Be Brave, BE-FIT! A Pilot Investigation of an ACT-informed Exposure Intervention to Reduce Exercise Fear-Avoidance in Older Adults

Abstract

Exercise sensitivity, fear of physical sensations of exertion, is particularly elevated in individuals with cardiovascular disease and can promote fear-avoidance of physical activity. We developed an ACT-informed exposure intervention to target exercise sensitivity, called Behavioral Exposure For Interoceptive Tolerance (BE-FIT). In this Stage I pilot trial, we developed and evaluated the feasibility, safety, and initial efficacy of BE-FIT in low active patients with elevated exercise sensitivity enrolled in outpatient cardiac rehabilitation. BE-FIT is a 6-session manualized program adjunctive treatment delivered during the initial weeks of cardiac rehabilitation and involves exposure to feared bodily sensations and exercise situations, bolstered by acceptance and values-focused processes. Patients (Mage=70.7 years) were assigned to BE-FIT (n=12) or an activity monitoring-only control (n=7). Patients in the BE-FIT condition reported high satisfaction, completed 100% of sessions, and 86.3% (SD=16.4%) of homework exposures. There were no adverse events reported. BE-FIT produced large-sized effects on reductions in exercise sensitivity and increases in both average steps/day and moderate-to-vigorous physical activity (MVPA) mins/day, from baseline to end-of-treatment. In contrast, the monitoring-only cohort evidenced small-sized reductions in exercise sensitivity and no change in average steps/day or MVPA mins/day. BE-FIT is safe, feasible, acceptable with promising findings from this Stage I trial.

Introduction

Regular physical activity is a potent lifestyle behavior that can improve and preserve health and functioning, quality of life and successful aging (Arnadottir et al., 2011; Groessl et al., 2019; Peel et al., 2005). Exercise helps to slow the progression of aging-associated changes to the structure and function of the heart that accounts for the marked increase in risk of cardiovascular disease with advancing age (Go et al., 2013; North & Sinclair, 2012; Yazdanyar & Newman, 2009), as well as vulnerability to frailty and falls (Afilalo et al., 2014), and neurological decline (Rosano & Newman, 2006). Physical activity also maintains factors critical for independent living and mobility (e.g., endurance, strength, flexibility, and balance) (Westerterp & Meijer, 2001; Wong et al., 2003). Despite these benefits, increasing age is associated with declining physical activity and exercise engagement (Hansen et al., 2012; Troiano et al., 2008), and exercise initiation and maintenance can be particularly difficult for older adults due to deconditioning, pain, frailty, and disability (Borg et al., 2019; Campkin et al., 2017).

Exercise sensitivity, fear about exercise and the physical sensations of exertion, is a psychological factor that can also undermine exercise participation (Farris et al., 2020), and is amplified in the context of medical conditions/symptoms (Campkin et al., 2017; El-Gabalawy et al., 2011). For example, among adults with cardiovascular disease or risk, exercise sensitivity was associated with lower exercise participation (Farris et al., 2020). Consistent with cognitive-behavioral theories of anxiety, the presence of heart-related symptoms or conditions can heighten awareness to bodily sensations and worry about health and safety. As a result, exercise – particularly high-intensity exercise (moderate-vigorous physical activity, MVPA) or unsupervised activity – can be particularly worrisome because the exercise sensations may be perceived as dangerous, intolerable, or indistinguishable from sensations experienced or attributed to cardiovascular disease (e.g., shortness of breath, chest tightness, dizziness, fatigue, pain). In turn, exercise fear can promote avoidance of physical activity and exercise. Given that exercise sensitivity is related to low exercise participation and theoretically maintained by cognitive-behavioral factors (fear-avoidance), reductions in exercise sensitivity should aid in physical activity and exercise uptake.

