinking) thinking tasks. An 8 min electrocardiogram prior to cognitive testing was taken to measure heart rate variability (HRV), which is an index of ANS functioning. Results: The hypothesized baseline pNN50 HRV measure was not predictive of enhanced creativity gains on convergent anagrams or divergent creativity on the Torrance when taking stimulants. Conclusions: In this pilot study, the relationship between baseline HRV and the impact of stimulants on anagram performance suggests the noradrenergic system may not play a role in the effect of stimulants on convergent or divergent creativity. The lack of a relationship between baseline HRV and stimulant-related changes in TTCT and anagram scores lends some support to the hypothesis that dopaminergic effects may be the predominant factor in the effect of stimulants on creativity in ADHD. Future research should further investigate the interaction between hypoactive neurotransmitter systems, particularly dopamine in divergent and norepinephrine in convergent creativity, using neuroimaging techniques to assess neurotransmitter dynamics during creativity-based tasks. Full article

Background/Objectives: Cirsium setosum (commonly known as thistle) is a traditional Chinese medicinal plant with significant therapeutic potential, exhibiting hemostatic, antioxidant, and wound-healing properties. Electrospinning offers a versatile platform for fabricating nanoscale scaffolds with tunable functionality, making them ideal for drug delivery and tissue engineering. Methods: In this study, a bioactive extract from thistle was obtained and incorporated into a thermosensitive triblock copolymer (PNNS) and polycaprolactone (PCL) to develop a multifunctional nanofibrous scaffold for enhanced wound healing. The prepared nanofibers were thoroughly characterized using Fourier-transform infrared spectroscopy (FTIR), contact angle measurements, thermogravimetric analysis (TGA), and tensile fracture testing to assess their physicochemical properties. Results: Notably, the inclusion of PNNS imparted temperature-responsive behavior to the scaffold, enabling controlled deformation in response to thermal stimuli—a feature that may facilitate wound contraction and improve scar remodeling. Specifically, the scaffold demonstrated rapid shrinkage at a physiological temperature (38 °C) within minutes while maintaining structural integrity at ambient conditions (20 °C). In vitro studies confirmed the thistle extract’s potent antioxidant activity, while in vivo experiments revealed their effective hemostatic performance in a liver bleeding model when delivered via the composite nanofibers. Thistle extract and skin temperature-responsive contraction reduced the inflammatory outbreak at the wound site and promoted collagen deposition, resulting in an ideal wound-healing rate of above 95% within 14 days. Conclusions: The integrated strategy that combines mechanical signals, natural extracts, and electrospinning nanotechnology offers a feasible design approach and significant technological advantages with enhanced therapeutic efficacy. Full article

The reaction of PtCl₂ with a PNN type ligand dppmaphen (N-(diphenylphosphanylmethyl)-2-amino-1,10-phenanthroline) yielded a new Pt(II) complex [Pt(dppmaphen)Cl]Cl·H₂O (1). Upon excitation at 370 nm, compound 1 emits yellow phosphorescence at 539 and 576 nm at room temperature. Exposure of compound 1 to MeOH vapor induces a shift in its emission to 645 nm, which can be attributed to the substitution of MeOH molecules for H₂O, resulting in the disruption and reorganization of weak interactions in 1. This response is selective for MeOH and, to a lesser extent, EtOH, the orange photoluminescence recovered in air. The emission change of 1 was reversible and visible to the naked eye. Full article

