Heart Rate Variability in Stroke Patients Submitted to an Acute Bout of Aerobic Exercise

Transcranial photobiomodulation therapy associated with cardiorespiratory rehabilitation in spastic subjects

The objective of this study was to evaluate the effects of cardiorespiratory rehabilitation (CR) and transcranial photobiomodulation (tPBM) on exercise tolerance (ET), heart rate variability (HRV), and peripheral muscle activity in individuals with spasticity. Fifteen participants with spasticity were randomly assigned to two groups: the tPBM group (tPBMG) consisted of eight volunteers who underwent tPBM (on mode) and CR, while the control group (CG) consisted of seven volunteers who underwent simulated tPBM (off mode) and CR. The CR program included 12 weeks of treatment, twice a week for one hour, involving aerobic exercises and lower limb strengthening. For tPBM, a cluster with three lasers (λ = 680 nm, 808 nm), with a power of 100 mW/laser and energy of 36 J, applied to the F7, F8, and Fpz points. The following parameters were evaluated after 8 and 12 weeks: ET, HRV, and surface electromyography (EMG) of the rectus femoris muscle during orthostasis (ORT), isometric squatting (ISOM), and isotonic squatting (ISOT). Both groups showed a 40% increase in ET for the CG and a 30% increase for the tPBMG. The CG had more pronounced parasympathetic modulation alterations during post-exercise effort and recovery compared to the tPBMG. The EMG results showed that the tPBMG exhibited progressive improvement in muscle activity during ISOM and ISOT, as well as a decrease in the interlimb difference. In conclusion, both CR and tPBMG demonstrated improvements in ET. However, tPBMG specifically showed promising effects on HRV modulation and peripheral muscle electrical activity, providing additional benefits compared to CR alone.

Cardiac Behavior and Heart Rate Variability in Elderly Hypertensive Individuals during Aerobic Exercise: A Non-Randomized Controlled Study

BACKGROUND

High blood pressure is an important public health problem due to its high prevalence, the difficulty to control it, and its high contribution to morbidity. A series of changes may be linked to the aging process, compromising cardiac conduction, and reducing cardiovascular baroreceptor function. Advancing age promotes a decline in heart rate variability and this decrease can increase the probability of cardiovascular disease. The aim of this study was to analyze the autonomic modulation of heart rate in hypertensive elderly individuals during and after a session of aerobic exercise, and to compare it with elderly individuals without cardiovascular or metabolic disease. Our study was a non-randomized controlled study with hypertensive elderly (HBP group) and elderly without cardiovascular and/or metabolic diseases (control group). Data on blood pressure and heart rate variability (HRV) were collected before, during, and after 30 min of aerobic physical exercise on a treadmill. There was a reduction in HF (ms2) and SD1 (ms) in the 5 min of recovery for the elderly in the control group. The elderly in the control group also had greater RMSSD and SD1 30 min post-exercise when compared to the initial mins of recovery. We concluded that there was no difference in autonomic modulation and global heart rate variability between elderly individuals without cardiovascular and metabolic diseases and hypertensive individuals after a bout of aerobic exercise. Elderly individuals without metabolic diseases showed a decrease in parasympathetic modulation and global variability between the time of rest and 5 min of recovery. However, up to 30 min of post-exercise recovery, they restored parasympathetic activity.

Evaluation of autonomic cardiac modulation and body composition in elderly submitted to the protocol of exercise and the gametherapy: A clinical trial protocol (SPIRIT compliant)

INTRODUCTION

Aging affects the cardiovascular system by impairing the amount and strength of cardiac pumping. Heart rate variability (HRV) is a safe parameter to assess variations in the cardiovascular system, providing data on sympathetic and parasympathetic activations.

OBJECTIVES

Our primary aim is to investigate the cardiac autonomic modulation and body composition of active older adults participating in a physical exercise protocol and gametherapy. Our secondary aim is to assess their functional capacity, cognitive function, balance, respiratory pressures, and functional autonomy.

METHOD

This randomized clinical trial will include 100 active older adults aged 60 to 80 years. The exercise group (EG) will perform 24 supervised training sessions (strength and aerobic) for 12 weeks (2 60-minutes sessions per week). The gametherapy group (GG) will exercise using gametherapy. Assessments will occur on the first week, after the 12th week, after wash out and in the end of cross over. The primary outcome will be HRV and body composition (bioimpedance). Secondary outcomes will be functional capacity (6-minute walk test), cognitive function (mini-mental state examination), risk of falls and balance (berg balance scale and timed up and go test), inspiratory and expiratory pressures (manovacuometry) and functional autonomy (functional reach test and group of Latin American development to maturity [GDLAM] protocol).

