Avaliação da cinética on da frequência cardíaca em pacientes asmáticos e em indivíduos saudáveis durante o Endurance Shuttle Walk Test / Evaluation of heart rate on kinetics in asthmatic patients and in healthy individuals during the endurance shuttle walk test

Introdução: O comportamento cinético da frequência cardíaca (FC) na transição do repouso para o exercício nos informa sobre a integridade do sistema nervoso autônomo. Recuperações mais lentas associam-se ao risco de mortalidade por eventos cardiovasculares, tornando-se imprescindível sua avaliação. Objetivo: Avaliar e comparar a resposta da cinética on da FC em pacientes asmáticos e indivíduos saudáveis durante o Endurance Shuttle Walk Test (ESWT). Métodos: Trata-se de um estudo prospectivo, transversal e controlado, com 14 adultos asmáticos e 8 controles saudáveis. Os indivíduos realizaram as seguintes avaliações: Teste de função pulmonar, Variabilidade da Frequência Cardíaca (VFC) e Incremental Shuttle Walk Test e ESWT. Resultados: O grupo asmático apresentou um atraso da cinética on da FC na transição do repouso para o teste, e uma correlação negativa moderada (r=-0,60; p<0,05) entre a distância percorrida (m) e o tempo de resposta (TRM) cinética on da FC. Conclusão: Os pacientes asmáticos apresentaram um atraso da cinética "on", quando comparados ao grupo de indivíduos saudáveis, demonstrando ser um importante marcador na avaliação da performance física.

Introduction: The kinetic behavior of heart rate (HR) in the transition from rest to exercise, as this assessment informs us about the integrity of the autonomic nervous system. Slower recoveries are associated with the risk of mortality from cardiovascular events, making their evaluation, essential. Objective: To evaluate and compare the HR on kinetics response in asthmatic patients and healthy individuals during the Endurance Shuttle Walk Test (ESWT). Methods: This is a prospective, cross-sectional, controlled study with 14 asthmatic adults and 8 healthy controls. Subjects performed the following assessments: Pulmonary Function Test, Heart Rate Variability (HRV) and Incremental Shuttle Walk Test and ESWT. Results: The asthmatic group showed a delay in the HR on kinetics in the transition from rest to the test, and a moderate negative correlation (r=-0.60; p<0.05) between the distance covered (m) and the response time (TRM) kinetics on from FC. Conclusion: Asthmatic patients showed a delay in "on" kinetics, in comparison to the group of healthy individuals, proving to be an important marker in physical performance assessments.

Heart rate variability: A biomarker of frailty in older adults?

Frailty is a state of critical loss of physiological complexity resulting in greater vulnerability to stressors and has been characterized as a debility syndrome in the older adult. Changes in functional capacity and the cardiovascular system during aging are the most significant and relevant for this population, including the clinically healthy. In this sense, this review aims to investigate methods to monitor the performance of older adults, such as heart rate variability and verify how it can be related to frailty. It contributes to understanding that the changes in heart variability can be a marker for frailty in older adults.

Early Life Microbial Exposure and Immunity Training Effects on Asthma Development and Progression.

Asthma is the most common inflammatory disease affecting the lungs, which can be caused by intrauterine or postnatal insults depending on the exposure to environmental factors. During early life, the exposure to different risk factors can influence the microbiome leading to undesired changes to the immune system. The modulations of the immunity, caused by dysbiosis during development, can increase the susceptibility to allergic diseases. On the other hand, immune training approaches during pregnancy can prevent allergic inflammatory diseases of the airways. In this review, we focus on evidence of risk factors in early life that can alter the development of lung immunity associated with dysbiosis, that leads to asthma and affect childhood and adult life. Furthermore, we discuss new ideas for potential prevention strategies that can be applied during pregnancy and postnatal period.

Emerging Cell-Based Therapies in Chronic Lung Diseases: What About Asthma?

Asthma is a widespread disease characterized by chronic airway inflammation. It causes substantial disability, impaired quality of life, and avoidable deaths around the world. The main treatment for asthmatic patients is the administration of corticosteroids, which improves the quality of life; however, prolonged use of corticosteroids interferes with extracellular matrix elements. Therefore, cell-based therapies are emerging as a novel therapeutic contribution to tissue regeneration for lung diseases. This study aimed to summarize the advancements in cell therapy involving mesenchymal stromal cells, extracellular vesicles, and immune cells such as T-cells in asthma. Our findings provide evidence that the use of mesenchymal stem cells, their derivatives, and immune cells such as T-cells are an initial milestone to understand how emergent cell-based therapies are effective to face the challenges in the development, progression, and management of asthma, thus improving the quality of life.

Acute Effects Using Light-Emitting Diode Therapy (LEDT) for Muscle Function during Isometric Exercise in Asthma Patients: A Pilot Study.

