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Department of Biological and Medical Sciences
Objetivo: El presente estudio tuvo como objetivo analizar los efectos de una técnica de relajación denominada entrenamiento autógeno, sobre la variabilidad no lineal de la frecuencia cardíaca, con la hipótesis de que la relajación en cuestión es capaz de promover una mayor sinergia entre los sistemas nerviosos simpático y parasimpático,evitando así altos niveles de estrés y futuras complicaciones. Métodos: Se llevó a cabo un estudio clínico transversal, controlado, no aleatorizado, abierto, con 19 participantes que realizaron una sola sesión de entrenamiento autógeno. Resultados: Los resultados muestran que ambos os grupos (experimental y placebo) tuvieron un valor de p <0,05 y, en ocasiones, marginalmente significativo. Esta consecuencia lleva a la siguiente pregunta: ¿el entrenamiento autógeno proporciona un estado de relajación solo por el efecto placebo? Conclusión: De acuerdo con el estudio, se concluye que durante el entrenamiento autógeno no hubo aumento en la respuesta caótica, y no hubo mejoría en la sinergia entre los sistemas nerviosos simpático y parasimpático. =
Objective: The present study intended to analyze the effects of a relaxation technique called autogenic training, on nonlinear heart rate variability, with the hypothesis that the relaxation in question is capable of promotegreater synergism between the sympathetic and the parasympathetic nervous system, thus avoiding high levels of stress and future complications. Methods: To this end, a controlled, non-randomized, open and cross-sectional clinical study was conducted, with19 participants who underwent a single session of autogenic training. Results: The results show that both groups (experimental and placebo) had p-value<0.05 and sometimes marginally significant. This consequence instigates the following question: does autogenic training AT provide a state of relaxation only by reason of the placebo effect? Conclusion: According to the study, it is concluded that during the autogenic training there was no increase in the chaotic response, in addition to no improvement in the synergism between the sympathetic and the parasympathetic nervous system.
Background: There are still no studies of the cardiovascular safety of the isolated use of Citrus aurantium in aerobic submaximal exercise.
Objective: To evaluate the effect of C. aurantium supplementation on the recovery of cardiorespiratory and autonomic parameters following a session of submaximal aerobic exercise.
Methods: Twelve healthy male adults achieved a crossover, randomized, double-blind, and placebo-controlled trial. C. aurantium (600 mg, p-synephrine at 30% amount [180 mg]) or placebo (600 mg of starch) were ingested 90 min before evaluation in randomized days. We evaluated systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), mean arterial pressure (MAP), heart rate (HR) and, HR variability indexes at Rest and during 60 min of recovery from exercise.
Results: Citrus aurantium ingestion accelerated the reduction in SBP after exercise, anticipated the return of vagal modulation of the heart after exercise via the HF (ms2), pNN50 (%), and 2 UV% indices. Moreover, rushed the output of sympathetic modulation after exercise via the 0V% index. No unfavorable cardiovascular effects were achieved for HR, DBP, PP, and MAP parameters.
Conclusions: Citrus aurantium was shown to be safe for the cardiovascular and autonomic systems alongside submaximal aerobic exercise in healthy males.
Background: Although there are a considerable number of clinical studies on nitrate (NO3) rich beetroot juice (BRJ) and hypertension, it is difficult to indicate the real effects of NO3 from BRJ on the BP of hypertensive patients because there are still no estimates of the effects of NO3 derived from BRJ on the BP of hypertension patients.
Objective: To clarify these effects, we developed a systematic literature review with a meta-analysis of randomized clinical trials (RCTs).
Design: The searches were accomplished through EMBASE, Cochrane Library, MEDLINE, CINAHL, Web of Science, and LILACS databases. The study included single or double-blinded RCTs and participants older than 18 years with hypertension [systolic BP (SBP) > 130 mmHg and diastolic BP (DBP) > 80 mmHg]. NO3 BRJ was required to be consumed in a format that possibly blinded participants/researchers. These studies should also report the SBP and DBP values (mmHg) measured before and after the treatment. Risk of Bias tools and GRADE were enforced.
Results: Seven studies were included (218 participants). BRJ intervention time ranged from 3 to 60 days with daily dosages of 70–250 mL of BRJ. After the intervention with NO3 from BRJ, SBP underwent significant changes (p < 0.001) of −4.95 (95% CI: −8.88; −1.01) (GRADE: ⊕⊕⊕○ Moderate), but not for DBP (p = 0.06) −0.90 mmHg (95% CI: −3.16; 1.36) (GRADE: ⊕⊕⊕○ Moderate), compared to the control group.
Conclusions: The NO3 derived from BRJ reduces SBP, but not DBP in patients with arterial hypertension.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. As a result of the rapid progression and severity of the disease, people with ALS experience loss of functionality and independence. Furthermore, it has already been described presence of autonomic dysfunction. Despite the increasing use of virtual reality (VR) in the treatment of different diseases, the use of virtual reality environment as an intervention program for ALS patients is innovative. The benefits and limitations have not yet been proven. Our objective was to evaluate the autonomic function of individuals with amyotrophic lateral sclerosis throughout the virtual reality task. The analysis of autonomic function was completed before, during, and after the virtual reality task using the upper limbs; also, all steps lasted ten minutes in a sitting position. Heart rate variability (HRV) was taken via the Polar® RS800CX cardiofrequencymeter. The following questionnaire was enforced: Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS) and Fatigue Severity Scale (FSS). Different types of HRV were revealed for the groups, indicating that the ALS group has reduced HRV, with most of the representative indices of the sympathetic nervous system. Besides, the physiological process of reducing parasympathetic activity from rest to VR activity (vagal withdrawal), with reduction in HF (ms2) and an increase in HR from rest to activity, and a further increase throughout recovery, with withdrawal of sympathetic nervous system, occurs just for the control group (CG), with no alterations between rest, activity, and recovery in individuals with ALS. We could conclude that patients with ALS have the reduction of HRV with the sympathetic predominance when equated to the healthy CG. Besides that, the ALS individuals have no capability to adapt the autonomic nervous system when likened to the CG during therapy based on VR and their recovery.