DISCUSSION

This study will provide relevant information about the effects of physical training (physical exercises and gametherapy) on HRV and other variables in active older adults.

Impact of Constraint-Induced Movement Therapy (CIMT) on Functional Ambulation in Stroke Patients-A Systematic Review and Meta-Analysis

Constraint-induced movement therapy (CIMT) has been delivered in the stroke population to improve lower-extremity functions. However, its efficacy on prime components of functional ambulation, such as gait speed, balance, and cardiovascular outcomes, is ambiguous. The present review aims to delineate the effect of various lower-extremity CIMT (LECIMT) protocols on gait speed, balance, and cardiovascular outcomes. Material and methods: The databases used to collect relevant articles were EBSCO, PubMed, PEDro, Science Direct, Scopus, MEDLINE, CINAHL, and Web of Science. For this analysis, clinical trials involving stroke populations in different stages of recovery, >18 years old, and treated with LECIMT were considered. Only ten studies were included in this review, as they fulfilled the inclusion criteria. The effect of CIMT on gait speed and balance outcomes was accomplished using a random or fixed-effect model. CIMT, when compared to controlled interventions, showed superior or similar effects. The effect of LECIMT on gait speed and balance were non-significant, with mean differences (SMDs) of 0.13 and 4.94 and at 95% confidence intervals (Cis) of (-0.18-0.44) and (-2.48-12.37), respectively. In this meta-analysis, we observed that despite the fact that several trials claimed the efficacy of LECIMT in improving lower-extremity functions, gait speed and balance did not demonstrate a significant effect size favoring LECIMT. Therefore, CIMT treatment protocols should consider the patient's functional requirements, cardinal principles of CIMT, and cardiorespiratory parameters.

HRV-Guided Training for Elders after Stroke: A Protocol for a Cluster-Randomized Controlled Trial

There are many consequences associated with having a stroke, all of which are important factors affecting long-term rehabilitation outcomes; these become important health issues for those of advanced age and require dedicated health strategies. High-intensity interval training (HIIT) is an effective training protocol used in cardiac rehabilitation programs; however, owing to the inter-individual variability in physiological responses to training associated with cardiovascular diseases, the exercise regimen given to each patient should be closely controlled and individualized to ensure the safety and efficiency of the exercise program. Heart rate variability (HRV) is currently being used for this purpose, as it is closely linked to parasympathetic nervous system activation, with high HRV scores associated with good cardiovascular adaptation. The objective of this protocol is to determine the effect of HIIT compared to HRV-guided training in terms of cardiorespiratory fitness, heart rate variability, functional parameters, body composition, quality of life, inflammatory markers, and cognitive function in patients who have had a stroke, as well as to assess the feasibility of patients undertaking an 8-week cardiac rehabilitation program, evaluating its safety and their adherence. The proposed protocol involved cluster-randomized controlled design in which the post-stroke patients are assigned either to an HRV-based training group (HRV-G) or a HIIT-based training group (HIIT-G). HIIT-G will train according to a predefined training program, whereas HRV-G will train depending on the patients' daily HRV. The outcomes considered are peak oxygen uptake (VO_2peak), endothelial and work parameters, heart rate variability, functional parameters, relative weight and body fat distribution, quality of life, inflammatory markers and cognitive function, as well as exercise adherence, feasibility, and safety. It is expected that this HRV-guided training protocol will improve functional performance in patients following a stroke and be safer, more feasible, and generate improved adherence relative to HIIT, providing an improved strategy for to optimize cardiac rehabilitation interventions.

The Use of Cardiac Autonomic Responses to Aerobic Exercise in Elderly Stroke Patients: Functional Rehabilitation as a Public Health Policy

BACKGROUND AND PURPOSE

The development of public policies must be guided by full knowledge of the health-disease process of the population. Aerobic exercises are recommended for rehabilitation in stroke patients, and have been shown to improve heart rate variability (HRV). Our aim was to compare the cardiac autonomic modulation of elderly stroke patients with that of healthy elderly people during and after an acute bout of aerobic exercise.

METHODS

A total of 60 elderly people participated in the study (30 in the control group, mean age of 67 ± 4 years; 30 in the stroke group, mean age of 69 ± 3 years). HRV was analyzed in rest-10 min of rest in supine position; exercise-the 30 min of peak exercise; and recovery-30 min in supine position post-exercise.

