The physiological effects of slow breathing in the healthy human

Integrating Breathing Techniques Into Psychotherapy to Improve HRV: Which Approach Is Best?

Introduction

Approaches to improve heart rate variability and reduce stress such as breathing retraining are more frequently being integrated into psychotherapy but little research on their effectiveness has been done to date. Specifically, no studies to date have directly compared using a breathing pacer at 6 breaths per minute with compassion focused soothing rhythm breathing.

Current Study

In this randomized controlled experiment, 6 breaths per minute breathing using a pacer was compared with compassion focused soothing rhythm breathing, with a nature video being used as a control group condition.

Methods

Heart rate variability (HRV) measures were assessed via electrocardiogram (ECG) and respiration belt, and an automated blood pressure machine was used to measure systolic diastolic blood pressure, and heart rate (HR). A total of 96 participants were randomized into the three conditions. Following a 5-min baseline, participants engaged in either 6 breath per minute breathing, soothing rhythm breathing, or watched a nature video for 10 min. To induce a stressful state, participants then wrote for 5 min about a time they felt intensely self-critical. Participants then wrote for 5 min about a time they felt self-compassionate, and the experiment ended with a 10-min recovery period.

Results

Conditions did not significantly differ at baseline. Overall, HRV, as measured by standard deviation of NN intervals (SDNN), low frequency HRV (LF HRV), and LF/HF ratio, increased during the intervention period, decreased during self-critical writing, and then returned to baseline levels during the recovery period. High frequency HRV (HF HRV) was not impacted by any of the interventions. The participants in the 6 breath per minute pacer condition were unable to consistently breathe at that rate and averaged about 12 breaths per minute. Time by Condition analyses revealed that both the 6 breaths per minute pacer and soothing breathing rhythm conditions lead to significantly higher SDNN than the nature video condition during breathing practice but there were no significant differences between conditions in response to the self-critical and self-compassionate writing or recovery periods. The 6 breath per minute pacer condition demonstrated a higher LF HRV and LF/HF ratio than the soothing rhythm breathing condition, and both intervention conditions had a higher LF HRV and LF/HF ratio than the nature video.

Conclusions

Although the 6 breath per minute pacer condition participants were not able to breath consistently at the low pace, both the participants attempting to breathe at 6 breaths per minute as well as those in the soothing rhythm breathing condition effectively increased HR variability as measured by SDNN, and attempting to breathe at 6 breaths per minute led to the highest LF HRV and LF/HF ratio. Both breathing approaches impacted HRV more than watching a relaxing nature video and can potentially be used as key adjuncts in psychotherapy to aid in regulating physiological functioning, although it appears that consistent breathing practice would be needed.

Flexible optical imaging band system for the assessment of arthritis in patients with systemic lupus erythematosus

We have developed a flexible optical imaging system (FOIS) to assess systemic lupus erythematosus (SLE) arthritis in the finger joints. While any part of the body can be affected, arthritis in the finger joints is one of the most common SLE manifestations. There is an unmet need for accurate, low-cost assessment of lupus arthritis that can be easily performed at every clinic visit. Current imaging methods are imprecise, expensive, and time consuming to allow for frequent monitoring. Our FOIS can be wrapped around joints, and multiple light sources and detectors gather reflected and transmitted light intensities. Using data from two SLE patients and two healthy volunteers, we demonstrate the potential of this FOIS for assessment of arthritis in SLE patients.

Diaphragmatic thickness and excursion by lung ultrasound in pediatric chronic pulmonary diseases

PURPOSE

Many patients with chronic pulmonary diseases, such as interstitial lung disease, cystic fibrosis, and non-cystic fibrosis bronchiectasis, suffer from dyspnea and exercise intolerance. Reduced lung compliance is the main cause of the patients' dyspnea, but weak respiratory muscles could be an additional factor. The diaphragm is considered the major respiratory muscle. Our study aimed to detect diaphragmatic thickness and excursion by ultrasound in pediatric patients with chronic pulmonary diseases to assess respiratory muscle weakness in these patients.

METHODS

A case-control study was conducted on 130 patients with pediatric chronic pulmonary diseases (childhood interstitial lung diseases, cystic fibrosis, and non-cystic fibrosis bronchiectasis) and 100 control subjects. Ultrasound was used to detect diaphragmatic excursion and thickness, which were correlated with the severity of the disease, both clinically and functionally.

RESULTS

The right and left diaphragmatic excursions were significantly lower in the patients (19.469 ± 9.984 and 18.5 ± 10.131, respectively) than in the control subjects (29.6 ± 14.131 and 25.6 ± 12.827, respectively) (p values of 0.002 and 0.019). In contrast, the difference in the right and left diaphragmatic thicknesses between the patients and the controls was statistically insignificant (p values of 0.884 and 0.344). The left diaphragmatic excursion was positively correlated with the patients' age and weight, while both the right and the left diaphragmatic excursion significantly correlated with the patients' height, FEV1/FVC ratio, and heart rate.

CONCLUSION

The diaphragmatic excursion is lower in children and adolescents with chronic pulmonary diseases than in healthy control subjects. The diaphragmatic excursion is positively correlated with patients' age, weight, height, FEV1/FVC ratio, and heart rate.

Extraction and Analysis of Respiratory Motion Using a Comprehensive Wearable Health Monitoring System

Respiratory activity is an important vital sign of life that can indicate health status. Diseases such as bronchitis, emphysema, pneumonia and coronavirus cause respiratory disorders that affect the respiratory systems. Typically, the diagnosis of these diseases is facilitated by pulmonary auscultation using a stethoscope. We present a new attempt to develop a lightweight, comprehensive wearable sensor system to monitor respiration using a multi-sensor approach. We employed new wearable sensor technology using a novel integration of acoustics and biopotentials to monitor various vital signs on two volunteers. In this study, a new method to monitor lung function, such as respiration rate and tidal volume, is presented using the multi-sensor approach. Using the new sensor, we obtained lung sound, electrocardiogram (ECG), and electromyogram (EMG) measurements at the external intercostal muscles (EIM) and at the diaphragm during breathing cycles with 500 mL, 625 mL, 750 mL, 875 mL, and 1000 mL tidal volume. The tidal volumes were controlled with a spirometer. The duration of each breathing cycle was 8 s and was timed using a metronome. For each of the different tidal volumes, the EMG data was plotted against time and the area under the curve (AUC) was calculated. The AUC calculated from EMG data obtained at the diaphragm and EIM represent the expansion of the diaphragm and EIM respectively. AUC obtained from EMG data collected at the diaphragm had a lower variance between samples per tidal volume compared to those monitored at the EIM. Using cubic spline interpolation, we built a model for computing tidal volume from EMG data at the diaphragm. Our findings show that the new sensor can be used to measure respiration rate and variations thereof and holds potential to estimate tidal lung volume from EMG measurements obtained from the diaphragm.

Physiology of Human Hemorrhage and Compensation

Hemorrhage is a leading cause of death following traumatic injuries in the United States. Much of the previous work in assessing the physiology and pathophysiology underlying blood loss has focused on descriptive measures of hemodynamic responses such as blood pressure, cardiac output, stroke volume, heart rate, and vascular resistance as indicators of changes in organ perfusion. More recent work has shifted the focus toward understanding mechanisms of compensation for reduced systemic delivery and cellular utilization of oxygen as a more comprehensive approach to understanding the complex physiologic changes that occur following and during blood loss. In this article, we begin with applying dimensional analysis for comparison of animal models, and progress to descriptions of various physiological consequences of hemorrhage. We then introduce the complementary side of compensation by detailing the complexity and integration of various compensatory mechanisms that are activated from the initiation of hemorrhage and serve to maintain adequate vital organ perfusion and hemodynamic stability in the scenario of reduced systemic delivery of oxygen until the onset of hemodynamic decompensation. New data are introduced that challenge legacy concepts related to mechanisms that underlie baroreflex functions and provide novel insights into the measurement of the integrated response of compensation to central hypovolemia known as the compensatory reserve. The impact of demographic and environmental factors on tolerance to hemorrhage is also reviewed. Finally, we describe how understanding the physiology of compensation can be translated to applications for early assessment of the clinical status and accurate triage of hypovolemic and hypotensive patients. © 2021 American Physiological Society. Compr Physiol 11:1531-1574, 2021.