The aim of this study was to evaluate the effectiveness of acute application of LEDT in improving peripheral muscle performance during isometric exercise in patients with asthma. Eleven patients, with a mean age 38 ± 10, underwent a single LEDT and sham application in the femoral quadriceps' dominant member (cluster with 50 LED λ = 850 nm, 50 mW, 15 s; 37.5 J), 48 h apart in a randomized crossover design. Before and after LEDT and sham application, the patients were submitted an isometric endurance test (60% of the maximum isometric voluntary contraction), up to the limit of tolerance simultaneous recording of surface electromyography. There were no statistically significant differences between groups at the time of contraction (before 41±14 versus 44±16; after 46±12 versus 45±20 s) during the isometric contraction test and inflammatory markers before and after a single LEDT application. A single application of LEDT in the parameters and dose according to the equipment used in the study were not able to promote differences in the time of contraction and the fatigue response in asthmatic patients. However, the chronic effects of LEDT application for improving muscle performance in these patients are unknown and may present different responses during applications for a long time.

Reliability of the Shuttle Walk Test With Controlled Incremental Velocity in Patients With Difficult-to-Control Asthma.

PURPOSE: Asthma is a chronic inflammatory condition characterized by bronchial hypersensitivity to endogenous or exogenous agents and variable airflow limitation, which is reversible either spontaneously or with the use of medication. The evaluation of functional capacity in these patients is commonly performed using field tests to gauge activity of daily living. However, the reliability of the symptom-controlled shuttle walk test has not yet been determined for individuals with difficult-to-control asthma. The aim of the present study was to determine the reliability of the shuttle walk test in patients with severe, difficult-to-control asthma. METHODS: Forty-five patients were evaluated including lung function tests, the International Physical Activity Questionnaire (IPAQ), and the Asthma Control Questionnaire. The participants performed a shuttle walk test twice, with a 20-min rest period between tests. RESULTS: The mean distance walked for this cohort was 330.5 m (range, 50-570 m) on the first walk test and 336.3 m (range, 60-571 m) on the second test. There was no statistical difference between the mean distances walked. The Bland-Altman plots of the 2 tests revealed a mean difference of -12.7 m, with a 95% CI of 37.9 to -63.2 m. Significant correlations were found between the distance walked in meters and the IPAQ (r = 0.36, P < .01) and distance in meters and muscle mass (r = 0.39, P < .009). CONCLUSION: The shuttle walk test is reliable for individuals with difficult-to-control asthma and can be used in the evaluation of functional capacity.

Influence of bilevel positive airway pressure on autonomic tone in hospitalized patients with decompensated heart failure.

[Purpose] This study evaluated the effect of Bilevel Positive Airway (BiPAP) on the autonomic control of heart rate, assessed by heart rate variability (HRV), in patients hospitalized with decompensated heart failure. [Subjects and Methods] This prospective cross-sectional study included 20 subjects (age: 69±8 years, 12 male, left ventricular ejection fraction: 36 ±8%) diagnosed with heart failure who were admitted to a semi-intensive care unit with acute decompensation. Date was collected for HRV analysis during: 10 minutes spontaneous breathing in the resting supine position; 30 minutes breathing with BiPAP application (inspiratory pressure = 20 cmH2O and expiratory pressure = 10 cmH2O); and 10 minutes immediately after removal of BiPAP, during the return to spontaneous breathing. [Results] Significantly higher values for indices representative of increased parasympathetic activity were found in the time and frequency domains as well as in nonlinear Poincaré analysis during and after BiPAP in comparison to baseline. Linear HRV analysis: standard deviation of the average of all R-R intervals in milliseconds = 30.99±4.4 pre, 40.3±6.2 during, and 53.3±12.5 post BiPAP. Non-linear HRV analysis: standard deviations parallel in milliseconds = 8.31±4.3 pre, 12.9±5.8 during, and 22.8 ±6.3 post BiPAP. [Conclusion] The present findings demonstrate that BiPAP enhances vagal tone in patients with heart failure, which is beneficial for patients suffering from acute decompensation.

Peripheral muscle strength and functional capacity in patients with moderate to severe asthma.

