The physiological effects of slow breathing in the healthy human

JD. RespiCo: A novel, flexible, and stand-alone electronic respiratory coaching device

Conscious respiratory pattern and rate control is desired by patients with some forms of pulmonary disease that are undergoing respiratory muscle conditioning and rehabilitation, by practitioners of meditation hoping to improve mindfulness and wellbeing, by athletes striving to obtain breathing control in order to increase competitiveness, and by engineers and scientists that wish to use the data from breathing subjects to test hypotheses and develop physiological monitoring systems. Although prerecorded audio sources and computer applications are available that guide breathing exercises, they often suffer from being inflexible and allow only limited customization of the breathing cues. Here we describe a small, lightweight, battery-powered, microprocessor-based respiratory coaching device (RespiCo), which through wireless or wired connections, can be easily customized to precisely guide subjects to breathe at desired respiratory rates using specific breathing patterns through visual, auditory, or haptic cues. Digital signals can also be captured from the device to document the breathing cues provided by the device for research purposes. It is anticipated that this device will have important utility for those who wish to be guided to breathe in a precise manner or in research and development of physiologic monitoring systems.

Women's Respiratory Movements during Spontaneous Breathing and Physical Fitness: A Cross-Sectional, Correlational Study

BACKGROUND

Abdominal/diaphragmatic breathing exercises are popular worldwide and have been proven to be beneficial for physical performance. Is abdominal motion (AM) during spontaneous breathing correlated with physical fitness? The present study aimed to answer this question.

METHODS

434 women (aged 20-59) were enrolled and participated in respiration tests using two respiration belts (one was tied at the height of the xiphoid and another at the navel) to detect AM and thoracic motion (TM). They also performed physical fitness tests to measure body size, muscular strength, muscular power, muscular endurance, balance, flexibility, reaction time, and cardiorespiratory endurance.

RESULTS

All the correlation coefficients between respiratory movements (AM, TM, AM + TM, AM/(AM + TM)) and physical fitness outcomes were less than 0.4/-0.4. Only AM and muscular power (countermovement jump height) had a weak correlation, with a correlation coefficient close to 0.4 in the 20-29-year age group (r_s = 0.398, p = 0.011, n = 40).

CONCLUSIONS

Women's respiratory movements during spontaneous breathing were not correlated with physical fitness. Future studies may focus on the relationship between AM and countermovement jump height in young women with a larger sample size and using ultrasound to directly test the excursion of the diaphragm.

Inhaled CO2 Concentration While Wearing Face Masks: A Pilot Study Using Capnography

Background

Face masks are recommended based on the assumption that they protect against SARS-CoV-2 transmission, however studies on their potential side effects are still lacking. We aimed to evaluate the inhaled air carbon dioxide (CO2) concentration, when wearing masks.

Methods

We measured end-tidal CO2 using professional side-stream capnography, with water-removing tubing, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator (for 5 minutes each while seated after 10 minutes of rest), in 146 healthy volunteers aged 10 to 90 years, from the general population of Ferrara, Italy. The inhaled air CO2 concentration was computed as: ([mask volume × end-tidal CO2] + [tidal volume - mask volume] × ambient air CO2)/tidal volume.

Results

With surgical masks, the mean CO2 concentration was 7091 ± 2491 ppm in children, 4835 ± 869 in adults, and 4379 ± 978 in the elderly. With FFP2 respirators, this concentration was 13 665 ± 3655 in children, 8502 ± 1859 in adults, and 9027 ± 1882 in the elderly. The proportion showing a CO2 concentration higher than the 5000 ppm (8-hour average) acceptable threshold for workers was 41.1% with surgical masks, and 99.3% with FFP2 respirators. Adjusting for age, gender, BMI, and smoking, the inhaled air CO2 concentration significantly increased with increasing respiratory rate (mean 10 837 ±3712 ppm among participants ⩾18 breaths/minute, with FFP2 respirators), and among the minors.

Conclusion

If these results are confirmed, the current guidelines on mask-wearing should be reevaluated.

Freedive Training Gives Additional Physiological Effect Compared to Pulmonary Rehabilitation in COPD

INTRODUCTION

Pulmonary rehabilitation (PR) is beneficial for lung mechanics, chest kinematics, metabolism, and inspiratory and peripheral muscle function. Freediving training (FD) can be effective in sportsmen and can improve breath-holding time.

AIMS

We sought to determine the effectiveness of freediving training in the pulmonary rehabilitation of COPD patients.

PATIENTS AND METHODS

Twenty-three COPD patients (15 men and 8 women; median age 63 years; FEV1: 41% pred; BMI: 28 kg/m²) participated in the FD + PR group (3 weeks PR and 3 weeks FD + PR) and 46 patients with COPD (25 men and 21 women; median age 66 years; FEV1: 43% pred; BMI: 27 kg/m²) participated in an inpatient PR program (6 weeks). Patients performed comfort zone breath holding for 30 min/day. Patients increased their breath-holding time within their comfort zone for 30 min. We detected lung function, chest expansion (CWE), inspiratory muscle pressure (MIP), peripheral muscle function (GS), and exercise capacity (6MWD), and we included breath-holding time (BHT), quality of life score (COPD Assessment Test (CAT)), modified Medical Research Dyspnea Scale (mMRC) score, and the severity of the disease assessed by the BODE index (FEV1, BMI, 6MWD, and mMRC) and an alternative scale (FEV1, BMI, 6MWD, and CAT).

RESULT

There were significant differences in the characteristics of the two groups. Significant improvement was detected in all functional and quality of life parameters except lung function in both groups. Significantly higher improvement was detected in CWE, GS, 6MWD, BHT, CAT, mMRC, alternative scale, and MIP. The improvement in forced vital capacity (FVC) was not significant. There were no side effects of FD training.

CONCLUSION

The FD method can potentiate the effect of PR, improving not only BHT but also other parameters.

TRIAL REGISTRATION

ISRCTN ISRCTN13019180. Registered 19 December 2017.

Investigating the Dose-Response Relationship between Deep Breathing and Heart Rate Variability in Healthy Participants and Across-Days Reliability in Patients with Rheumatoid Arthritis and Systemic Lupus Erythematosus

Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE) are associated with autonomic dysfunction, potentially through reduced vagus nerve tone. Vagus nerve stimulation has been proposed as an anti-inflammatory treatment, and it can be performed through deep breathing (DB) exercises. In this study, the dose-response relationship between DB exercises and heart rate variability (HRV) was investigated in healthy participants and reliability across days in patients with RA and SLE. On three separate days, 41 healthy participants performed DB for: 5, 15, or 30 min. On two separate days, 52 RA or SLE patients performed DB with the dose associated with the highest HRV increase in healthy participants. The HRV was estimated from ECG-recordings recorded prior and post the DB exercises. Increases in dose led to larger HRV-responses. Thirty minutes led to the largest HRV-response. In the RA and SLE patients, this dose increased the HRV-parameters consistently across the two days, indicating reliability. DB increases HRV in healthy participants and RA or SLE patients, which indicates stimulation of the vagus nerve. Of the tested durations, 30 min of DB was the optimal period of stimulation. A potential anti-inflammatory effect of DB exercises should be investigated in future studies.

Thoracic surgery may alter body static balance via diaphragm dysfunction

Many diseases and conditions can alter an ability to maintain body balance. The aim of the present study was to investigate whether thoracic surgery may elicit diaphragm dysfunction thereby impairing postural stability. 40 patients qualified to video-assisted thoracoscopy (VATS) lobectomy or lobectomy via thoracotomy due to pulmonary carcinoma were examined two times: a day before lung resection and 3–5 days after surgical procedure. Diaphragm assessment was performed using ultrasonography, while postural sways were evaluated by Zebris FDM-S stabilometric platform. Thoracic surgery was associated with decrease of diaphragm thickness and movement, as well as, with deterioration of static body balance maintenance. Upper lobe resection was linked with greater diaphragm excursion restriction and worse body sway parameters than middle and lower lobe resection. VATS lobectomy was associated with better postoperative diaphragm function and better postural sway parameters than lobectomy via thoracotomy. Patients after lobectomy via thoracotomy had significantly more load on lower limb on the operated side than patients after VATS lobectomy. Impairment of diaphragm function is closely associated with equilibrium impairment after pulmonary resection. VATS lobectomy was less invasive than lobectomy via thoracotomy in terms of primary respiratory muscle function and body balance maintenance parameters.