Physiological Responses and User Feedback on a Gameful Breathing Training App: Within-Subject Experiment

BACKGROUND

Slow-paced breathing training (6 breaths per minute [BPM]) improves physiological and psychological well-being by inducing relaxation characterized by increased heart rate variability (HRV). However, classic breathing training has a limited target group, and retention rates are very low. Although a gameful approach may help overcome these challenges, it is crucial to enable breathing training in a scalable context (eg, smartphone only) and ensure that they remain effective. However, despite the health benefits, no validated mobile gameful breathing training featuring a biofeedback component based on breathing seems to exist.

OBJECTIVE

This study aims to describe the design choices and their implementation in a concrete mobile gameful breathing training app. Furthermore, it aims to deliver an initial validation of the efficacy of the resulting app.

METHODS

Previous work was used to derive informed design choices, which, in turn, were applied to build the gameful breathing training app Breeze. In a pretest (n=3), design weaknesses in Breeze were identified, and Breeze was adjusted accordingly. The app was then evaluated in a pilot study (n=16). To ascertain that the effectiveness was maintained, recordings of breathing rates and HRV-derived measures (eg, root mean square of the successive differences [RMSSDs]) were collected. We compared 3 stages: baseline, standard breathing training deployed on a smartphone, and Breeze.

RESULTS

Overall, 5 design choices were made: use of cool colors, natural settings, tightly incorporated game elements, game mechanics reflecting physiological measures, and a light narrative and progression model. Breeze was effective, as it resulted in a slow-paced breathing rate of 6 BPM, which, in turn, resulted in significantly increased HRV measures compared with baseline (P<.001 for RMSSD). In general, the app was perceived positively by the participants. However, some criticized the somewhat weaker clarity of the breathing instructions when compared with a standard breathing training app.

CONCLUSIONS

The implemented breathing training app Breeze maintained its efficacy despite the use of game elements. Moreover, the app was positively perceived by participants although there was room for improvement.

Development of a modular stress management platform (Performance Edge VR) and a pilot efficacy trial of a bio-feedback enhanced training module for controlled breathing

This paper describes the conceptual design of a virtual reality-based stress management training tool and evaluation of the initial prototype in a pilot efficacy study. Performance Edge virtual-reality (VR) was co-developed with the Australian Defence Force (ADF) to address the need for practical stress management training for ADF personnel. The VR application is biofeedback-enabled and contains key stress management techniques derived from acceptance and commitment and cognitive behavioural therapy in a modular framework. End-user-provided feedback on usability, design, and user experience was positive, and particularly complimentary of the respiratory biofeedback functionality. Training of controlled breathing delivered across 3 sessions increased participants' self-reported use of breath control in everyday life and progressively improved controlled breathing skills (objectively assessed as a reduction in breathing rate and variability). Thus the data show that a biofeedback-enabled controlled breathing protocol delivered through Performance Edge VR can produce both behaviour change and objective improvement in breathing metrics. These results confirm the validity of Performance Edge VR platform, and its Controlled Breathing module, as a novel approach to tailoring VR-based applications to train stress management skills in a workplace setting.

Breathing Re-Education and Phenotypes of Sleep Apnea: A Review

Four phenotypes of obstructive sleep apnea hypopnea syndrome (OSAHS) have been identified. Only one of these is anatomical. As such, anatomically based treatments for OSAHS may not fully resolve the condition. Equally, compliance and uptake of gold-standard treatments is inadequate. This has led to interest in novel therapies that provide the basis for personalized treatment protocols. This review examines each of the four phenotypes of OSAHS and explores how these could be targeted using breathing re-education from three dimensions of functional breathing: biochemical, biomechanical and resonant frequency. Breathing re-education and myofunctional therapy may be helpful for patients across all four phenotypes of OSAHS. More research is urgently needed to investigate the therapeutic benefits of restoring nasal breathing and functional breathing patterns across all three dimensions in order to provide a treatment approach that is tailored to the individual patient.

Coupling between Blood Pressure and Subarachnoid Space Width Oscillations during Slow Breathing

The precise mechanisms connecting the cardiovascular system and the cerebrospinal fluid (CSF) are not well understood in detail. This paper investigates the couplings between the cardiac and respiratory components, as extracted from blood pressure (BP) signals and oscillations of the subarachnoid space width (SAS), collected during slow ventilation and ventilation against inspiration resistance. The experiment was performed on a group of 20 healthy volunteers (12 females and 8 males; BMI =22.1±3.2 kg/m2; age 25.3±7.9 years). We analysed the recorded signals with a wavelet transform. For the first time, a method based on dynamical Bayesian inference was used to detect the effective phase connectivity and the underlying coupling functions between the SAS and BP signals. There are several new findings. Slow breathing with or without resistance increases the strength of the coupling between the respiratory and cardiac components of both measured signals. We also observed increases in the strength of the coupling between the respiratory component of the BP and the cardiac component of the SAS and vice versa. Slow breathing synchronises the SAS oscillations, between the brain hemispheres. It also diminishes the similarity of the coupling between all analysed pairs of oscillators, while inspiratory resistance partially reverses this phenomenon. BP–SAS and SAS–BP interactions may reflect changes in the overall biomechanical characteristics of the brain.

Low-Hysteresis and Ultrasensitive Microcellular Structures for Wearable Electronic Applications

Wearable technologies offer the opportunity to record human physiological signals in real time, in a noninvasive way, and the data can be used to aid in the early detection of abnormal health conditions. Here, we demonstrate how the interconnected porosity can be used to increase the sensitivity and linearity of capacitive pressure sensors. The finite element analysis supports the experimental observation that the movement of air during the dynamic mechanical loading is responsible for the high sensitivity observed (0.18 ± 0.01 kPa^-1) when compared with the solid poly(glycerol sebacate) sensor (0.0042 ± 0.0002 kPa^-1). The porous sensors present strain insensitivity and remarkable linearity over the entire range of applied mechanical pressure (0-6 kPa), capable of detecting both static and dynamic mechanical stimuli (17 nm/s), and a response time of 50 ms, without evidence of fatigue or electrical hysteresis over 10,000 mechanical cycles. The outstanding features of the porous sensors can find a broad range of applications in real-time health monitoring, from demanding movements like walking/running, to small deformations resulting from breathing or heart beating. The ultrasensitive microcellular structures synthesized in this study can be applied to other types of sensing transductions to obtain tunable and function-specific sensors with high sensitivity.

Exploring in vitro to in vivo extrapolation for exposure and health impacts of e-cigarette flavor mixtures

In vitro to in vivo extrapolation (IVIVE) leverages in vitro biological activities to predict corresponding in vivo exposures, therefore potentially reducing the need for animal safety testing that are traditionally performed to support the hazard and risk assessment. Interpretation of IVIVE predictions are affected by various factors including the model type, exposure route and kinetic assumptions for the test article, and choice of in vitro assay(s) that are relevant to clinical outcomes. Exposure scenarios are further complicated for mixtures where the in vitro activity may stem from one or more components in the mixture. In this study, we used electronic cigarette (EC) aerosols, a complex mixture, to explore impacts of these factors on the use of IVIVE in hazard identification, using open-source pharmacokinetic models of varying complexity and publicly available data. Results suggest in vitro assay selection has a greater impact on exposure estimates than modeling approaches. Using cytotoxicity assays, high exposure estimates (>1000 EC cartridges (pods) or > 700 mL EC liquid per day) would be needed to obtain the in vivo plasma levels that are corresponding to in vitro assay data, suggesting acute toxicity would be unlikely in typical usage scenarios. When mechanistic (Tox21) assays were used, the exposure estimates were much lower for the low end, but the range of exposure estimate became wider across modeling approaches. These proof-of-concept results highlight challenges and complexities in IVIVE for mixtures.