BACKGROUND: The adequate control of asthma includes the absence of nocturnal symptoms, minimal use of medication, normal or nearly normal lung function and no limitations to physical activity. The choice of a more sedentary lifestyle can lead to physical de-conditioning, thereby aggravating asthma symptoms and increasing the risk of obesity. METHODS: This study aimed at performing a battery of function-related assessments in patients with asthma and comparing them to a healthy control group. A prospective, transversal and case-control study was designed. It was set up at Santa Casa de Misericórdia Hospital -Sao Paulo and Nove de Julho University on a population of outpatients. Subjects of the study were patients affected by moderate to severe asthma. A case-control study was carried out involving 20 patients with moderate to severe asthma and 15 healthy individuals (control group). All participants underwent body composition analysis (BMI and BIA) and a controlled walk test (Shuttle test), resistance muscle test (1RM) and answered a physical activity questionnaire (IPAQ). The group with asthma also answered a questionnaire addressing the clinical control of the illness (ACQ). RESULTS: In comparison to the control group (unpaired Student's t-test), the patients with asthma had a significantly higher BMI (31.09 ± 5.98 vs. 26.68 ± 7.56 kg/m(2)) and percentage of body fat (38.40 ± 6.75 vs. 33.28 ± 8.23%) as well as significantly lower values regarding distance traveled on the walk test (369 ± 110 vs. 494 ± 85 meters) and metabolic equivalents (3.74 ± 0.87 vs. 4.72 ± 0.60). A strong correlation was found between the distance completed and peripheral muscle strength (r: 0.57, p < 0.05) and METs (Metabolic equivalents - minutes/week) and peripheral muscle strength of 1RM (r: 0.61, p = 0.009). CONCLUSIONS: The individuals with asthma had lower functional capacity and levels of physical activity as well as a higher percentage of body fat compared to healthy individuals. This suggests that such patients have a reduced physical performance stemming from a sedentary lifestyle. Despite the existence of few studies reporting moderate to severe asthmatic patients and functional capacity assessment, it is clear that the assessment presented in the current study is a valid and accessible tool in clinical practice.

Analysis of heart rate variability in individuals subjected to different positive end expiratory pressure levels using expiratory positive airway pressure.

INTRODUCTION: The increase in the number of studies has led to greater security in the application of this method and the determination of its effectiveness in adults.. The purpose of the present study was to evaluate heart rate variability in healthy individuals submitted to different levels of positive expiratory pressure using an expiratory positive airway pressure (EPAP) device. MATERIAL AND METHODS: The study involved 27 healthy male individuals ranging in age from 20 to 35 years. Patient histories were taken and the subjects were submitted to a physical examination. The volunteers were monitored using the Polar 810s(®) and submitted to the EPAP experiment. Analyses were performed on variables of the frequency domain. Sympathetic and parasympathetic bands and their relationship with sympathovagal response were also analyzed. RESULTS: The mean value of this variable was 526.89 (55.50) ms(2) in the first period, 2811.0 (721.10) ms(2) in the fourth period and 726.52 (123.41) ms(2) in the fifth period. Regarding the parasympathetic area, significant differences were detected when Periods 1 and 5 (no load) were compared with periods in which the individuals were subjected to the use of the therapy. Sympathetic and parasympathetic areas together, a significant difference was detected regarding the sympathetic/parasympathetic ratio in the comparison between Periods 1 and 4 (p < 0.01) as well as Periods 2 and 4 (p < 0.05). CONCLUSIONS: The findings of the present study suggest that the therapeutic use of EPAP significantly alters the parameters of heart rate variability in the frequency domain, highlighting the importance of monitoring and care during the practice of EPAP.

Analysis of autonomic modulation during maximal and submaximal work rate and functional capacity in asthmatic children.

BACKGROUND: Children with asthma experience changes in functional capacity and autonomic control. The literature suggests that this imbalance is responsible for bronchial hyperresponsiveness, primarily during physical effort. OBJECTIVE: The aim of the present study was to evaluate variables of autonomic modulation and functional capacity in asthmatic children after maximum and submaximum work rate. METHODS: A cross-sectional study was carried out with 24 children [18 in the asthma group (AG) and 6 in the control group (CG)]. Evaluations involved heart rate variability (HRV) and functional capacity [shuttle walk test (SWT) and three-minute step test]. Pulmonary function was also evaluated through spirometry and the fractional concentration of expired nitric oxide (FeNO). RESULTS: The asthma diagnostic variables FEV(1) and FeNO differed significantly between groups (p = .01). Distance traveled on the SWT was lower in the AG (333.13 ± 97.25 m vs. 442.66 ± 127.21 m; p = .04). Perceived exertion was greater in the AG. The HRV variables rMSSD and HF did not decrease significantly during the SWT (maximum work rate) in the AG (p = .01 and .04). FeNO was negatively correlated with FEV(1)/FVC (r = -0.70; p = .004) and positively correlated with pNN50 (r = 0.50; p = .03) in the AG. CONCLUSION: From the autonomic standpoint, asthmatic and non-asthmatic children respond differently to stress. No withdrawal of parasympathetic cardiac modulation occurs in asthmatic children after maximum work rate. Children with asthma experience changes in functional capacity and lung function may vary depending on the degree of inflammation of the airways.