Results regarding the effects of caffeine (CAF) intake on the autonomic control of heart rate recovery exercise remain inconclusive. Thus far, no study has used effect measures to pool the results of different experiments. We aim to assess the acute effect of CAF intake before exercise on the recovery of heart rate variability (HRV) after exercise through a systematic review and meta-analysis.
Randomized controlled clinical trials were included; sample composed of physically active or trained adults; CAF should be offered/ingested before exercise, with dosage between 100-400 mg or between 2-6 mg/kg and administration/ingestion route analogous in the protocols; studies required to present results of HRV indices before and after exercise. Bias risk analysis and meta-analysis were performed. Twelve studies were included in the qualitative synthesis and five studies were encompassed in the quantitative synthesis (meta-analysis). For the Root-mean-square standard deviation (RMSSD) index we revealed p=0.67, Total 95% confidence interval (95% CI) ranged from -0.45 to 0.29, and 66.7% for heterogeneity between groups were reported. Concerning the High Frequency (HF) index, we observed p=0.22, Total 95% CI that ranged from -0.34 to 0.30, and 44% for heterogeneity between groups.
CAF intake did not affect heart rate variability recovery after exercise.
Objectives. We studied the effects of oral L-arginine on post-exercise blood pressure (BP).
Update. Throughout October 2020 and February 2021, the electronic databases Medline, Web of Science, CINAHL, Embase, Cochrane, Bireme, Open Gray, MedRxiv, Clinical Trials and Scopus were considered. The terms enforced to search randomized, double-blind and placebo-controlled clinical trials were, “Arginine” AND “Post-exercise”. Three studies were involved in the meta-analysis, the original results of the three studies demonstrated a trend related to L-arginine intervention. The 95% CI ranged from −7.94 to −2.14 with a combined effect size of −5.04 for systolic BP and −4.96 to −0.97 with a combined effect size of −2.96 for diastolic BP.
Perspectives and projects. Our meta-analysis revealed a combined effect size of 3.40 (P = 0.0007) for systolic BP and 2.91 (P = 0.004) for diastolic BP supportive of L-arginine intervention.
Conclusions. Our review delivers evidence that oral L-arginine supplementation has the potential to reduce post-exercise systolic and diastolic BP in hypertensive patients.
= RésuméObjectifs. Nous avons évalué les effets de la L-arginine orale sur la tension artérielle après l’exercice.
Actualités. Tout au long d’octobre 2020 et février 2021, les bases de données électroniques Medline, Web of Science, CINAHL, Embase, Cochrane, Bireme, Open Gray, MedRxiv, Clinical Trials et Scopus ont été étudiées. Les termes utilisés pour rechercher des essais cliniques randomisés, en double aveugle et contrôlés par placebo étaient «Arginine» ET «Post-exercice». Trois études ont été impliquées dans la méta-analyse, les résultats originaux des trois études ont démontré une tendance liée à l’intervention avec la L-arginine. L’IC à 95 % variait de −7,94 à −2,14 avec une taille d’effet combiné de −5,04 pour la PA systolique et de −4,96 à −0,97 avec une taille d’effet combiné de −2, 96 pour la PA diastolique.
Perspectives et projets. Notre méta-analyse a révélé une taille d’effet combiné de 3,40 (p = 0,0007) pour la tension artérielle systolique et de 2,91 (p = 0,004) pour la tension artérielle diastolique en faveur d’une intervention avec la L-arginine.
Conclusions. Notre revue fournit des preuves que la supplémentation orale en L-arginine a le potentiel de réduire la tension artérielle systolique et diastolique post-exercice chez les patients hypertendus.
BackgroundIt has been suggested that the consumption of energy drinks (ED) may affect cardiovascular activity.
Objectivesto investigate the acute effects of ED intake on heart rate variability (HRV) and cardiovascular recovery after moderate aerobic exercise in males with different cardiorespiratory capacities.
MethodsThis is a randomized, double-blind, crossover, placebo-controlled study. Twenty-eight young adults were split into two groups according to their peak oxygen consumption (VO2peak) values: (1) High VO2 peak (HO) – VO2 peak > 52.15 mL/kg/min, and (2) low VO2 peak (LO) – peak VO2 <52.15 mL/kg/min. Subjects of both groups underwent two exercise protocols in randomized order: moderate aerobic exercise (60% of VO2peak) following the intake of 250 mL of water (placebo protocol) or 250 mL of ED (ED protocol). During the exercise tests, values of cardiorespiratory and HRV parameters were recorded.
ResultsSignificant differences were observed for the LF (normalized units) index between rest and Rec1 in HO energy and LO groups during the ED protocol. For the LF/HF ratio, significant differences were seen between rest and Rec1 in HO and LO during ED protocols.
ConclusionAcute ED intake delayed heart rate recovery after exercise in subjects with low and high cardiorespiratory fitness.
Introduction: Due to functional and autonomic difficulties faced by individuals with Duchenne Muscular Dystrophy (DMD), the use of assistive technology is critical to provide or facilitate functional abilities. The key objective was to investigate acute cardiac autonomic responses, by application of Heart Rate Variability (HRV), during computer tasks in subjects with DMD via techniques based on non-linear dynamics.
Method: HRV was attained via a Polar RS800CX. Then, was evaluated by Chaotic Global Techniques (CGT). Forty-five male subjects were included in the DMD group and age-matched with 45 in the healthy Typical Development (TD) control group. They were assessed for 20 min at rest sitting, and then 5 min whilst performing the maze task on a computer.
Results: Both TD and DMD subjects exhibited a significantly reduced HRV measured by chaotic global combinations when undertaking the computer maze paradigm tests. DMD subjects presented decreased HRV during rest and computer task than TD subjects.
Conclusion: While there is an impaired HRV in subjects with DMD, there remains an adaptation of the ANS during the computer tasks. The identification of autonomic impairment is critical, considering that the computer tasks in the DMD community may elevate their level of social inclusion, participation and independence.