RESULTS

Taking rest and exercises together, for SDNN, RMSSD, pNN50, RRTri, and TINN, there was no difference between the stroke and control groups (p = 0.062; p = 0.601; p = 0.166; p = 0.224, and p = 0.059, respectively). The HF (ms2) was higher and the LF/HF ratio was lower for the stroke group than the control group (p < 0.001 and p = 0.007, respectively). The SD2 was lower for the stroke group than for the control group (p = 0.041).

CONCLUSION

Stroke patients present reduced variability at rest, sympathetic predominance during exercise, and do not return to baseline after the 30 min of recovery, with similar responses found in the healthy elderly group.

Effects of rehabilitation programs on heart rate variability after stroke: a systematic review

BACKGROUND

It has been shown that the autonomic nervous system can be modulated by physical exercise after stroke, but there is a lack of evidence showing rehabilitation can be effective in increasing heart rate variability (HRV).

OBJECTIVE

To investigate the effectiveness and safety of rehabilitation programs in modulating HRV after stroke.

METHODS

The search strategy was based in the PICOT (patients: stroke; interventions: rehabilitation; comparisons: any control group; outcomes: HRV; time: acute, subacute and chronic phases of stroke). We searched MEDLINE, CENTRAL, CINAHL, LILACS, and SCIELO databases without language restrictions, and included randomized controlled trials (RCTs), quasi-randomized controlled trials (quasi-RCTs), and non-randomized controlled trials (non-RCTs). Two authors independently assessed the risk of bias and we used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology to rate the certainty of the evidence for each included study.

RESULTS

Four studies (two RCTs with low certainty of the evidence and two non-RCTs with very low certainty of the evidence) were included. Three of them showed significant cardiac autonomic modulation during and after stroke rehabilitation: LF/HF ratio (low frequency/high frequency) is higher during early mobilization; better cardiac autonomic balance was observed after body-mind interaction in stroke patients; and resting SDNN (standard deviation of normal R-R intervals) was significantly lower among stroke patients indicating less adaptive cardiac autonomic control during different activities.

CONCLUSIONS

There are no definitive conclusions about the main cardiac autonomic repercussions observed in post-stroke patients undergoing rehabilitation, although all interventions are safe for patients after stroke.

Development of a prediction model for ascent and descent staircase independence during the sub-acute rehabilitation phase in individuals post-stroke

BACKGROUND

Nearly half of individuals post-stroke are dependent in their daily activities. The ability to ascend and descend stairs is an important component of independence in the community.

OBJECTIVE

To predict the future ability of post-stroke individuals at the beginning of the sub-acute rehabilitation phase to achieve ascending and descending staircase independence.

METHODS

36 participants were recruited for the study.

OUTCOME MEASURES

independence in ascending and descending stairs up to the end of the sub-acute rehabilitation phase. Predictive measures included the knee extensors Muscles Strength (MS), the seated Modified Functional Reach (MFR) test, and Heart Rate Variability (HRV) measures. Logistic and Cox regression were used.

RESULTS

Twenty-four participants (66.7%) completed the sub-acute rehabilitation phase being independent in ascending and descending stairs. MFR was the best predictor (R2 = 0.18), and with MS the best predictors for the time (days) to achieve this goal during the sub-acute rehabilitation. HRV measure was found to be the main predictor of the staircase ascent model (R2 = 0.32), and MFR the best predictor for the descent model (R2 = 0.24).

CONCLUSIONS

Balance performance is the main predictor of independence in ascending and descending stairs. Improving this component during the sub-acute rehabilitation phase might be reflected in achieving staircase independence.

Birth weight and heart rate autonomic recovery following exercise in healthy term-born adults

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.

Effects of effortful swallowing on cardiac autonomic control in individuals with neurogenic dysphagia: a prospective observational analytical study

Considering that neurogenic oropharyngeal dysphagia is a prevalent condition with or without cardiac disease we should contemplate issues surrounding cardiovascular difficulties during rehabilitation. This study aims to evaluate the effects of effortful swallowing maneuver (ESM) on heart rate variability (HRV) in subjects with neurogenic oropharyngeal dysphagia. We studied 22 individuals [8 Stroke and 14 Parkinson Disease (PD) subjects aged between 41 and 75 years old] with neurogenic oropharyngeal dysphagia regardless of gender. HRV was assessed under two circumstances: spontaneous swallowing versus ESM. Surface electromyography of the suprahyoid muscles was undertaken to measure the swallowing muscle excitation, which then confirmed higher muscle activity during ESM. We attained no changes in HRV between the two swallowing events [HR: spontaneous swallowing 78.68 ± 13.91 bpm vs. ESM 102.57 ± 107.81 bpm, p = 0.201; RMSSD (root-mean square of differences between adjacent normal RR intervals in a time interval): spontaneous swallowing 16.99 ± 15.65 ms vs. ESM 44.74 ± 138.85 ms, p = 0.312; HF (high frequency): spontaneous swallowing 119.35 ± 273 ms² vs. ESM 99.83 ± 194.58 ms², p = 0.301; SD1 (standard deviation of the instantaneous variability of the beat-to-beat heart rate): spontaneous swallowing 12.02 ± 1.07 ms vs. ESM 31.66 ± 98.25 ms, p = 0.301]. The effortful swallowing maneuver did not cause clinically significant changes in autonomic control of HR in this group of subjects with oropharyngeal dysphagia.

