Breathing on the Mind: Treating Dyspnea and Anxiety Symptoms with Biofeedback in Chronic Lung Disease – A Qualitative Analysis

Abstract

Rationale:

Chronic obstructive pulmonary disease (COPD) is characterized by dysfunctional breathing patterns that contribute to impaired lung function and symptoms of dyspnea, anxiety, and abnormal carbon dioxide (CO₂) levels.

Objective:

The study objective was to measure the acceptability of a new mind-body intervention we developed called Capnography-Assisted, Learned Monitored (CALM) Breathing, implemented before pulmonary rehabilitation.

Methods:

CALM Breathing is a 4-week (8-session) intervention designed to treat dyspnea and anxiety in adults with COPD by targeting dysfunctional breathing behaviors (guided by end-tidal CO₂ levels). CALM Breathing consists of ten core breathing exercises, CO₂ biofeedback, and motivational interviewing. Using qualitative methods and semi-structured interviews immediately post-intervention, we evaluated the acceptability and participation process of CALM Breathing. Themes were identified using constant comparative analysis.

Results:

Sixteen participants were interviewed after receiving CALM Breathing. Three main themes of CALM Breathing were identified: (1) Process of learning self-regulated breathing, (2) Mechanisms of a mind-body intervention, (3) Clinical and implementation outcomes.

Conclusions:

Positive themes supported the acceptability of CALM Breathing and described participants’ process of learning more self-regulated breathing to manage their dyspnea and anxiety. Positive signals from qualitative participant feedback provided support for CALM Breathing as an intervention for COPD, but larger scale efficacy trials are needed.

Adults with chronic obstructive pulmonary disease (COPD) demonstrate dysfunctional breathing habits (such as breath holding, rapid and shallow breathing through open mouth, and hyperventilation.^1–3 These inefficient, thoracic-dominant breathing patterns increase dead space and contribute to abnormal carbon dioxide (CO₂) output. In COPD, abnormalities of CO₂ gases increase breathing drive⁴ and impair ribcage biomechanics (e.g., as evidenced by thoraco-abdominal asynchrony and excessive reliance on accessory breathing muscles) increasing the work of breathing and contributing to a vicious cycle of dyspnea and anxiety, and neuromechanical dissociation.^5,6

Interoceptive dysfunction in COPD may underly dysfunctional breathing patterns and contribute to dyspnea. Interoceptive dysfunction is defined as “an imbalance of processing bodily signals and errors in somatic interpretation or missed somatic signals contributing to psychosomatic symptoms.”^{7, p.84} Interoception “includes two forms of perception, proprioception or signals from skin and musculoskeletal systems, and visceroception or signals from inner organs, to sense the physiological condition of the body and motivate homeostatic and survival action”.^{8, p.693}

Given the close links between dyspnea and anxiety, a more effective, multidimensional approach is needed that treats dyspnea and anxiety together.^9,10 Preliminary research suggests that mind-body therapies (such as biofeedback with a focus on the breath) reduce both symptoms and physiological effects of psychosocial stress in chronic disease.^11–13 A meta-analysis found mind-body exercise (tai chi, yoga, and qigong) to significantly reduce anxiety and depression in COPD,¹⁴ but their effects on dyspnea have not been adequately studied. A Cochrane meta-analysis found the effects of ten mind-body movement therapies as adjuncts or comparisons to pulmonary rehabilitation (PR) to be inconclusive because of the reduced quality of available evidence,¹⁵ suggesting more research is needed.

We therefore developed a new mind-body intervention called, Capnography-Assisted, Learned Monitored (CALM) Breathing, that targets both dysfunctional breathing patterns (marked by CO₂) and interoception to treat dyspnea and anxiety together in COPD. The aim of this study was to evaluate the acceptability of CALM Breathing implemented before PR in adults with COPD.

Methods

Design

As part of a larger hybrid randomized, controlled trial, we conducted semi-structured interviews after participants completed CALM Breathing. Building on our previous mind-body capnography-assisted respiratory therapy (CART) proof-of-concept trial and lessons learned,^16,17 this pilot study aimed to test the acceptability of CALM Breathing in a more targeted clinical group of patients with both COPD and dyspnea anxiety using qualitative methods. The ORBIT model for developing a behavioral treatment guided our study design.¹⁸ The ORBIT model supports the use of qualitative methods and an iterative process to optimize treatment development (e.g., content and delivery refinement) in a target population in preparation for a Phase III efficacy trial.

Participants

Using a purposive sampling approach, all participants in the study who received at least one CALM Breathing session were invited to participate in semi-structured interviews. The study inclusion criteria were: (1) 18 years or older, (2) a diagnosis of COPD (FEV₁/FVC of <0.70 on spirometry)¹⁹ or a diagnosis of emphysema or chronic bronchitis on chest computed tomography, (3) receive standard care bronchodilators, (4) stable medical condition (i.e., do not require acute care), (5) dyspnea documented in their EMR problem list, or based on ≥1 on modified Medical Research Council (mMRC) questionnaire, or ≥ 2 dyspnea score (a few days a month or more frequent) on 0–4 item: “Over the last 4 weeks, I have had shortness of breath”, or endorsement of dyspnea-related activity avoidance with binary item, “Have you avoided any activities due to shortness of breath?”)], (6) <24 hours/day supplemental oxygen, (7) Scored ≥24 on the Mini Mental State Examination²⁰, (8) able to speak, read and write English, (9) stably medicated for ≥4 weeks on any anti-anxiety medication prior to study entry, (10) did not receive PR in past 12 months, and (11) Elevated dyspnea-related anxiety symptoms – dyspnea anxiety and activity avoidance scores ≤50 on Dyspnea Management Questionnaire Computer Adaptive Test (DMQ-CAT)²¹, ≥20 VAS dyspnea anxiety scale with 6-minute walk test, ≥ “some” score on Anxiety Sensitivity Index (ASI-16) item #10, and/or ≥18 on ASI-16.²² Anxiety sensitivity was defined as “the tendency to view interoceptive sensations as dangerous or threatening”.^{23, p.384}

