Search Results (49)

Background: Parkinson’s disease (PD) often involves autonomic dysfunction, most notably impaired baroreflex sensitivity (BRS), which disrupts cardiovascular homeostasis and contributes to orthostatic hypotension (OH). Pharmacological and invasive treatments, including deep brain stimulation, have yielded inconsistent benefits and carry procedural risks, highlighting the need for safer, more accessible alternatives. In this systematic review, we evaluated non-invasive interventions—spanning somatosensory stimulation, exercise modalities, thermal therapies, and positional strategies—aimed at improving cardiovascular autonomic function in PD. Methods: We searched PubMed, Embase, MEDLINE (Ovid), Google Scholar, ScienceDirect, and Web of Science for studies published between January 2014 and December 2024. Eight original studies (n = 8) including 205 participants met the inclusion criteria for analyzing cardiac sympathovagal balance. Results: Five studies demonstrated significant post-intervention increases in BRS. Most reported favorable shifts in heart rate variability (HRV) and favorable changes in the low-frequency/high-frequency (LF/HF) ratio. Across modalities, systolic blood pressure (SBP) decreased by an average of 5%, and some interventions produced benefits that persisted up to 24 h. Conclusion: Although sample sizes were small and protocols heterogeneous, the collective findings support the potential of non-invasive neuromodulation to enhance BRS and overall cardiovascular regulation in PD. Future research should focus on standardized, higher-intensity or combined protocols with longer follow-up periods to establish durable, clinically meaningful improvements in autonomic function and quality of life for people living with PD. Full article

Non-pharmacological interventions, such as physical activity and exercise, are essential in managing type 1 diabetes mellitus by improving glycemic control, cardiovascular health and autonomic function. Given the chronic nature and long-term complications associated with type 1 diabetes, strategies beyond pharmacotherapy are essential. This review examines the effects of exercise on heart rate variability, a key indicator of autonomic nervous system activity. A systematic search was conducted in March 2024 across PubMed, Embase, Cochrane and CINAHL databases. Studies evaluating the retrospective or prospective impact of exercise or physical activity on heart rate variability parameters were included. Utilizing best evidence synthesis, the methodological quality of the included studies was evaluated. Seven studies met the inclusion criteria, all of which were rated as methodologically weak. Moderate evidence suggests that exercise may enhance heart rate variability, particularly by increasing parasympathetic activity and improving sympathovagal balance. However, evidence remains limited regarding the optimal type, frequency and intensity of exercise. Exercise appears to support autonomic function in individuals with type 1 diabetes mellitus. Nonetheless, further high-quality research is needed to determine the most effective exercise modalities and to inform evidence-based clinical guidelines. Full article

This study aimed to explore the sleep conditions and obstructive sleep apnea (OSA) risk in athletes with poor sleep quality. Athletes with poor sleep quality before competition were recruited. Cardiopulmonary coupling analysis, the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and Insomnia Severity Index were used to assess and compare athletes at risk of OSA (apnea-hypopnea index (AHI) ≥ 5 events per hour) with those not at risk (AHI < 5 events per hour). Comparisons were made between the non-OSA group (n = 23) and the OSA risk group (n = 19, AHI = 10.79 ± 4.47 events per hour). The OSA risk group exhibited a significantly higher percentage of Stage 1 (S1) and Stage 2 (S2) sleep and greater heart rate variability (HRV) (p < 0.05). Positive correlations were found between AHI and the percentage of S1 and S2 sleep, low-frequency (LF), and the LF/HF ratio (p < 0.05). Conversely, significant negative correlations were observed between AHI and the percentage of Stage 3 (S3) and Stage 4 (S4) sleep, as well as HRV (p < 0.05). Athletes with poor sleep quality and high OSA risk demonstrated reduced parasympathetic activity, increased sympathetic activity, and affected sympathovagal balance during nocturnal HRV. 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