Energy Drink before Exercise Did Not Affect Autonomic Recovery Following Moderate Aerobic Exercise: A Crossover, Randomized and Controlled Trial

Introduction: Energy drink (ED) intake could initiate physiological changes owing to its stimulant characteristics and, it improves endurance and athletic performance. We evaluated the acute effects of ED on autonomic heart rate (HR) control during recovery after a session of submaximal aerobic exercise.Method: The study was completed by submitting 29 healthy males between 18 and 30 years old to three conventions: (A) Maximum exercise test by the adapted Bruce protocol; (B) Placebo protocol (PP) - water intake 15 minutes prior to exercise, rest in dorsal decubitus for 15 minutes followed by 5 minutes of treadmill running at 1% inclination, initial speed of 5 km/h for 5 minutes 25 minutes with 60% of the velocity consistent to the maximum oxygen consumption (VO2max), and finally 60 minutes of recovery at rest in the supine position; (C) Experimental protocol (PE) - similar to PP previously, but with ED intake 15 minutes before physical exercise. The time, frequency and geometric indexes of HR variability (HRV) were inspected before and after exercise.Results: There was a significant (p < 0.05, <5%) effect on the HRV index (HR-nu and ms², LF-nu and ms², LF/HF, SD1, SDNN and RMSSD), indicating a reduction in HRV in the first 5 minutes after exercise in both protocols (PP and PE). Yet, no protocol interaction was detected, suggesting no effect of ED on HRV throughout recovery after submaximal aerobic exercise.Conclusion: There was no significant effect of ED on the autonomic control of HR in the recovery phase after submaximal aerobic exercise.

Lower Systolic Blood Pressure in Normotensive Subjects is Related to Better Autonomic Recovery Following Exercise

Blood pressure (BP) is a cardiovascular parameter applied to detect cardiovascular risk. Recently, the pre-hypertension state has received greater consideration for prevention strategies. We evaluated autonomic and cardiorespiratory recovery following aerobic exercise in normotensive individuals with different systolic BP (SBP) values. We investigated 30 healthy men aged 18 to 30 years divided into groups according to systolic BP (SBP): G1 (n = 16), resting SBP <110 mmHg and G2 (n = 14), resting SBP between 120-110 mmHg. The groups endured 15 minutes seated at rest, followed by a submaximal aerobic exercise on a treadmill and then remaining seated for 60 minutes also at rest, during recovery from the exercise. Cardiorespiratory parameters and heart rate (HR) variability (HRV) (rMSSD, SD1, HF [ms2]) were evaluated before and during recovery from exercise. G2 displayed slower return of SBP, rMSSD and SD1 HRV indices during recovery from exercise compared to G1. In conclusion, normotensive subjects with higher resting SBP (110 to 120 mmHg) offered delayed autonomic recovery following moderate exercise. We suggest that this group may be less physiologically optimized leading to cardiac risks.

Heart rate variability helps to distinguish the intensity of menopausal symptoms: A prospective, observational and transversal study

Heart Rate Variability (HRV) represents cardiac autonomic behavior and have been related to menopausal symptoms, mainly vasomotor symptoms and their imbalance to cardiovascular risk. It is not clear in the literature which index represents this imbalance and what is their involvement with the menopausal state. The aim of this study was to evaluate HRV in menopausal transition and post-menopausal symptoms with different intensities. This cross-sectional study was conducted in Rio Branco, State of Acre, Brazil from October 2016 to July 2017. We used Kupperman-Blatt Menopausal Index (KMI) to measure menopausal symptoms intensity. HRV analysis was performed based on the guidelines of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. HRV is lower in the group with moderate/intense menopausal symptoms compared to mild symptoms. (RMSSD: p = 0.005, Cohen’s d = 0.53, pNN50: p = 0.0004, Cohen’s d = 0.68; HF: p = 0.024, Cohen’s d = 0.44). There was association between HRV and KMI (RMSSD: r = -1.248, p = 0.004; and pNN50: r = -0.615, p: 0.029) in inverse relation to the intensity of vasomotor symptoms in women in TM. In conclusion, HRV was able to distinguish menopausal symptoms, indicating reduced vagal control in women with more intense symptoms.