Background: Sedentary lifestyles are increasingly common amongst children, and insufficient physical activity is a global epidemic estimated to contribute to future incapacities and potential deaths. Objective: We aimed to increase the amount of evidence concerning the effect of chronic exposure to exercise on heart rate variability in children and adolescents affected by obesity. Methods: A systematic review commenced following the PRISMA guidelines developed by Web of Science, Virtual Health Library, PubMed, Cochrane Library, Embase, Ovid, Medline Complete, and Scopus using keywords obtained from the Descriptors in Health Sciences and Medical Subject Headlines (MeSH) terms. We considered (1) Population: Pediatric individuals affected by obesity; (2) Intervention: Exercise; (3) Control: Pre-intervention and sedentary; (4) Outcomes: Clearly presented primary parameters; and (5) Studies: Clinical trials, case controls, case reports, and case series. Results: 11 articles were involved and predominantly included procedures observed during approximately 12 weeks with a distribution of three sessions per week, each session being 30–60 min of aerobic exercise; additionally, the exercise grades were typically completed at a percentage of subjects’ maximum heart rates. The meta-analyses displayed a significant effect on the domains of time (R-R interval, SDNN, rMSSD), frequency (HF ms2, HF (n.u.), LF/HF), and the non-linear index (SD1). Conclusions: Chronic exposure to exercise influences heart rate variability in children and adolescents affected by obesity by elevating the variability and parasympathetic activity and improving the sympathetic-vagal balance. Exercises should be recommended for the improvement of cardiac autonomic modulation to prevent the likelihood of further chronic diseases.
Individuals with Duchenne Muscular Dystrophy (DMD) have an impairment of cardiac autonomic function categorized by parasympathetic reduction and sympathetic predominance. The objective of this study was to assess the cardiac autonomic modulation of individuals with DMD undergoing therapy with Prednisone/Prednisolone and Deflazacort and compare with individuals with DMD without the use of these medications and a typically developed control group. Methods: A cross-sectional study was completed, wherein 40 boys were evaluated. The four treatment groups were: Deflazacort; Prednisone/Prednisolone; no corticoid use; and typical development. Heart Rate Variability (HRV) was investigated via linear indices (Time Domain and Frequency Domain) and non-linear indices Results: The results of this study revealed that individuals with DMD undertaking pharmacotherapies with Prednisolone demonstrated HRV comparable to the Control Typically Developed (CTD) group. In contrast, individuals with DMD undergoing pharmacotherapies with Deflazacort achieved lower HRV, akin to individuals with DMD without any medications, as demonstrated in the metrics: RMSSD; LF (n.u.), HF (n.u.), LF/HF; SD1, α1, and α1/α2, and a significant effect for SD1/SD2; %DET and Ratio; Shannon Entropy, 0 V%, 2 LV% and 2 ULV%. Conclusions: Corticosteroids have the potential to affect the cardiac autonomic modulation in adolescents with DMD. The use of Prednisone/Prednisolone appears to promote improved responses in terms of sympathovagal activity as opposed to Deflazacort.
Introduction:Approximate Entropy is an extensively enforced metric to evaluate chaotic responses and irregularities of RR intervals sourced from an eletrocardiogram. However, to estimate their responses, it has one major problem – the accurate determination of tolerances and embedding dimensions. So, we aimed to overt this potential hazard by calculating numerous alternatives to detect their optimality in malnourished children.
Materials and methods:We evaluated 70 subjects split equally: malnourished children and controls. To estimate autonomic modulation, the heart rate was measured lacking any physical, sensory or pharmacologic stimuli. In the time series attained, Approximate Entropy was computed for tolerance (0.1→0.5 in intervals of 0.1) and embedding dimension (1→5 in intervals of 1) and the statistical significances between the groups by their Cohen’s d s and Hedges’s g s were totalled.
Results:The uppermost value of statistical significance accomplished for the effect sizes for any of the combinations was −0.2897 (Cohen’s d s) and −0.2865 (Hedges’s g s). This was achieved with embedding dimension = 5 and tolerance = 0.3.
Conclusions:Approximate Entropy was able to identify a reduction in chaotic response via malnourished children. The best values of embedding dimension and tolerance of the Approximate Entropy to identify malnourished children were, respectively, embedding dimension = 5 and embedding tolerance = 0.3. Nevertheless, Approximate Entropy is still an unreliable mathematical marker to regulate this.
Objectives. Our study aimed to explore the influence of Bariatric Surgery (BS) on heart rate (HR) variability (HRV) through a systematic review.
Data Sources.Manuscripts were selected based on electronic searches of MEDLINE, EMBASE and CINAHL databases from the inception of each database up to year 2020 and followed the PRISMA protocol. Searching of these studies was systematized using the PICOS strategy.
Eligibility Criteria for Selecting Studies. We selected randomized and non-randomized controlled trials and cohorts’ prospective studies that reported the influence of BS on HRV. We assessed the quality rating using the Black and Downs questionnaire.
Results. Following the screening and eligibility stages, 14 studies were included in the review. All studies agreed that BS promotes an increase in parasympathetic HR control and HRV and, a decrease in HR. Yet, the literature does not provide evidence that this outcome was directly caused by the surgical procedure. There is limited evidence to support that patients with type 2 Diabetes Mellitus (TDM2) have greater improvement in HRV as an interim measure, to individuals without. The decrease in insulin resistance was correlated with the increase in HRV in some studies, but, other studies are unsupportive of this outcome. Improvements in two metabolic parameters (e.g., Leptin, NT-proBNP) were connected with a superior increase in HRV.
Parkinson's disease (PD) produces autonomic changes, indicating lower parasympathetic modulation and global variability, but these changes need further studying regarding geometric methods.
To investigate the autonomic modulation in individuals with PD using heart rate variability (HRV) indices obtained through geometric methods.
This is a cross-sectional study that assessed 50 individuals, split into two groups: PD group (PDG; n=26; 75.36±5.21 years) and control group (CG; n=24; 75.36±5.21 years). We evaluated the autonomic modulation by measuring the heart rate beat-to-beat for 30 min with the individual in supine rest using a heart rate monitor and assessed geometric indices (RRtri, TINN, SD1, SD2, SD1/SD2 ratio, and qualitative analysis of the Poincaré plot).
Significant reductions were found in RRtri, TINN, SD1, and SD2 indices among PDG compared to CG. Regarding the SD1/SD2 ratio, no significant changes were detected between the groups. The Poincaré plot demonstrated that individuals with PD had lower beat-to-beat dispersion in RR intervals, in addition to greater long-term dispersion of RR intervals compared to CG.