The exclusion criteria were: (1) ineligible for PR, (2) actively being treated for cancer, (3) body mass index >40, (4) hypercapnia of ETCO₂ >50 mmHg at rest, (5) musculoskeletal disorder or neuromuscular disease that interferes with exercise, (6) seizure in the past 3 months, (7) Resides in sub-acute care or assisted living, (8) active smoking, (9) pregnant, (10) clinically significant cardiac disease, (11) low literacy based on scores of 4 or 5 on Single Item Literacy Screener,²⁴ (12) schizophrenia, psychotic disorder, or bipolar disorder diagnosis, (13) alcohol or substance abuse or serious suicidal risk, and (14) taking prescribed opioids ≥50 morphine mg equivalents per day²⁵ or both opioids and benzodiazepines.²⁶

Intervention: CALM Breathing

Intervention consisted of ten core exercises combined with capnography (numeric and waveform ETCO₂) biofeedback and motivational interviewing (client-centered counseling) that emphasized eucapnic breathing.²⁷ Ten core breathing exercises, previously described in detail,¹⁶ focused on elongating (slowing) the exhale, promoting nasal inhalation, regulating tidal volume, respiratory rhythm and rate, and improving thoracoabdominal coordination. Ten breathing exercises were introduced in the following sequence, and based on biofeedback response and patient preference, were adopted and tailored as part of a home program: (1) Slow, nasal respiration, (2) coordinated breathing with ribcage stretches,²⁸ (3) tongue maneuver,^29,30 (4) breath counting, (5) pursed-lips breathing (PLB) with physical exertion,³¹ (6) interoceptive awareness,³ (7) control pause (CP),¹¹ (8) volume-regulation,³² (9) humming,³³ and (10) breathing differentiation and negative practice training.³⁴ In-session capnography biofeedback provided numeric values of end-tidal CO₂ and respiratory rate (RR), and a capnogram of airflow patterns with the CapnoTrainer (Better Physiology, Santa Fe, NM), Fig. 1.^35,36 Mind-body intervention was delivered to individuals through eight clinic-based sessions and remote monitoring of a home program. This standardized intervention was implemented by two physical therapists and two occupational therapists. The home exercise program consisted of device-assisted RR biofeedback using the MightySat^™ fingertip pulse oximeter and Masimo^® Personal Health app [Irvine, CA], tailored breathing exercises (with a target goal of ≥10-minutes daily), exercise logging, and therapist-guided audio exercises.³⁷

Fig. 1.

Theoretical model of biofeedback in COPD symptom management. Adapted from Joanneke Weerdmeester et al. 2020.⁴²

Key goal-directed behavioral strategies of CALM Breathing were: (1) self-regulated breathing behaviors, (2) completing daily breathing and ribcage stretching exercises, and (3) health-promoting physical activity and/or sleeping behaviors and routines. CALM Breathing targeted unlearning dysfunctional breathing habits, and improving self-efficacy and awareness of misconceptions of breathing (cognitive re-appraisal). CALM Breathing applied the Generative Model of Perception.³⁴

Assessment

Two trained interviewers (BH and AN) conducted 30–45 minute semi-structured interviews either in person or via the telephone using an open-ended question topic guide developed from our previous research (see Appendix for interview guide).^17,38 Example questions and topics included: (1) Please tell me about your experience with the CALM Breathing therapy program, (2) What can we do to improve the CALM Breathing therapy and make it better for future participants? (3) Would you recommend this treatment to others? (4) Did you like how the sessions were given? (5) How was your experience with the breathing exercises at home?

Data Analyses

We used a constant comparative approach to guide inductive thematic analysis assisted by Dedoose^™ software.³⁹ Through an iterative process of analysis, qualitative analyses of transcribed interviews were conducted. To guide data analyses, we developed an initial set of core codes (codebook), informed by our prior qualitative research.^17,40 Core codes were also informed by two conceptual frameworks, the Developmental Perspective on Embodiment⁴¹ and the Model of Biofeedback Developmental Change.⁴² Intercoder reliability was established between raters (BH and SM) by independent, double-coding of the first three transcribed interviews. Themes emerged through data analysis focused on explaining behavior and refining theoretical concepts.^43–46,47 We also used means and standard deviations (SD) and frequencies (%) to analyze demographic and clinical characteristics.