Aerobic Training Is Better Than Resistance Training on Cardiac Function and Autonomic Modulation in Female ob/ob Mice

Objective: This study evaluated the effects of aerobic, resistance, and combined exercise training on cardiac function and autonomic modulation in female ob/ob mice. Methods: Four-week-old female wild type and obese (ob/ob) mice were divided into five groups (n = 8): control (WT), obese (OB) obese + aerobic training (OBA), obese + resistance training (OBR), and obese + combined training (OBC). The exercise training was performed on treadmill and/or ladder at 40-60% maximum test during 8 weeks. Cardiac function was measured using echo machine. Heart rate variability (HRV) was evaluated in the time and frequency domain. Results: OB group presented higher body weight gain (~600%), glycemia (~44%) and glucose intolerance (~150%), reduction of cardiac vagal modulation, evidenced by a lower RMMSD (~56%), total power and high frequency band, and a higher isovolumic relaxation time (IVRT) (~24%) in relation to the WT group. Aerobic and combined training led to a lower IVRT (OBA: ~14%; OBC: ~14%) and myocardial global index (OBA: ~37%; OBC: ~44%). The OBA group presented an increased in vagal indexes of HRV than the other ob/ob groups. A negative correlation was observed between the delta of aerobic exercise capacity and MPI (r = 0.45; p = 0.002) and exercise capacity and body weight gain (r = 0.39; p = 0.002). Conclusion: Only the obese females underwent to aerobic exercise training showed improvement in cardiac function and HRV. Moreover, the aerobic exercise capacity as well as a greater responsivity to aerobic exercise training is intimately associated with these improvements, reinforcing the importance of aerobic exercise training to this population.

Association Between Hospital Anxiety Depression Scale and Autonomic Recovery Following Exercise

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.

Heart rate variability in people with visual disability: Study Protocol

INTRODUCTION

People with visual impairment (VI) have loss of vision that causes impact on their daily living activities. Synonymous of VI are blindness, low vision, subnormal vision, visual incapacity, although there are peculiarities among them. The autonomic nervous system (ANS) provides the body with dynamic adaptation, moment by moment, according to changes in the internal and/or external body environment. As VI is an adverse condition, it is expected to be associated with changes in systemic autonomic activity, such as heart rate (HR) variability.

OBJECTIVE

To analyze the blindness stress by monitoring the activity of the ANS in the heart in subjects submitted acutely to low vision and also in subjects with chronic visual deficiency.

METHOD

This is a randomized trial experimental study. In this clinical trial, initially, patients will undergo an ophthalmologic medical evaluation, along with monitoring of HR and systolic blood pressure /diastolic blood pressure. Volunteers with normal vision (Group i); and people with VI (Group ii) will be evaluated, all of them inhabitants of Rio Branco City, capital of Acre State, Brazilian Amazon. The intervention will consist of simulating blindness by sealing both eyes of each participant with good eyesight, using a sleep mask and allowing maximum occlusion for 45 minutes, split into 3 periods of 15 minutes each. Still blindfolded, participants will be requested to perform different tasks as walking, serve themselves water and/or cookies, and engaging in playful-pedagogical activity. Identical procedure will be done with the group with VI. The HR will be recorded by the Polar RS800 HR monitor. All findings with a value of P < .05 will be considered statistically significant. As a risk measure the odds ratio will be calculated, adjusted, and not adjusted with their respective 95% confidence intervals. The odds ratio = 1 of lowest risk for the outcome of interest will be considered as the base category for each independent variable.

ETHICS AND DISSEMINATION

This study will be carried out in accordance with the guidelines that regulate human research in Resolution No. 466/12 of the National Health Council. We obtained the approval of the Research Ethics Committee of the ABC Medical School/Faculdade de Medicina do ABC, with CAAE: 73945017.0.0000.0082, and Opinion No. 2,275,101. All individuals who agreed to participate in the study will sign the free and informed consent form (FICF). The FICF is also available in audio and Braille versions. The results will be disseminated through peer-reviewed journal articles and conferences. This study is registered in the Brazilian Registry of Clinical Trials under the number RBR-9sm9dp.

The effects of musical auditory stimulation on heart rate autonomic responses to driving: A prospective randomized case-control pilot study

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.

