Monitoring autonomic responses in Parkinson's disease individuals: non-linear and chaotic global metrics of heart rate variability.

AIM: To examine and compare the autonomic responses, as assessed through the non-linear and chaotic global metrics of heart rate variability in two groups: the Parkinson's Disease Group (PDG) and the Control Group (CG), both at rest and during an active tilt test. METHODS: The study encompassed 46 participants (PDG: n = 23; 73.73 ± 7.28 years old; CG: n = 23; 70.17 ± 8.20 years old). Initial data collection involved the acquisition of participant's characteristics. The autonomic modulation was estimated both at rest and during the active tilt test. For this assessment, we computed non-linear indices derived from five entropies (Approximate, Sample, Shannon, Renyi, Tsallis), Detrended Fluctuation Analysis and the seven chaotic global metrics (hsCFP1-hsCFP7). RESULTS: At rest, the PDG exhibited lower values of hsCFP3 (0.818 ± 0.116 vs. 0.904 ± 0.065; p < 0.05) and Sample Entropy (0.720 ± 0.149 vs. 0.799 ± 0.171; p < 0.05). During the test, the PDG demonstrated lower values of ApEn, while the CG presented lower values of SampEn, hsCFP1, hsCFP3, hsCFP7, and higher values of hsCFP5. An interaction was observed, indicating that hsCFP1 and hsCFP3 exhibit differential behavior for the CG and PDG in response to the test. CONCLUSION: subjects with PD exhibited reduced complexity of the RR interval series at rest, and a diminished autonomic response to the active tilt test when compared with the CG. The test, together with non-linear indices, may serve for assessing the Autonomic Nervous System in individuals with PD in a clinical setting. The interpretation of these data should be approached with caution, given the possible influences of pharmacotherapies and the inclusion of diabetic participants.

The effect of paroxetine on heart rate variability in patients with major depressive disorder: A systematic review and meta-analysis.

INTRODUCTION: The impacts of antidepressant pharmacotherapies on cardiovascular risk are unclear. We completed a systematic review with meta-analysis to assess the effect of paroxetine on heart rate variability (HRV) in patients with major depressive disorder (MDD). METHODS: The searches were accomplished via EMBASE, MEDLINE/PubMed (using the National Library of Medicine), Cochrane Library, CINAHL, Scopus, and Web of Science databases. We included non-blind, single, or double-blind randomized control trials in patients older than 18 diagnosed with MDD. Paroxetine needs to be enforced as a chronic therapeutic medication. We included individual studies that investigated resting HRV. RESULTS: We documented 402 studies, only following screening and eligibility phases; only six were included (five studies in the meta-analysis). No significant change was noticed for the SDNN index: subtotal = 8.23 [CI: -2.17, 18.63], p = 0.12, I2 = 54 % (very low quality of evidence). A significant change was distinguished for the LF index: subtotal = 0.74 [CI: 0.33, 1.15], p = 0.0004, I2 = 0 % (low quality of evidence). A significant alteration was perceived for the HF index: subtotal = 0.33 [CI: 0.06, 0.6], p = 0.02, I2 = 0 % (low quality of evidence). CONCLUSION: Meta-analysis demonstrated that paroxetine could advance HRV in MDD patients. Nevertheless, our supposition is founded only on statistical analysis and the very low quality of evidence breakdown reinforces the necessity for further studies to confirm or reject this theory.

Effects of dietary inorganic nitrate on blood pressure during and post-exercise recovery: A systematic review and meta-analysis of randomized placebo-controlled trials.

OBJECTIVES: A systematic review with meta-analysis was completed to study the effects of dietary inorganic nitrate (NO3-) oral ingestion from vegetables and salts on blood pressure responses during and following exercise. BACKGROUND: NO3- is a hypotensive agent with the potential to reduce blood pressure peaks during exercise and amplify exercise-induced hypotensive effects. Several randomized and controlled trials have investigated the effects of NO3- on hemodynamic responses to physical exercise, however this still has yet to be studied systematically. METHODS: The searches were conducted on EMBASE, Medline, and SPORTSDiscus databases. The study included masked randomized controlled trials (RCTs) with participants ≥18 years old. The NO3-intervention group received at least 50 mg NO3-/day with similar sources amid NO3- and placebo conditions. Included studies reported systolic blood pressure (SBP) or diastolic blood pressure (DBP) values during or following exercise performance. RESULTS: 1903 studies were identified, and twenty-six achieved the inclusion criteria. NO3- daily dosages ranged from 90 to 800 mg/day. Throughout exercise, SBP had smaller increases in the NO3- group (-2.81 mmHg (95%CI: -5.20 to -0.41), p=0.02. DBP demonstrated lower values in the NO3- group (-2.41 mmHg (95%CI: -4.02 to -0.79), p=0.003. In the post-exercise group, the NO3- group presented lower SBP values (-3.53 mmHg (95%CI: -5.65 to 1.41), p=0.001, while no changes were identified in DBP values between NO3- and placebo groups (p=0.31). Subgroup meta-analysis revealed that SBP baseline values, exercise type, duration of NO3- ingestion, and its dosages mediated blood pressure responses during and following exercise. CONCLUSIONS: NO3- ingestion prior to exercise attenuated the increases in SBP and DBP during exercise, and increased the decline in SBP after exercise. These results are dependent on factors that moderate the blood pressure responses (e.g., health status, type of exercise, resting blood pressure values).