The effects of slow breathing on postural muscles during standing perturbations in young adults

Maintaining standing balance is vital to completing activities in daily living. Recent findings suggest an interaction between cardiovascular and postural control systems. Volitional slow breathing can modulate the cardiovascular response and affect postural control during quiet standing. However, the effects of slow breathing during threats to standing balance have not been studied. The study examined the effect of slow breathing on the latency and amplitude of postural muscle responses to perturbations of the base of support in healthy, young adults. Twenty-seven participants completed two balance perturbation tasks in standing on an instrumented split-belt treadmill while breathing spontaneously and breathing at 6 breaths per minute. Each perturbation task consisted of 25 posteriorly directed translations of the treadmill belts every 8-12 s. Muscle latency and muscle burst amplitude were measured using surface electromyography from the right limb for the quadriceps (QUADS), medial hamstring (MH), gastrocnemii (GASTROC), soleus (SOL), and tibialis anterior (TA) muscle groups, while a respiratory belt was used to record respiratory rate. Results indicated that during the slow breathing task both muscle latency (p = 0.022) and muscle burst amplitude (p = 0.011) decreased compared to spontaneous breathing. The EMG pre-perturbation activation was not significantly different in any muscle group between conditions (p > 0.167). The study found that reducing respiratory rate to approximately 6 breaths per minute affects the neuromuscular responses in the lower limb muscles to perturbations.

Quo Vadis, Dottore? Religious, Philosophical and Medical Perspectives on the Quest for Immortality

In the daily practice of medicine, health care providers oftentimes confront the dilemma of offering 'maximum care' based on available technologies and advances versus ethical concerns about futility. Regardless of cultural backgrounds and differences, most human beings aspire to an illness-free life, or better yet, a life lived with utmost quality and longevity. On account on ongoing advances in science and technology, the possibility of achieving "immortality" (a term used as a metaphor for an extremely long and disease-free life) is increasingly perceived as a realistic goal, which is aggressively pursued by some of the world's wealthiest individuals and corporations. However, this quest is not taking place in a philosophical or religious vacuum, which is why we attempt to evaluate the current state of knowledge on religious beliefs revolving around immortality and their alignments with today's medical advancements. The literature searches were performed using relevant databases including JSTOR and PubMed, as well as primary religious sources. Most religions present longevity as a blessing and believe in some sort of immortality, afterlife or reincarnation for the immortal soul. The quest for immortality beyond life in a "body of death" remains consistent with access to medical care and the legitimate possibility of achieving longevity-as long as certain ethical and religious parameters are preserved.

Ferroelectricity-Coupled 2D-MXene-Based Hierarchically Designed High-Performance Stretchable Triboelectric Nanogenerator

Triboelectric nanogenerators based on the state-of-the-art functional materials and device engineering provide an exciting platform for future multifunctional electronics, but it remains challenging to realize due to the lack of in-depth understanding on the functional properties of nanomaterials that are compatible with microstructural engineering. In this study, a high-performance stretchable (∼60% strain) triboelectric nanogenerator is demonstrated via an interlocked microstructural device configuration sandwiched between silver-nanowire-(Ag-NW) electrodes and hierarchically engineered spongy thermoplastic polyurethane (TPU) polymer composite with ferroelectric barium-titanate-coupled (BTO-coupled) 2D MXene (Ti₃C₂T_x) nanosheets. The use of MXene results in an increase in the dielectric constant whereas the dielectric loss is lowered via coupling with the ferroelectricity of BTO, which increases the overall output performance of the nanogenerator. The spongy nature of the composite film increases the capacitance variation under deformation, which results in improved energy-conversion efficiency (∼79%) and pressure sensitivity (4.6 VkPa^-1 and 2.5 mAkPa^-1) of the device. With the quantum-mechanically calculated electronic structure, the device converts biomechanical energy to electrical energy and generates an open-circuit output voltage of 260 V, short-circuit output current of 160 mA/m², and excellent power output of 6.65 W/m², which is sufficient to operate several consumer electronics. Owing to its superior pressure sensitivity and efficiency, the device enables a broad range of applications including real-time clinical human vital-sign monitoring, acoustic sensing, and multidimensional gesture-sensing functionality of a robotic hand. Considering the ease of fabrication, excellent functionality of the hierarchical polymer nanocomposite, and outstanding energy-harvesting performance of nanogenerators, this work is expected to stimulate the development of next-generation self-powered technology.

Impact of yoga breathing and relaxation as an add-on therapy on quality of life, anxiety, depression and pulmonary function in young adults with bronchial asthma: A randomized controlled trial

BACKGROUND

The impact of combinations of yogic practices on bronchial asthma have been studied. Such yoga modules tend to be too lengthy for comfortable practice long-term, giving high dropouts. Returning to conventional medicine despite improvement is common. This study tested a shorter, easier yoga routine to improve asthma condition.

MATERIAL AND METHODS

Sixty young adults aged 18-30 years diagnosed with bronchial asthma of mild to moderate severity were randomly assigned to the Yoga Group, add-on yoga therapy and continuing prescribed medication, or the Control Group, continuing prescribed medication only. Measurements on days 0 and 90, included Asthma Quality of Life Questionnaire, Hamilton Anxiety Rating Scale, Beck's Depression Inventory and Pulmonary Function Tests. The yoga therapy module, practised 30 mins daily, included four kinds of yoga breathing practices, and ended with guided relaxation.

RESULTS

All Asthma Quality of Life subdomains improved greatly for the Yoga Group as did Hamilton Anxiety and Becks Depression Inventory scores, t statistics were high (40 -75), all p<.0001. Pulmonary Function also improved greatly in all variables, with smaller t statistics from 2 to 14. The Control Group showed some small improvements. Differences observed in scores were highly significant, with large effect sizes. Finally, no dropouts occurred.

DISCUSSION

Zero dropouts represents an unprecedented result. The yoga module was completely acceptable to participants, Yoga Group improvements were highly significant. The study indicates that the new yoga module effectively improves quality of life, levels of anxiety, depression and pulmonary function in young adults with above-stated bronchial asthma.

Numerical modeling and development of a dual lung simulator using partitioned fluid-structure interaction approach for ventilator testing

New designs of mechanical ventilators require extensive testing before utilizing the ventilator on a patient. Test lungs are commonly used to understand the behavior of new designs of ventilators and the lung mechanics. The current study aims to develop a numerical model of dual test lungs utilizing the partitioned fluid-structure interaction (FSI) approach and test it against the available experimental data of volume-controlled ventilation. Two breathing rates of 12 and 18 bpm were studied at two different tidal volumes of 500 and 600 ml for spontaneous breathing. It is found that with an increase in the compliance (tidal volume/pressure rise) of the lung, the peak pressure rise inside the test lung decreases irrespective of the breathing rate. The maximum average pressure of 44.73, 27.45, and 14 cm H₂ O is observed for static lung compliances of 10, 21 , and 39 ml/cm H₂ O, respectively at a tidal volume of 600 ml. Similarly, the maximum von-misses stress was higher (498 kPa) for the lung with lower compliance (10 ml/cm H₂ O) as compared to the lung with higher compliance (39 ml/cm H₂ O) at the end of inspiration. This study forms a basis for using computational methods to model simple lung simulators that can effectively investigate the lung mechanics for both spontaneous and ventilated breathing. Thus, it can be utilized as a reference to test novel designs of mechanical ventilators.