Heart rate variability (HRV), which is the variation between consecutive heartbeats, reflects the electrical activity of the heart and provides insight into the autonomic nervous system (ANS) function. This study uses wavelet transform-based HRV feature extraction to investigate cardiac sympatho-vagal balance. Both the continuous wavelet transform (CWT) and discrete wavelet transform (DWT) methods were applied in different steps. DWT was used for R-peak detection and CWT and MODWT were used to generate spectrograms from RR intervals. Frequency components (HF, LF, and VLF) within 0.003–0.4 Hz were extracted, and power estimation was performed. The LF/HF ratio, indicating sympatho-vagal balance, was calculated. ECG data from 42 arrhythmia patients and 18 normal sinus rhythm subjects were analyzed. The results showed a lower LF/HF ratio in arrhythmia patients, with higher HF power in arrhythmia subjects and higher LF power in normal sinus rhythm subjects. The study suggests that the parasympathetic nervous system dominates the ANS in arrhythmia patients, while the sympathetic nervous system dominates in normal sinus rhythm patients. Full article

This study aimed to examine the acute and chronic effects of an exercising table tennis program on cardiac Autonomic Nervous System (ANS) and functional capacity in people with tetraplegia. Twenty males with tetraplegia (C6–C7), with a mean age of 38.50 ± 4.04 years old, were randomly assigned into two equal groups: A, who followed a 6-month exercise training program with table tennis 3 times per week, and B, who remained untrained. Additionally, 11 healthy sedentary men (group C) with a mean age of 39.71 ± 5.87 years old participated in the study as healthy controls. At baseline, all participants underwent a short-term (5 min) and a long-term (24 h ambulatory) ECG monitoring to evaluate the heart rate variability (HRV) indices and a maximal arm ergometric and dynamometric testing of the upper limbs. Moreover, the acute cardiac autonomic responses to maximal arm cycle exercise test were evaluated by Polar S810i sensor chest strap. At the end of the 6-month study, all parameters were revaluated only in groups A and B. At baseline, there was no statistically significant difference between the two patient groups. However, intra-group changes at the end of the 6-month study regarding the 24-h HRV monitoring indicated that group A statistically increased the standard deviation of R-R intervals (SDNN) by 13.9% (p = 0.007), the standard deviation of R-R intervals calculated every 5 min (SDANN) by 8.4% (p = 0.007), the very low frequency (VLF) by 7.1% (p = 0.042), and the low frequency [LF (ms²)] by 10.5% (p = 0.009), which almost reached the levels of group C. Favorable improvements were also noticed at the end of the study for group A in maximal exercise time of the upper limbs by 80.4% (p < 0.001) and maximal strength of the right hand by 27.8% (p < 0.001). Linear regression analysis after training showed that maximal exercise time was positively correlated with SDNN (r = 0.663, p = 0.036) and with LF (ms²) (r = 0.623, p = 0.045). Our results indicate that a 6-month table tennis training program is efficient and can improve cardiac ANS activity mainly by increasing sympathovagal balance. Full article

Background: Parkinson’s disease (PD) is a multifaceted neurodegenerative disorder that progressively affects both the central and peripheral nervous systems. This pilot study aimed to examine the effects of repeated whole-body cryostimulation (WBC) sessions on the sympathovagal balance in PD patients and correlate heart rate variability (HRV) indexes with peripheral biomarkers of the autonomic nervous system (ANS). Methods: Seventeen PD patients with mild to moderate motor severity underwent a 10-session WBC cycle over 5 consecutive days. Thirteen patients (6 males, 7 females; mean age 64.5 ± 9.01 years; mean disease duration 5.4 ± 2.3 years) completed the protocol. Cardiac autonomic activity was assessed through HRV measures including RR interval variability (RR mean, RR min, RR max), power density of high and low frequencies (HF, LF), RMSSD, and the LF/HF ratio. Systemic sympathetic activity was evaluated via circulating blood catecholamine levels. Results: Significant increases were observed in RR mean, RR min, RR max, RMSSD, and HF spectrum, indicating enhanced parasympathetic activity. Blood pressure remained stable, suggesting safety. Conclusions: These findings provide initial support to WBC as a potential “rehabilitation booster” in PD, enhancing sympathovagal balance. Further research is needed to explore the long-term benefits of WBC in PD management. Full article