Risk Assessment of Infection by Airborne Droplets and Aerosols at Different Levels of Cardiovascular Activity

Since end of 2019 the COVID-19 pandemic, caused by the SARS-CoV-2 virus, is threatening humanity. Despite the fact that various scientists across the globe try to shed a light on this new respiratory disease, it is not yet fully understood. Unlike many studies on the geographical spread of the pandemic, including the study of external transmission routes, this work focuses on droplet and aerosol transport and their deposition inside the human airways. For this purpose, a digital replica of the human airways is used and particle transport under various levels of cardiovascular activity in enclosed spaces is studied by means of computational fluid dynamics. The influence of the room size, where the activity takes place, and the aerosol concentration is studied. The contribution aims to assess the risk of various levels of exercising while inhaling infectious pathogens to gain further insights in the deposition behavior of aerosols in the human airways. The size distribution of the expiratory droplets or aerosols plays a crucial role for the disease onset and progression. As the size of the expiratory droplets and aerosols differs for various exhaling scenarios, reported experimental particle size distributions are taken into account when setting up the environmental conditions. To model the aerosol deposition we employ OpenFOAM  by using an Euler-Lagrangian frame including Reynolds-Averaged Navier-Stokes resolved turbulent flow. Within this study, the effects of different exercise levels and thus breathing rates as well as particle size distributions and room sizes are investigated to enable new insights into the local particle deposition in the human airway and virus loads. A general observation can be made that exercising at higher levels of activity is increasing the risk to develop a severe cause of the COVID-19 disease due to the increased aerosolized volume that reaches into the lower airways, thus the knowledge of the inhaled particle dynamics in the human airways at various exercising levels provides valuable information for infection control strategies.

Suspended fine particulate matter (PM2.5), microplastics (MPs), and polycyclic aromatic hydrocarbons (PAHs) in air: Their possible relationships and health implications

Exposure to fine particulate matter (PM_2.5) and their associated microcontaminants have been linked to increased harmful effects on the human health. In this study, the possible relationships between PM_2.5, microplastics (MPs), and polycyclic aromatic hydrocarbons (PAHs) were analyzed in an urban area of Bushehr port, in the northern part of the Persian Gulf. Presence, sources, and health risks of MPs and PAHs in both normal and dusty days were also investigated. The median of PM_2.5 and ƩPAHs were 52.8 μg/m³ and 14.1 ng/m³, respectively, indicating high pollution levels especially in dusty days. The mean level of MPs in urban suspended PM_2.5 was 5.2 items/m³. Fragments were the most abundant shape of identified MPs and polyethylene terephthalate (PET) was the most plastic types in urban dust of Bushehr port. The results revealed that PM_2.5 and MPs may possibly act as a carrier for airborne MPs and PAHs, respectively. In addition, the significant positive relationships between MPs, wind speed and wind direction, confirmed that the MPs transportation were highly controlled by atmospheric condition. Moreover, the source identification methods and trajectory analyses indicated that petrogenic sources from both proximal and distal origins play an important role in the level of PAHs. The results of chronic health risk evaluation via inhalation revealed that PM_2.5-bound PAHs had high potential cancer risk in winter, while, the estimated risks for non-carcinogenic PAHs were not considerable. In the case of MPs, the assessment of human intake of MPs via inhalation highlighted the possible risks for habitants.

The effect of education on nursing personnel's knowledge and attitudes regarding the use of integrative care techniques with hospice and palliative care patients

PURPOSE

To examine the effect of education on nursing personnel's knowledge and attitudes regarding the use of hand massage, breathing techniques, and essential oils with hospice and palliative care patients.

BACKGROUND

Unrelieved, end of life pain is common among hospitalized patients on hospice and palliative care units. Integrative care techniques such as hand massage, breathing techniques, and essential oils can be available to use with these individuals. Nursing personnel are often unaware of other techniques that are not a traditional pharmacology approach to pain.

METHODS

A quasi-experiment was conducted to evaluate the effect of an educational intervention on nursing personnel's knowledge and attitudes regarding the use of three integrative care techniques (hand massage, breathing techniques, and essential oils) with hospice and palliative care patients in an acute care setting. Data on knowledge and attitudes were collected pre- and postintervention.

RESULTS

Following the intervention, improvements in nursing personnel's attitudes and knowledge toward the use of the three techniques were found.

CONCLUSION

Results of this study suggest that education of nursing personnel may positively influence knowledge and attitudes toward providing hand massage, breathing techniques, and essential oil for end of life patients.

MOF based flexible, low-cost chemiresistive device as a respiration sensor for sleep apnea diagnosis

The monitoring of respiratory disorders requires breath sensors that are fast, robust, and convenient to use and can function under real time conditions. A MOF based flexible sensor is reported for the first time for breath sensing applications. The properties of a highly porous HKUST-1 MOF and a conducting MoS2 material have been combined to fabricate an electronic sensor on a flexible paper support for studying sleep apnea problems. Extensive breath sensing experiments have been performed and interestingly the fabricated sensor is efficient in detecting various kinds of breaths such as deep, fast, slow and hydrated breath. The MOF breath sensor shows a fast response time of just ∼0.38 s and excellent stability with no decline in its performance even after a month. A plausible mechanism has been proposed and a smartphone based prototype has been prepared to demonstrate the real time applications of the hybrid device. This work demonstrates great potential for the application of MOFs in healthcare with a special focus on breath sensing and sleep apnea diagnosis.

Assessment of baroreceptor reflex sensitivity in young obese Saudi males at rest and in response to physiological challenges

Autonomic imbalance in overweight/obese persons could lead to an increased risk of cardiovascular complications including hypertension and arrhythmias. Baroreceptor reflex sensitivity is a sensitive indicator to detect an altered sympathovagal balance in overweight/obese individuals. This study investigated the effects of overweight/obesity on baroreceptor sensitivity in young Saudi males at rest and in response to physiological challenges.

SUBJECTS AND METHODS

In this cross-sectional study, spontaneous baroreceptor sensitivity at rest and in response to deep breathing, isometric hand grip exercise and moderate intensity isotonic exercise were recorded in 20 normal weight and 20 overweight/obese subjects. Finger arterial blood pressure signal, recorded through Finometer, was used to calculate baroreceptor sensitivity through cross-correlation method. The baroreceptor sensitivity data were log transformed before application of parametric tests.

RESULTS

The spontaneous baroreceptor sensitivity was similar in both groups at baseline, but exhibited a significant increase during deep breathing only in normal weight (p < .001). Immediately after the isotonic exercise the baroreceptor sensitivity was significantly lower than baseline in both normal weight and overweight/obese and remained significantly lower in overweight/obese individuals compared to normal weight (p < .05) throughout the recovery period. There was a significant rise in baroreceptor sensitivity after isometric exercise in overweight/obese group only (p = .001). Pearson's correlation showed a significant negative correlation of baroreceptor sensitivity with body mass index during deep breathing (r = -.472, p = .004) and in post-isotonic exercise recovery period (r = -.414, p = .013).

CONCLUSION

A significantly reduced baroreceptor sensitivity response to deep breathing, reduced baroreceptor sensitivity recovery after isotonic exercise, and an exaggerated shoot up after isometric exercise in overweight/obese suggests an altered sympathovagal balance. Baroreceptor sensitivity measurements in response to physiological challenges, deep breathing, and isotonic exercise, may be more sensitive investigations for detection of early attenuation of cardiac autonomic function. This would enable timely intervention thereby delaying complications and improving the quality of life.