Is aerobic exercise training during hemodialysis a reliable intervention for autonomic dysfunction in individuals with chronic kidney disease? A prospective longitudinal clinical trial

Introduction

Physical exercises help in the rehabilitation and recovery of various diseases. Cardiovascular and hypertension problems are the main causes of people being affected by kidney problems, which as a consequence, affects the heart rate variability (HRV) of the individual. Physical activity developed in a well-planned and thorough way can be a component in the treatment of this problem.

Objective

We aimed to evaluate the effects of aerobic exercise intervention during hemodialysis on autonomic heart rate regulation in individuals with chronic kidney disease (CKD).

Methods

This was a longitudinal trial conducted in 19 CKD patients. The patients underwent three weekly sessions of aerobic exercise during hemodialysis for 30 mins for 12 weeks (three months).

Results

HRV was analyzed before and after the protocol training. Linear indices of HRV were not different between before and after the protocol training. Nonlinear HRV analysis indicated reduced values of determinism (p=0008, Cohen's d=0.82) and entropy (p=003, Cohen's d=0.84) after the training protocol.

Conclusion

In conclusion, aerobic exercise training during hemodialysis did not improve autonomic control of heart rate in CKD patients.

Evaluation of the effects of aerobic training during hemodialysis on autonomic heart rate modulation in patients with chronic renal disease

INTRODUCTION

Chronic renal disease (CRD) affects a large portion of the population and is directly related to cardiovascular problems and hypertension, among others. Studies show that heart rate variability is directly affected by these problems. Physical-oriented exercises have been shown to be of fundamental importance in improving the adverse effects to dialysis treatment.

OBJECTIVE

To analyze the effects of aerobic training during hemodialysis on autonomic heart rate modulation in patients with CRD.

METHOD

Experimental study of an open, single group clinical trial. In this clinical trial, patients with CRD will initially undergo international physical activity questionnaire and kidney disease quality of life short form protocols, as well as monitoring of heart rate systolic, and diastolic blood pressure. After evaluation of the initial parameters, patients will undergo an aerobic exercise program for 12 weeks, in 3 weekly sessions, lasting 30 minutes a session. These evaluations will allow for a greater control of the disease, and monitoring of any improvements in the quality of life and self-esteem of these patients.

ETHICS AND DISSEMINATION

This study was approved following the guidelines and norms that regulate research involving human subjects, in Resolution No. 466/12 of the National Health Council. It was approved by the Research Ethics Committee of the Faculty of Juazeiro do Norte, with the number 1962 092. All patients who agree to participate in the research will sign the informed consent form. The results will be disseminated through peer-reviewed journal articles and conferences.

Effects of inclined treadmill training on functional and cardiovascular parameters of stroke patients: study protocol for a randomized controlled trial

Background

Treadmill training has been widely used for gait recovery after stroke. Gait re-establishment is one of the main objectives of rehabilitation programs after stroke, aiming to acquire more functional patterns and increase walking speed, along with improvement in cardiovascular function. The aim of this study is to evaluate the effects of a treadmill gait training protocol on functional and cardiovascular variables in patients with chronic stroke.

Methods

A single-blind randomized clinical trial will be conducted. The sample will consist of 36 patients, who will be allocated in three groups: control group (n = 12), experimental group 1 (n = 12), and experimental group 2 (n = 12). The intervention will occur for 6 consecutive weeks, three times a week, 30 min each session, in all groups. The control group will perform a treadmill gait training without inclination, experimental group 1 will perform a treadmill gait training with anterior inclination of 5%, and experimental group 2 will perform a treadmill gait training with anterior inclination of 10%. All participants will be assessed for sample characterization measures, gait speed, functional capacity, systemic arterial blood pressure, heart rate, peripheral oxygen saturation, exercise capacity, neuromuscular torque, and quality of life. Evaluations of outcome measures will occur at the end of the interventions (post-training) and after 1 month and 1 year after the end of the interventions (short- and long-term follow-up). Statistical analysis will be performed descriptively and inferentially. Alpha equals 5% will be considered for inferential analysis. Mixed analysis of variance with repeated measures will be used to compare outcome measures between groups and between baseline, post-training, and follow-up. Normality test (Shapiro–Wilk) and subsequently t test (or Mann–Whitney) will be used to compare groups during the same training session.

Discussion

It is believed that treadmill training, especially treadmill training with anterior inclination, may result in improved exercise capacity in patients with stroke, reduced blood pressure and heart rate values, and an improvement in functional parameters with increased gait speed, functional capacity, quadriceps muscle torque, and quality of life.