Influence of Fluid Ingestion on Heart Rate, Cardiac Autonomic Modulation and Blood Pressure in Response to Physical Exercise: A Systematic Review with Meta-Analysis and Meta-Regression.

A systematic review was undertaken to investigate the involvement of hydration in heart rate (HR), HR variability (HRV) and diastolic (DBP) and systolic (SBP) blood pressure in response to exercise. Data synthesis: The EMBASE, MEDLINE, Cochrane Library, CINAHL, LILACS and Web of Science databases were searched. In total, 977 studies were recognized, but only 36 were included after final screening (33 studies in meta-analysis). This study includes randomized controlled trials (RCTs) and non-RCTs with subjects > 18 years old. The hydration group consumed water or isotonic drinks, while the control group did not ingest liquids. For the hydration protocol (before, during and after exercise), the HR values during the exercise were lower compared to the controls (-6.20 bpm, 95%CI: -8.69; -3.71). In the subgroup analysis, "water ingested before and during exercise" showed lower increases in HR during exercise (-6.20, 95%CI: 11.70 to -0.71), as did "water was ingested only during exercise" (-6.12, 95%CI: -9.35 to -2.89). Water intake during exercise only revealed a trend of avoiding greater increases in HR during exercise (-4,60, 95%CI: -9.41 to 0.22), although these values were not significantly different (p = 0.06) from those of the control. "Isotonic intake during exercise" showed lower HRs than the control (-7.23 bpm, 95% CI: -11.68 to -2.79). The HRV values following the exercise were higher in the hydration protocol (SMD = 0.48, 95%CI: 0.30 to 0.67). The values of the SBP were higher than those of the controls (2.25 mmHg, 95%CI: 0.08 to 4.42). Conclusions: Hydration-attenuated exercise-induced increases in HR during exercise, improved autonomic recovery via the acceleration of cardiac vagal modulation in response to exercise and caused a modest increase in SBP values, but did not exert effects on DBP following exercise.

Negligible Effects of Nutraceuticals from Beetroot Extract on Cardiovascular and Autonomic Recovery Response following Submaximal Aerobic Exercise in Physically Active Healthy Males: A Randomized Trial.

BACKGROUND: There is little evidence that nutraceuticals from beetroot extract are beneficial with regards to recovery of the cardiovascular parameters and the autonomic nervous system (ANS) after submaximal aerobic exercise, though this formulation is employed widely for this purpose. OBJECTIVE: To study the effects of beetroot extract supplementation on the recovery of cardiorespiratory and autonomic parameters after a session of submaximal aerobic exercise. METHODS: Sixteen healthy male adults commenced a cross-over, randomized, double-blind and placebo-controlled trial. Beetroot extract (600 mg) or placebo (600 mg) were ingested 120 min prior to evaluation on randomized days. We assessed systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), mean arterial pressure (MAP), heart rate (HR) and HR variability (HRV) indexes at Rest and during 60 min of recovery from submaximal aerobic exercise. RESULTS: Beetroot extract ingestion slightly accelerated HR, SBP, DBP and MAP reduction following exercise associated to the placebo protocol (vs. rest). Yet no group effect (p = 0.99) was identified between the beetroot and placebo protocols on HR mean, in addition to interaction (group vs. time) (p = 0.60). No group effect was attained between the SBP (p = 0.90), DBP (p = 0.88), MAP (p = 0.73) and PP (p = 0.99) protocols and no significant differences (group vs. time) were observed between the values of SBP (p = 0.75), DBP (p = 0.79), MAP (p = 0.93) and PP (p = 0.63) between placebo and beetroot protocols. Similarly, the reoccurrence of cardiac vagal modulation after exercise via the HF (ms2) was enhanced, but not with regards to the RMSSD index. No group effect (p = 0.99) was identified for the HF (p = 0.90) and RMSSD (p = 0.67) indices. Likewise, we observed no significant differences (group vs. time) amongst the values of HF (p = 0.69) and RMSSD (p = 0.95) between the placebo and beetroot protocols. CONCLUSION: Whilst beetroot extract might assist the recovery of the cardiovascular and autonomic systems following submaximal aerobic exercise in healthy males, these results seem insignificant owing to minor differences between interventions and are weak clinically.