Mechanoadaptive organization of stress fiber subtypes in epithelial cells under cyclic stretches and stretch release

Cyclic stretch applied to cells induces the reorganization of stress fibers. However, the correlation between the reorganization of stress fiber subtypes and strain-dependent responses of the cytoplasm and nucleus has remained unclear. Here, we investigated the dynamic involvement of stress fiber subtypes in the orientation and elongation of cyclically stretched epithelial cells. We applied uniaxial cyclic stretches at 5%, 10%, and 15% strains to cells followed by the release of the mechanical stretch. Dorsal, transverse arcs, and peripheral stress fibers were mainly involved in the cytoplasm responses whereas perinuclear cap fibers were associated with the reorientation and elongation of the nucleus. Dorsal stress fibers and transverse arcs rapidly responded within 15 min regardless of the strain magnitude to facilitate the subsequent changes in the orientation and elongation of the cytoplasm. The cyclic stretches induced the additional formation of perinuclear cap fibers and their increased number was almost maintained with a slight decline after 2-h-long stretch release. The slow formation and high stability of perinuclear cap fibers were linked to the slow reorientation kinetics and partial morphology recovery of nucleus in the presence or absence of cyclic stretches. The reorganization of stress fiber subtypes occurred in accordance with the reversible distribution of myosin II. These findings allowed us to propose a model for stretch-induced responses of the cytoplasm and nucleus in epithelial cells based on different mechanoadaptive properties of stress fiber subtypes.

Psychophysiological responses to various slow, deep breathing techniques

Deep breathing exercises are commonly used for several health conditions including pain and hypertension. Various techniques are available to practice deep breathing, whereas possible differential psychophysiological effects have not been investigated. We compared four deep breathing techniques and examined outcomes in blood pressure variability, respiratory sinus arrhythmia, baroreflex function, and emotional state. Healthy adult volunteers performed pursed-lips breathing, left and right unilateral nostril breathing, and deep breathing with an inspiratory threshold load (loaded breathing), all at a frequency of 0.1 Hz (i.e., controlled breathing) and for three minutes each. Results showed that blood pressure variability was higher during loaded breathing versus other conditions and higher during pursed-lips breathing versus left and right unilateral nostril breathing. Respiratory sinus arrhythmia was higher during loaded breathing versus other conditions and higher during pursed-lips breathing versus left unilateral nostril breathing. The effect of breathing condition on respiratory sinus arrhythmia was mediated by alterations in blood pressure variability. There was no difference between the breathing conditions in baroreflex sensitivity or effectiveness. Participants rated pursed-lips breathing as more calming and pleasant and with more sense of control (vs. other conditions). Overall, among the four tested deep breathing techniques, loaded breathing was associated with enhanced cardiovascular effects and pursed-lips breathing with better emotional responses, while also enhancing cardiovascular effects (albeit less than loaded breathing). These findings can be informative in applying deep breathing techniques as self-management interventions for health conditions, in which baroreceptors stimulation and autonomic and emotional modulations can be beneficial, such as pain and hypertension.

Effects of Diaphragmatic Breathing on Health: A Narrative Review

Background: Breathing is an essential part of life. Diaphragmatic breathing (DB) is slow and deep breathing that affects the brain and the cardiovascular, respiratory, and gastrointestinal systems through the modulation of autonomic nervous functions. However, the effects of DB on human health need to be further investigated. Methods: The author conducted a PubMed search regarding the current evidence of the effect of DB on health. Results: This review consists of a total of 10 systematic reviews and 15 randomized controlled trials (RCTs). DB appears to be effective for improving the exercise capacity and respiratory function in patients with chronic obstructive pulmonary disease (COPD). Although the effect of DB on the quality of life (QoL) of patients with asthma needs to be investigated, it may also help in reducing stress; treating eating disorders, chronic functional constipation, hypertension, migraine, and anxiety; and improving the QoL of patients with cancer and gastroesophageal reflux disease (GERD) and the cardiorespiratory fitness of patients with heart failure. Conclusions: Based on this narrative review, the exact usefulness of DB in clinical practice is unclear due to the poor quality of studies. However, it may be a feasible and practical treatment method for various disorders.

A Practical Guide to Resonance Frequency Assessment for Heart Rate Variability Biofeedback

Heart rate variability (HRV) represents fluctuations in the time intervals between successive heartbeats, which are termed interbeat intervals. HRV is an emergent property of complex cardiac-brain interactions and non-linear autonomic nervous system (ANS) processes. A healthy heart is not a metronome because it exhibits complex non-linear oscillations characterized by mathematical chaos. HRV biofeedback displays both heart rate and frequently, respiration, to individuals who can then adjust their physiology to improve affective, cognitive, and cardiovascular functioning. The central premise of the HRV biofeedback resonance frequency model is that the adult cardiorespiratory system has a fixed resonance frequency. Stimulation at rates near the resonance frequency produces large-amplitude blood pressure oscillations that can increase baroreflex sensitivity over time. The authors explain the rationale for the resonance frequency model and provide detailed instructions on how to monitor and assess the resonance frequency. They caution that patterns of physiological change must be compared across several breathing rates to evaluate candidate resonance frequencies. They describe how to fine-tune the resonance frequency following an initial assessment. Furthermore, the authors critically assess the minimum epochs required to measure key HRV indices, resonance frequency test-retest reliability, and whether rhythmic skeletal muscle tension can replace slow paced breathing in resonance frequency assessment.

Temporal orders and causal vector for physiological data analysis

In addition to the global parameter- and time-series-based approaches, physiological analyses should constitute a local temporal one, particularly when analyzing data within protocol segments. Hence, we introduce the R package implementing the estimation of temporal orders with a causal vector (CV). It may use linear modeling or time series distance. The algorithm was tested on cardiorespiratory data comprising tidal volume and tachogram curves, obtained from elite athletes (supine and standing, in static conditions) and a control group (different rates and depths of breathing, while supine). We checked the relation between CV and body position or breathing style. The rate of breathing had a greater impact on the CV than does the depth. The tachogram curve preceded the tidal volume relatively more when breathing was slower.

Traube-Hering waves are formed by interaction of respiratory sinus arrhythmia and pulse pressure modulation in healthy men

Excessive blood pressure variation is linked to the development of hypertension and other diseases. This study assesses the relative role of respiratory sinus arrhythmia (RSA) and pulse pressure (PP) on the amplitude and timing of blood pressure variability with respiration [Traube-Hering (TH) waves]. We analyzed respiratory, electrocardiogram, and blood pressure traces from healthy, supine male subjects (n = 10, mean age = 26.7 ± 1.4) during 20-min epochs of resting, slow deep breathing (SDB), and recovery. Across all epochs, blood pressure and heart rate (HR) were modulated with respiration and the magnitude of RSA; TH waves increased during SDB. The data were deconstructed using a simple mathematical model of blood pressure to dissect the relative roles of RSA and PP on TH waves. We constructed the time series of the R-wave peaks and compared the recorded TH waves with that predicted by the model. Given that cardiac output is determined by both heart rate and stroke volume, it was surprising that the magnitude of the TH waves could be captured by only HR modulation. However, RSA alone did not accurately predict the timing of TH waves relative to the respiratory cycle. Adding respiratory modulation of PP to the model corrected the phase shift showing the expected pattern of BP rising during inspiration with the peak of the TH wave during early expiration. We conclude that short-term variability of blood pressure referred to as TH waves has at least two independent mechanisms whose interaction forms their pattern: RSA and respiratory-driven changes in PP.NEW & NOTEWORTHY Variability in blood pressure has become an important metric to consider as more is learned about the link between excessive blood pressure variability and adverse health outcomes. In this study using slow deep breathing in human subjects, we found that heart rate and pulse pressure variations have comparable effects on the amplitude of blood pressure waves, and it is the common action of the two that defines the phase relationship between respiration and blood pressure oscillations.

The Effects of Fast and Slow Yoga Breathing on Cerebral and Central Hemodynamics

BACKGROUND

Yoga breathing has shown to impose significant cardiovascular and psychological health benefits.