Background/Objectives: Cognitive decline has been increasingly linked to cardiac autonomic regulation; however, its specific associations with cognitive domains, such as information processing speed and executive function, remain unclear. This preliminary study examined the relationship between cardiac autonomic modulation and cognitive performance in older adults. Methods: A cross-sectional study was conducted with 101 older adults (aged ≥60 years) attending a university hospital outpatient clinic. Participants were classified as without cognitive impairment (WCI) or cognitively impaired and not demented (CIND) based on neuropsychological assessments. Heart rate variability (HRV) was measured at rest, focusing on the time-domain parameters (SDNN, rMSSD, and pNN50). Trail making test parts A and B (TMT-A and TMT-B) were used to assess information processing speed and executive function, respectively. Analyses of covariance (ANCOVAs) were performed, adjusting for confounding variables including age, sex, and comorbidities. Results: Participants in the CIND group had significantly lower HRV indices than those in the WCI group (SDNN, p < 0.05, d = 0.44; rMSSD, p < 0.05, d = 0.39; pNN50, p < 0.05, d = 0.40), indicating reduced parasympathetic modulation. Higher HRV values were observed in individuals with preserved processing speed and executive function. Specifically, pNN50 was significantly associated with processing speed (p = 0.04), and SDNN was significantly correlated with executive function (p = 0.02). These associations persisted even after adjusting for confounding factors. Conclusions: Reduced cardiac autonomic modulation, especially lower parasympathetic activity, is significantly associated with cognitive impairment in older adults. Lower pNN50 values were correlated with slower information processing speed, and lower SDNN was associated with poorer executive function. These findings support the potential use of HRV as a physiological biomarker to detect cognitive changes during ageing. Full article

In this paper, a fault diagnosis method for permanent magnet synchronous motors is proposed, combining wavelet packet transform (WPT) energy feature extraction and a genetic algorithm (GA)-optimized back propagation (BP) neural network. Firstly, for the common types of motor faults (turn-to-turn short-circuit, phase-to-phase short-circuit, loss of magnetism, inverter open-circuit, rotor eccentricity), a corresponding motor fault model is established. The stator current signals during motor operation are analyzed using wavelet packet transform, and energy features are extracted from them as feature vectors for fault diagnosis. Then, a BP neural network is constructed, and a genetic algorithm is used to optimize its initial weights and thresholds, thereby improving the network’s classification accuracy. The results show that the GA-BP model outperforms the SSA-PNN diagnostic model in terms of fault classification accuracy. In particular, for the diagnosis of normal operation, inverter open-circuit, and demagnetization faults, the accuracy rate reaches 100%. This method demonstrates high diagnostic accuracy and practical application value. Full article

Canine monocytic ehrlichiosis (CME) is a globally prevalent disease transmitted by the tick Rhipicephalus sanguineus and caused by the Gram-negative bacterium Ehrlichia spp. Following an incubation period, the infection is categorized based on the progression of the disease into acute, subclinical, and chronic stages. Besides hematological alterations, the cardiovascular system is significantly impacted by the hemodynamic effects of the disease, as persistent anemia can lead to myocardial hypoxia and the activation of inflammatory processes, potentially causing myocarditis. It is known that in dogs infected with Ehrlichia canis, there is a higher occurrence of arrhythmias and a predominance of sympathetic activity. This study assessed arrhythmogenic parameters, including P wave dispersion (Pd), QT dispersion (QTd), and QT instability, along with heart rate variability (HRV) analysis from 24 h Holter monitoring in naturally infected dogs during the acute phase (n = 10) and chronic phase (n = 10) compared to a control group (n = 10). The Pd and QTd values were higher in the infect group, confirming the arrhythmogenic character. Instability parameters (TI, LTI, and STI) were higher in sick animals, but no worsening was observed in the chronic phase. All HRV metrics in the time domain were higher in the control group, indicating a balanced sympathovagal activity throughout the day in healthy dogs. Additionally, parameters linked to parasympathetic activity (rMSSD and pNN50) were reduced in the sick groups, confirming the dominance of sympathetic activity. These findings indicate a decrease in HRV in sick individuals and reinforce this useful marker for assessing the influence of the autonomic nervous system on the cardiovascular system. In conclusion, CME exhibits arrhythmogenic activity characterized by the deterioration of predictive parameters for ventricular arrhythmias and increased activity of the sympathetic autonomic nervous system in the heart. This is likely secondary to myocarditis, myocardial hypoxia, and structural damage to cardiomyocytes. Full article