Effects of voluntary slow breathing on heart rate and heart rate variability: A systematic review and a meta-analysis

Voluntary slow breathing (VSB) is used as a prevention technique to support physical and mental health, given it is suggested to influence the parasympathetic nervous system (PNS). However, to date, no comprehensive quantitative review exists to support or refute this claim. We address this through a systematic review and meta-analysis of the effects of VSB on heart rate variability (HRV). Specifically, we focus on HRV parameters indexing PNS activity regulating cardiac functioning, referred to as vagally-mediated (vm)HRV: (1) during the breathing session (i.e., DURING), (2) immediately after one training session (i.e., IM-AFTER1), as well as (3) after a multi-session intervention (i.e., AFTER-INT). From the 1842 selected abstracts, 223 studies were suitable for inclusion (172 DURING, 16 IM-AFTER1, and 49 AFTER-INT). Results indicate increases in vmHRV with VSB, DURING, IM-AFTER1, and AFTER-INT. Given the involvement of the PNS in a large range of health-related outcomes and conditions, VSB exercises could be advised as a low-tech and low-cost technique to use in prevention and adjunct treatment purposes, with few adverse effects expected.

Effects of sleep deprivation and 4-7-8 breathing control on heart rate variability, blood pressure, blood glucose, and endothelial function in healthy young adults

This study investigated the effects of sleep deprivation on heart rate variability (HRV), blood pressure (BP), fasting blood glucose (FBG), and endothelial function as well as the immediate effects of 4-7-8 breathing control on HRV and BP. In total, 43 healthy participants aged 19-25 years were classified into two groups: Twenty two in the with sleep deprivation group and 21 in the without sleep deprivation (control) group. Resting heart rate (HR), BP, HRV, FBG, and endothelial function were examined. Subsequently, participants practiced 4-7-8 breathing control for six cycles/set for three sets interspersed between each set by 1-min normal breathing. Thereafter, the HR, BP, and HRV were immediately examined. The HRV, HR, and BP variables and FBG were not significantly different between the two groups. However, endothelial function was significantly lower in the sleep deprivation group than that in the control group (p < 0.05). In response to 4-7-8 breathing control, low- and very-low-frequency powers significantly decreased (p < 0.05), whereas high-frequency power significantly increased (p < 0.05) in the control group. Moreover, time domain, total power, and very-low-frequency power significantly decreased (p < 0.05) in the sleep deprivation group. Both groups had significantly decreased HR and systolic BP (p < 0.05). HRV, HR, and BP variables showed no significant differences between the groups. Healthy young adults with and without sleep deprivation may have similar HRV, BP, and FBG values. However, sleep deprivation may cause decreased endothelial function. Furthermore, 4-7-8 breathing control can help participants improve their HRV and BP, particularly in those without sleep deprivation.

Immediate impact of yogic breathing on pulsatile cerebrospinal fluid dynamics

Cerebrospinal fluid (CSF), a clear fluid bathing the central nervous system (CNS), undergoes pulsatile movements. Together with interstitial fluid, CSF plays a critical role for the removal of waste products from the brain, and maintenance of the CNS health. As such, understanding the mechanisms driving CSF movement is of high scientific and clinical impact. Since pulsatile CSF dynamics is sensitive and synchronous to respiratory movements, we are interested in identifying potential integrative therapies such as yogic breathing to regulate CSF dynamics, which has not been reported before. Here, we investigated the pre-intervention baseline data from our ongoing randomized controlled trial, and examined the impact of four yogic breathing patterns: (i) slow, (ii) deep abdominal, (iii) deep diaphragmatic, and (iv) deep chest breathing with the last three together forming a yogic breathing called three-part breath. We utilized our previously established non-invasive real-time phase contrast magnetic resonance imaging approach using a 3T MRI instrument, computed and tested differences in single voxel CSF velocities (instantaneous, respiratory, cardiac 1st and 2nd harmonics) at the level of foramen magnum during spontaneous versus yogic breathing. In examinations of 18 healthy participants (eight females, ten males; mean age 34.9 ± 14 (SD) years; age range: 18-61 years), we observed immediate increase in cranially-directed velocities of instantaneous-CSF 16-28% and respiratory-CSF 60-118% during four breathing patterns compared to spontaneous breathing, with the greatest changes during deep abdominal breathing (28%, p = 0.0008, and 118%, p = 0.0001, respectively). Cardiac pulsation was the primary source of pulsatile CSF motion except during deep abdominal breathing, when there was a comparable contribution of respiratory and cardiac 1st harmonic power [0.59 ± 0.78], suggesting respiration can be the primary regulator of CSF depending on the individual differences in breathing techniques. Further work is needed to investigate the impact of sustained training yogic breathing on pulsatile CSF dynamics for CNS health.

The Effect of a Brief Mindfulness Practice on Perceived Stress and Sustained Attention: Does Priming Matter?

Objectives

The objective of the current study was to investigate the effect of a brief mindfulness practice on perceived stress and sustained attention, and to determine whether priming the benefits of mindfulness meditation enhances this effect.

Methods

Two hundred and twenty undergraduate students were randomly assigned to a control condition (CC), a meditation condition (MC), or a priming + meditation condition (PMC). Baseline and post-treatment measures included subjective stress ratings on a visual analog scale (VAS) and performance on a Sustained Attention to Response Task (SART), determined by reaction time coefficient of variability (RTCV) and three measures of accuracy: correct responses, errors of commission, and errors of omission.

Results

Repeated measures analyses revealed that both the MC and the PMC displayed a decline in perceived stress relative to the CC. Analyses further revelated that the MC and PMC displayed fewer errors of omission relative to the CC. However, only the PMC displayed better performance relative to the CC with respect to total correct response and errors of commission. There were no significant between-group differences for RTCV.

Conclusions

These findings are novel and provide a foundation to further investigate the effect of priming on mindfulness engagement and its potential benefits.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12671-022-01913-8.

Pulling the Trigger: The Effect of a 5-Minute Slow Diaphragmatic Breathing Intervention on Psychophysiological Stress Responses and Pressurized Pistol Shooting Performance

This study examined the effect of slow diaphragmatic breathing on psychophysiological stress responses and pressurized performance. Sixty-seven participants (40 female; Mage = 20.17 ± 2.77 years) were randomly assigned to either a diaphragmatic-breathing, paced-breathing, or control group. Participants completed a nonpressurized shooting task and then received instructions about a pressurized version. Next, the diaphragmatic group was told to breathe at 6 breaths/min, the paced group at 12 breaths/min, and the control group received no instructions. Following a 5-min intervention period, participants completed the pressurized task while performance was assessed. Psychophysiological stress responses (e.g., cognitive anxiety, heart rate) were recorded throughout. Results revealed that diaphragmatic breathing had mixed effects on stress responses, with some unaffected (e.g., heart rate) and others reduced (e.g., cognitive anxiety), and little effect on performance. Findings suggested that slow diaphragmatic breathing might not aid pressurized performance but could benefit psychological stress responses.