OBJECTIVE

The mechanism (s) responsible for these health benefits remain unclear. The aim of the present study was to assess the differences in cerebral and central hemodynamic responses following fast breathing (FB) and slow breathing (SB) protocols compared to breathing awareness (BA) as a control.

METHODS

Twenty healthy participants (10 males and 10 females) volunteered to take part in the study. Participants were between ages 18-55 years (group mean: 24 ± 5 years), with a height of 168.7 ± 9.8 cm and a weight of 70.16 ± 10.9 kg. A familiarization trial including FB and SB protocols were performed by each participant at least 24 h before the testing day. The breathing protocols were designed to achieve 6 breath/min for SB and ~ 120 breaths/min for FB.

RESULTS

FB resulted in an increase in both right prefrontal cortex (RPFC) and left prefrontal cortex (LPFC) hemoglobin difference (Hbdiff) (brain oxygenation) compared to BA (P < 0.05). FB resulted in an increased Hbdiff in LPFC compared to RPFC SB (P < 0.05). FB resulted in an increased Hbdiff in LPFC compared to SB (P < 0.05).

CONCLUSION

FB may be an effective yoga breathing technique for eliciting cerebral brain oxygenation indicated by increased Hbdiff. These results may be applicable to both healthy and clinical populations.

A Cross-Sectional Study on Central Sensitization and Autonomic Changes in Fibromyalgia

Fibromyalgia is a multi-symptomatic disorder characterized by generalized pain. The pathophysiology of fibromyalgia is supposedly an interplay between central nervous system hyper-responsiveness, autonomic dysfunction, and peripheral pain. In this cross-sectional study, the objective was to assess central sensitization and autonomic activity in patients with fibromyalgia compared with control. Fifty adults diagnosed with fibromyalgia by the modified American College of Rheumatology 2010 criteria and an equal number of age- and sex-matched controls participated in the study in an urban tertiary care hospital. Central sensitization was assessed by history and by evidence of increased prefrontal cortical activity as measured by cortical oxygenation using functional near-infrared spectroscopy. Autonomic activity was assessed by heart rate variability, electrodermal activity, and deep breathing test in three physiological states: rest, sympathetic stress (cold pressor test), and deep breathing. Mann–Whitney U-test, paired t-test, Wilcoxon test, and Friedman test with Bonferroni a priori were used to analyze the data. Cortical activity was significantly higher in the fibromyalgia group than control. There was no significant difference in autonomic activity between the fibromyalgia and control groups. In the fibromyalgia group, variable degrees of sympathetic hyperactivity and normal parasympathetic activity were observed. Central sensitization may be playing a primary role in the pathophysiology of generalized pain in fibromyalgia.

Sex differences in dynamic blood pressure regulation: beat-by-beat responses to muscle sympathetic nerve activity

It has been suggested that sex differences in acute blood pressure fluctuations occur during the periods of time between bursts of muscle sympathetic nerve activity. Therefore, we tested the hypothesis that men experience more dynamic changes in mean arterial pressure (Finometer MIDI) than women during acute sympathoinhibition (i.e., slow breathing) in which bursts of sympathetic activity occur more infrequently than at rest. We tested healthy women (n = 9) and men (n = 9) of similar age (22 ± 2 vs. 23 ± 3 yr, P = 0.6). Custom software was used to calculate beat-by-beat changes in blood pressure following sympathetic burst and nonburst sequences (recorded using microneurography) during 10 min of supine rest and a 15-min bout of slow breathing. During slow breathing following nonburst sequences, women demonstrated smaller overall reductions in mean arterial pressure compared with men over the subsequent 15 cardiac cycles (P < 0.01). In addition, following a burst of sympathetic activity, women experienced greater overall increases in mean arterial pressure compared with men over the following 15 cardiac cycles (P < 0.01). Despite these differences, the peak and nadir changes in arterial pressure following burst and nonburst sequences were not different between the sexes (P = 0.45 and P = 0.48, burst and nonburst sequences, respectively). As such, these data suggest that women respond to a burst of sympathetic activity with more sustained increases in blood pressure than men, coupled with improved maintenance of blood pressure during acute periods of sympathetic quiescence. In other words, these findings suggest that men rely more on frequent bursts of sympathetic activity to acutely regulate arterial pressure than women.NEW & NOTEWORTHY We demonstrate that during acute sympathoinhibition, women demonstrate more sustained increases in blood pressure following sympathetic bursts of activity than men. Likewise, during prolonged sympathetic quiescence, blood pressure is less labile in women than men. This suggests that lower overall blood pressure in young women may not be mediated by smaller beat-by-beat changes in blood pressure in response to sympathetic outflow but may instead be mediated by a lower frequency of sympathetic bursts.

Heart Rate Variability and Direct Current Measurement Characteristics in Professional Mixed Martial Arts Athletes

This study’s purpose was to examine heart rate variability (HRV) and direct current potential (DC) measures’ sensitivity and correlations between changes in the acute recovery and stress scale (ARSS) and the previous day’s training load. Training load, HRV, DC and ARSS data were collected from fourteen professional mixed martial arts athletes (32.6 ± 5.3 years, 174.8 ± 8.8 cm, 79.2 ± 17.5 kg) the following morning after hard, easy and rest days. Sensitivity was expressed as a signal-to-noise ratio (SNR, inter-day typical error (TE) or coefficient of variation (%CV) divided by intra-day TE or %CV). Correlations between HRV, DC and ARSS with training load were also examined. The SNRs for the various HRV and DC measures were acceptable to good (1.02–2.85). There was a 23.1% CV average increase between measures taken between different locations versus the same location. Training load changes were not correlated with HRV/DC but were correlated with ARSS stress variables. Practitioners should be aware of HRV/DC variability; however the daily training signal was greater than the test-retest error in this investigation. Upon awakening, HRV/DC measures appear superior for standardization and planning. HRV and DC measures were less sensitive to the previous day’s training load than ARSS measures.

Thingspeak-based respiratory rate streaming system for essential monitoring purposes

Introduction

Chronic obstructive pulmonary diseases are the most common disease worldwide. Asthma and sleep apnea are the most prevalent of pulmonary diseases. Patients with such chronic diseases require special care and continuous monitoring to avoid any respiratory deterioration. Therefore, the development of a dedicated and reliable sensor with the aid of modern technologies for measuring and monitoring respiratory parameters is very necessary nowadays.

Objective

This study aims to develop a small and cost-effective respiratory rate sensor.

Methods

A microcontroller and communication technology (NodeMCU) with the ThingSpeak platform is used in the proposed system to view and process the respiratory rate data every 60 s. The total current consumption of the proposed sensor is about 120 mA. Four able-bodied participants were recruited to test and validate the developed system.

Results

The results show that the developed sensor and the proposed system can be used to measure and monitor the respiratory rate.

Conclusions

The demonstrated system showed applicable, repeatable, and acceptable results.

A randomized trial of the immediate effect of Bee-Humming Breathing exercise on blood pressure and heart rate variability in patients with essential hypertension

OBJECTIVES

Bee-Humming Breathing (BHB) exercise is a simple yogic practice recommended for its favorable effect on cardiac physiology, including blood pressure (BP) and autonomic nervous system. However, strong evidence supporting its effectiveness is lacking. The present study was designed to evaluate the immediate effect of BHB exercise on blood pressure parameters and heart rate variability (HRV) in patients with essential hypertension.

STUDY METHODS

We conducted a randomized control trial including 70 patients with essential hypertension, randomly allocated to perform either BHB exercise (n=35) or placebo slow breathing exercise (n = 35) for 5-minutes duration. Blood pressure and HRV were measured before, during, and after the practice.

RESULTS

There was no significant decrease in systolic [effect size (95% CI): 2.22 (-13.20, 17.64); p 0.77], diastolic [4.54 (-17.40, 26.48); p 0.68] and mean blood pressures [1.37 (-8.78, 11.52); p 0.78] after BHB exercise in comparison to the control group in our study. The HRV analysis showed a significant increase in the HF power [6.8 (1.47, 12.12); p 0.01], and decrease in the LF power [-26.47 (-34.25, -18.68); p < 0.01] during the recovery phase of the 5-minute BHB exercise in comparison to the control group.