Myxomatous mitral valve disease (MMVD) is the most prevalent cardiac disease in dogs. This study aimed to compare the arrhythmogenic profile and heart rate variability (HRV) of dogs with MMVD in stages B1 and B2. Electrocardiographic exams and the medical records of 60 dogs were analyzed, and HRV, P wave dispersion, QT interval dispersion, and QT interval instability parameters were determined. The results showed significantly increased values in stage B2 compared with stage B1 (p < 0.05) regarding P wave maximum and minimum duration (Pmax and Pmin) and short-term instability (STI). In contrast, no statistically significant differences were observed regarding HRV parameters, P wave dispersion, or QT interval dispersion. Our findings showed that cardiac remodeling in stage B2 could not significantly alter the sympathovagal balance and showed little interference with the predisposition of arrhythmias in dogs with MMVD. Full article

In this study, we aimed to investigate the relationships between sleep duration and autonomic nervous system (ANS) regulation. This cross-sectional pilot study included 27 older patients with probable Alzheimer’s disease who were hospitalized at a psychiatric center. We measured heart rate variability to assess ANS regulation at night, evaluated dementia severity via the Clinical Dementia Rating scale, and obtained sleep duration data from sleep diaries maintained by psychiatric nurses. The data were analyzed using repeated-measures generalized linear models with age, sex, dementia severity, hypertension status, and medication use (antipsychotics) as covariates. A sleep duration of 6–9 h per night compared to shorter than 6 h was associated with a greater increase in parasympathetic nervous system activity (p = 0.03), and a sleep duration longer than 9 h was associated with a decrease sympathovagal balance (p = 0.02). In addition, we observed an inverted U-shaped association between sleep duration and ANS regulation. In this pilot study, we demonstrated that a sleep duration of 6–9 h per night may be beneficial for ANS regulation; however, the present study involved only a few participants and had some limitations. Additional research with a larger cohort is needed to confirm these findings. Full article

Background: Stroke survivors often experience autonomic nervous system (ANS) dysfunction. While Transcranial Direct Current Stimulation (tDCS) has been shown to modulate the ANS when applied to the left hemisphere, its effects on the right hemisphere remain unexplored. Objective: We aimed to compare the effects of tDCS applied to both the injured and the contralateral hemispheres on heart rate variability (HRV) and functional capacity in individuals post-stroke. Methods: Twenty individuals with cerebral hemisphere lesions (ten with right-hemisphere lesions and ten with left-hemisphere lesions) were randomized into four groups: anodal and sham tDCS on the left temporal cortex (T3) and anodal and sham tDCS on the right temporal cortex (T4). HRV was assessed before the intervention, after the six-minute walk test (6MWT), and following tDCS. HRV data were categorized into frequency ranges: low frequency (LF), high frequency (HF), and sympathovagal balance. The 6MWT (meters) was conducted both pre- and post-tDCS. Results: In individuals with right-hemisphere lesions, a higher global LF value was observed (right side: 71.4 ± 16.8 nu vs. left side: 65.7 ± 17.3 nu; p = 0.008), as well as lower values of the HF component (right side: 29.5 ± 18.9 nu vs. left side: 34.0 ± 17.4 nu; p = 0.047), consequently exhibiting higher global values of the low/high-frequency ratio (right side: 3.9 ± 2.8 vs. left side: 2.9 ± 2.4). Regarding the stimulation site, tDCS over T3 led to a lower overall value of the low/high-frequency ratio (left hemisphere: 3.0 ± 2.2 vs. right hemisphere: 3.7 ± 2.9; p = 0.040) regardless of the lesion location. A significant increase in the distance covered in the 6MWT was observed for individuals with lesions in both hemispheres after tDCS at T3. Conclusions: Participants with right-hemisphere lesions exhibited superior global sympathetic autonomic nervous system activity. When the tDCS was applied on the left hemisphere, it maintained lower sympathovagal balance values and improved functional capacity regardless of the hemisphere affected by the stroke. Full article