The results suggest a reduction in the parasympathetic autonomic modulation and global variability in individuals with PD compared to controls, regardless of sex, age, and body mass index
Introduction: Approximate entropy (ApEn) is a widely imposed metric to evaluate a chaotic response and irregularities of RR-intervals from an electrocardiogram. Yet, the technique is problematic due to the accurate choice of the tolerance (r) and embedding dimension (M). We prescribed the metric to evaluate these responses in subjects exhibiting symptoms of chronic obstructive pulmonary disease (COPD) and we strived to overcome this disadvantage by applying different groupings to detect the optimal.
Methods: We examined 38 subjects split equally: COPD and control. To evaluate autonomic modulation the heart rate was measured beat-by-beat for 30 min in a supine position without any physical, sensory, or pharmacological stimuli. In the time-series obtained the ApEn was then applied with set values for tolerance, r and embedding dimension, M. Then, the differences between the two groups and their effect size by two measures (Cohen’s ds and Hedges’s gs) were computed.
Results: The highest value of statistical significance accomplished for any effect size statistical combinations undertaken was -1.13 for Cohen’s ds, and -1.10 for Hedges’s gs with embedding dimension, M = 2 and tolerance, r = 0.1.
Conclusion: ApEn was capable of optimally identifying the decrease in chaotic response in COPD. The optimal combination of r and M for this were 0.1 and 2, respectively. Despite this, ApEn is a relatively unpredictable mathematical marker and the use of other techniques to evaluate a healthy or pathological condition is encouraged.
Introduction and objectives.Studies assessing the effects of caffeine (CAF) on the cardiovascular system have demonstrated that CAF can delay cardiac recovery following exercise. This study intended to assess the impact of CAF intake before physical exercise on heart rate variability (HRV) and cardiovascular parameters.
Methods.This is a prospective, crossover, controlled clinical trial conducted at the University of Pernambuco, Petrolina, PE, Brazil. The experimental protocol was split into three stages with a minimum of 48 hours between them. Exercises intensity was standardized based on the one repetition maximum test (1RM), obtaining the load of each volunteer for the intensity of 75% of 1RM. In the second and third phases, the control protocols were applied and 300 mg caffeine was given 45 minutes before training. HRV indices were determined at the subsequent times: 0 to 5 minutes of rest (before) and during 30 minutes of recovery (Rec) (after exercise), divided into six intervals, each of 5 minutes.
Results.The final sample involved 30 volunteers. CAF delayed HRV recovery after resistance exercise. In general, CAF impaired recovery of HRV after resistance exercise. Significant changes were observed in the RMSSD, SDNN, TINN, SD1, low frequency and high frequency indices between the control and CAF group.
Conclusion.CAF protocol delayed parasympathetic regulation of heart rhythm following exercise, slowing recovery of HR, blood pressure and HRV indices after exercise.
= Resumo.Introdução e objetivos.Estudos avaliando os efeitos da cafeína (CAF) sobre o sistema cardiovascular mostraram que a CAF pode retardar a recuperação dos batimentos cardíacos ao estado de repouso após o exercício. Este estudo teve como objetivo avaliar o impacto da ingestão de cafeína (CAF) antes do exercício físico de força sobre variabilidade da frequência cardíaca (VFC) na recuperação.
Metodologia.Trata-se de um ensaio clínico prospetivo, controlado por cruzamento, realizado na Universidade de Pernambuco, em Petrolina, PE. Está registrado no ClinicalTrials.gov (Number NCT03899675). O procedimento experimental foi dividido em três etapas com um mínimo de 48 horas entre elas. A intensidade do exercício foi padronizada com base no teste de 1 repetição máxima (1RM), obtendo-se a carga de cada voluntário para a intensidade de 75% de 1RM. Na segunda e terceira fase da pesquisa, os protocolos de controle e cafeína (300 mg) foram aplicados. A ingestão de cafeína aconteceu 45 minutos antes do treinamento. Os índices de VFC foram determinados nos seguintes tempos: 0 a 5 minutos de repouso (antes) e durante 30 minutos de recuperação (Rec) (após o exercício), divididos em seis intervalos de 5 minutos cada.
Resultados.A amostra final foi composta por 30 voluntários. No geral, a cafeína prejudicou a recuperação da VFC no período de recuperação após o exercício resistido. Diferenças significativas foram observadas nos índices RMSSD, SDNN, TINN, SD1, LF e HF entre o grupo controle e o grupo CAF.
Conclusão.O protocolo CAF foi capaz de intensificar reduções na atividade parassimpática após o exercício, causando atraso na recuperação da FC, pressão arterial e índices de VFC após o exercício.
Objective: the complexity of heart-rate variability (HRV) in amyotrophic lateral sclerosis (ALS) patients with different pulmonary capacities was evaluated. Methods: We set these according to their pulmonary capacity, and specifically forced vital capacity (FVC). We split the groups according to FVC (FVC > 50% (n = 29) and FVC < 50% (n = 28)). In ALS, the presence of an FVC below 50% is indicative of noninvasive ventilation with two pressure levels and with the absence of other respiratory symptoms. As the number of subjects per group was different, we applied the unbalanced one-way analysis of variance (uANOVA1) test after three tests of normality, and effect size by Cohen’s d to assess parameter significance. Results: with regard to chaotic global analysis, CFP4 (p < 0.001; d = 0.91), CFP5 (p = 0.0022; d = 0.85), and CFP6 (p = 0.0009; d = 0.92) were enlarged. All entropies significantly increased. Shannon (p = 0.0005; d = 0.98), Renyi (p = 0.0002; d = 1.02), Tsallis (p = 0.0004; d = 0.99), approximate (p = 0.0005; d = 0.97), and sample (p < 0.0001; d = 1.22). Detrended fluctuation analysis (DFA) (p = 0.0358) and Higuchi fractal dimension (HFD) (p = 0.15) were statistically inconsequential between the two groups. Conclusions: HRV complexity in ALS subjects with different pulmonary capacities increased via chaotic global analysis, especially CFP5 and 3 out of 5 entropies.