CONCLUSIONS

This is the first randomized controlled trial to show that though a single short session of BHB exercise in hypertensive patients does not significantly reduce BP, it significantly augments the parasympathetic tone as indicated by a significant improvement in HRV parameters.

CLINICAL TRIAL REGISTRATION NUMBER

CTRI/2018/08/015215.

Breathing Biofeedback Relaxation Intervention for Wheelchair Users in City Navigation

Manual wheelchair users experience numerous invisible barriers while navigating cities, often reporting how stressful journeys are. This stress affects a wheelchair user's quality of life. To alleviate such psychological burden, we propose a novel intervention strategy with a respiratory biofeedback interface which is designed to help users feel relaxed in urban navigation. We conducted a study in a real-world setting to explore its potential to provide real-time psychological support. From qualitative and quantitative analysis, we report on the strengths and weaknesses of the approach.

Physiological fractals: visual and statistical evidence across timescales and experimental states

A marker of engaging in compassion meditation and related processes is an increase in heart-rate variability (HRV), typically interpreted as a marker of parasympathetic nervous system response. While insightful, open questions remain. For example, which timescale is best to examine the effects of meditation and related practices on HRV? Furthermore, how might advanced time-series analyses--such as stationarity--be able to examine dynamic changes in the mean and variance of the HRV signal across time? Here we apply such methods to previously published data, which measured HRV pre- and post- a two-week compassionate mind training (CMT) intervention. Inspection of these data reveals that a visualization of HRV correlations across resting and compassion meditation states, pre- and post-two-week training, is retained across numerous recording timescales. Here, the fractal-like nature of our data indicates that the accuracy of representing HRV data can exist across timescales, albeit with greater or lesser granularity. Interestingly, inspection of the HRV signal at Time 2 compassion meditation versus Time 1 revealed a more highly correlated (i.e. potentially more stable) signal. We followed up these results with tests of stationarity, which revealed Time 2 had a less stochastic (variable) signal than Time 1, and a measure of distance in the time series, which showed that Time 2 had less of an average difference between rest and meditation than at Time 1. Our results provide novel assessment of visual and statistical markers of HRV change across distinct experimental states.

Heart rate as a predictor of cardiovascular risk

Heart rate is a parameter that is very easy to measure and is widely used both in clinic and during daily life activities. Its value gained more relevance with the evidence, in prospective studies and meta-analysis, of association between elevated heart rate values and diseases and outcomes.The increased knowledge of physiological mechanisms of heart rate control and the pathophysiological mechanisms responsible for its dysfunction allows to identify the cut-off value of normalcy providing info for non-pharmacological and pharmacological treatments to reduce the cardiovascular risk both in general population and in pathophysiological conditions. This paper overviews the knowledges of the role of resting heart rate as predictor of cardiovascular risk.

Immediate effect of Kapalbhathi pranayama on short term heart rate variability (HRV) in healthy volunteers

OBJECTIVES

Kapalbhathi Pranayam (Kapal = forehead; bhati = shining) is a breathing exercise that has been practiced to cleanse the frontal brain in traditional practices like yoga. Still, there exists a dearth of literature on the effect of Kapalbhathi pranayama on physiological systems. So this present study was carried out to find the immediate effect of "kapalbhathi Pranayam" practice for the period of 5 min on cardiac autonomic function among the healthy volunteers.

MATERIALS AND METHODS

Apparently 50 healthy volunteers includes both sex were participated. They were randomly divided into Pranayama (n-25) and control (n-25) group. Pranayama group was practiced kapalbhathi pranayama 5 min (5 cycles) and control group was allowed to do normal breathing (12-16 breath/min). Lead II ECG was recorded for 5 min using simple AD converter before, immediately after practice and 20 min of recovery period.

RESULTS

One way Analysis of variance (ANOVA) followed by post hoc test was done using R statistical software. There was a significant (p < 0.05) parasympathetic withdrawal (Root Mean Square of the Successive Differences (RMSSD) - p < 0.04 and HF n.u - p < 0.05) was found in the pranayama group immediately after practice and its was changed to parasympathetic domination (RMSSD - p < 0.04 and HF n.u - p < 0.05) after 20 min of recovery period.

CONCLUSION

The present study suggested that though there was parasympathetic withdrawal immediately after practicing kapalbhathi pranayama, 20 min after the recovery period showed a parasympathetic domination in the pranayama group subjects. However, further studies are required to warrant the findings of this study.

The Effects of Biofeedback Training and Smartphone-Delivered Biofeedback Training on Resilience, Occupational Stress, and Depressive Symptoms among Abused Psychiatric Nurses

Psychiatric ward (PW) nurses are at a higher risk to encounter workplace violence than are other healthcare providers, and many interventions have been developed to improve their mental health. We compared the effectiveness of biofeedback training (BT) and smartphone-delivered BT (SDBT) interventions on occupational stress, depressive symptoms, resilience, heart rate variability, and respiration rate in a sample of abused PW nurses. This was a quasi-experimental study. Structured questionnaires were administered before and six weeks after the intervention. Data were collected from April 2017 to October 2017. A total of 159 abused PW nurses were randomly assigned to BT, SDBT, and control groups, and 135 of them completed all processes of our protocol, with the study consisting of 119 females (88.1%) and 16 males (11.9%) and their age range being from 22 to 59 with the mean age of 35.61 and a standard deviation of 8.16. Compared to the controls, both the BT and the SDBT intervention groups experienced significant improvements in depressive symptoms, resilience, and respiration rate; and the SDBT group experienced significant reductions in occupational stress. Considering the cost, accessibility, restrictions time and space, SDBT be used as an effective intervention in people with resilience or occupational stress.

Bilateral and unilateral odor processing and odor perception

Imagine smelling a novel perfume with only one nostril and then smelling it again with the other nostril. Clearly, you can tell that it is the same perfume both times. This simple experiment demonstrates that odor information is shared across both hemispheres to enable perceptual unity. In many sensory systems, perceptual unity is believed to be mediated by inter-hemispheric connections between iso-functional cortical regions. However, in the olfactory system, the underlying neural mechanisms that enable this coordination are unclear because the two olfactory cortices are not topographically organized and do not seem to have homotypic inter-hemispheric mapping. This review presents recent advances in determining which aspects of odor information are processed unilaterally or bilaterally, and how odor information is shared across the two hemispheres. We argue that understanding the mechanisms of inter-hemispheric coordination can provide valuable insights that are hard to achieve when focusing on one hemisphere alone.

A pilot study: Wavelet cross-correlation of cardiovascular oscillations under controlled respiration in humans

The influence of deep controlled respiration on cardiovascular oscillations in 13 healthy young volunteers was studied. A measurement system comprising electrocardiography, laser Doppler flowmetry (LDF) and photoplethysmography (PPG) was used to estimate heart rate variability (HRV), tissue blood volume and skin blood perfusion at spontaneous respiration and during three tests at controlled conditions. In the latter case, respiration was controlled in both rate (0.04, 0.1 and 0.25 Hz) and depth. During respiration at 0.04 and 0.1 Hz, the amplification of a respiratory-related component in the spectra of HRV and PPG signals turned out to be more significant than that at spontaneous respiration, and at 0.25 Hz this component remained unchanged. Controlled respiration caused a significant increase in correlation in HRV-PPG, HRV-LDF and PPG-LDF pairs of signals compared to spontaneous one. At 0.25 Hz controlled respiration, no significant increase in correlation in these pairs of signals was found. The differences observed in this study can be attributed to the effects of the sympathetic nerve activity on vascular tone regulation.

Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling

Objective: We explored the physiological background of the non-linear operating mode of cardiorespiratory oscillators as the fundamental question of cardiorespiratory homeodynamics and as a prerequisite for the understanding of neurocardiovascular diseases. We investigated 20 healthy human subjects for changes using electrocardiac RR interval (RRI) and respiratory signal (Resp) Detrended Fluctuation Analysis (DFA, α1RRI, α2RRI, α1Resp, α2Resp), Multiple Scaling Entropy (MSERRI1-4, MSERRI5-10, MSEResp1-4, MSEResp5-10), spectral coherence (CohRRI-Resp), cross DFA (ρ1 and ρ2) and cross MSE (XMSE1-4 and XMSE5-10) indices in four physiological conditions: supine with spontaneous breathing, standing with spontaneous breathing, supine with 0.1 Hz breathing and standing with 0.1 Hz breathing. Main results: Standing is primarily characterized by the change of RRI parameters, insensitivity to change with respiratory parameters, decrease of CohRRI-Resp and insensitivity to change of in ρ1, ρ2, XMSE1-4, and XMSE5-10. Slow breathing in supine position was characterized by the change of the linear and non-linear parameters of both signals, reflecting the dominant vagal RRI modulation and the impact of slow 0.1 Hz breathing on Resp parameters. CohRRI-Resp did not change with respect to supine position, while ρ1 increased. Slow breathing in standing reflected the qualitatively specific state of autonomic regulation with striking impact on both cardiac and respiratory parameters, with specific patterns of cardiorespiratory coupling. Significance: Our results show that cardiac and respiratory short term and long term complexity parameters have different, state dependent patterns. Sympathovagal non-linear interactions are dependent on the pattern of their activation, having different scaling properties when individually activated with respect to the state of their joint activation. All investigated states induced a change of α1 vs. α2 relationship, which can be accurately expressed by the proposed measure-inter-fractal angle θ. Short scale (α1 vs. MSE1-4) and long scale (α2 vs. MSE5-10) complexity measures had reciprocal interrelation in standing with 0.1 Hz breathing, with specific cardiorespiratory coupling pattern (ρ1 vs. XMSE1-4). These results support the hypothesis of hierarchical organization of cardiorespiratory complexity mechanisms and their recruitment in ascendant manner with respect to the increase of behavioral challenge complexity. Specific and comprehensive cardiorespiratory regulation in standing with 0.1 Hz breathing suggests this state as the potentially most beneficial maneuver for cardiorespiratory conditioning.

Response of the autonomic activity to stress provocation in females with cervicogenic headache compared to asymptomatic controls: a cross-sectional study

BACKGROUND

Because abnormal activity of the autonomic nervous system is associated with chronification of pain, early detection of such dysfunction is important.

AIM

Although several studies highlight autonomic dysfunction in the chronification of headache, no study discussed its role in episodic cervicogenic headache.

DESIGN

Case-controlled cross-sectional single-blind comparative study between women with episodic cervicogenic headache and matched controls.

SETTING

Outpatient setting, Hasselt University.

POPULATION

Autonomic activity of 17 females with episodic cervicogenic headache (26.6±11.6 years) was compared with 17 age, gender and socio-economic matched asymptomatic controls (26.8±11.9 years).

METHODS

Autonomic activity was compared via repeated measures of the activity of the dermal sweat glands (µmho), peripheral circulation (%), electrical activity of the bilateral upper trapezius (μV) before, during and after cognitive stress provocation.

RESULTS

Whereas the autonomic parameters of the control group behaved as expected, participants in the headache group showed: 1) to stress provocation a significant lower dermal sweat gland activity (3.03±0.44 vs. 4.19±0.91 µmho, P<0.0001), higher vasodilatation (-5.56±1.45% vs. -5.61±1.85%, P=0.03), lower activity of the left upper trapezius (0.21±0.44 vs. 0.89±0.59 µV, P=0.03), significant less recuperation of the dermal sweat gland activity (-2.57±0.40 vs. -3.29±0.84 µmho, P<0.0001); 2) no recuperation of the activity (μV) of the left (P=0.83) and right (P=0.99) upper trapezius; 3) from stress provocation to recuperation a significant negative correlation (ρ=0.69, P=0.04) between dermal sweat gland and right upper trapezius activity.

CONCLUSIONS

Females with episodic cervicogenic headache reacted less to cognitive stress provocation. Recuperation after such provocation was absent. More research is needed to associate autonomous responses with a possible chronification process.

CLINICAL REHABILITATION IMPACT

A dysfunctional reaction to cognitive stress could be a threat to allostasis.

A comparison of methods used for inducing mental fatigue in performance research: individualised, dual-task and short duration cognitive tests are most effective

Despite research indicating the negative impact that mental fatigue has on physical and cognitive performance, whether this is a result of mental fatigue or a state of under-arousal remains unclear. The current research aimed to explore the effectiveness of the methods being used to induce mental fatigue. Twelve participants attended six sessions in which two cognitive tests, the AX-continuous performance test (AX-CPT) and the TloadDback test, were compared for their effectiveness in inducing mental fatigue. Both tests were set at a standard processing speed (1.2 ms) for two conditions, and a further condition involved the individualisation of the TloadDback test. Participants presented significantly higher physiological and psychological arousal (p < 0.05) in the individualised dual-task test compared to the AX-CPT. The individualised TloadDback test is a more effective method of inducing mental fatigue compared to the AX-CPT, as it sustains physiological arousal whilst inducing measurable reductions in mental resources. Practitioner summary: Mental fatigue negatively impacts physical and cognitive performance. It is unclear whether the current methods being used to induce mental fatigue are effective. This study compared different methods and confirmed that short, individualised and dual-task tests are most effective for inducing mental fatigue whilst maintaining arousal.

Randomized clinical trial of capnometry-assisted respiratory training in veterans with posttraumatic stress disorder hyperarousal

OBJECTIVE

To investigate whether capnometry-assisted antihyperventilation respiratory training, successful in treating panic, and sleep hygiene instructions would reduce posttraumatic stress disorder (PTSD) hyperarousal symptoms in U.S. military veterans.

METHOD

We conducted a parallel, nonblinded clinical trial and randomized 80 veterans with PTSD hyperarousal into treatment or wait list. Primary treatment outcomes from baseline to 1st follow-up were analyzed using mixed modeling. Baseline physiological measures were compared between the PTSD hyperarousal group and a no-PTSD group (n = 68).

RESULTS

Baseline respiration rate but not partial-pressure of end-tidal carbon dioxide (PCO₂) was higher in the PTSD hyperarousal group than in the no-PTSD group during 3 min of quiet sitting, indicating no difference in baseline hyperventilation. There was no significant effect of the intervention on PTSD hyperarousal symptoms or hyperventilation compared to wait list, but treatment did lower respiratory rate.

CONCLUSION

This intervention did not reduce PTSD hyperarousal symptoms, perhaps due to differences between underlying mechanisms of PTSD hyperarousal and panic disorder or to differences between veteran and civilian populations. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

E-Textiles for Healthy Ageing

The ageing population has grown quickly in the last half century with increased longevity and declining birth rate. This presents challenges to health services and the wider society. This review paper considers different aspects (e.g., physical, mental, and social well-being) of healthy ageing and how health devices can help people to monitor health conditions, treat diseases and promote social interactions. Existing technologies for addressing non-physical (e.g., Alzheimer's, loneliness) and physical (e.g., stroke, bedsores, and fall) related challenges are presented together with the drivers and constraints of using e-textiles for these applications. E-textiles provide a platform that enables unobtrusive and ubiquitous deployment of sensors and actuators for healthy ageing applications. However, constraints remain on battery, integration, data accuracy, manufacturing, durability, ethics/privacy issues, and regulations. These challenges can only effectively be met by interdisciplinary teams sharing expertise and methods, and involving end users and other key stakeholders at an early stage in the research.

A systematic review on the effects of group singing on persistent pain in people with long-term health conditions

Background and Objectives

Singing can have a range of health benefits; this paper reviews the evidence of the effects of group singing for chronic pain in people with long‐term health conditions.