Exploring Meditation Profiles and Predictors in Nursing Students

Background: Nursing students face unique academic and clinical workloads linked to increased stress. Previous studies indicate formal and informal mindfulness meditation provide stress-reducing benefits. This practice aligns with holistic nursing core values of self-care and self-reflection; little is known about meditation practice in nursing students. Objectives: Our study aimed to describe meditation practice and predictors in pre-licensure nursing students. Design: Cross-sectional, multi-site. Methods: Qualtrics surveys queried individual demographics, personal meditation and exercise habits, and indicators of wellbeing. Results: Of 417 participants, 65% (n  =  271) reported at least one type of meditation practice. Prayer/spiritual activities were most prevalent (almost 70%), followed by breathing exercises (41%). Meditators reported good or excellent self-rated health status or engaged in exercise (p < .05). Meditators also reported more self-compassion, happiness, and satisfaction with life, and perceived less stress than non-meditators (p < .05). Of all factors studied, only engaging in exercise significantly predicted practicing meditation (OR = 2.05, 95%CI 1.10-3.82). Conclusion: Nursing students who engage in meditation report signs of health and well-being and utilize holistic methods such as prayer and breathing. The intrinsic motivation to engage in healthy habits such as exercise may also help students engage in mindfulness meditation and is an important finding for nursing educators.

Reducing Test Anxiety by Device-Guided Breathing: A Pilot Study

Test anxiety remains a challenge for students and has considerable physiological and psychological impacts. The routine practice of slow, Device-Guided Breathing (DGB) is a major component of behavioral treatments for anxiety conditions. This paper addresses the effectiveness of using DGB as a self-treatment clinical tool for test anxiety reduction. This pilot study sample included 21 healthy men and women, all college students, between the ages of 20 and 30. Participants were randomly assigned to two groups: DGB practice (n = 10) and wait-list control (n = 11). At the beginning and the end of 3-weeks DGB training, participants underwent a stress test, followed by measures of blood pressure and reported anxiety. Anxiety reduction in the DGB group as compared to controls was not statistically significant, but showed a large effect size. Accordingly, the clinical outcomes suggested that daily practice of DGB may lead to reduced anxiety. We assume that such reduction may lead to improved test performance. Our results suggest an alternative treatment for test anxiety that may also be relevant for general anxiety, which is likely to increase due to the ongoing COVID-19 pandemic.

Breathing Exercises for Improving Cognitive Function in Patients with Stroke

Patients with stroke may experience a certain degree of cognitive decline during the period of recovery, and a considerable number of such patients have been reported to show permanent cognitive damage. Therefore, the period of recovery and rehabilitation following stroke is critical for rapid cognitive functional improvements. As dysfunctional breathing has been reported as one of the factors affecting the quality of life post stroke, a number of studies have focused on the need for improving the breathing function in these patients. Numerous breathing exercises have been reported to enhance the respiratory, pulmonary, cognitive, and psychological functions. However, scientific evidence on the underlying mechanisms by which these exercises improve cognitive function is scattered at best. Therefore, it has been difficult to establish a protocol of breathing exercises for patients with stroke. In this review, we summarize the psychological, vascular, sleep-related, and biochemical factors influencing cognition in patients and highlight the need for breathing exercises based on existing studies. Breathing exercises are expected to contribute to improvements in cognitive function in stroke based on a diverse array of supporting evidence. With relevant follow-up studies, a protocol of breathing exercises can be developed for improving the cognitive function in patients with stroke.

Content, Structure and Delivery Characteristics of Yoga Interventions for Managing Rheumatoid Arthritis: A Systematic Review Protocol

The global burden of rheumatoid arthritis among adults is rising. Yoga might be a potential solution for managing rheumatoid arthritis. This systematic review aims to synthesise the content, structure and delivery characteristics of effective yoga interventions for managing rheumatoid arthritis. The JBI methodology for systematic reviews of effectiveness and the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines will be followed. PRISMA for systematic review protocols (PRISMA-P) was used to write the protocol. Randomised controlled trials assessing the effectiveness of yoga interventions for managing rheumatoid arthritis in adults will be included in this review. We aim to search the following databases to find published and unpublished studies: ABIM, AMED, AYUSH Research Portal, CAM-QUEST, CINAHL, CENTRAL, EMBASE, MEDLINE, PeDro, PsycInfo, SPORTDiscus, TRIP, Web of Science, DART-Europe-e-theses portal, EthOS, OpenGrey and ProQuest Dissertations and Theses. No date or language restrictions will be applied. A narrative synthesis will be conducted. Meta-regression will be conducted to explore the statistical evidence for which components (content, structure and delivery characteristics) of yoga interventions are effective.

Breathing as Input Modality in a Gameful Breathing Training App: Development and Evaluation of Breeze 2 (Preprint)

Background

Slow-paced breathing training can have positive effects on physiological and psychological well-being. Unfortunately, use statistics indicate that adherence to breathing training apps is low. Recent work suggests that gameful breathing training may help overcome this challenge.

Objective

This study aimed to introduce and evaluate the gameful breathing training app Breeze 2 and its novel real-time breathing detection algorithm that enables the interactive components of the app.

Methods

We developed the breathing detection algorithm by using deep transfer learning to detect inhalation, exhalation, and nonbreathing sounds (including silence). An additional heuristic prolongs detected exhalations to stabilize the algorithm’s predictions. We evaluated Breeze 2 with 30 participants (women: n=14, 47%; age: mean 29.77, SD 7.33 years). Participants performed breathing training with Breeze 2 in 2 sessions with and without headphones. They answered questions regarding user engagement (User Engagement Scale Short Form [UES-SF]), perceived effectiveness (PE), perceived relaxation effectiveness, and perceived breathing detection accuracy. We used Wilcoxon signed-rank tests to compare the UES-SF, PE, and perceived relaxation effectiveness scores with neutral scores. Furthermore, we correlated perceived breathing detection accuracy with actual multi-class balanced accuracy to determine whether participants could perceive the actual breathing detection performance. We also conducted a repeated-measure ANOVA to investigate breathing detection differences in balanced accuracy with and without the heuristic and when classifying data captured from headphones and smartphone microphones. The analysis controlled for potential between-subject effects of the participants’ sex.

Results

Our results show scores that were significantly higher than neutral scores for the UES-SF (W=459; P<.001), PE (W=465; P<.001), and perceived relaxation effectiveness (W=358; P<.001). Perceived breathing detection accuracy correlated significantly with the actual multi-class balanced accuracy (r=0.51; P<.001). Furthermore, we found that the heuristic significantly improved the breathing detection balanced accuracy (F_1,25=6.23; P=.02) and that detection performed better on data captured from smartphone microphones than than on data from headphones (F_1,25=17.61; P<.001). We did not observe any significant between-subject effects of sex. Breathing detection without the heuristic reached a multi-class balanced accuracy of 74% on the collected audio recordings.

Conclusions

Most participants (28/30, 93%) perceived Breeze 2 as engaging and effective. Furthermore, breathing detection worked well for most participants, as indicated by the perceived detection accuracy and actual detection accuracy. In future work, we aim to use the collected breathing sounds to improve breathing detection with regard to its stability and performance. We also plan to use Breeze 2 as an intervention tool in various studies targeting the prevention and management of noncommunicable diseases.

[Recommendations for outpatient respiratory rehabilitation of long COVID patients]

The appearance of COVID-19 has been a problem for public health on a global scale, putting pressure on health care systems. The after-effects of this illness have highlighted the importance of rehabilitation in long COVID patients involv-ing different health professionals. The treatment of the respiratory after-effects of this disease in an outpatient setting is a specialized field. It is appropriate to offer a series of practical recommendations of cardio-respiratory rehabilitation that are helpful to the professionals involved in the after-effects when ending hospitalisation. This review of the literature includes ten key aspects of respiratory physiotherapy that range from assessment, parameters to monitor, signs of alarm and respiratory rehabilitation techniques and other exercises for this population.