Results

All active participants randomized to CALM Breathing (n=16) agreed to be interviewed post-intervention for this qualitative study, and these 16 participants had completed all 8 CALM Breathing sessions. A participant who dropped out of the study after one CALM Breathing session, and two participants who were withdrawn from CALM Breathing and the study due to unstable health, could not be interviewed. One participant was withdrawn after 5 sessions and prolonged hospitalization. A second participant was withdrawn after one session due to a new lung cancer diagnosis. Demographics were provided in Table 1. High agreement between the two coders was established with intercoder reliability of 92.8%. Three main themes emerged from the qualitative analyses with saturation achieved⁴⁸: (1) Process of learning self-regulated breathing, (2) Mechanisms of a mind-body intervention, (3) Clinical and implementation outcomes (Fig. 2). Eleven subthemes were also identified in Table 2 with example quotes provided.

Table 1.

Demographics and clinical characteristics of sample at baseline.¹

Characteristic	N = 16
Gender
Female	9 (56%)
Age	72 (7)
Home Oxygen Use = Yes	5 (31%)
COPD Severity
Mild 1	1 (6%)
Moderate 2	8 (50%)
Severe 3	6 (38%)
Very Severe 4	1 (6%)
FEV1 % predicted	50.1 (18.4)
Bronchitis	1 (6.3%)
Emphysema	10 (63%)
mMRC dyspnea	2.3 (1.1)
Smoking pack-years	45.4 (43.6)
Body Mass Index, kg/m2	26.6 (5.6)
AECOPD in previous year	2.0 (1.2)
DMQ Anxiety	52.5 (6.4)
DMQ Activity Avoidance	50.6 (3.6)
ASI	17.2 (10.5)
GAD-7	4.1 (6.1)
PHQ-8(SD)	5.6 (6.1)
MMSE	29.2 (1.7)
Marital status
Married	7 (44%)
Not married	9 (56%)
Education
College or higher	6 (38%)
High school or less	10 (62%)
Taking anxiety medication	4 (25%)
Lonely
Never	6 (38%)
Rarely	4 (25%)
Sometimes	5 (31%)
Usually	1 (6%)
Always	0 (0%)
Race
White	12 (75%)
Black or African American	4 (25%)
Hispanic
Non-Hispanic	14 (88%)
Hispanic	2 (12%)
Heart Failure	1 (6%)

Note.

¹n (%) or mean (SD).

Data were missing for age for n=3, smoking pack-years for n=1. AECOPD: acute exacerbation of COPD. ASI: Anxiety Sensitivity Index; COPD: chronic obstructive pulmonary disease. DMQ: Dyspnea Management Questionnaire. GAD-7: Generalized Anxiety Disorder Scale. GOLD: Modified Medical Research Council Questionnaire. mMRC: Modified Medical Research Council Questionnaire. MMSE: Mini Mental State Examination. PHQ-8: Patient Health Questionnaire.

Fig. 2.

CALM Breathing concept mapping.

Table 2:

Themes and subthemes

Theme 1: Process of learning self-regulated breathing
Subtheme	Quotes
Real-time Biofeedback is a Powerful Learning Tool: There’s Something Very Immediate About This Breathing	I could look at the graph and the graph would tell me how I’m doing, and how far apart the waves are. The further apart and the higher they were, the more successful I was in doing the breathing. And when I first started, the graph only went up half-way. And most of the time, after I learned different breathing techniques, it would almost come up to the top….I probably would consider that the most important part of the intervention. How it had this even flow – it was rewarding for me to be able to see that. It just gave me this visual of what I am capable of doing – deep and high – being able to use my airways. The airways now make sense to me …. I felt this sense of relief … it just made me think as I’m looking at those numbers that I am feeling in control. You’re seeing the screen and you see the breathing level at the same time.… Those lines help to control your breathing to a certain level as you see the needle goes up and down and keep a steady pattern and an even pattern.
Motivational Interviewing: A Process of Discovering It For Myself	She created situations where I would discover what I was doing myself rather than pointing it out. I was really rediscovering it in myself…. As a teacher, she was very thoughtful, very analytical, very cautious about what she would say, and non-judgmental. There was some real personal touch there, real personal care, and very encouraging. There was a lot of sort of personal attention… in terms of somebody actually mapping your progress and knowing you as a patient… Much of the wellness factor should be about positivity and encouragement, especially with breathing for some reason…. It’s just so important to hear positive words of encouragement. She would constantly check in on how I was feeling or what I thought about something.
Home Program and mHealth: Easy to Do and Takes a While to Integrate	It’s a matter of unlearning bad habits. So, if I normally did shallow breathing – which apparently, I did – it takes a while to integrate. When I’m walking and I catch myself, if my tongue isn’t in the right position, I still remind myself because it takes a little while to get used to doing it right. And it’s easy enough for somebody, once the sessions are over, to follow through on. You know, it doesn’t mean that once you end the sessions, that’s the end of the exercises. There’s enough for you to take home with you and follow them at home… No matter where you are you can put the exercises into effect because they’re nothing strenuous; there’s no equipment that you need. It is still a work in progress. My numbers were a little higher, but my biggest problem is getting it together when I exert. I have to pace myself better, maybe go slower, and remember, but sometimes it gets all thrown out the window when I am walking. I am trying to focus on what I have learned and incorporate it into my daily life but that takes some doing.
Theme 2: Mechanisms of a mind-body intervention
Interoception of breathing: A New Way of Being	Sometimes when I get upset, I notice that my breathing gets agitated again. But I noticed I get upset if I get nervous. I start getting palpitations and, sometimes the wheezing acts up. … But with the exercises, it helps take your mind off of things. It’s helped me a lot with my anxiety. The breathing exercises and the pursed breathing have helped me quite a bit…. It made me aware of when I’m rushing, and I stop and say take a deep breath and why am I rushing? It’s just not necessary. It helped me to slow down with all my routines during the day. Every once in a while, I’ll catch myself. If I’m walking upstairs, I’ll remind myself to take a breath before I start (to exhale as I’m going up). It’s almost like standing outside of yourself and watching yourself do it, because you’re creating new habits and trying to coordinate everything.
Cognitive Re-appraisal: A Fresh Outlook on My Life – It’s Become Manageable	I was really thinking like I was doomed in the beginning. This has given me a fresh outlook on my life…. We think these things and they’re not correct…. I was really thinking that life was basically over for me. I wasn’t breathing properly. I was holding in and holding back. I don’t know why I thought I was saving energy or oxygen by the shallow breathing. I thought if I just didn’t move around too much, if I didn’t breathe too hard, that would be better for me… so I can live longer. And that’s just not the case…. I’m able to walk. I wasn’t walking before. I wasn’t thinking about walking. I was like, oh no, that’s going to take too much energy. I better not do that. Let me just go to work and come home and just sit down, and not move around. And then I was avoiding stairs. I’m not avoiding stairs. I’m not avoiding walking. I’m not avoiding anything. I’m planning to travel. You know these are things I wasn’t planning on before CALM Breathing. [I gained] some sense of confidence and positivity, optimism that I can manage, that this is going to be manageable with these techniques that I have now. But it’s been a real turning point for me and before I wasn’t sure that I could manage. It’s become manageable. I think being in touch with your body and being in touch with your breathing is really so important to prevent the downslide. It is psychosomatic and much more. Getting mind in touch with body, I totally believe in that. I just feel it was a gift. …. I mean, it’s kind of emotional and a very doable realization that I have the power to somewhat heal myself through breathing and breathing exercises that I was not aware that would empower me so much…. What I mean by that is it changed my thinking about COPD and me having this disease. I didn’t have to open my mouth and knew I could breathe my way out of this without opening my mouth, and I did. You know I used to go into a panic breathing before and I am sure I would gasp. But I could control it, I could actually control it.
Motivation: Understanding the Benefit	What motivated me would be doing certain exercises, and then while I’m doing them, I’m looking at the graph and seeing how it improved. So that was an incentive for me to go home and do it because I know that it’s helping. …The graph – the biofeedback – was really motivating. I don’t miss a day even if it’s just walking and humming. …. I wanted to help myself because I wasn’t finding help any other way and that’s what prompted me. That was very important and for me and it turned out very well… I was willing to take the challenge. Rather than just say, oh God, I’m too tired to do anything, too short of breath, I’ll do the exercise. That’s a consciousness. When I’m in the middle of being engaged in something and I’m losing the ability to breathe at a maximum rate, that I know I can reach, I will use those exercises and, I say go from 92 to 95. It’ll go up definitively and I’ll feel better…. I’m very proud of myself. It was important for me to continue the exercises even when I wasn’t in the sessions. And it’s helped…like I said, it’s helped with the breathing; it’s helped mentally…. I put my best foot forward to do this program. I found within a short period of time that, mentally and physically, the wheezing – the breathing – was getting better. I really give it my full concentration because I can really see a difference right now.