Cardiac rehabilitation (CR) provides a valuable window-of-opportunity to promote physical activity and exercise, particularly in aging adults (Ades, 2001; Schopfer & Forman, 2016), and to address exercise sensitivity. CR is a comprehensive secondary prevention program that is a standardized component of treatment typically used to help speed recovery from acute cardiac events such as myocardial infarction, revascularization, or surgical procedure, or for management of heart failure or valvular heart disease. CR is also designed to promote and facilitate physical activity and healthy lifestyle in the context of cardiovascular disease (Clark et al., 2005; Fihn et al., 2014; Schopfer & Forman, 2016). An essential component of CR is electrocardiogram-monitored aerobic exercise at moderate-to-vigorous intensity and resistance training (Ades, 2001; Anderson et al., 2016; Spruit et al., 2013). Patients receive an individually-tailored exercise prescription that can address age-related complexities (e.g., functional or cognitive limitation), and exercise supervision at initiation can ensure safe uptake and maintenance of physical activity (Schopfer & Forman, 2016). These aspects of CR can also be leveraged to optimally target exercise sensitivity and fear-avoidance behaviors.

Behavioral Exposure For Interoceptive Tolerance (BE-FIT)

To this end, we developed a brief, manualized cognitive-behavioral intervention called Behavioral Exposure For Interoceptive Tolerance (BE-FIT) designed to target exercise sensitivity. BE-FIT is an ACT-informed exposure intervention that is delivered as a supplement to CR over six 45-minute individual sessions delivered twice-weekly during the initial weeks of CR. The intervention is designed to be delivered by a psychologist, in consultation with the CR team (e.g., exercise physiologist, cardiac nurse). The intervention was developed in consultation with experts in cardiovascular medicine, kinesiology, and exercise physiology. Here, we present the Stage I study of BE-FIT, which includes a detailed description of the intervention components and a test of the feasibility, safety, acceptability and initial efficacy of the intervention.

Interventionist Training and Supervision

The intervention was delivered or co-delivered by doctoral-level clinical psychology students and the PI, a licensed clinical psychologist. Doctoral student interventionists received training and weekly group supervision from a licensed clinical psychologist. Training began with a list of required and recommended readings that were reviewed by study interventionists, followed by didactics with the PI regarding how to deliver the intervention from an ACT-informed perspective. ACT perspectives -- openness to experience in the moment, acceptance of difficult sensations and thoughts, and engagement in values-consisted committed action -- were integrated with the exposure exercises. Additional components of training included the following: (a) self-study of the treatment manual (including introductory rationale and didactic content, example session scripts and patient materials, and broad exercise recommendations for CR and specific medical comorbidities, general safety considerations, and indications for stopping or slowing exercise); (b) audio recording review of example sessions conducted by the PI; and (c) practice role play of the intervention sessions that were reviewed by the PI to confirm fidelity to the manual. Feedback was provided to improve manual adherence and treatment delivery competence as needed. In preparation for weekly supervision, the PI reviewed select clips from intervention sessions and the interventionists prepared questions regarding case conceptualization, exposure prescription and planning, and physical activity goal setting.

Recruitment and Enrollment

Patients were enrolled during orientation for Phase II outpatient CR, during which medical clearance is determined. For this study, patients included those ≥40 years of age who were low in daily physical activity (< 30 minutes self-reported MVPA/day in the past three months) with elevated exercise sensitivity (Exercise Sensitivity Questionnaire [ESQ] score ≥30) (Farris et al., 2020). The BE-FIT intervention was developed with older adult patients in mind and optimized to meet the needs of aging adults (i.e., ≥65 years old) with a variety of potential co-morbid medical conditions as well as psychosocial characteristics specific to their developmental stage. However, we also screened and enrolled younger patients who otherwise met other study inclusion criteria given to allow for broad representation of adults who enroll in CR. The age range of all patients screened for potential inclusion was 47–92 (M = 71.8, SD = 8.7 years), and 84% of patients screened were aged 65 or older. Only patients who were proficient in English were enrolled. For this trial, we excluded patients with cognitive impairment or severe disabling medical comorbidities determined during medical assessment.

Enrolled patients were given a Polar M200 activity watch with GPS tracking and wrist-based heart rate sensor to track physical activity (steps/day and MVPA mins/day) and were instructed to wear the watch for a minimum of 10 waking hours/day throughout the intervention. The study protocol was approved by the University Institutional Review Board where the study took place, and written informed consent was obtained from all patients prior to initiation of the study. Identifying information in the case examples described was masked to maintain confidentiality.