Differences in stress system (re-)activity between single and dual- or multitasking in healthy adults: A systematic review and meta-analysis

AbstractIn the age of digitization, multitasking requirements are ubiquitous, especially in the workplace. Multitasking (MT) describes the activity of performing multiple (at least two) tasks at the same time. Dual tasking (DT) refers to the sequential switching between two tasks. The aim of our systematic review and meta-analysis was first to investigate whether physiological stress systems become activated in response to or during MT/DT and, secondly, whether this (re-)activity is higher compared to single tasking. We focused on the Sympathetic Nervous System (SNS), the Parasympathetic Nervous System (PNS), the hypothalamic-pituitary adrenal (HPA) axis, and the immune system. The systematic review has been pre-registered with PROSPERO (CRD42020181415). A total of twenty-five articles were identified as eligible, in which n = 26 studies were reported, with N = 1,142 participants. Our main findings are that SNS activity is significantly higher and PNS activity is significantly lower during MT/DT than during single tasking. Only two studies were found, in which HPA axis (re-)activity was surveyed. No eligible study was identified in which immune system (re-)activity was investigated. This is the first systematic synthesis of the literature base showing that stress system activity is increased during MT/DT in comparison to single-tasking.

Dimensionality-Dependent Mechanical Stretch Regulation of Cell Behavior

A variety of cells are subject to mechanical stretch in vivo, which plays a critical role in the function and homeostasis of cells, tissues, and organs. Deviations from the physiologically relevant mechanical stretch are often associated with organ dysfunction and various diseases. Although mechanical stretch is provided in some in vitro cell culture models, the effects of stretch dimensionality on cells are often overlooked and it remains unclear whether and how stretch dimensionality affects cell behavior. Here we develop cell culture platforms that provide 1-D uniaxial, 2-D circumferential, or 3-D radial mechanical stretches, which recapitulate the three major types of mechanical stretches that cells experience in vivo. We investigate the behavior of human microvascular endothelial cells and human alveolar epithelial cells cultured on these platforms, showing that the mechanical stretch influences cell morphology and cell-cell and cell-substrate interactions in a stretch dimensionality-dependent manner. Furthermore, the endothelial and epithelial cells are sensitive to the physiologically relevant 2-D and 3-D stretches, respectively, which could promote the formation of endothelium and epithelium. This study underscores the importance of recreating the physiologically relevant mechanical stretch in the development of in vitro tissue/organ models.

Does Wim Hof Method Improve Breathing Economy during Exercise?

(1) Background: Breathing economy during endurance sports plays a major role in performance. Poor breathing economy is mainly characterized by excessive breathing frequency (BF) and low tidal volume (VT) due to shallow breathing. The purpose of this study was to evaluate whether a 4 week intervention based on the Wim Hof breathing method (WHBM) would improve breathing economy during exercise in adolescent runners. (2) Methods: 19 adolescent (16.6 ± 1.53 years) middle- and long-distance runners (11 boys and 8 girls) participated in the study. Participants were randomly divided into experimental (n = 11) and control groups (n = 8). The study was set in the transition period between competitive race seasons and both groups had a similar training program in terms of running volume and intensity over the course of the study. The experimental group performed breathing exercises every day (~20 min/day) for 4 weeks. The control group did not perform any kind of breathing exercise. The breathing exercises consisted of three sets of controlled hyperventilation and consecutive maximum breath holds. Before and after the intervention, participants performed incremental cycle ergometer testing sessions consisting of two minute stages at 1, 2, 3, and 4 W·kg−1 with breath-by-breath metabolic analysis. During the testing sessions, BF, VT, and minute ventilation (VE) were assessed and compared. (3) Results: There were no statistically significant differences (p > 0.05) in BF, VT, or VE between experimental and control groups before or after the intervention. A nonsignificant small-to-large effect for an increase in VE and BF in both groups following the 4 week intervention period was observed, possibly due to a reduction in training volume and intensity owing to the down period between competitive seasons. (4) Conclusions: The 4 week intervention of WHBM did not appear to alter parameters of breathing economy during a maximal graded exercise test in adolescent runners.

Photoplethysmography-Based Respiratory Rate Estimation Algorithm for Health Monitoring Applications

Purpose

Respiratory rate can provide auxiliary information on the physiological changes within the human body, such as physical and emotional stress. In a clinical setup, the abnormal respiratory rate can be indicative of the deterioration of the patient's condition. Most of the existing algorithms for the estimation of respiratory rate using photoplethysmography (PPG) are sensitive to external noise and may require the selection of certain algorithm-specific parameters, through the trial-and-error method.

Methods

This paper proposes a new algorithm to estimate the respiratory rate using a photoplethysmography sensor signal for health monitoring. The algorithm is resistant to signal loss and can handle low-quality signals from the sensor. It combines selective windowing, preprocessing and signal conditioning, modified Welch filtering and postprocessing to achieve high accuracy and robustness to noise.

Results

The Mean Absolute Error and the Root Mean Square Error of the proposed algorithm, with the optimal signal window size, are determined to be 2.05 breaths count per minute and 2.47 breaths count per minute, respectively, when tested on a publicly available dataset. These results present a significant improvement in accuracy over previously reported methods. The proposed algorithm achieved comparable results to the existing algorithms in the literature on the BIDMC dataset (containing data of 53 subjects, each recorded for 8 min) for other signal window sizes.

Conclusion

The results endorse that integration of the proposed algorithm to a commercially available pulse oximetry device would expand its functionality from the measurement of oxygen saturation level and heart rate to the continuous measurement of the respiratory rate with good efficiency at home and in a clinical setting.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40846-022-00700-z.

Effects of arousal modulation via resonance breathing on craving and affect in women with substance use disorder

BACKGROUND

Craving for alcohol and other drugs is a complex in-the-moment experience that involves within-person changes in physiological arousal and affect. We evaluated the utility of a just-in-time, self-administered resonance breathing smartphone application (app) to reduce craving and improve affect in women during outpatient treatment for substance use disorders (SUD).

METHODS

Women (N = 57) receiving outpatient addiction treatment were randomized to practice either cardiovascular resonance breathing (0.1 Hz/6 breaths per minute) or a sham (∼0.23 Hz/14 breaths per minute) in the face of urges over an 8-week intervention. Craving (Penn Alcohol Craving Scale) and affect (Positive and Negative Affect Scale) were collected weekly throughout the intervention. App data were uploaded weekly to assess frequency of use. Generalized Estimated Equations modeled craving and affect as a function of group randomization and app use frequency across the 8-week intervention.

FINDINGS

Higher levels of craving were associated with more frequent app use. The group X app use interaction was significant for craving. Frequent app use during the intervention phase was associated with lower craving levels in the resonance breathing group relative to the sham group over the 8-week intervention. There was no effect of app use frequency on affect measures.

CONCLUSIONS

Women assigned to practice sham breathing who used the intervention frequently experienced elevations in craving that are commonly reported during outpatient SUD treatment. Women assigned to resonance breathing who used the intervention frequently did not experience such increases. Resonance breathing may be protective against triggers in outpatient treatment. Physiological mechanisms are discussed.

Breath Tools: A Synthesis of Evidence-Based Breathing Strategies to Enhance Human Running

Running is among the most popular sporting hobbies and often chosen specifically for intrinsic psychological benefits. However, up to 40% of runners may experience exercise-induced dyspnoea as a result of cascading physiological phenomena, possibly causing negative psychological states or barriers to participation. Breathing techniques such as slow, deep breathing have proven benefits at rest, but it is unclear if they can be used during exercise to address respiratory limitations or improve performance. While direct experimental evidence is limited, diverse findings from exercise physiology and sports science combined with anecdotal knowledge from Yoga, meditation, and breathwork suggest that many aspects of breathing could be improved via purposeful strategies. Hence, we sought to synthesize these disparate sources to create a new theoretical framework called “Breath Tools” proposing breathing strategies for use during running to improve tolerance, performance, and lower barriers to long-term enjoyment.