Children with obstructive sleep apnea (OSA) frequently experience chronic low-grade systemic inflammation, with the inflammasome playing a central role in OSA. This cross-sectional study evaluated the relationship between weight status, autonomic function, and systemic inflammation in a cohort of 55 children with OSA, predominantly boys (78%) with an average age of 7.4 ± 2.2 years and an apnea-hypopnea index of 14.12 ± 17.05 events/hour. Measurements were taken of body mass index (BMI), sleep heart-rate variability, morning circulatory levels of interleukin-1β, interleukin-1 receptor antagonist, and interleukin-6, and tumor necrosis factor-α, anthropometry, and polysomnography. Multiple linear regression modeling showed that an apnea-hypopnea index was significantly associated with BMI, the standard deviation of successive differences between normal-to-normal intervals during N3 sleep, and the proportion of normal-to-normal interval pairs differing by more than 50 ms during rapid-eye-movement sleep. A moderated mediation model revealed that interleukin-1 receptor antagonist levels mediated the association between BMI and interleukin-6 levels, with sympathovagal balance during N3 sleep and minimum blood oxygen saturation further moderating these relationships. This study highlights the complex relationships between BMI, polysomnographic parameters, sleep heart-rate-variability metrics, and inflammatory markers in children with OSA, underlining the importance of weight management in this context. Full article

Background: We investigate the role of galantamine on autonomic dysfunction associated with early cardiometabolic dysfunction in the offspring of fructose-overloaded rats. Methods: Wistar rats received fructose diluted in drinking water (10%) or water for 60 days prior to mating. Fructose overload was maintained until the end of lactation. The offspring (21 days after birth) of control and fructose-overloaded animals were divided into three groups: control (C), fructose (F) and fructose + galantamine (GAL). GAL (5 mg/kg) was administered orally until the offspring were 51 days old. Metabolic, hemodynamic and cardiovascular autonomic modulation were evaluated. Results: The F group showed decreased insulin tolerance (KITT) compared to the C and GAL groups. The F group, in comparison to the C group, had increased arterial blood pressure, heart rate and sympathovagal balance (LF/HF ratio) and a low-frequency band of systolic arterial pressure (LF-SAP). The GAL group, in comparison to the F group, showed increased vagally mediated RMSSD index, a high-frequency band (HF-PI) and decreased LF/HF ratio and variance in SAP (VAR-SAP) and LF-SAP. Correlations were found between HF-PI and KITT (r = 0.60), heart rate (r = −0.65) and MAP (r = −0.71). Conclusions: GAL treatment significantly improved cardiovascular autonomic modulation, which was associated with the amelioration of cardiometabolic dysfunction in offspring of parents exposed to chronic fructose consumption. Full article

Background/Objective: The relationship between heart rate and heart rate variability (HRV) indices has been repeatedly studied in adults but limited data are available on the relationship in paediatric populations. Methods: Continuous 12-lead electrocardiograms were recorded in 1016 healthy children and adolescents (534 females) aged 4 to 19 years during postural manoeuvres with rapid changes between 10-min positions of supine → sitting → standing → supine → standing → sitting → supine. In each position, the averaged RR interval was measured together with four HRV indices, namely the SDNN, RMSSD, quasi-normalised high-frequency components (qnHF), and the proportions of low- and high-frequency components (LF/HF). In each subject, the slope of the linear regression between the repeated HRV measurements and the corresponding RR interval averages was calculated. Results: The intra-subject regression slopes, including their confidence intervals, were related to the age and sex of the subjects. The SDNN/RR, RMSSD/RR, and qnHF/RR slopes were significantly steeper (p < 0.001) and the (LF/HF)/RR slopes were significantly shallower (p < 0.001) in younger children compared to older children and adolescents. Conclusions: The study suggests that sympathetic and vagal influences on heart rate are present in both younger and older children. With advancing age, the sympatho-vagal balance gradually develops and allows the vagal control to suppress the sympathetic drive towards higher heart rates seen in younger age children. Full article