A cohort of 12 patients was assigned to the BE-FIT intervention. A subsequent cohort of 7 patients was recruited as a comparison group (monitoring-only control); these cohorts were recruited and enrolled using identical procedures and wore the activity watch. Cohorts were recruited in two separate waves (rather than running the two conditions simultaneously, with patients randomized to the two groups) to avoid cross-contamination (i.e., monitoring-only control cohort patient activities overlapping with active BE-FIT intervention cohort patients) and to achieve equipoise. Patients were on average 70.7 ± 8.0 years of age (range = 53–84yrs), primarily male (78.9%), and identified race as white (78.9%), black (10.5%) and Asian (10.5%). The majority of patients were married (89.5%). Employment status was reported as retired (63.2%), employed full time (26.3%) and disabled (10.5%). CR admission diagnoses were as follows (not mutually exclusive): percutaneous coronary intervention (68.4%), myocardial infarction (26.3%), coronary bypass surgery (15.8%), heart value replacement/repair (10.5%), heart failure (10.5%), implanted cardiodefibrillator (10.5%). Medical comorbidities most commonly included were coronary artery disease (36.8%), hypertension (94.7%), hyperlipidemia (89.5%), type 2 diabetes (42.1%), current/former smoker (36.8%), primary pain disorder (26.3%), gastroesophageal reflux disease (15.8%), and arthritis (10.5%). On average, patients completed 1.8 ± 1.7 CR sessions prior to starting the BE-FIT or monitoring protocols. There were no differences in patient characteristics between the BE-FIT and comparison cohort.

BE-FIT Theoretical Framework

Traditional exposure-based CBT focuses on challenging the accuracy of fears about bodily sensations (e.g., my heart racing might mean I am having a heart attack) through corrective learning experiences (e.g., exposure) and cognitive reappraisal. However, these existing interventions for fears of bodily sensations associated with interoceptive sensitivity assume that patients are healthy, and without medical conditions. To address this issue, Tully and colleagues developed a modified CBT framework for treating panic attacks and comorbid coronary heart disease (PATCHD), which involves tailored psychoeducation and chest pain action planning, low-risk exposure instruction, in addition to cognitive reappraisal to target maladaptive and hypervigilant thinking (Tully et al., 2017).

An alternative to cognitive reappraisal approaches, BE-FIT was developed from an acceptance-based framework, wherein the focus is on acceptance of internal experience (e.g., sensations, thoughts, emotions) and acting towards valued-living -- core processes of Acceptance and Commitment Therapy (ACT). Thus, rather than targeting the content of the anxious appraisals of bodily sensations, the BE-FIT intervention was designed to target the function of anxious appraisals in terms of their impact on avoidance behaviors. Instead of restructuring worry thoughts about exercise sensations, which may be related to broader health concerns, patients learn to tolerate the thoughts and sensations just as they are, while engaging in behaviors that are aligned to their personal values (Eifert et al., 2009), such as participation in (safe) physical activities, which will improve heart health and enhance mobility and independence. Exposure practice can help patients learn to acknowledge, observe, and tolerate unpleasant thoughts and feelings (Eifert et al., 2009) rather than viewing them as dangerous sensations to be avoided at all costs. The goal of BE-FIT is to foster openness to and acceptance of these uncomfortable thoughts and feelings that may arise during physical activity, to notice them mindfully while persisting in action that is guided by values, rather than withdrawing from values-consistent activities because of anxiety (Eifert et al., 2009). Facing challenges in life with bravery via exposure therapy is an important step toward preserving self-efficacy, independence, and mobility for aging adults, and highlights the importance of utilizing exposure interventions to capitalize on these benefits among this population. From this perspective, the goal of exposure therapy is learning to build tolerance to discomfort while functioning in a more flexible and values-based way. While some physical discomfort and worrisome thoughts related to medical conditions may be a persistent and unchangeable reality of life for aging, medically complex patients, an ACT-based approach to exposure allows individuals to both accept that reality and make progress toward more active daily living, enhancing independent functioning and mobility, and broadening their behavioral repertoire at a stage of life when it might otherwise begin to narrow due to fears or frailty. The focus on living a full and meaningful life aligned to one’s personal values provides the rationale for willingness to engage in exposure practice and experience distressing sensations and/or worrisome thoughts (Arch et al., 2015; Twohig et al., 2018), which has been shown to increase adherence to exposure activities (Levitt et al., 2004; Meuret et al., 2012).