Interbeat interval-based sleep staging: work in progress toward real-time implementation

Objective. Cardiac activity changes during sleep enable real-time sleep staging. We developed a deep neural network (DNN) to detect sleep stages using interbeat intervals (IBIs) extracted from electrocardiogram signals.Approach. Data from healthy and apnea subjects were used for training and validation; 2 additional datasets (healthy and sleep disorders subjects) were used for testing. R-peak detection was used to determine IBIs before resampling at 2 Hz; the resulting signal was segmented into 150 s windows (30 s shift). DNN output approximated the probabilities of a window belonging to light, deep, REM, or wake stages. Cohen's Kappa, accuracy, and sensitivity/specificity per stage were determined, and Kappa was optimized using thresholds on probability ratios for each stage versus light sleep.Main results. Mean (SD) Kappa and accuracy for 4 sleep stages were 0.44 (0.09) and 0.65 (0.07), respectively, in healthy subjects. For 3 sleep stages (light+deep, REM, and wake), Kappa and accuracy were 0.52 (0.12) and 0.76 (0.07), respectively. Algorithm performance on data from subjects with REM behavior disorder or periodic limb movement disorder was significantly worse, with Kappa of 0.24 (0.09) and 0.36 (0.12), respectively. Average processing time by an ARM microprocessor for a 300-sample window was 19.2 ms.Significance. IBIs can be obtained from a variety of cardiac signals, including electrocardiogram, photoplethysmography, and ballistocardiography. The DNN algorithm presented is 3 orders of magnitude smaller compared with state-of-the-art algorithms and was developed to perform real-time, IBI-based sleep staging. With high specificity and moderate sensitivity for deep and REM sleep, small footprint, and causal processing, this algorithm may be used across different platforms to perform real-time sleep staging and direct intervention strategies.Novelty & Significance(92/100 words) This article describes the development and testing of a deep neural network-based algorithm to detect sleep stages using interbeat intervals, which can be obtained from a variety of cardiac signals including photoplethysmography, electrocardiogram, and ballistocardiography. Based on the interbeat intervals identified in electrocardiogram signals, the algorithm architecture included a group of convolution layers and a group of long short-term memory layers. With its small footprint, fast processing time, high specificity and good sensitivity for deep and REM sleep, this algorithm may provide a good option for real-time sleep staging to direct interventions.

Characterizing and Modeling Breathing Dynamics: Flow Rate, Rhythm, Period, and Frequency

The characterization of breathing dynamics provides researchers and clinicians the ability to differentiate respiratory compensation, impairment, disease progression, ventilator assistance, and the onset of respiratory failure. However, within many sub-fields of respiratory physiology, we still have challenges identifying changes within the breathing dynamics and critical respiratory states. We discuss one fundamental modeling of breathing and how modeling imprecise assumptions decades ago regarding breathing are still propagating into our quantitative analysis today, limiting our characterization and modeling of breathing. The assumption that breathing is a continuous sinusoidal wave that can consist of a single frequency which is composed of a stationary time-invariant process has limited our expanded discussion of breathing dynamics, modeling, functional testings, and metrics. Therefore, we address major misnomers regarding breathing dynamics, specifically rate, rhythm, frequency, and period. We demonstrate how these misnomers impact the characterization and modeling through the force equations that are linked to the Work of Breathing (WoB) and our interpretation of breathing dynamics through the fundamental models and create possible erroneous evaluations of work of breathing. This discussion and simplified non-periodic WoB models ultimately sets the foundation for improved quantitative approaches needed to further our understanding of breathing dynamics, compensation, and adaptation.

A calming hug: Design and validation of a tactile aid to ease anxiety

Anxiety disorders affect approximately one third of people during their lifetimes and are the ninth leading cause of global disability. Current treatments focus on therapy and pharmacological interventions. However, therapy is costly and pharmacological interventions often have undesirable side-effects. Healthy people also regularly suffer periods of anxiety. Therefore, a non-pharmacological, intuitive, home intervention would be complementary to other treatments and beneficial for non-clinical groups. Existing at-home anxiety aids, such as guided meditations, typically employ visual and/or audio stimuli to guide the user into a calmer state. However, the tactile sense has the potential to be a more natural modality to target in an anxiety-calming device. The tactile domain is relatively under-explored, but we suggest that there are manifold physiological and affective qualities of touch that lend it to the task. In this study we demonstrate that haptic technology can offer an enjoyable, effective and widely accessible alternative for easing state anxiety. We describe a novel huggable haptic interface that pneumatically simulates slow breathing. We discuss the development of this interface through a focus group evaluating five prototypes with embedded behaviours (‘breathing’, ‘purring’, ‘heartbeat’ and ‘illumination’). Ratings indicated that the ‘breathing’ prototype was most pleasant to interact with and participants described this prototype as ‘calming’ and ‘soothing’, reminding them of a person breathing. This prototype was developed into an ergonomic huggable cushion containing a pneumatic chamber powered by an external pump allowing the cushion to ‘breathe’. A mixed-design experiment (n = 129) inducing anxiety through a group mathematics test found that the device was effective at reducing pre-test anxiety compared to a control (no intervention) condition and that this reduction in anxiety was indistinguishable from that of a guided meditation. Our findings highlight the efficacy of this interface, demonstrating that haptic technologies can be effective at easing anxiety. We suggest that the field should be explored in more depth to capture the nuances of different modalities in relation to specific situations and trait characteristics.

Deep-Breathing Biofeedback Trainability in a Virtual-Reality Action Game: A Single-Case Design Study With Police Trainers

It is widely recognized that police performance may be hindered by psychophysiological state changes during acute stress. To address the need for awareness and control of these physiological changes, police academies in many countries have implemented Heart-Rate Variability (HRV) biofeedback training. Despite these trainings now being widely delivered in classroom setups, they typically lack the arousing action context needed for successful transfer to the operational field, where officers must apply learned skills, particularly when stress levels rise. The study presented here aimed to address this gap by training physiological control skills in an arousing decision-making context. We developed a Virtual-Reality (VR) breathing-based biofeedback training in which police officers perform deep and slow diaphragmatic breathing in an engaging game-like action context. This VR game consisted of a selective shoot/don’t shoot game designed to assess response inhibition, an impaired capacity in high arousal situations. Biofeedback was provided based on adherence to a slow breathing pace: the slower and deeper the breathing, the less constrained peripheral vision became, facilitating accurate responses to the in-game demands. A total of nine male police trainers completed 10 sessions over a 4-week period as part of a single-case experimental ABAB study-design (i.e., alternating sessions with and without biofeedback). Results showed that eight out of nine participants showed improved breathing control in action, with a positive effect on breathing-induced low frequency HRV, while also improving their in-game behavioral performance. Critically, the breathing-based skill learning transferred to subsequent sessions in which biofeedback was not presented. Importantly, all participants remained highly engaged throughout the training. Altogether, our study showed that our VR environment can be used to train breathing regulation in an arousing and active decision-making context.

Primary and secondary care approach to paediatric mental health conditions: a novel model of care

The enforced isolation caused by the COVID-19 pandemic has led to an increase in mental health issues and severity of presentations to emergency departments in Ireland. Long waiting lists for both Psychology and Psychiatry are further impacting on children's mental well-being. We proposed the creation of a 'Happiness Toolkit' that can be given to children on presentation to their primary or secondary care provider with a mental health issue. The toolkit is comprised of six evidence-based techniques that are proven to boost self-esteem, develop resilience and promote positive mental health. A leaflet detailing the practices along with a physical 'box' that the children must make were created. This resource may therefore provide immediate support to those children that may endure long waiting periods, sometimes greater than a year and a half, for referral to tertiary services. Our toolkit allows children and their families to engage in positive mental health practices that may prevent regression during this waiting period and lead to improved mental health or cessation of symptoms.