Optimized Breathing Biomechanics and Physiology: It’s How I Use the Breath I Have– I’m Breathing Slower and Calmer	Because when you’re breathing up around your neck rather than with your lungs, my breathing becomes very rapid that way. And the other problem was slowing my breathing down…. It made me aware that I can do activities … in a calmer manner, with slower breathing. My particular problem was shallow breathing and breathing from the top of my chest rather than deep breathing…. Just being aware of that, and trying to breathe from the diaphragm, like a singer, and widen my ribs was essential. I like all the exercises but especially the one I breathe in with my nose and breathe out with my mouth because it makes me relax. I mean when I am short of breath and I’m working, I do these five or six times, and I feel better. Yeah, I used to walk with my mouth open all the time now I consciously don’t. I started to learn how to breathe out. My tongue automatically went to the roof of my mouth, behind the top of my teeth, which is obviously where it is supposed to go. I didn’t have a problem with that which maybe is what made it so much easier for me and I just fell into it. At first, I could only do 20–30 but it just got so much easier…. I don’t use the chest anymore; I use the belly all the time. I never really thought about how I breathed. I guess I didn’t realize I was shallow breathing, and I don’t do that anymore. Or if I do, I catch myself doing it and I stop. … And I use the techniques when I’m walking now…and I get into a rhythm, which I never really did before. It does work, it’s calming.
Theme 3: Clinical and implementation outcomes
Beyond surviving: Improved Well-Being and Resilience: It just helped me mentally, spiritually, and physically	[When] I get stressed out, I go back to this…. It doesn’t bother me anymore.…. Sometimes you’re outside and you get stuck while you’re walking and have one of these episodes, like the neck breathing. I was outside the other day and that caught me, and I remembered one of the techniques and I took a knee, and I did it for a few seconds, maybe 20–30 seconds, and my breathing came back. I was okay…. Struggling with breathing creates stress, stress is another added on, so doing these exercises you can eliminate that stress and eliminate the shortness of breath and finish doing what you’re doing. During the 8 sessions for 4 weeks, I felt mentally that I didn’t dwell upon what had happened in the past and I was very stable in my mood, mentally and physically. I didn’t dwell on the issue that brought me to CALM breathing and I thought that was very good. It was something that I needed….. [My traumatic event] was kind of on my mind. But with the sessions I found it relieved me mentally of continuously thinking and even now mentally I’m not continuously thinking about the episode that occurred 5 years ago [when] I needed to be hospitalized. ….I’m less stressed out. Mainly I felt better both physically and also psychologically, just by being engaged in something. So, I wasn’t thinking about how alone I feel. I wasn’t thinking about anything except doing the exercise and that engagement.
Less exertional dyspnea and anxiety, and greater autonomy: It’s less of an effort breath-wise and I can recover my breath faster	Because it is increasing my awareness of how [I was breathing]. I felt it was extremely important. Because very often I would tend to ignore things and now I’m more tuned into what I should do before I start an activity…. It makes life easier. I breathe easier. …. Now I just find myself quieter and having less trouble with my breathing when I’m doing activities. I’ll remember and begin breathing in a certain way, stretch or roll my shoulders to calm down while doing my routine. And I’m breathing slower and calmer. I feel more comfortable going up hills – I feel less out of breath. You feel less strained going uphill. It’s less of an effort breath wise. I’m much more confident about that. I don’t avoid. … The hills that I have around here, I can handle them. It helped me to do housework that I couldn’t do. It helped me walk without stopping. It helped me go to babysit my grandkids and pick them up because I couldn’t pick them up. It changed my life around, getting back to normal. It helped me a lot because I thought I wasn’t going to be able to get back to normal. Like I said I’m back to my normal life now. My physical capability is that I was able to do what I wanted to do because I couldn’t even clean my house, I couldn’t even walk my dogs, I couldn’t do anything! I couldn’t even go food shopping. Now, I could do all that by myself. It feels great. Because I don’t like to depend on anybody. I have my own independence back. I can control it now. I am not getting out of breath when I am walking up the stairs because I do the deep breathing. I do it while I am walking, and when I am going up the stairs…. I walked up 22 steps! I mean, that was great without stopping. I used to look at the stairs. I had stopped walking up about a year ago.
Relaxation for Improved sleep: I relax and fall asleep faster	It was perfect timing as I was at an incredible sleep deficit. And it just sort of like all happened at once. Phillips finally sent my machine, and I started getting sleep. So those exercises actually helped build a sleep routine for me, because I do a few of them, right before I go to bed as I’m setting up my CPAP machine…. And it’s exciting to wake up to know that you just got six, seven, or eight hours of sleep [teary and emotional] when I was not sleeping. It’s so bizarre that I’m getting sleep and learning to breathe. I mean it has just changed my life. I wear a mask for sleep apnea and I got a new machine… and have restless leg syndrome …. I try to incorporate the breathing so I can kind of like relax and go to sleep more quickly. And that’s helped a little bit…. The routine I had was when I went to bed, I would practice my breathing to slow down my breathing because I have really poor sleep. …. With the machine, sometimes I sleep through the night. You know, either diaphragmatic breathing or the wide ribcage breathing and also, I was sleeping on my back …. So now I’m concentrating on sleeping on the side and I’m getting longer blocks of sleep.
Acceptability of CALM Breathing – A Bridge to Pulmonary Rehab: This program is way overdue	It’s the best thing that could happen to you. It’s going to teach you how to breathe. We don’t really know how to breathe. And if you don’t breathe right, you’re not going live right, especially with COPD. … it just teaches you a lot about yourself, your breathing, and posture. This program is way overdue but it’s here and I’m glad it’s here and I’m just sorry that my time is ending here. But I still have the information with me. Anybody that I know that might be having difficulty breathing, asthma, or a lung problem, I would definitely suggest they come over here. …. I’ve learned some techniques that were very helpful. I learned how to catch my breath. It was absolutely wonderful…. When I was going to those sessions, they meant so much to me. I kind of like feel lost without coming to see you and because she was a great teacher and the exercises really do help me a lot. They help me to remain calmer, they help with the wheezing and it means a lot because I can really see a difference right now….So to me it was a very successful program.