Intervention Components

There are six intervention components in BE-FIT. (1) Assessment and case formulation is used to evaluate fears about exercise sensations and the specific expression of symptoms in light of medical symptoms and comorbidities, and functionally understand nature of avoidance. (2) Psychoeducation is used to provide patients with information about disease-specific factors including exercise limits, true warning signs for medical risk, and guidelines for distinguishing between catastrophic fears about benign exercise sensations (that can be targets for acceptance and tolerance) versus legitimate warning signs that indicate exercise should be stopped to preserve physical safety. (3) Physical activity tracking and goal-setting is conducted throughout the intervention and facilitated by the use of a wrist-worn activity monitor. (4) Values clarification and committed action is used to improve functioning despite the presence of fear. (5) Repeated exposure to bodily sensations (interoceptive exposure) and exercise activities are implemented to foster tolerance and acceptance of sensations. (6) Safety behaviors and exercise avoidance behaviors are assessed and addressed directly during intervention.

It is important to note here that while psychoeducation regarding the differences between true warning signs that indicate exercise should be stopped for safety and normal sensations related to exercise that will need to be accepted and tolerated during BE-FIT may lay the foundation for cognitive restructuring, its main purpose is to help the patient make informed decisions about when it is medically safe to continue with a given activity (even while accepting/tolerating the presence of feared sensations and anxious cognitions) versus when there is a legitimate sign of physiological danger that should not be disregarded. Furthermore, though some cognitive restructuring is a likely consequence of violated expectations during exposures (e.g., “I expected something might go wrong if I continued exercising, but I was perfectly ok”), the main focus is demonstrating to patients that they can tolerate feared sensations and worrisome thoughts during physical activity and continue with values-focused exercise behaviors even with physical discomfort and anxious thoughts on board (e.g., “I never know what activity might trigger my arthritis;” or, “What if the surgeon missed something when she did my bypass?”).

Assessment and Case Formulation

During session one, general history with physical activity and exercise is discussed, and, specifically, how the medical symptoms/conditions have shaped physical activity behavior. The Exercise Sensitivity Questionnaire (ESQ) (Farris et al., 2020) is used to assess feared exercise sensations and inform intervention planning. The ESQ is an 18-item self-report measure that taps fear of various physical sensations of exercise and includes two dimensions: fear of cardiopulmonary sensations during exercise (i.e., blurry vision, chest pain/tightness, difficulty breathing) and fear of pain/weakness sensations during exercise (i.e., joint/back/body pain, aches, soreness). The extent of fear in response to each sensation is rated on a severity scale from 0 (“not at all”) to 4 (“very much”). The interventionist and patient review the ESQ to identify the primary feared sensations. The most feared exercise sensations reported in the pilot investigation were chest tightness, chest pain, blurry vision, feeling faint, and difficulty breathing (see Figure 1 for full list). One patient, “Jane”, had severe physical deconditioning because of previously untreated heart failure. She shared, “I rarely go out of my home anymore because it’s so difficult to make it back up the stairs when I return, especially if I’m carrying groceries… I feel wobbly and shaky, out of breath… I practically crawl up the last few steps to my place. My sister is looking for a new home, and I would love to go with her to open houses, but I just can’t do all that walking and then come home and face those 14 steps; so she just goes by herself.”

Figure 1.

Pre-Treatment (baseline) feared exercise sensations for the full sample (N=19) per the Exercise Sensitivity Questionnaire (ESQ)

Note: Means and standard error are depicted. Solid bars are item associated with the ESQ-Cardiopulmonary factor and dashed bars are items associated with the ESQ-Pain/Weakness factor.