Beat-to-beat Estimation of Peripheral Arterial Stiffness from Local PWV for Quantitative Evaluation of Sympathetic Nervous System Activity

Sympathetic nervous system activity (SNSA) can rapidly modulate arterial stiffness, thus making it an important biomarker for SNSA evaluation. Pulse wave velocity (PWV) is a well-known quantitative indicator of arterial stiffness, but its functional responsivity to SNSA has not been elucidated. This paper reports a method to estimate rapid changes in peripheral arterial stiffness induced by SNSA using local PWV (LPWV) and to further quantify SNSA based on the estimated stiffness. LPWV was measured from the artery near the wrist to the artery near the forefinger using a biodegradable piezoelectric sensor and a photoplethysmography sensor in an electrocutaneous stimulus experiment in which pain indicts the SNSA. The relationship between LPWV, simultaneously measured peripheral arterial stiffness index, and self-reported pain intensity was quantified. The stiffness estimated by LPWV alone and the stiffness estimated by LPWV and arterial pressure both approximate the peripheral arterial stiffness index (R² = 0.9775 and 0.9719). Pain intensity can be quantitatively evaluated in a sigmoidal relationship by either the estimated stiffness based on LPWV alone (r = 0.8594) or the estimated stiffness based on LPWV and arterial pressure (r = 0.9738). Our results demonstrated the validity of LPWV in the quantitative evaluation of SNSA and the optionality of blood pressure correction depending on application scenarios. This study advances the understanding of sympathetic innervation of peripheral arteries through the sympathetic responsivity of LPWV and contributes a quantitative biomarker for SNSA evaluation.

Evaluation of Inhalation Exposures and Potential Health Impacts of Ingredient Mixtures Using in vitro to in vivo Extrapolation

In vitro methods offer opportunities to provide mechanistic insight into bioactivity as well as human-relevant toxicological assessments compared to animal testing. One of the challenges for this task is putting in vitro bioactivity data in an in vivo exposure context, for which in vitro to in vivo extrapolation (IVIVE) translates in vitro bioactivity to clinically relevant exposure metrics using reverse dosimetry. This study applies an IVIVE approach to the toxicity assessment of ingredients and their mixtures in e-cigarette (EC) aerosols as a case study. Reported in vitro cytotoxicity data of EC aerosols, as well as in vitro high-throughput screening (HTS) data for individual ingredients in EC liquids (e-liquids) are used. Open-source physiologically based pharmacokinetic (PBPK) models are used to calculate the plasma concentrations of individual ingredients, followed by reverse dosimetry to estimate the human equivalent administered doses (EADs) needed to obtain these plasma concentrations for the total e-liquids. Three approaches (single actor approach, additive effect approach, and outcome-oriented ingredient integration approach) are used to predict EADs of e-liquids considering differential contributions to the bioactivity from the ingredients (humectant carriers [propylene glycol and glycerol], flavors, benzoic acid, and nicotine). The results identified critical factors for the EAD estimation, including the ingredients of the mixture considered to be bioactive, in vitro assay selection, and the data integration approach for mixtures. Further, we introduced the outcome-oriented ingredient integration approach to consider e-liquid ingredients that may lead to a common toxicity outcome (e.g., cytotoxicity), facilitating a quantitative evaluation of in vitro toxicity data in support of human risk assessment.

Role of Breathing Exercises in Asthma-Yoga and Pranayama

Asthma is a chronic airway inflammatory disease that results from a complex interplay of genetic, environmental, and lifestyle factors. There is no cure for asthma, and the management is usually as per published guidelines. As in many chronic diseases conditions, various alternative or complimentary therapies have been tried. Of these, yoga and pranayama have gained wider attention in recent years. While the term yoga is a complex term encompassing eight limbs as per Patamjai in the yoga sutras, in simple terms, yoga is described as a combination of 'asana' (physical exercises) and 'pranayama' (breathing exercise). The term "asthma" has been derived from the Greek word "panting,", which indicates a rapid and shallow breathing. The main aim of yoga and pranayama in asthma is to synchronize and control breathing, thus decreasing hyperventilation. Besides this, they also decrease the stress/strain/anxiety, change in behavior, boost immunity, and improve strength/endurance of respiratory muscles that are helpful in any subject with asthma. There have been a good number of studies including clinical trials in children with asthma that have found some beneficial effects. In the present review, the physiology of yoga and pranayama, rationale for their use in children with asthma along with a summary of various studies conducted till date, have been discussed. These are followed by recommendations regarding their incorporation in the standard of care of children with asthma.

Room to breathe: Using adaptive architecture to examine the relationship between alexithymia and interoception

OBJECTIVE

Individuals with alexithymia experience difficulties interpreting emotional states in self and others, which has been associated with interoceptive impairment. Current theories are primarily based on subjective and conscious measures of interoceptive sensitivity, such as heartrate detection, but it is unclear whether similar observations would be found for objective or implicit psychophysiological measures. The present exploratory study assesses the potential of a novel assay through the use of adaptive immersive architecture [ExoBuilding].

METHODS

N = 88 participants were screened for alexithymic traits and N = 27 individuals, representing the range of scores, were sampled to participate in the behavioural task. In a repeated-measures design, participants were placed within ExoBuilding and asked to match their respiration to its movement. Performance was compared to a two-dimensional pacer condition. Behavioural (accuracy) and psychophysiological (Respiratory Sinus Arrhythmia [RSA] and heartrate) measures were compared across conditions, and also related to individual alexithymic traits.

RESULTS

Participants with higher levels of alexithymia performed less accurately than participants with lower levels, in both conditions. High-alexithymia participants showed a smaller reduction in heartrate over the course of the ExoBuilding condition than low-alexithymia participants, although there were no differences in RSA between conditions or participants.

CONCLUSION

Alexithymia extends beyond conscious interoceptive activities and is also observed in immersive contexts that usually exert psychophysiological effects on typical occupants. These initial findings highlight the importance of considering both conscious and implicit measures of interoception, and we suggest ways in which theories of alexithymia might benefit from capturing this distinction.

EEG signatures change during unilateral Yogi nasal breathing

Airflow through the left-and-right nostrils is said to be entrained by an endogenous nasal cycle paced by both poles of the hypothalamus. Yogic practices suggest, and scientific evidence demonstrates, that right-nostril breathing is involved with relatively higher sympathetic activity (arousal states), while left-nostril breathing is associated with a relatively more parasympathetic activity (stress alleviating state). The objective of this study was to further explore this laterality by controlling nasal airflow and observing patterns of cortical activity through encephalographic (EEG) recordings. Thirty subjects participated in this crossover study. The experimental session consisted of a resting phase (baseline), then a period of unilateral nostril breathing (UNB) using the dominant nasal airway, followed by UNB using the non-dominant nasal airway. A 64-channel EEG was recorded throughout the whole session. The effects of nostril-dominance, and nostril-lateralization were assessed using the power spectral density of the neural activity. The differences in power-spectra and source localization were calculated between EEG recorded during UNB and baseline for delta, theta, alpha, beta and gamma bands. Cluster-based permutation tests showed that compared to baseline, EEG spectral power was significantly (1) decreased in all frequency bands for non-dominant nostril UNB, (2) decreased in alpha, beta and gamma bands for dominant nostril UNB, (3) decreased in all bands for left nostril UNB, and (4) decreased in all bands except delta for right nostril UNB. The beta band showed the most widely distributed changes across the scalp. our source localisation results show that breathing with the dominant nostril breathing increases EEG power in the left inferior frontal (alpha band) and left parietal lobule (beta band), whereas non-dominant nostril breathing is related to more diffuse and bilateral effects in posterior areas of the brain.These preliminary findings may stimulate further research in the area, with potential applications to tailored treatment of brain disorders associated with disruption of sympathetic and parasympathetic activity.