The impact of birth weight (BW) on adult health has been studied, related to the autonomic nervous system, and implicated in cardiovascular risk. We investigated cardiorespiratory and heart rate (HR) autonomic recovery after moderate effort in healthy term-born adults with different BWs. We studied 28 healthy physically active women aged between 18 to 30 years split equally into two groups according to BW: G1 (n = 14), BW between 2500 g and 3200 g and G2 (n = 14), BW > 3200 g. The groups remained seated at rest for 15 min, followed by aerobic exercise on a treadmill (five minutes at 50–55% of maximum HR and 25 min 60–65% of maximum HR) and then remained seated for 60 min during recovery from the exercise. Cardiorespiratory parameters and HR variability (HRV) [RMSSD, HF (ms2)] were assessed before and during recovery from exercise. In G1, HR was increased from 0 to 20 min after exercise whilst in G2 HR was higher from 0 to 7 min following exercise. In G1, short-term HRV was increased from 5 to 10 min after exercise but in G2 it recovered prior to 5 min following effort. In conclusion, healthy term-born women with low normal BW present slower HR autonomic recovery after exercise.
Objectives. We aimed to assess the effect of both classical and heavy metal music on short-term and long-term memory.
Methods. Male rats were separated into three groups: Mozart (n=14), rats were exposed to Mozart´s K-448 piano sonata; Heavy Metal (n=15), rats were exposed to Psychosocial (band: Slipknot), and Control (n=12), rats were exposed to ambient sounds in an acoustically isolated room. The animals were exposed to the music for 8 hours per day, between 10:00 pm to 06:00 am, with an intensity of 50-75 dB, for 61 consecutive days. Twenty-four hours after the final day of adjustment to the enclosure the animals were individually exposed for 5 minutes in the enclosure to explore two identical objects. Ninety minutes after the object recognition training session, the animals were submitted to the short-term memory test and twenty-eight days after the object recognition training session, the animals were submitted to a long-term memory test.
Results. There was no modification amongst the three groups during the object recognition training. Regarding the short-term memory test both Mozart (U=33.00, p=0.016, FDR-corrected) and Heavy Metal (U=44.00, p=0.033, FDR-corrected) groups revealed a higher percentage value of significance compared to the control group. In contrast, there was no significant change in relation to the long-term memory test.
Conclusion. Mozart Sonata K-448 and heavy metal music achieved beneficial effects on the short-term memory in rats.
Objective. To assess the acute response of cardiac autonomic modulation (ACAM) during and after a session of virtual reality-based therapy (VRBT) compared to a session of conventional cardiovascular rehabilitation (CR) and to evaluate the effects of 12 weeks of training on this response.
Methods. We assessed 28 volunteers (63.4 ± 12.5 years). The ACAM was judged by linear indexes of heart rate variability (HRV) in VRBT and CR sessions. Later, patients completed 12 weeks of VRBT+CR and the assessment was repeated at the 12th week.
Results. Throughout the 1st VRBT session vagal withdrawal occurred (RMSSD/HFnu); sympathetic nervous system stimulation (LFnu) and progressive decrease of global HRV (SDNN). During the recovery, the SDNN, HFnu, and LFnu improved from the 5thminute on both therapies. After 12 weeks, the LFnu, HFnu, and the LF/HF-ratio revealed no significant changes in Ex3-Ex4 equated to Rep during VRBT. In recovery, the HFnu and LFnu improved before the 5thminute on both therapies.
Conclusions. ACAM during and after the VRBT was comparable to CR, yet, the extents were greater in the VRBT. After 12 weeks of VRBT training, the subjects adapted to the exercises from the 15thminute and exhibited faster recovery of HFnu and LFnu indexes compared to the 1st week.
Introduction.Considering that heart rate (HR) autonomic control is impaired in cancer and subsequent respiratory effort may overload the heart, we aimed to evaluate the effect of a respiratory physical therapy session on HR autonomic regulation in children with leukemia so as to confirm its safety.
Methods.We selected children with leukemia (n = 10) and healthy children (n = 11), which were submitted to a session of respiratory physical therapy. We used Spiron Kids (NCS, Brazil), Children’s Voldyne (HUDSON RCI, USA), and Shaker (NCS, Brazil) as respiratory devices. The respiratory exercise protocols were founded on three standardized protocols. HR variability (HRV) was analyzed before, in the first minute and 5 to 10 min after intervention.
Results.We recognized no change between rest and recovery from intervention in HRV (rMSSD—square root mean square of the differences between adjacent normal R-R intervals)—Control: p = 0.8111, Leukemia: p = 0.1197, among groups: p = 0.6574; SD1—standard deviation from instantaneous beat-to-beat variability—Control: p = 0.8111, Leukemia: p = 0.131, among groups: p = 0.6556; 0V—with no variation (3 equal symbols, for example (2,2,2)—Control: p = 0.3679, Leukemia: p = 0.3553, among groups: p = 0.7421); 2UV—with two variations to the contrary (the three symbols form a peak or a valley, for instance (3,5,3)—Control: p = 0.3679, Leukemia: p = 0.2359, among groups: p = 0.4007). HF—high frequency component, range 0.15 to 0.4 Hz—decreased 0 to 1 min after intervention in the leukemia group (p = 0.0303) and no change was observed in the control group between rest versus recovery from intervention (p = 0.9761). No significant change was reported in HF between groups (p = 0.8700). Two leukemia subjects treated with vincristine presented different HRV responses to the intervention group.
Conclusion.A respiratory physical therapy session did not significantly change autonomic control of HR in children with leukemia. Yet, clinicians should be mindful of subjects undergoing treatment with vincristine.
Introduction: Approximate Entropy (ApEn) is a widely enforced metric to evaluate the chaotic response and irregularities of RR intervals from an electrocardiogram. We applied the metric to estimate these responses in subjects with type 1 diabetes mellitus (DM1). So far, as a technique it has one key problem - the accurate choices of the tolerance (r) and embedding dimension (M). So, we attempted to overcome this drawback by applying different groupings to detect the optimum.