A Single Dose of Beer after Moderate Aerobic Exercise Did Not Affect the Cardiorespiratory and Autonomic Recovery in Young Men and Women: A Crossover, Randomized and Controlled Trial.

Background: Beer is a choice beverage worldwide and is often consumed after sports for social interaction. Beer has been suggested for hydration after exercise, but the effects on cardiovascular and autonomic systems in men and women after effort are unknown. Objectives: We assessed the effect of beer absorption immediately after moderate exercise on heart rate (HR) variability (HRV) and cardiovascular recovery after effort in women and men separately. Methods: This is a crossover, randomized and controlled trial performed on 15 healthy female and 17 male adults submitted to two protocols on two randomized days: (1) Water (350 mL) and (2) Beer (350 mL). The subjects underwent 15 minutes seated at rest, 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 3 min stood on treadmill and 57 min seated for recovery from the exercise. Water or beer was consumed between four and ten minutes after exercise cessation. Blood pressure, HR and HRV were evaluated before exercise, during exercise and during recovery from exercise. Results: Systolic and diastolic blood pressure, HRV and HR changes during and following recovery from exercise were similar when women consumed beer or water. HR, systolic and diastolic blood pressures also returned to baseline levels in the beer and water protocols in males. Yet, parasympathetic indices of HRV recovery from exercise were comparable between protocols in males. Conclusions: Ingestion of 300 mL of beer did not significantly affect HRV and cardiovascular parameters following effort. Our data indicate that beer was safe for this population.

Efeitos Agudos da Bebida Energética sobre Parâmetros Autonômicos e Cardiovasculares em Indivíduos com Diferentes Capacidades Cardiorrespiratórias: Um Ensaio Controlado, Randomizado, Crossover e Duplo Cego / Acute Effects of Energy Drink on Autonomic and Cardiovascular Parameters Recovery in Individuals with Different Cardiorespiratory Fitness: A Randomized, Crossover, Double-Blind and Placebo-Controlled Trial

Resumo Fundamento Tem-se sugerido que o consumo de bebidas energéticas (BEs) possa afetar a atividade cardiovascular. Objetivos Investigar os efeitos agudos da ingestão de BE sobre a variabilidade da frequência cardíaca (VFC) recuperação cardiovascular após exercício aeróbico moderado em homens de diferentes capacidades cardiorrespiratórias. Métodos Este é um estudo randomizado, duplo cego, crossover, controlado por placebo. Vinte e oito jovens adultos foram divididos em dois grupos de acordo com o pico de consumo de oxigênio (pico de VO2): (1) pico de VO2 alto (AO) - pico de VO2 > 52,15 mL/Kg/min, e (2) pico de VO2 baixo (BO) - pico de VO2 <52,15 mL/Kg/min. Os indivíduos de ambos os grupos foram submetidos a dois protocolos de exercícios em ordem aleatória: exercício moderado aeróbico (60% de pico de VO2) após a ingestão de 250 mL de água (protocolo placebo) ou 250 mL de BE (protocolo BE). Durante os testes de exercício, foram registrados valores de parâmetros cardiorrespiratórios e de VFC. Resultados Foram observadas diferenças significativas para o índice de LF (unidades normalizadas) entre "repouso" e "Rec1" nos grupos de AO e BO durante o protocolo BE. Para a razão LF/HF, foram observadas diferenças significativas entre "repouso" e Rec1 nos grupos AO e BO nos protocolos BE. Conclusão A ingestão aguda de BE retardou a recuperação da frequência cardíaca após o exercício em indivíduos com capacidade cardiorrespiratória baixa e indivíduos com capacidade cardiorrespiratória alta.

Abstract Background It has been suggested that the consumption of energy drinks (ED) may affect cardiovascular activity. Objectives to 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. Methods This 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. Results Significant 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. Conclusion Acute ED intake delayed heart rate recovery after exercise in subjects with low and high cardiorespiratory fitness.

Recovery of Nonlinear Heart Rate Variability After Submaximal Exercise in Young Persons With Symptoms of Anxiety and Depression.

Prior studies have demonstrated that anxiety and depression explain the increase of adverse cardiovascular events an failure to modulate cardiac activity. This study of the nonlinear heart rate (HR) variability (HRV) behavior can provide additional information concerning the autonomic recovery of HR after exercise. The dynamics of these indices in exercise-mediated situations may reveal other ways to assess HRV recovery after physical effort. We studied nonlinear HRV recovery after submaximal exercise in subjects with higher Hospital Anxiety and Depression Scale (HADS) scores. Sixty-six young adults were recruited, and 50 completed the HADS rating scale to quantify their degree of anxiety and depression for later allocation to a suitable group. After experimental procedures, the final sample involved 20 participants (15 female) who were allocated to the group with low HADS scores (LHADS) and 21 (16 female) to the group with high HADS scores (HHADS). We logged HRV data before and during recovery from submaximal aerobic exercise and analyzed this data using symbolic analysis. Young adults with High HADS scores (HHADS) had a slower recovery of the symbolic analysis of HRV via index 2LV% (two like variations) and 2ULV% (two unlike variations) after aerobic exercise. Participants with higher HADS scores presented delayed nonlinear HRV recovery after submaximal exercise.