Trial registration

Registration in Brazilian Registry of Clinical Trials (ReBEC) identifier RBR-5ffbxz, date of registration October 25 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3298-3) contains supplementary material, which is available to authorized users.

Interaction Between Cortical Auditory Processing and Vagal Regulation of Heart Rate in Language Tasks: A Randomized, Prospective, Observational, Analytical and Cross-Sectional Study

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.

The cardiac autonomic nervous system response to different daily demands among patients at the sub-acute phase post ischemic stroke and healthy controls

BACKGROUND

Autonomic disturbances are a common phenomenon in patients' post-stroke, characterized by hypo function of the para-sympathetic and/or overactive sympathetic system. The impact of autonomic disturbances on physical therapy tasks during the rehabilitation period has not yet been assessed.

OBJECTIVE

To describe the response of the cardiac autonomic nervous system during different tasks, among patients and age-matched healthy controls.

METHODS

Nineteen patients in the subacute phase post first-ever ischemic stroke, and 16 controls. The Polar advanced heart rate monitor (RS800CX) was used to record RR intervals at rest, during paced breathing exercise, while performing different types of muscle contractions, and during single and dual task conditions.

RESULTS

RR intervals and heart-rate variability (HRV) parameters were significantly lower among patients post stroke, both at rest and during most of the activities tested. Among the control group a significant autonomic adaptation was seen in the form of reduced RR intervals and HRV during muscle contraction and a significant increase in these parameters during slow breathing, no significant changes were observed among patients post stroke.

CONCLUSION

Patients post-stroke experience hyper sympathetic function at rest and less adaptive cardiac autonomic control during different activities, which all may have an impact on rehabilitation outcomes.

Heart Rate Variability and Cardiopulmonary Dysfunction in Patients with Duchenne Muscular Dystrophy: A Systematic Review

Duchenne muscular dystrophy (DMD) is a genetic recessive disorder with progressive muscle weakness. Despite the general muscle wasting, degeneration and necrosis of cardiomyocytes have been the main causes of morbidity and death in individuals with DMD. Cardiac failure is generally preceded by disturbances in heart rate variability (HRV), and non-invasive measurement of the autonomic nervous system has been an important tool to predict adverse cardiovascular events. Hence, the application of HRV to study autonomic modulation in DMD individuals, and the establishment of correlations between HRV and heart/lung diseases, age, and mortality will have the potential to improve quality of life and life expectancy of individuals with DMD. In order to evaluate the state of the art in this field, we conducted a systematic search in Medline/PubMed and BVS (virtual library in health) databases. We selected 8 studies using pre-defined criteria and meta-analysis revealed decreased parasympathetic activity and increased sympathetic predominance in individuals with DMD as major observations. Moreover, there is a strong association between diminished HRV and myocardial fibrosis with DMD. These patterns are evident in patients at early-stage DMD and become more prominent as disease severity and age increase. Thus, data minning clearly indicates that HRV assessment can be used as a predictor for sudden death in individuals with DMD. The use of the HRV, which is inexpensive, ubiquitously available in clinics and hospitals, and a non-invasive analysis tool, can save lives and decrease the morbity in DMD by alerting care givers to consider autonomic nervous system intervention.

Cardiorespiratory parameters and glycated hemoglobin of patients with type 2 diabetes after a rehabilitation program

INTRODUCTION

Cardiovascular autonomic dysfunction reflex of the pathophysiology of diabetes mellitus (DM) favors an increase in morbidity and mortality related to cardiovascular events, and for this reason has been one of the most studied clinical entities.

METHOD

An experimental study of a randomized clinical trial type was therefore proposed to analyze the hemodynamic and glycemic response after the practice of a rehabilitation program in patients with type 2 diabetes mellitus (T2DM). In this clinical trial the patients will initially be submitted to an evaluation protocol that consists of assessing blood pressure, heart rate, Borg scale, respiratory rate, oxygen saturation, distance traveled through the 6-minute walk test, quality of life questionnaire, Pittsburgh sleep quality questionnaire, and still glycated hemoglobin and heart rate variability through the cardiofrequency meter. After careful evaluation of the patients, they will be submitted to a metabolic rehabilitation program composed of aerobic and resisted exercises, performed for 12 weeks, in 3 weekly meetings of 60 minutes each. With such evaluations, it will be possible to construct with evidence that it is possible to work safer metabolic rehabilitation programs in patients with T2DM or other diseases that generate cardiovascular risks, guaranteeing them an improvement in cardiorespiratory fitness, hemodynamic and glycemic variables, allowing improvement of the quality of life.