The interventionists ask open-ended questions to identify the core underlying cognitions. Common cognitive themes involve catastrophizing, uncertainty, and discomfort intolerance; see Table 1 for examples of types of anxious cognitions reported by patients. The functional link between the sensations, thoughts, and subsequent exercise (avoidance) behaviors are established. For example, one patient “Andrew”, a taxicab driver who had recently recovered from an emergency percutaneous coronary intervention, said, “Well, the last time I noticed my heart racing like that I didn’t know what was going on… I thought it was just indigestion…, and the next thing I knew, I ended up in the hospital scheduling an emergency surgery.” As a result, “Andrew” had excessive worry characterized by uncertainty and doubt: “What if I don’t take these sensations seriously this time and there is something wrong with my heart again?”. For many, declining cardiovascular health and functioning appear to contribute to patients’ perception of themselves (e.g., identity is now a “heart patient”), their exercise abilities (e.g., “I cannot do the kinds of activities I used to do”), and safety (i.e., “better safe than sorry”).

Table 1.

Examples of fear-based versus acceptance cognitions in BE-FIT

Before BE-FIT: Fearful Cognitions			After BE-FIT
Catastrophizing	Uncertainty	Discomfort Intolerance	Acceptance
“I’m tired and breathless— I might be having another heart attack!”	“I’m tired and breathless—what’s causing that? Is something wrong with my heart that they didn’t fix?”	“I’m tired and breathless—that’s a sign that I should sit down and rest. I need a break.”	“I’m tired and breathless—that’s a sign that I’m doing good work to strengthen my heart!”
“My heart is beating faster— if I don’t slow down, I will pass out!”	“My heart is beating faster — Am I trying to do too much? Is this really safe?”	“My heart’s beating faster — I can’t stand that feeling. I guess I can’t walk this fast.”	“My heart is beating faster — This walk is doing a great job of getting me to my target.”
“My legs are starting to ache. If I keep walking, I will not be able to move tomorrow due to pain.”	“Why are my legs aching? Does that mean there’s a problem with my circulation?”	“My legs are achy, and I shouldn’t have to put up with that. I can’t finish this walk.”	“My legs are aching from working hard. It will take more time for my muscles to build some strength.”
“I feel wobbly on the treadmill. There must be something wrong with my balance. I could fall.”	“What if I lose my balance? What if I fall off the treadmill?”	“I just hate walking on the treadmill. I feel wobbly, and I’m not used to it. I can’t do it.”	“Walking on the treadmill is new for me, and it makes sense that I will not feel comfortable right away.”

Others find that they are feeling much more physically robust after a surgical procedure that corrected the medical source of their previous fatigue and dyspnea, yet exercise fear-avoidance persists. For example, one patient “John”, who recently had angioplasty and a stent placement, described, “I was a lifelong runner and used to manage the running club at work. I was the one who got it up and going, but I certainly haven’t been doing any running lately. I used to love to go golfing and walk the golf course, too. But I remember the last time I tried to climb that big hill on the back-nine. That’s when I really realized something was wrong. I started huffing and puffing, and I just couldn’t get up that hill. I didn’t realize it was my heart at the time--I guess I just thought it was a part of getting old and it was time to ride in the golf cart with the other old folks--but the doctor later explained that my heart problem was probably what caused me to be so short of breath and run out of steam. The doc finally cleared me to go back to golfing after my surgery. He says I’m good to go, and I do feel a lot better now than I did the last time I walked that hill, but I guess I’ll probably stick to riding in the golf cart between holes.” In this example, the BE-FIT should always ask “why?” to clarify the reasons for the exercise avoidance. Patients often respond, “What if something goes wrong?” or “How will I know if I’m doing too much?” or even, “What if the doctor didn’t do the surgery right, and I’m not really better?” These fearful beliefs and intolerance of uncertainty tend to limit the extent to which patients fully embrace the physical activity necessary for regaining mobility and independent function. The BE-FIT intervention does not necessarily aim to correct these cognitions, but a clear case conceptualization identifying the links between feared sensations, cognitions about the meaning of those sensations as related to the patient’s medical history, and associated fear-avoidance behaviors is necessary for informing development of the exposure hierarchy at a later session. In many cases, the cognitions do change because of exposure, but that is not a required outcome. Increased acceptance and tolerance of sensations and cognitions to facilitate increases values-focused behavior is sufficient.

Gaining a clear picture of each patient’s physical activity trajectory – from what their physical activity was like when they were at their most active to what it was like when they were most restricted by poor cardiovascular health – is important information to gather during an initial assessment. In addition, it is important to assess the feared sensations and associated cognitions, as well as exercise avoidance or safety strategies used as part of their coping process, to help the interventionist to personally tailor delivery of BE-FIT.