Acute Effects of Energy Drink on Autonomic and Cardiovascular Parameters Recovery in Individuals with Different Cardiorespiratory Fitness: A Randomized, Crossover, Double-Blind and Placebo-Controlled Trial. / Efeitos Agudos da Bebida Energética sobre Parâmetros Autonômicos e Cardiovasculares em Indivíduos com Diferentes Capacidades Cardiorrespiratórias: Um Ensaio Controlado, Randomizado, Crossover e Duplo Cego.

BACKGROUND: It has been suggested that the consumption of energy drinks (ED) may affect cardiovascular activity. OBJECTIVES: to 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. METHODS: This 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. RESULTS: Significant 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. CONCLUSION: Acute ED intake delayed heart rate recovery after exercise in subjects with low and high cardiorespiratory fitness.

FUNDAMENTO: Tem-se sugerido que o consumo de bebidas energéticas (BEs) possa afetar a atividade cardiovascular. OBJETIVOS: Investigar os efeitos agudos da ingestão de BE sobre a variabilidade da frequência cardíaca (VFC) recuperação cardiovascular após exercício aeróbico moderado em homens de diferentes capacidades cardiorrespiratórias. MÉTODOS: Este é um estudo randomizado, duplo cego, crossover, controlado por placebo. Vinte e oito jovens adultos foram divididos em dois grupos de acordo com o pico de consumo de oxigênio (pico de VO2): (1) pico de VO2 alto (AO) ­ pico de VO2 > 52,15 mL/Kg/min, e (2) pico de VO2 baixo (BO) - pico de VO2 <52,15 mL/Kg/min. Os indivíduos de ambos os grupos foram submetidos a dois protocolos de exercícios em ordem aleatória: exercício moderado aeróbico (60% de pico de VO2) após a ingestão de 250 mL de água (protocolo placebo) ou 250 mL de BE (protocolo BE). Durante os testes de exercício, foram registrados valores de parâmetros cardiorrespiratórios e de VFC. RESULTADOS: Foram observadas diferenças significativas para o índice de LF (unidades normalizadas) entre "repouso" e "Rec1" nos grupos de AO e BO durante o protocolo BE. Para a razão LF/HF, foram observadas diferenças significativas entre "repouso" e Rec1 nos grupos AO e BO nos protocolos BE. CONCLUSÃO: A ingestão aguda de BE retardou a recuperação da frequência cardíaca após o exercício em indivíduos com capacidade cardiorrespiratória baixa e indivíduos com capacidade cardiorrespiratória alta.

Bitter Orange (Citrus aurantium L.) Intake Before Submaximal Aerobic Exercise Is Safe for Cardiovascular and Autonomic Systems in Healthy Males: A Randomized Trial.

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.

Nitrate Derived From Beetroot Juice Lowers Blood Pressure in Patients With Arterial Hypertension: A Systematic Review and Meta-Analysis.

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. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=269339.

Caffeine intake and its influences on heart rate variability recovery in healthy active adults after exercise: A systematic review and meta-analysis.

AIMS: 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. DATA SYNTHESIS: 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 and 400 mg or between 2 and 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. CONCLUSIONS: CAF intake did not affect heart rate variability recovery after exercise.

Cardiac Autonomic Modulation in Subjects with Amyotrophic Lateral Sclerosis (ALS) during an Upper Limb Virtual Reality Task: A Prospective Control Trial.

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.

Comparison of acute response of cardiac autonomic modulation between virtual reality-based therapy and cardiovascular rehabilitation: a cluster-randomized crossover trial.

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.

HRV analysis: undependability of approximate entropy at locating optimum complexity in malnourished children.

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 ds and Hedges's gs were totalled. RESULTS: The uppermost value of statistical significance accomplished for the effect sizes for any of the combinations was -0.2897 (Cohen's ds) and -0.2865 (Hedges's gs). 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.

Autonomic Modulation in Duchenne Muscular Dystrophy During a Computer Task: A Prospective Transversal Controlled Trial Assessment by Non-linear Techniques.

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.

Influence of Chronic Exposure to Exercise on Heart Rate Variability in Children and Adolescents Affected by Obesity: A Systematic Review and Meta-Analysis.

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.

Influence of Different Types of Corticosteroids on Heart Rate Variability of Individuals with Duchenne Muscular Dystrophy-A Pilot Cross Sectional Study.

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.

Caffeine slows heart rate autonomic recovery following strength exercise in healthy subjects.

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.