Resonance frequency is not always stable over time and could be related to the inter-beat interval

Heart Rate Variability Biofeedback (HRVB) is based on breathing at an optimal rate (or resonance frequency, RF) corresponding to the respiratory sinus arrhythmia (RSA). Our aim is to check whether the RF is a stable factor and analyse the HRV parameters individually per each breathing rate, comparing it with free slow breathing. A sample of 21 participants were trained in a test–retest HRVB protocol. The results indicated that RF changed between Test and Retest sessions in 66.7% of participants. This instability could be related to the average of interbeat interval (IBI). HRV time domain parameters (SDNN and RMSSD) were significantly higher for RF than for other breathing rates, including 6 breath/min and free slow breathing. Free slow breathing showed a lower heart rate averages than RF and other slow breathing rates. Overall, our study suggests the relevance of assessing RF individually and before each HRVB session, because the maximum cardiovascular benefits in terms of increasing HRV were found only at RF. Thus, breathing at the individualized and momentary frequency of resonance increases cardiac variability.

Can HRV Biofeedback Improve Short-Term Effort Recovery? Implications for Intermittent Load Sports

As intensity and physical demands continue to rise in sport competition, faster and better recovery becomes essential. The aim of this study was to assess the effects of HRV biofeedback (HRVB) while recovering from a submaximal aerobic exercise. Ten physically-active graduate students participated in the study, which was conducted in four sessions: exercise with free-breathing recovery, first resonance frequency (RF) detection, second RF detection, and exercise applying HRVB during recovery. Measurements included time spent running and recovering, HRV parameters, and recovery/exertion perceptions. The results indicate that using HRVB during recovery improves cardiac variability (RRmean, SDNN, RMSSD and LF; p < 0.01). HRVB also lowers recovery time (p < 0.05) and seems to be improving the perception of recovery (p = 0.087). Moreover, time spent exercising (p < 0.01) and perceived physical exertion (p < 0.05) were higher when applying HRVB. The improvement in the psychophysiological adaptation after intensive aerobic exercise provided by the HRVB is a valuable benefit, not only for competition-driven athletes, but also for the general population.

The Impact of Murmur’s Severity on the Cardiac Variability

Phonocardiogram (PCG) signal is one of the useful approach to explore cardiac activity, and extract many features to help researchers to develop technic that may serve medical stuff to the diagnosis of several cardiac diseases. For people when it comes to a heart activity problem it is a serious health matter that need special care. In this paper, the importance is given to heart murmurs to highlight their impact. Heart murmurs are very common disease in world and depend on their severity they could be life-threatening point; therefore, the purpose of this paper is focused on three essential steps: first is to design an algorithm to extract only heart murmurs from a pathological phonocardiogram signal (PCG) as a basic background to the whole work. Than calculate their severity based on energy ratio (ER) which is recommended by recent studies as an effective factor, in order to classify them to mild, medium and severe murmurs. In other hand, this classification will served to study the impact of severity of systolic and diastolic murmurs on cardiac variability, which is very important indicator on general health of human body. This study is done on consider number of patients and its reveal on very interesting results.

The Impact of Murmur’s Severity on the Cardiac Variability

Phonocardiogram (PCG) signal is one of the useful approach to explore cardiac activity, and extract many features to help researchers to develop technic that may serve medical stuff to the diagnosis of several cardiac diseases. For people when it comes to a heart activity problem it is a serious health matter that need special care. In this paper, the importance is given to heart murmurs to highlight their impact. Heart murmurs are very common disease in world and depend on their severity they could be life-threatening point; therefore, the purpose of this paper is focused on three essential steps: first is to design an algorithm to extract only heart murmurs from a pathological Phonocardiogram (PCG) signal as a basic background to the whole work. Than calculate their severity based on Energy Ratio (ER) which is recommended by recent studies as an effective factor, in order to classify them to mild, medium and severe murmurs. In other hand, this classification will served to study the impact of severity of systolic and diastolic murmurs on cardiac variability, which is very important indicator on general health of human body. This study is done on consider number of patients and its reveal on very interesting results.

Analysis of the NPT effect in women with chronic LBP: a pilot study

Introduction: low back pain (LBP) is characterized by pain in the region between the last costal arches and the gluteal fold. It can occur due to several intrinsic and extrinsic factors, and it has a very high prevalence in adulthood, causing several problems which directly influence the quality of life. Neurosensory Postural Therapy (NPT) is a technique which uses manual neural stimulation to adjust muscle tone. Objective: The aim of the present study was to verify the effects of NPT on pain, mobility, flexibility, functionality, cardiac variability and body oscillation. Methodology: Seven women over 20 years old were recruited, which were evaluated before and after the technique, which consisted of pressure on the upper and lower roots of the sciatic nerve at 3 points for 60 seconds. Results: The mean pain score was 2.71 ± 1.38 and 1.35 ± 1.18, with a value of p = 0.02. For the Schöber test we obtained a mean of 21.93 ± 1.36 and 22.34 ± 1.30 cm in the pre- and post-test with p=0.01. No statistical difference was found in the Rolland Morris questionnaire. The electromyography obtained statistical difference in the analysis of the gluteus medius with p=0.02. Significant results (p=0.0001) were found in the lateral evaluation by the stabilometry and the HF/LF ratio showed difference with p=0.03 in the pretest and after 30 days. Conclusion: The technique of NPT has benefits in the parameters studies, demonstration being a fast technique with period of efficiency.