Methods: We studied 46 subjects split into two equal groups: DM1 and control. To evaluate autonomic modulation the heart rate was measured for 30 min in a supine position without any physical, sensory, or pharmacological stimuli. For the time-series, the ApEn was applied with set values for r (0.1→0.5 in intervals of 0.1) and M (1→5 in intervals of 1) and the differences between the two groups and their effect size by two measures (Cohen’s ds and Hedges’s gs) were computed.
Results: The highest value of statistical significance accomplished for the effect sizes (ES) for any of the combinations performed was -0.7137 for Cohen’s ds and -0.7015 for Hedges’s gs with M = 2 and r = 0.08.
Conclusion: ApEn was able to identify the reduction in chaotic response in DM1 subjects. Still, ApEn is relatively unreliable as a mathematical marker to determine this.
Judging to make a decision amidst several possibilities that rise to risks, losses, gains and uncertainties is not a simple matter. In this process, the subject needs to verify the situation considering the alternatives that are made up of several elements, among them, the analysis of how much this decision will cost and what benefit it will have in response, and what the consequences will be in the long, medium and short term. In this sense, decision-making is associated with the deliberative and affective process that relates to multiple variables that are interconnected with the flow of information assimilated by the agent who is responsible for the judgment and the decision. This process is interdependent on the subject’s structure with external stimuli. Thus, the individual’s forces and social pressure are important elements to be considered for decision making. For the adolescent, this issue becomes even more important, as it is a phase of human development in which the person exhibits behaviors of risk and during this stage of life there is a process of maturation of the central nervous system, which are related to decision-making and motivational processes. Therefore, decision making among adolescents is a complex issue that in addition to biological factors are directly related to social and psychological elements, depends on a maturity in development, but can be impaired if stressful situations are constant stimuli in the lives of adolescents. =
O distanciamento social foi planejado como uma medida preventiva para controlar a disseminação extensiva da COVID-19. Nós analisamos as mortes relacionadas à COVID-19 no Brasil durante o período de medidas de distanciamento social. Os dados de mortalidade do COVID-19 foram obtidos no site da Worldometer (www.worldometer.info). As mortes foram estimadas até o 31º dia após a 5ª morte. O distanciamento social foi medido por meio dos relatórios de mobilidade comunitária COVID-19; Google (https://www.google.com/covid19/mobility/). As curvas epidêmicas brasileiras foram interligadas e os modelos matemáticos foram avaliados para se ajustarem às curvas de estimativa de mortalidade. O modelo otimista foi fundado no período de abertura da distância social e, portanto, na menor mobilidade (40-60%). O modelo realista foi calculado de acordo com medidas de distanciamento social relaxado (<40%) e o modelo pessimista foi calculado com base em R0 entre 2-3. Sob essa situação, o modelo matemático realista estimou 40.623 mortes em 9 de junho de 2020, enquanto o modelo pessimista antecipou 64.310 mortes e o modelo otimista projetou 31.384. Até hoje (24 de maio de 2020), um total de 22.965 foram relatadas, enquanto nosso modelo projetou 17.452 para o modelo otimista, 22.623 para o modelo realista e 32.825 para o modelo pessimista. Observamos movimento reduzido ao longo deste período. Em resumo, o modelo matemático sugere que a mobilidade reduzida da comunidade diminuiu o total estimado de mortes relacionadas à COVID-19 no Brasil. Enfatizamos que mais procedimentos metodológicos serão necessários para confirmar esta teoria.
Objective: We assessed the acute effect of beetroot extract intake on cardiovascular and autonomic recovery subsequent to strength exercise.Methods: This is a crossover, randomized, double-blind and placebo-controlled trial. We assessed 16 subjects but only 12 healthy male adults completed the two protocols in two randomized days: Beetroot extract (600 mg in capsule) and placebo (600 mg starch in capsule). Beetroot extract or placebo was ingested, the subjects endured 120 minutes seated at rest, followed by a 75% 1RM strength exercise and then remained seated for 60 minutes at rest. Cardiorespiratory parameters, heart rate (HR) variability (HRV) (SDNN, rMSSD, pNN50, SD1, SD2 HF [ms(2)]) were estimated before, during exercise and during recovery from exercise.Results: ingestion of beetroot extract before exercise: accelerates the recovery of SBP following physical effort; improves HR recovery to baseline resting levels (beetroot protocol: change in ∼62% vs. placebo protocol: change in ∼80%), and intensifies the return of vagal HR control during recovery after exercise.Conclusions: Beetroot extract acutely improved cardiovascular and autonomic recovery after exercise.
Metabolic syndrome (MetS) is a growing epidemic related with higher values of blood pressure (BP) and autonomic dysfunction. Scientific evidence has been indicating that functional resistance training (FRT) is superior over conventional (CRT) for muscle fatigue and pain, yet its effects on autonomic modulation (AM), BP and heart rate in MetS are unclear. We theorized that FRT can be superior to CRT in MetS patients because of larger muscle activation. This study compares FRT and CRT on AM, blood pressure, heart rate and muscle strength. Thirty-eight sex and age matched individuals (40 to 60 years) were randomized for FRT or CRT, with training intensity varying gradually from 30%?100% of one maximal repetition test (1MR), 3 times/week for 30 sessions. All outcomes were evaluated at baseline and post training. AM was assessed by heart rate variability (mean RR, RMSSD, SDNN, LF, HF, TINN, RRtri, SD1 and SD2). BP (mmHg) was obtained by cuff measures. Muscle strength was assessed by 1MR. An increase in cardiac parasympathetic activity was observed in individuals allocated to FRT in comparison to CRT group (RMSSD ?40%; SD1 ?39%; and HF ms2 ?80%). Moreover, just FRT was capable of reducing BP post intervention (SBP from 129.21 ± 19.02 to 118.94 ± 14.14 mmHg, p < .009,/d/ = 0.49; DBP from 85.26 ± 11.48 to 77.76 ± 8.93 mmHg, p < .01,/d/ = 0.51). Both groups had a similar increase in muscle strength and no changes between HR. Progressive FRT was more beneficial to CRT regarding AM, increasing vagal activity, and reducing blood pressure in MetS individuals.