Database and Data Treatment

We searched for published peer‐reviewed singing studies reporting pain measures (intensity, interference and depression) using major electronic databases (last search date 31 July 2018). After screening 123 full texts, 13 studies met the inclusion criteria: five randomized controlled trials (RCTs), seven non‐RCTs and one qualitative study. Included studies were appraised using Downs and Black and the Critical Appraisals Skills Programme quality assessments.

Results

Included studies reported differences in the type of singing intervention, long‐term condition and pain measures. Due to the high heterogeneity, we conducted a narrative review. Singing interventions were found to reduce pain intensity in most studies, but there was more equivocal support for reducing pain interference and depression. Additionally, qualitative data synthesis identified three key linked and complementary themes: physical, psychological and social benefits.

Conclusion

Group singing appears to have the potential to reduce pain intensity, pain interference and depression; however, we conclude that there is only partial support for singing on some pain outcomes based on the limited available evidence of varied quality. Given the positive findings of qualitative studies, this review recommends that practitioners are encouraged to continue this work. More studies of better quality are needed. Future studies should adopt more robust methodology and report their singing intervention in details. Group singing may be an effective and safe approach for reducing persistent pain and depression in people with long‐term health conditions.

Significance

This systematic review assesses research evidence for the effectiveness of group singing on chronic pain in people with long‐term health conditions. Narrative syntheses revealed that there is partial support for singing effects on some pain outcomes based on the limited available evidence of varied quality. Qualitative data provided additional support of physical, psychological and social benefits. The review highlights implications for practice and future studies.

Device-guided slow breathing reduces blood pressure and sympathetic activity in young normotensive individuals of both sexes

Slow breathing (SLOWB) is recommended for use as an adjuvant treatment for hypertension. However, the extent to which blood pressure (BP) responses to SLOWB differ between men and women are not well-established. Therefore, we tested the hypothesis that an acute bout of SLOWB would induce larger decreases in BP in males than in females, given that males typically have higher resting BP. We also examined autonomic contributors to reduced BP during SLOWB; that is, muscle sympathetic nerve activity and spontaneous cardiovagal (sequence method) and vascular sympathetic baroreflex sensitivity. We tested normotensive females ( n = 10, age: 22 ± 2 y, body mass index: 22 ± 2 kg/m2) and males ( n = 12, age: 23 ± 3 y, body mass index: 26 ± 4 kg/m2). Subjects were tested at baseline and during the last 5 min of a 15-min RESPeRATE-guided SLOWB session. Overall, SLOWB reduced systolic BP by 3.2 ± 0.8 mmHg (main effect, P < 0.01). Females had lower systolic BP (main effect, P = 0.02); we observed no interaction between sex and SLOWB. SLOWB also reduced muscle sympathetic nerve activity burst incidence by −5.0 ± 1.4 bursts/100 heartbeats (main effect, P < 0.01). Although females tended to have lower burst incidence (main effect, P = 0.1), there was no interaction between sex and SLOWB. Cardiovagal baroreflex sensitivity improved during SLOWB (21.0 vs. 36.0 ms/mmHg, P = 0.03) with no effect of sex. Despite lower overall BP in females, our data support a lack of basement effect on SLOWB-induced reductions in BP, as SLOWB was equally effective in reducing BP in males and females. Our findings support the efficacy of the RESPeRATE device for reducing BP in both sexes, even in young, normotensive individuals.

NEW & NOTEWORTHY We provide support for the effectiveness of device-guided slow breathing for blood pressure reduction in young normotensive women and men. Despite having lower baseline blood pressure and sympathetic nerve activity, women experienced equivalent reductions in both measures in response to RESPeRATE-guided slow breathing as men. Thus, slow breathing appears to be effective in young healthy normotensive individuals of both sexes and may be an ideal preventative therapy against future hypertension.

Hypothesis: Pulmonary Afferent Activity Patterns During Slow, Deep Breathing Contribute to the Neural Induction of Physiological Relaxation

Control of respiration provides a powerful voluntary portal to entrain and modulate central autonomic networks. Slowing and deepening breathing as a relaxation technique has shown promise in a variety of cardiorespiratory and stress-related disorders, but few studies have investigated the physiological mechanisms conferring its benefits. Recent evidence suggests that breathing at a frequency near 0.1 Hz (6 breaths per minute) promotes behavioral relaxation and baroreflex resonance effects that maximize heart rate variability. Breathing around this frequency appears to elicit resonant and coherent features in neuro-mechanical interactions that optimize physiological function. Here we explore the neurophysiology of slow, deep breathing and propose that coincident features of respiratory and baroreceptor afferent activity cycling at 0.1 Hz entrain central autonomic networks. An important role is assigned to the preferential recruitment of slowly-adapting pulmonary afferents (SARs) during prolonged inhalations. These afferents project to discrete areas in the brainstem within the nucleus of the solitary tract (NTS) and initiate inhibitory actions on downstream targets. Conversely, deep exhalations terminate SAR activity and activate arterial baroreceptors via increases in blood pressure to stimulate, through NTS projections, parasympathetic outflow to the heart. Reciprocal SAR and baroreceptor afferent-evoked actions combine to enhance sympathetic activity during inhalation and parasympathetic activity during exhalation, respectively. This leads to pronounced heart rate variability in phase with the respiratory cycle (respiratory sinus arrhythmia) and improved ventilation-perfusion matching. NTS relay neurons project extensively to areas of the central autonomic network to encode important features of the breathing pattern that may modulate anxiety, arousal, and attention. In our model, pronounced respiratory rhythms during slow, deep breathing also support expression of slow cortical rhythms to induce a functional state of alert relaxation, and, via nasal respiration-based actions on olfactory signaling, recruit hippocampal pathways to boost memory consolidation. Collectively, we assert that the neurophysiological processes recruited during slow, deep breathing enhance the cognitive and behavioral therapeutic outcomes obtained through various mind-body practices. Future studies are required to better understand the physio-behavioral processes involved, including in animal models that control for confounding factors such as expectancy biases.

Impact of slow breathing on the blood pressure and subarachnoid space width oscillations in humans

The aim of the study was to assess cardiac and respiratory blood pressure (BP) and subarachnoid space (SAS) width oscillations during the resting state for slow and fast breathing and breathing against inspiratory resistance. Experiments were performed on a group of 20 healthy volunteers (8 males and 12 females; age 25.3 ± 7.9 years; BMI = 22.1 ± 3.2 kg/m2). BP and heart rate (HR) were measured using continuous finger-pulse photoplethysmography. SAS signals were recorded using an SAS monitor. Oxyhaemoglobin saturation (SaO2) and end-tidal CO2 (EtCO2) were measured using a medical monitoring system. Procedure 1 consisted of breathing spontaneously and at controlled rates of 6 breaths/minute and 6 breaths/minute with inspiratory resistance for 10 minutes. Procedure 2 consisted of breathing spontaneously and at controlled rates of 6, 12 and 18 breaths/minute for 5 minutes. Wavelet analysis with the Morlet mother wavelet was applied for delineation of BP and SAS signals cardiac and respiratory components. Slow breathing diminishes amplitude of cardiac BP and SAS oscillations. The overall increase in BP and SAS oscillations during slow breathing is driven by the respiratory component. Drop in cardiac component of BP amplitude evoked by slow-breathing may be perceived as a cardiovascular protective mechanism to avoid target organ damage. Further studies are warranted to assess long-term effects of slow breathing.

Implementing laughter therapy to enhance the well-being of patients and nurses

Most people enjoy laughing and having fun, and this can enable individuals to socialise and bond. However, there is a difference between spontaneous laughter and laughter therapy, which consists of physical exercise, relaxation techniques and simulated vigorous laughter. This article aims to enhance nurses' knowledge and understanding of laughter therapy, which is a practice within complementary and alternative medicine. It discusses the evolution of laughter therapy, and describes its components and how it is practised. This article also identifies the physical and psychosocial benefits of laughter therapy, and how patients and nurses can engage with this activity to enhance their well-being.