Maternal physical activity prevents the overexpression of hypoxia-inducible factor 1-α and cardiorespiratory dysfunction in protein malnourished rats

Maternal physical activity attenuates cardiorespiratory dysfunctions and transcriptional alterations presented by the carotid body (CB) of rats. Rats performed physical activity and were classified as inactive/active. During gestation and lactation, mothers received either normoprotein (NP-17% protein) or low-protein diet (LP-8% protein). In offspring, biochemical serum levels, respiratory parameters, cardiovascular parameters and the mRNA expression of hypoxia-inducible factor 1-alpha (HIF-1α), tyrosine hydroxylase (TH) and purinergic receptors were evaluate. LP-inactive pups presented lower RF from 1st to 14th days old, and higher RF at 30 days than did NP-inactive and NP-active pups. LP-inactive pups presented with reduced serum protein, albumin, cholesterol and triglycerides levels and an increased fasting glucose level compared to those of NP-inactive and NP-active groups. LP and LP-inactive animals showed an increase in the cardiac variability at the Low-Frequency bands, suggesting a major influence of sympathetic nervous activity. In mRNA analyses, LP-inactive animals showed increased HIF-1α expression and similar expression of TH and purinergic receptors in the CB compared to those of NP groups. All these changes observed in LP-inactive pups were reversed in the pups of active mothers (LP-active). Maternal physical activity is able to attenuate the metabolic, cardiorespiratory and HIF-1α transcription changes induced by protein malnutrition.

Efeito agudo da ventilação não invasiva associada ao exercício físico sobre parâmetros cardiovasculares e respiratórios: um estudo de caso

Introdução: O método de suprimento de ventilação não invasivo (VNI) durante a realização de exercícios físicos tem sido utilizado como uma ferramenta auxiliar no tratamento de pacientes com doenças pulmonares. A literatura mostra que ainda há escassez de dados acerca dos efeitos da utilização da VNI durante a realização do exercício físico sobre os parâmetros cardiorrespiratórios.Objetivo: Avaliar o efeito do exercício físico associado a VNI sobre parâmetros cardiovasculares e respiratórios.Métodos: Participou deste estudo de caso um indivíduo do sexo masculino, saudável, com 27 anos de idade. Foram mensurados: frequência cardíaca (FC), variabilidade cardíaca (VFC), saturação periférica de oxigênio (SPO2), pressão arterial sistólica (PAS) e diastólica (PAD) e duplo produto (DP). Foram realizados dois treinos cardiorrespiratórios em esteira ergométrica, um sem VNI e o outro com VNI. As sessões de treinamento contemplaram duração de 40 min divididos em 5 min de aquecimento com intensidade entre 50% e 55% da FC reserva, 30 min de fase específica com intensidade entre 60% e 85% da FC reserva, e 5 min de desaquecimento com intensidade de 50% a 55% da FC reserva. Para avaliar as alterações das variáveis desfecho, foi estimada a variação percentual pelo coeficiente de variação.Resultados: A realização do exercício com VNI provocou alterações nos parâmetros cardiovasculares e respiratórios analisados, com destaque para redução da VFC (Δ%= -64,14) e PAD (Δ%= -45,82) em comparação à realização sem VNI.Conclusão: Os resultados do presente estudo sugerem que a realização do exercício físico com VNI pode beneficiar as respostas dos parâmetros cardiovasculares e respiratórios. Os resultados foram discutidos.Acute Effect of Non-Invasive Ventilation Associated with Physical Exercise on Cardiovascular and Respiratory Parameters: a Case StudyIntroduction: The noninvasive ventilation (NIV) method during physical exercise has been used as an auxiliary tool in the treatment of patients with pulmonary diseases. However, there is a lacune on the knowledge about cardiorespiratory parameters effects of NIV during physical exercise.Objective: To evaluate the effect of physical exercise associated with NIV on cardiovascular and respiratory parameters.Methods: A healthy, 27-year-old male was enrolled in this case study. Heart rate (HR), cardiac variability (HRV), peripheral oxygen saturation (SPO2), systolic blood pressure (SBP) and diastolic blood pressure (DBP) and double product (SD) were measured. Two cardiorespiratory treadmills were performed on treadmill, one without NIV and the other with NIV. The training sessions included 40 min duration divided in 5 min of heating with intensity between 50% and 55% of reserve HR, 30 min of specific phase with intensity between 60% and 85% of reserve HR, and 5 min of cooling with intensity of 50% to 55% of reserve FC. To express the changes of the variables, the percentage change was estimated by the coefficient of variation.Results: The exercise with NIV caused changes in cardiovascular and respiratory parameters, with a reduction in HRV (Δ% = -64.14) and DBP (Δ% = -45.82) in comparison with non-NIV.Conclusion: Our findings suggested that physical exercise with NIV use may benefit in association with exercise in relation to cardiovascular and respiratory parameters. The results were discussed.