Aim. Previous studies have described the substantial impact of different types of noise on the linear behaviour of heart rate variability (HRV). Yet, there are limited studies about the complexity or nonlinear dynamics of HRV during exposure to traffic noise. Here, we evaluated the complexity of HRV during traffic noise exposure via six power spectra and, when adjusted by the parameters of the Multi-Taper Method (MTM).
Material and methods. We analysed 31 healthy female students between 18 and 30 years old. Subjects remained at rest, seated under spontaneous breathing for 20 minutes with an earphone turned off and then the volunteers were exposed to traffic noise through an earphone for a period of 20 minutes. The traffic noise was recorded from a busy urban street and the sound involved car, bus, trucks engineers and horn sounds (71-104 dB).
Results. The results stipulate that CFP3 and CFP6 are the best metrics to distinguish the two groups. The most appropriate power spectra were, Welch and MTM. Increasing the DPSS parameter of MTM increased the performance of both CFP3 and CFP6 as mathematical markers. Adaptive was the preferred type for Thomson’s nonlinear combination method.
Conclusion. CFP3 with the adaptive option for MTM, and increased DPSS is designated as the best mathematical marker on the basis of five statistical tests.
Evaluating different doses of caffeine (CAF) on heart rate (HR) variability (HRV) during and following exercise in order to assess its impact on autonomic control. We intended to evaluate the influence of CAF as a supplement before exercise on HRV through a systematic review. Manuscripts were selected based on electronic searches of MEDLINE, EMBASE and CINAHL databases from 2010 to 2019 and followed the protocol Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA). Blind randomized designs and controlled trials that reported the influence of CAF on HRV during exercise and during recovery from exercise, with strength of evidence assessed using the GRADE system; the search for the studies was organized using the PICOS strategy. A total of 1797 articles were recognized, following the screening and eligibility stages, 9 studies continued to the final sample. Six studies reported that the combination of CAF supplementation with physical exercise exhibited higher HR when compared to the placebo group during post-exercise recovery; additionally, prolonged activation of sympathetic cardiac control and delayed parasympathetic reactivation following exercise was observed. However, three studies demonstrated no CAF influence when using similar doses. This review observed equivocal results in HR and HRV recovery following exercise with the presence of CAF consumption. These findings cannot confirm the cardiac autonomic changes observed where entirely due to the influence of CAF, and further studies should be performed to better understand this relationship.KEY TEACHING POINTSCAF increased HR during exercise and throughout the recovery period.CAF prolonged post exercise sympathetic activity.CAF delayed vagal reactivation.Deviations in HRV and HR are dependent on the combination of three main factors: CAF dosage, type of exercise, and cardiorespiratory fitness.
The hospital anxiety depression scale (HADS) is a benchmark used to investigate possible and probable cases of psychosomatic illness. Its affiliation with autonomic recovery after exercise is unclear and, as a technique applied to evaluate cardiovascular risk. We assessed a possible link between HADS and autonomic recovery after exercise. We studied healthy subjects split into two groups: Low HADS (n = 20) and High HADS (n = 21). Subjects consented to moderate aerobic exercise on a treadmill at 60% to 65% of the maximum heart rate (HR) for 30 min. We studied HR variability (HRV) before and during 30 min after exercise. Subjects with higher HADS values presented delayed recovery of HR and root-mean square of differences between adjacent normal RR intervals (RMSSD) after submaximal exercise. RMSSD during recovery from exercise had a significant association with HADS. In summary, subjects with higher HADS presented slower vagal recovery following exercise.
Backgound and aims. In this study we analyzed heart rate variability (HRV) via chaotic global techniques so as to discriminate diabetics from control subjects. Matherial and method. Chaotic global analysis of the RR-intervals from the electrocardiogram and preprocessing adjustments were undertaken. The effect of varying two parameters to adjust the Multi-Taper Method (MTM) power spectrum were evaluated. Then, cubic splineinterpolations from 1Hz to 13Hz were applied whilst the spectral parameters were fixed. Precisely 1000 RR-intervals of data were recorded. Results. CFP1 and CFP3 are the only significant combinations of chaotic globals when the default standard conditions are enforced. MTM spectral adjustments and cubic spline interpolation are trivial at effecting the outcome between the two datasets. The most influencial constraint on the outcome is data length. Conclusion. Chaotic global analysis was offered as a reliable, low-cost and robust technique to detect autonomic dysfunction in subjects with diabetes mellitus.
Stress induced by driving has been revealed to increase the chances of cardiovascular complications and is involved or related to traffic accidents. In order to develop strategies to avoid health problems during driving we aimed to evaluate the acute effects of auditory stimulation with music on heart rate variability (HRV) during driving in congested urban traffic. This is a prospective cross-sectional randomized controlled pilot study conducted with five healthy women. Subjects were evaluated on two different random days, whose order of execution was established through a randomization process. In the music protocol the volunteers were exposed to music for the entire 20 min of traffic while in the control protocol the subjects performed the same procedures but were not exposed to any music. We noted that all Higuchi fractal dimension parameters except Kmax 10, Kmax 130 and Kmax 140 were reduced between pre-driving in the control protocol vs. driving in the control protocol. The same changes were noted between pre-driving in the music protocol vs. driving in the control protocol. In conclusion, musical auditory stimulation improved nonlinear HRV changes induced by driving.
Cortical auditory evoked potentials (CAEP) throughout a language task is beneficial during psychophysiological evaluation to advance identification of language disorders. So as to better comprehend human communication and to provide additional elements for neuropsychological examinations we aimed to (1) examine the influence of language tasks on cortical auditory processing and vagal control of heart rate and (2) to verify a possible association between the parasympathetic cardiac regulation and cortical auditory processing in language tasks. This study was completed with 49 women. The subjects were separated into two groups: (1) phonological language tasks (N = 21) and (2) semantic (N = 21) language tasks. Heart rate variability (HRV) and CAEP were evaluated before and after the tests. HRV reduced (small effect size) and P3 wave latency increased after the phonological task. Identical variables were significantly correlated after the phonological task and linear regression indicated significant interaction between pNN50 (percentage of adjacent RR intervals with a difference of duration greater than 50 milliseconds) and P3 latency (16.9%). In conclusion, phonological language tasks slightly reduced parasympathetic control of HR and increased cognitive effort. The association between HRV and CAEP are anticipated to be involved in this mechanism.