Background: The modulation of cardiac sympathovagal balance alters following acute resistance training (RT) sessions. Nevertheless, the precise influence of RT at varying load intensities on this physiological response remains to be fully elucidated. Therefore, the aim of this study was to compare the time course of recovery following low- (40%), moderate- (60%), and high- (80%) load-intensity RT protocols performed up to muscle repetition failure in resistance-trained men. Method: Sixteen young, resistance-trained men (mean age: 21.6 ± 2.5 years, mean height: 175.7 ± 8.9 cm, mean weight: 77.1 ± 11.3 kg) participated in a randomized crossover experimental design involving three sessions, each taken to the point of muscle failure. These sessions were characterized by different load intensities: low (40% of 1-repetition maximum, 1RM), moderate (60% of 1RM), and high (80% of 1RM). The exercise regimen comprised four exercises—back squat (BS), bench press (BnP), barbell row (BR), and shoulder press (SP)—with each exercise consisting of three sets. Throughout each session, heart rate variability (HRV) and blood pressure (BP) parameters were assessed both pre-exercise and during a 40 min post-exercise period, segmented into 10 min intervals for stabilization. Statistical analysis involved the use of a repeated measures ANOVA. Results: It was observed that the 40% and 60% RT sessions resulted in a significantly higher root mean square of successive R-R intervals (RMSSD) value compared to the 80% RT session in the post-exercise recovery process in 30 min (respectively, p = 0.025; p = 0.028) and 40 min (respectively, p = 0.031; p = 0.046), while the 40% and 60% RT sessions produced similar responses. The 40% RT session was significantly higher in the high frequency (HF) value post-exercise in 40 min compared to the 80% RT session (p = 0.045). Conclusions: Our findings suggest that engaging in resistance training (RT) sessions to muscle failure at an intensity of 80% induces acute increases in sympathetic activity, potentially leading to elevated cardiovascular stress. For individuals with normal blood pressure, it is advisable to opt for lighter loads and higher repetition volumes when prescribing RT, as heavier-load RT may carry an increased risk of cardiac-related factors. Full article

Polyunsaturated fatty acid (PUFA) metabolites play important roles in the modulation of vascular tone, heart rate variability (HRV), and cardiovascular diseases. This study was undertaken to examine the relationship between HRV and the plasma levels of essential acids. Methods: Highly trained cross-country skiers participated in the study (n = 19). Time-domain and frequency-domain HRV analyses were performed. The plasma levels of fatty acids were determined using gas–liquid chromatography. Results: Plasma eicosapentaenoic acid and docosahexaenoic acid were found to be negatively correlated with resting heart rate (HR) (p = 0.026). The plasma levels of alpha-linolenic acid (ALA) were positively associated with the relative value of high-frequency power (rs = 0.465, p = 0.045) and negatively correlated with the sympathovagal balance ratio (rs = −0.493, p = 0.032) and the absolute and relative values of low-frequency power (rs = −0.490, p = 0.028). The plasma levels of arachidonic acid (ARA) were positively associated with the relative value of high-frequency power (rs = 0.59, p = 0.006) and negatively correlated with the sympathovagal balance ratio (rs = −0.54, p = 0.017) and the relative values of low-frequency power (rs = −0.52, p = 0.022). No correlation was found between n6/n3 and HRV parameters except for HR and pNN50. Conclusions: n-3 PUFAs and ARA play an important role in the autonomic regulation of heart rate in highly trained skiers. Athletes with substantial deficiencies in plasma ALA and excess levels of ARA had increased sympathetic and decreased parasympathetic activity. Full article