Theme 1: Process of learning self-regulated breathing

Real time biofeedback is a powerful learning tool: There’s something very immediate about this breathing.

Participants described the CO₂ capnogram as motivating and simplifying breathing to promote learning. By providing immediate results, they found continuous, real-time biofeedback helpful and rewarding in understanding and reinforcing the benefits of the breathing exercises. They said the traces provided concrete and important feedback. One participant said, It may even make people want to do the exercise more.

Motivational interviewing – A process of discovery for myself.

Participants perceived strong social support from their CALM Breathing therapist. They described this relationship as collaborative, positive, motivating, and encouraging. They also described the therapy process as one of discovery and a lovely place to learn to breathe. One participant said, “I looked forward to coming. I appreciated her demeanor …. It was very easy to get involved, wanting to do this for myself.” The therapist also motivated participants to meet their goals. One participant said, “I promised her I was going to make that my goal.”

Home program and mHealth: Easy to do and takes a while to integrate.

The home program was described as important in applying new breathing skills to daily living. Participants described a process of transferring skills from clinic-based sessions to their home practice. Specific home exercises highlighted included slow breathing, ribcage stretches, tongue maneuver, humming, and rhythmical breathing with a sphere.

The Masimo wearable pulse oximeter and app reportedly helped participants to see that they were getting better and able to slow their breathing down. The homework and time commitment was described as easy to do and fit in, and manageable. The exercises were described as a “calm form of exercise”.

Participants expressed a desire to continue with the home exercises. One participant said, I’m motivated for the exercises to be a part of my learned way of life. They described integrating their new skills as a work in progress.

Theme 2: Mechanisms of a Mind-body Intervention

Interoception of breathing: A new way of being.

Participants articulated more attunement to their breathing and ability to listen and respond to somatic respiratory cues. A participant said, “The breath goes with me wherever I am…. I’m aware of my body.” Although the changes seemed subtle, gaining more awareness of how they were breathing and utilizing their breath better with physical exertion were described as transformative. As stated by one participant, “You would be surprised that certain things could be so huge in health.” Participants described connecting with their breath to develop more body grounding, body ownership, emotional regulation, and energy.

Their new connection and perception of their body and inner bodily signals altered their sense of self. One participant said, “It took almost till the end of the eight sessions to actually feel like I could access that, and it belonged to me.” Similarly, another participant said, “They become a part of you just like everyday life – doing things you like doing every day”.

One participant thought that perception of the body may be underappreciated by physicians because “the numbers don’t always drive how the person feels.” One participant said he noticed new sensations in his chest wall and shoulders as part of his muscle retraining. They developed healthy inner inquiry to better understand themselves.

Cognitive re-appraisal: A fresh outlook on my life – It’s become manageable.

Participants developed a more positive mindset about their breathlessness – with less negative judgement, more positive thoughts and optimism, and self-confidence. They had positive thoughts about mind-body integration.

Improved ability to breathe seemed to help improve participants’ outlook on their life. They expressed greater agency and less respiratory distress. They embraced the idea that breathing exercises and biomechanical strategies could improve their physical performance and lung capacity. One participant said, “I definitely think there’s lung capacity for a lot of people that could be utilized better. I obviously have damaged lungs, but even just a little bit of improvement would be great.”

Participants became aware of misguided beliefs or misconceptions. For example, one participant said, “I was taking one big breath, and then a little breath with it, to make sure I had enough breath, that I wouldn’t run out. At least that was my mental process.”

Participants described greater self-confidence knowing that they could breathe easier and calmer while walking. For example, one participant said, “I can walk now and not have to open my mouth. It’s comforting knowing I can do it and I know when I get a little short of breath all I’ve got to do is breathe.” Their improved self-confidence in their skill set to manage their breathing was reassuring to them. They described gaining a sense of control and better awareness to anticipate and take steps to prevent an escalation of breathing symptoms.

Motivation: Understanding the benefit.

Participants were open and motivated to learn breathing exercises. Participants found the capnography biofeedback to be especially motivating. They expressed excitement and readiness to participate in the program. For example, one participant said, “I want to integrate this breathing, so I use my body to the best that I’m able – to maximize the air that I have and get rid of the carbon dioxide.” Similarly, another participant said, “I came here with an open mind to try and learn as much as possible, and to apply myself, to help my breathing and my anxiety.” Many participants described strong motivation to complete the breathing exercise daily to optimize their lung capacity and breathing. For some, their motivation was increased by a perceived limited availability of other dyspnea therapy options.

They expressed understanding of the importance of paying attention to their breathing, embodiment, and continuing to do the exercises. One participant said, I know they are going to help me, and I have to do them. Reasons for valuing CALM Breathing included (1) managing humidity and cold weather triggers, (2) part of psychological being, (3) to feel better, (4) opening up the airways, and (5) emptying the air out of your system.

Optimized breathing biomechanics and physiology: It’s how I use the breath I have – I’m breathing slower and calmer.

Participants described less dysfunctional breathing, such as panting. One participant said, “It’s very different because now I’m not breathing hard and not breathing really fast.” They described initially not being aware of how shallow they were breathing or that they were breathing with an open mouth. Many adopted pursed lips breathing and found this breathing maneuver helpful with physical exertion and reducing stress. They described training their respiratory muscles to develop a muscle memory. Participants acknowledged the challenge of unlearning dysfunctional breathing, “There would be times when I would be out of breath and I would try to breathe through my nose and slow down my breathing, but I was just so out of breath.”

Theme 3: Clinical and Implementation Outcomes

Beyond surviving: Improved well-being and resilience – it just helped me mentally, spiritually, and physically.

In their positive narratives and reflections, participants described intentionally using new breathing strategies (active coping) to manage stress. They described less passive coping behaviors, such as avoiding and helplessness. Participants described reduced reactivity to stressors. Stressors identified were difficulty breathing, lung congestion, receiving an unexpected phone call, acute illness, loneliness and missing family, feeling frail, and fear about dying. CALM Breathing exercises were described as helping to ease the feeling of loneliness and stress. They described reduced distress after major traumatic medical events they had experienced.

Less exertional dyspnea and anxiety, and greater autonomy: It’s less of an effort breath-wise and I can recover my breath faster.