Numerous studies have investigated the connection between autonomic control of heart rate (HR) and auditory stimulus. Yet, the literature lacks evidence of a close association between auditory brainstem processing and HR autonomic control. We aimed to evaluate and verify the relationship between auditory brainstem response (ABR) and HR variability (HRV) in healthy women. Forty‑six healthy female subjects, between the ages of 18 and 30 years old participated in the study. They were subjected to an audiometry examination, followed by rest for 10 minutes for HR recording. Next, ABR evaluation was completed discretely in both ears, with I, III and V wave components. Linear regression revealed that the root‑mean square of differences between adjacent normal RR intervals (RMSSD) and the triangular interpolation of RR interval (TINN) exhibited a significant association with Wave I in the right ear. These variables contributed to 28.2% (R²) of Wave I. In conclusion, there was a significant interaction between the autonomic control of HR and auditory processing in the right ear, suggesting that vagal tone interacts with the cochlear nerve.
Introduction. Heart rate variability (HRV) can be assessed from RR-intervals. These are derived from an electrocardiographic PQRST-signature and can deviate in a chaotic or irregular manner. In the past, techniques from statistical physics have allowed researchers to study such systems.Objective. This study planned to assess the heart rate dynamics in young obese subjects by nonlinear metrics to heart rate variability. Method. 86 subjects were split equally according to status. Heart rate was recorded with the subjects resting in a dorsal (prone) position for 30 minutes. The complexity of the RR-intervals was assessed by five Entropies, Detrended Fluctuation Analysis, Higuchi and Katz’s fractal dimensions Following inconclusive tests of normality we calculated the One-Way Analysis of Variance, Kruskal-Wallis, and the Effect Sizes by Cohen’s d significances. Results. It was established that Shannon, Renyi and Tsallis Entropies and the Higuchi and Katz’s fractal dimensions could significantly discriminate the two groups. The three entropies were higher in obese youths, suggesting less predictable sets of RR intervals (p<0.0001; d≈1.0). Whilst the Higuchi (p<0.003; d≈0.76) and Katz’s (p≈0.02; d≈0.57) fractal dimensions were lower in obese youths. Conclusion. As with chaotic globals an increase in response was detected by three measures of entropy in young obese. This is counter to the decreasing response detected by fractal dimensions. Chaotic globals and entropies are more dependable than fractal dimensions when assessing the responses to obesity.
Background and aims. Statistical markers are valuable when assessing physiological status over periods of time and in certain disease states. We assess if type 1 diabetes mellitus promote modification in the autonomic nervous system using the main two types of algorithms to estimate a Fractal Dimension: Higuchi and Katz. Material and methods. 46 adults were divided into two equal groups. The autonomic evaluation consisted of recording heart rate variability (HRV) for 30 minutes in supine position in absence of any other stimuli. Fractal dimensions ought then able to determine which series of interbeat intervals are derived from diabetics’ or not. We then equated results to observe which assessment gave the greatest significance by One-way analysis of variance (ANOVA1), Kruskal-Wallis technique and Cohen’s d effect sizes. Results. Katz’s fractal dimension is the most robust algorithm when assisted by a cubic spline interpolation (6 Hz) to increase the number of samples in the dataset. This was categorical after two tests for normality; then, ANOVA1, Kruskal-Wallis and Cohen’s d effect sizes (p≈0.01 and Cohen’s d=0.814143–medium effect size). Conclusion. Diabetes significantly reduced the chaotic response as measured by Katz’s fractal dimension. Katz’s fractal dimension is a viable statistical marker for subjectswith type 1 diabetes mellitus.
Background: The priniciple objective here is to analyze cardiovascular dynamics in diabetic subjects by actions related to heart rate variability (HRV). The correlation of chaotic globals is vital to evaluate the probability of dynamical diseases. Methods: Fortysix adults were split equally. The autonomic evaluation consisted of recording HRV for 30 minutes in supine position without any additional stimuli. “Chaotic globals” are then able to statistically determine which series of interbeat intervals are diabetic and which are not. Two of these chaotic globals, spectral Entropy and spectral Detrended fluctuation analysis were derived from six alternative power spectra: Welch, Multi-Taper Method, Covariance, Burg, Yule-Walker and the Periodogram. We then compared results to observe which power spectra provided the greatest significance by three statistical tests: One-way analysis of variance (ANOVA1); Kruskal-Wallis technique and the multivariate technique, principal component analysis (PCA). Results: The Chaotic Forward Parameter One (CFP1) applying all three parameters is proven the most robust algorithm with Welch and MTM spectra enforced. This was proven following two tests for normality where ANOVA1 (p=0.09) and Kruskal-Wallis (p=0.03). Multivariate analysis revealed that two principal components represented 99.8% of total variance, a steep scree plot, with CFP1 the most influential parameter. Conclusion: Diabetes reduced the chaotic response.
Introduction: Fetal heart rate and its variability during the course of gestation have been extensively re-searched. The overall reduction in heart rate and increase in fetal HRV is associated with fetal growth and the increase in neural integration. The increased complexity of the demands on the cardiovascular system leads to more variation in the temporal course of the heart rate which has been shown to be refl ected in measures of complexity. The aim of this work was to investigate novel complexity measures with respect to their ability to quantify changes over gestational age in individual fetuses consistently and in a stable manner.
Methods: We examined 215 fetal magnetocardiograms (FMCG), each of 5 min duration, in 11 fetuses during the second and third trimesters (at least 10 data sets per fetus). From the FMCG we determined the fetal RR beat durations. For each 5 min time-series of RR intervals we then calculated Shannon entropy, high spectral entropy, high spectral Detrended Fluctuation Analysis, spectral Multi-Taper Method as well as the standard deviation and two commonly used complexity measures: Approximate Entropy and Sample Entropy. For each subject and HRV measure, we performed regression analysis with respect to ges tational age. The coeffi cient of determination R2 was used to es timate ‘goodness-of-fi t’, the slope of the regression indicated the strength of the individual dependency on gestational age.
Results: We found that the new complexity measures do not outperform ApEn.
Conclusion: This study has now rejected the hypothesis that the spectral complexity measures outperform those applied previously