Influence of Spontaneous and Mechanical Ventilation on Frequency-Based Measures of Heart Rate Variability

Frequency-based measures of heart rate variability have been shown to be a useful physiological marker in both clinical and research settings providing insight into the functioning of the autonomic nervous system. Ongoing interactions between the autonomic nervous system control of the heart and lung occurs during each ventilation cycle because of their anatomical position within the closed thoracic cavity. Mechanical ventilation and subsequent removal change the normal ventilator mechanics producing alterations in the tidal volume, intrathoracic pressure, and oxygen delivery. A noninvasive method called heart rate variability (HRV) can be used to evaluate this interaction during ventilation and can be quantified by applying frequency-based measures of the variability between heartbeats. Although HRV is a reliable method to measure alteration of the autonomic nervous system (ANS) function and cardiopulmonary interaction, there have been limited reports concerning the changes in the frequency-based measure of HRV during both spontaneous and mechanical ventilation. The purpose of this methodological study is therefore to describe the physiological influence of both spontaneous and mechanical ventilation on frequency-based measures of HRV.

Inhaled CO2 Concentration While Wearing Face Masks: A Pilot Study Using Capnography

BACKGROUND

Face masks are recommended based on the assumption that they protect against SARS-CoV-2 transmission, however studies on their potential side effects are still lacking. We aimed to evaluate the inhaled air carbon dioxide (CO₂) concentration, when wearing masks.

METHODS

We measured end-tidal CO₂ using professional side-stream capnography, with water-removing tubing, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator (for 5 minutes each while seated after 10 minutes of rest), in 146 healthy volunteers aged 10 to 90 years, from the general population of Ferrara, Italy. The inhaled air CO₂ concentration was computed as: ([mask volume × end-tidal CO₂] + [tidal volume - mask volume] × ambient air CO₂)/tidal volume.

RESULTS

With surgical masks, the mean CO₂ concentration was 7091 ± 2491 ppm in children, 4835 ± 869 in adults, and 4379 ± 978 in the elderly. With FFP2 respirators, this concentration was 13 665 ± 3655 in children, 8502 ± 1859 in adults, and 9027 ± 1882 in the elderly. The proportion showing a CO₂ concentration higher than the 5000 ppm (8-hour average) acceptable threshold for workers was 41.1% with surgical masks, and 99.3% with FFP2 respirators. Adjusting for age, gender, BMI, and smoking, the inhaled air CO₂ concentration significantly increased with increasing respiratory rate (mean 10 837 ±3712 ppm among participants ⩾18 breaths/minute, with FFP2 respirators), and among the minors.

CONCLUSION

If these results are confirmed, the current guidelines on mask-wearing should be reevaluated.

Immediate Effects of OM Chanting on Heart Rate Variability Measures Compared Between Experienced and Inexperienced Yoga Practitioners

Background

Chanting "OM" is a form of meditation that has numerous health benefits. However, the neurophysiological mechanisms underpinning its effect are surprisingly scarce. The present study aimed to investigate the effect of OM chanting on autonomic modulation, using heart rate variability (HRV), on experienced yoga practitioners and yoga naïve persons.

Methods

This prospective study included 19 yoga practitioners (9 females and 10 males; group mean age ± standard deviation [SD]; 25.9 ± 3.2 years) and 17 yoga naïve persons (8 females and 9 males; group mean age ± SD; 24.8 ± 3.6 years) of both sexes and similar age range. Both the groups were assessed for HRV indices (time and frequency domain measures) before and after loud OM chanting for 5 min.

Results

Baseline comparison using Mann-Whitney U test between groups showed yoga practitioners had significantly increased high frequency (HF) power (P < 0.029) than nonyoga practitioners, signifying a state of tranquility before the chanting of OM. After 5 min of loud chanting of OM, a comparison between groups assessed using Wilcoxon Signed Ranks test revealed: HF Power, a component of the parasympathetic nervous system, was further amplified with a significantly increase (P < 0.001) in the yoga practitioners group compared to nonyoga practitioners. Furthermore, this increase in HF power was positively correlated with the years of experience in yoga.

Conclusion

The present study showed that a brief chanting of OM (5 min) might enhance parasympathetic nervous system activity, promote relaxation, and provide calmness. Further, this experience may be achieved effectively in individuals experienced in yoga than nonyoga practitioners.

A virtual reality-based mind-body approach to downregulate psychophysiological arousal in adolescent insomnia

Objective

In this study, we describe the rationale, supported by preliminary data, for a novel, digital, immersive virtual reality (VR)-based mind-body approach, designed to reduce bedtime arousal in adolescents with insomnia.

Methods

Fifty-two high-school students (16-20 years; 32 female) with (N = 18) and without (N = 34) DSM-5 insomnia symptoms engaged with 20 min of immersive VR-guided meditation and paced breathing (0.1 Hz) (intervention condition) and 20 min of quiet activity (control condition), right before bedtime, on two separate evenings.

Results

The intervention resulted in acute autonomic and cortical modulation (p < 0.05), leading to reduced physiological arousal (↓heart rate, ↓cortisol) compared with the control condition, with similar effects in adolescents with and without insomnia. No significant changes were detected for cognitive arousal levels. During the intervention, all participants were able to achieve the targeted 0.1 Hz breathing rate, and the majority experienced no discomfort associated with the VR exposure. However, 30-40% of the participants experienced some trouble slowing down their breathing.

Conclusions

The study provides supporting preliminary evidence for the mechanism behind a novel VR-based digital approach, designed to regulate psychophysiological arousal levels by acting on neurocognitive and autonomic pathways. Further studies (e.g. randomized clinical trials) are needed to evaluate the isolated and synergistic effects of its components (e.g. VR vs. VR + paced breathing), and its efficacy, acceptance, and feasibility in alleviating insomnia symptoms in adolescents.

Reductions in anxiety, depression and insomnia in health care workers using a non-pharmaceutical intervention

The COVID-19 pandemic has caused significant medical and psychological challenges worldwide, and not only exceeded the capacity of hospitals and intensive care units but also an individuals' ability to cope with life. Health-care workers have continued to provide care for patients despite exhaustion, fear of transmission to themselves and their family, illness or death of friends and colleagues, and losing many patients. They have also faced additional stress and anxiety due to long shifts combined with unprecedented population restrictions, including personal isolation. In this study, we study the effect of an app-based Yoga of Immortals (YOI) intervention on mental health of healthcare workers. In this study, the health care workers were digitally recruited, and their psychological parameters were measured using validated questionaries. The participants were randomly grouped into control and test groups. The validated psychological measures were the Patient Health Questionnaire-8 (PHQ-8), Insomnia Severity Index (ISI) and generalized anxiety disorder (GAD-7) scales. The digital YOI intervention significantly reduced the anxiety, depression symptoms, and insomnia in healthcare workers of all age groups. In contrast, there was no improvement in the control group. This study details the effectiveness of an app-based YOI intervention in healthcare workers.

Singing at 0.1 Hz as a Resonance Frequency Intervention to Reduce Cardiovascular Stress Reactivity?

Slow breathing at 6 breaths per min (corresponding to ~ 0.1 Hz) has been found to benefit psychological and physical health. In this study, we aimed to examine if paced singing at 0.1 Hz has beneficial acute effects on physiological function as compared to slow breathing. Participants were randomized to one of four experimental interventions prior to performing a mental stress task: paced breathing at 0.1 Hz (n = 26), paced singing at 0.1 Hz (n = 26), spontaneous breathing (n = 24), or spontaneous singing (n = 25). Heart rate, heart rate variability in the low (LF-HRV) and high frequency (HF-HRV) domain, blood pressure and affective wellbeing were assessed. As expected, both paced breathing and paced singing resulted in elevated LF-HRV. Moreover, both singing groups evidenced increases in heart rate, blood pressure and positive affect, thus indicating elevated sympathetic activation. Breathing and singing at 0.1 Hz had no robust effect on cardiovascular stress reactivity. Findings suggest that paced singing could constitute a promising alternative to slow paced breathing as it increases cardiovascular coherence, although more studies are needed to elucidate whether slow breathing and/or singing could ameliorate acute stress responses.