Participants described less trouble breathing, panic, and gasping for air. They described less struggling with dyspnea-triggering activities, managing a more physically active lifestyle, and more vitality if they were conscious of their breathing. One participant said, “If I weigh out what was more helpful to me, the breathing or the anxiety, I would say it’s pretty much equal. CALM Breathing helped to relieve emotional distress and ease the mind. One participant said, “It helped with nervousness and anxiety in terms of the unexpected.” They identified anxiety symptoms earlier so they didn’t spiral out of control.

Relaxation for improved sleep: I relax and fall asleep faster.

Several participants reported fragmented sleep and difficulty falling asleep associated with sleep apnea and insomnia. However, some said their sleep improved by adopting breathing exercises as part of a night routine to fall asleep more efficiently. Breathing exercises were added to some participants’ bedtime routines to complement their use of continuous positive airway pressure (CPAP).

Acceptability of CALM Breathing – A bridge to pulmonary rehab – This program is way overdue.

Participants consistently expressed deep gratitude for their personalized experience of CALM Breathing and the health benefits they experienced. Several participants anticipated that CALM Breathing may serve as a helpful bridge to their upcoming PR, even though most individuals had no prior experience attending PR. For example, one participant said, “you don’t go into rehab not knowing how to breathe properly…. that way, you’ve got a chance.”

Participant recommendations for CALM Breathing.

Half of the participants recommended refinements to CALM Breathing. Participants’ recommendations included: (1) slightly longer sessions for more time to plan home exercises, (2) provision of instructional videos for each exercise and online patient educational materials to aid memory recall and exercise tracking, (3) availability of weekly patient progress reports summarizing the exercises and biofeedback traces, and home exercise prescriptions, (4) a clearer overview and introduction to know what to expect, (5) More CALM Breathing sessions, such as a booster or check-up session, (6) Breathing exercises combined with 5 to 10 minutes of light intensity treadmill or bike exercise, and (7) a home version of the CapnoTrainer device.

Discussion

Participants described anxiety sensitivity associated with their symptoms of dyspnea. Many articulated that, after CALM Breathing, they were less fearful of and distressed (emotionally triggered) by their dyspnea symptoms and felt less physically impacted by dyspnea sensations. The relationship between dyspnea and anxiety, therefore, is likely interrelated, whereby dyspnea can trigger anxiety, and anxiety and related catastrophic thinking can trigger dyspnea.^3,49–51 Anxiety triggers dysfunctional breathing (such as breath holding or impaired diaphragmatic excursion) or respiratory muscle tension contributing to dyspnea. Dyspnea associated with dysregulated breathing or airflow limitation can trigger anxiety in a vicious circle.

Qualitative data supported the acceptability of CALM Breathing. Practice and tailoring in sessions and ease of completing the exercises may have promoted behavior change and home exercise adherence.⁵² Qualitative evidence supported targeting dysfunctional breathing and interoception dysfunction as promising treatment mechanisms for relieving dyspnea and related anxiety. In particular, preliminary positive findings supported targeting end-tidal CO₂ as a physiological risk factor in the treatment of anxiety and respiratory symptoms. A strength of this study was our careful consideration of inclusion criteria and recruitment of patients with both COPD and anxiety sensitivity, who may benefit the most from CALM Breathing because of its treatment of both dyspnea and anxiety together. This is the first pilot study to test the acceptability of capnography biofeedback (i.e., application of capnogram biofeedback to optimize ETCO₂ and airflow patterns) combined with interoceptive-based, slow nasal breathing exercises specifically in COPD to treat both dyspnea and anxiety together.

CALM Breathing is novel because it treats dyspnea and anxiety together in COPD with a comprehensive biopsychosocial approach to address limitations of other breathing exercise or mind-body approaches. CALM Breathing combines ETCO₂ and airflow (waveform) pattern biofeedback with breathing exercises that together address dysfunctional breathing behaviors, symptom misinterpretations and catastrophizing cognitions, and inefficient ribcage and asynchronous thoracoabdominal biomechanics in COPD. By treating both the lungs and the mind, CALM Breathing may have more acceptability and benefits for improving dyspnea compared with mindfulness⁵³ and cognitive⁵⁴ approaches alone.⁹ For example, mindfulness-based cognitive therapy was found to reduce psychological distress, but did not improve dyspnea in COPD.⁵⁴

Participants described CALM Breathing exercises as important in improving their mental and physical health. They connected with their breath for a more embodied mind. Participants described learning improved self-regulated breathing patterns and respiratory muscle function. Consistent with our findings, other studies have emphasized that breathing therapy involves retention of new motor skills and respiratory muscle memory.⁵⁵ Similarly, recent meta-analyses of breathing exercise and yoga studies in asthma found small improvements in asthma quality of life and asthma symptom management compared with usual care or sham intervention, but more research in COPD specifically is needed.^56,57