ETHICS AND DISSEMINATION

The protocol is approved by the host institution's ethics committee under the number 1.616.721. Results will be disseminated via peer-reviewed journal articles and conferences. This clinical trial is registered at ClinicalTrials.gov identifier: NCT3094767.

Is there influence of the load addition during treadmill training on cardiovascular parameters and gait performance in patients with stroke? A randomized clinical trial

BACKGROUND

Although exercises involving both lower limbs are indicated for aerobic training, stroke patients have shown expressive asymmetry between the paretic and non-paretic lower limb (NPLL). Performing activities that stimulate the paretic limb during aerobic exercise may optimize training results.

OBJECTIVE

To evaluate if there is influence of load addition on NPLL during treadmill training on cardiovascular parameters and gait performance of subacute stroke patients.

METHODS

Thirty-eight stroke subjects with gait deficits were randomized into experimental group, which underwent treadmill training with a mass attached on NPLL, and control group, which underwent only treadmill training. Interventions lasted 2 weeks (9 sessions). Main outcomes were heart rate, arterial blood pressure, gait speed and distance covered. Assessments occurred at rest, 10th and 20th minutes of the session and immediately after each session.

RESULTS

There was improvement in speed and walking distance in both groups. All cardiovascular parameters had showed no changes compared to 1st and 9th sessions and there were no differences between groups within each session.

CONCLUSIONS

Load addition on NPLL did not alter cardiovascular parameters and gait training provide better gait performance of subacute stroke patients, which indicates this therapy can be considered useful and safe for these patients.

Association between Diastolic Dysfunction with Inflammation and Oxidative Stress in Females ob/ob Mice

Objective: To evaluate autonomic and cardiovascular function, as well as inflammatory and oxidative stress markers in ob/ob female mice.

Methods: Metabolic parameters, cardiac function, arterial pressure (AP), autonomic, hormonal, inflammatory, and oxidative stress markers were evaluated in 12-weeks female wild-type (WT group) and ob/ob mice (OB group).

Results: OB animals showed increased body weight, blood glucose, and triglyceride levels, along with glucose intolerance, when compared to WT animals. Ejection fraction (EF) and AP were similar between groups; however, the OB group presented diastolic dysfunction, as well as an impairment on myocardial performance index. Moreover, the OB group exhibited important autonomic dysfunction and baroreflex sensitivity impairment, when compared to WT group. OB group showed increased Angiotensin II levels in heart and renal tissues; decreased adiponectin and increased inflammatory markers in adipose tissue and spleen. Additionally, OB mice presented a higher damage to proteins and lipoperoxidation and lower activity of antioxidant enzymes in kidney and heart. Correlations were found between autonomic dysfunction with angiotensin II and inflammatory mediators, as well as between inflammation and oxidative stress.

Conclusions: Our results showed that female adult ob/ob mice presented discrete diastolic dysfunction accompanied by autonomic disorder, which is associated with inflammation and oxidative stress in these animals.

Delayed Varenicline Administration Reduces Inflammation and Improves Forelimb Use Following Experimental Stroke

BACKGROUND

Pharmacological activation of the cholinergic anti-inflammatory pathway (CAP), specifically by activating α7 nicotinic acetylcholine receptors, has been shown to confer short-term improvements in outcome. Most studies have investigated administration within 24 hours of stroke, and few have investigated drugs approved for use in human patients. We investigated whether delayed administration of varenicline, a high-affinity agonist at α7 nicotinic receptors and an established therapy for nicotine addiction, decreased brain inflammation and improved functional performance in a mouse model of experimental stroke.

METHODS

CSF-1R-EGFP (MacGreen) mice were subjected to transient middle cerebral artery occlusion and administered varenicline (2.5 mg/kg/d for 7 days) or saline (n = 10 per group) 3 days after stroke. Forelimb asymmetry was assessed in the Cylinder test every 2 days after surgery, and structural lesions were quantified at day 10. Enhanced green fluorescent protein (EGFP) and growth associated protein 43 (GAP43) immunohistochemistry were used to evaluate the effect of varenicline on inflammation and axonal regeneration, respectively.

RESULTS

Varenicline-treated animals showed a significant increase in impaired forelimb use compared with saline-treated animals 10 days after stroke. Varenicline treatment was associated with reduced EGFP expression and increased GAP43 expression in the striatum of MacGreen mice.

CONCLUSION

Our results show that delayed administration of varenicline promotes recovery of function following experimental stroke. Motor function improvements were accompanied by decreased brain inflammation and increased axonal regeneration in nonpenumbral areas. These results suggest that the administration of an exogenous nicotinic agonist in the subacute phase following stroke may be a viable therapeutic strategy for stroke patients.