Improved breathing patterns and interoception also appeared to have downstream benefits of increased health-enhancing physical activity. Participants said they were able to slow down and better self-regulate their breathing and be more physically active. Participants’ more positive mindset (optimism) may have reduced overestimation of the challenge of physical activity and reduced threat bias.⁵⁸ By targeting both intrapersonal (breathing patterns and pace, chest wall motion, beliefs, and cognition) and interpersonal (social support from therapist) factors, CALM Breathing may have promoted improved physical activity in COPD.⁵⁹ Physical activity has been shown to be associated with reduced acute exacerbation of COPD, slowed lung function decline, and reduced mortality.^60–62 Real-time home digital health technology seemed to improve breathing pattern self-monitoring and self-efficacy. These qualitative findings may support the application of CALM Breathing in stepped care in which only some patients progress on to PR to optimize limited healthcare utilization and resources.⁶³

Participants’ active coping responses showed resilience. Resilience is the “process of adapting well in the face of adversity, trauma, tragedy, threats, or significant sources of stress.”^{64, p.410} Stress resilience is a modifiable causal mechanism for optimizing health and physical activity in COPD.⁶⁵ Social support (e.g., motivational strategies and physical activity goal setting) from the therapist may have improved resilience by promoting active coping strategies and facilitating dyspnea re-appraisal.⁶⁶ Participants described less rumination about their past major medical-related traumatic events.⁷ Active coping strategies, social support, and optimism have previously been associated with resilience.⁶⁴ CALM Breathing appeared to improve sense of agency and autonomy, which are known to have profound benefits for health and well-being.⁶⁷ Participants’ perceptions added support for the principles of self-determination theory and intrinsic motivation.⁶⁸ Intrinsic motivation was evidenced by participants’ descriptions of enjoyment and satisfaction with completing breathing exercises and incorporating new breathing and interoceptive skills into their daily routines.

Our qualitative findings of improved dyspnea, mental health (less anxiety, improved self-efficacy and embodiment, and positive mindset and sense of agency), and quality of life in adults with COPD and anxiety sensitivity are novel. For example, a meta-analysis of sixteen studies of breathing exercises in COPD identified improvements in exercise capacity but found inconsistent effects on dyspnea and quality of life.⁶⁹ Also in contrast to our study, a clinical trial of capnometry-assisted respiratory therapy (CART) biofeedback with auditory paced, slow breathing in patients with asthma (focused on remediating hyperventilation) found both ETCO2 (CART) biofeedback or slow breathing interventions improved dyspnea and other respiratory symptoms, but did not improve mental health as measured by mental SF-12 quality of life scale, p=.24 (n=120).⁷⁰ Nonetheless, the authors in a follow-up secondary subgroup moderator analysis in adults with asthma and elevated anxiety symptoms (i.e., Hospital Anxiety and Depression Scale score ≥9.0, 1 SD above mean, met by 21.7% of sample) revealed greater improvements in ASI and negative affect (sustained over 6 months) in CART group compared with slow breathing alone group, which was more in line with our findings.⁷¹

Participants said their breathing exercises helped to induce a relaxation response to reduce sleep onset latency. Consistent with our findings, there is a strong relationship between stress and impaired sleep.⁷² While there is some evidence to support the role of mind-body interventions in improving sleep in the short-term,⁷³ the long-term impact of mind-body interventions on sleep health is still unknown. Sleep disturbances are known to increase the risk of dementia and Alzheimer’s disease,^74,75 which are more common comorbidities in COPD.⁷⁶ Therefore, improved sleep may be an important outcome warranting more attention in future COPD research.

Positive acceptability signals add support for a future efficacy trial of CALM Breathing that targets risk factors of dysfunctional breathing behavior and anxiety sensitivity. This qualitative pilot study was part of a larger randomized controlled trial; therefore, considerations of quantitative findings will also be needed prior to refining CALM Breathing and engaging in future research. Given the inconsistency in mind-body study findings,^53,77 adequately powered randomized controlled trials are needed. More clinical trials of breathing exercises are needed, especially for COPD.^69,78

A limitation of our study was that we included only English speaking patients. Minority, non-English speaking patients’ perspectives may have differed. We were not able to interview three participants who attended at least one session of CALM Breathing due to study drop-out or withdrawal. Finally, our qualitative analyses may have been enhanced by specifically enquiring about participants’ previous history with PR participation.

Conclusions

CALM Breathing is a novel, patient-centered mind-body approach to dyspnea treatment in adults with COPD and elevated anxiety, which targets ETCO2, breath flow, and thoraco-abdominal asynchrony as biomedical risk factors.^79–83 Participants reported reduced dyspnea intensity and distress, less avoidance of physical activity, and improved well-being and resilience after participating in 4-week (8-session) CALM Breathing. They described several components of improved resilience, including self-efficacy, empowerment, self-control, motivation, and agency. Participants overall expressed acceptance and endorsement of CALM Breathing, recommending it be made available to other patients. These qualitative results provide early support for the acceptability of CALM Breathing as part of a larger feasibility randomized clinical trial. More research is needed for how to best integrate mind-body and comprehensive breathing exercise interventions into standard clinical practice to reduce respiratory suffering and shift the course of COPD.^84,85 Future research of CALM Breathing is also needed to evaluate its potential impact on improving PR use.

Highlights.

• CALM Breathing is novel because it treats dyspnea and anxiety together in COPD.

• Inclusion of patients with both COPD and anxiety sensitivity was a study strength.

• CALM Breathing improved anxiety, dyspnea, and quality of life.

• Novel qualitative findings were part of a larger randomized controlled trial.

• Participants expressed emphatic acceptance and endorsement of CALM Breathing.