Psychoeducation

BE-FIT patients are introduced to the cognitive-behavioral model of anxiety and the role of avoidance in maintaining anxiety and suffering. Psychoeducation includes information to help distinguish normal (healthy) responses to exercise (e.g., a steadily elevated heart rate, commensurate with exertion during exercise) versus true safety indications (e.g., heart rate that fails to increase in response to exertion). The interventionist also reviews the role of exercise and lifestyle physical activity for healthy aging and discusses how daily accumulation of short bouts (≥10 minutes) of both planned and unplanned activities as part of everyday life can aid in manageable and sustainable changes to lifestyle activity. A key point of interventionist communication here is that by “starting low and going slow,” patients can recover function, independence, and physical capacity that has diminished while actually improving their heart health through physical activity, rather than increasing risk by remaining sedentary. By building from a conservative, manageable physical activity regimen, sprinkled into daily life activities, patients learn to tolerate feared sensations, accept the presence of anxious cognitions, and gradually improve their capacity for physical activity as a result of reconditioning—eventually helping patients to reclaim aspects of their former identity that they may mistakenly have assumed would be lost due to older age and inevitable health decline.

Physical Activity Monitoring and Goal Setting

In the BE-FIT intervention, patients are provided a wrist-worn activity monitor to objectively monitor daily physical activity (Goode et al., 2017). Activity watches record wrist movements using an internal accelerometer to monitor frequency, intensity, and regularity of movement, which is transformed into quantifiable data (e.g., steps/day, MVPA). During session one, the interventionist reviews physical activity levels from the baseline assessment, a pre-intervention period of at least 7 days during which patients wore the activity monitor for ≥10 hours per day to record their normally occurring engagement in physical activity, including daily steps and MVPA. The interventionist uses these data, consulting with the exercise physiologist as needed, to tailor two possible prescriptions (goals): (1) Increasing steps/day: If baseline steps/day reflect sedentary/low activity (accumulated average<4,000 steps/day) (Tudor-Locke & Bassett Jr., 2004), patients can be given the goal of achieving 4,500 steps/day and increasing each session by 500 steps/day (about 1/4 mile increase), as recommended by physical activity guidelines (2018 Physical Activity Guidelines Advisory Committee, 2018). At this rate, patients reach ~7,500 steps/day by end-of-treatment, which is an empirically-derived minimum for daily physical activity in older adults for longevity (Lee et al., 2019); and/or (2) Increasing physical activity intensity: If baseline active minutes/day reflect low MVPA (accumulated average < 30 active minutes/day), patients are given the goal of working gradually towards achieving and maintaining 30 very active minutes/day (i.e., minutes of activity recognized by the wrist-worn monitor as consistent with the intensity levels of brisk walking) on at least 5 days per week, as recommended for older adults by the American Heart Association and American College of Sports Medicine (Nelson et al., 2007). The manual provides an example script to instruct patients to begin with individual “bouts of at least 5–10 minutes, increasing gradually” each session by 5 daily MVPA minutes until reaching the goal of 30 minutes aggregated from one longer or several shorter bouts (≥10 minutes) throughout the day. Depending on their level of conditioning and medical comorbidities (e.g., arthritis pain or peripheral artery disease), patients may necessitate fewer shorter bouts of exercise to reach the aggregate goal without evoking unhelpful symptoms (e.g., pain from inflammation or claudication).

The gradual increases in physical activity over the course of the intervention is consistent with hierarchical exposure therapy practices (Barlow & Craske, 2007). In cases when low steps/day and low MVPA are evident at baseline, the interventionist can set both goals and/or prioritize the goal that will most directly target the patient’s fear.

At session 1, patients are provided with normative feedback and praise, “We can see here that you are averaging almost 10 minutes of MVPA per day, and the American Heart Association recommends at least 30 minutes a day, 5–7 days per week for someone your age as secondary prevention for improved heart health. But even a little exercise is better than nothing--so good for you for squeezing in these 10 minutes on most days! We can work together to help you nudge this average up little by little until you’re keeping up with AHA recommendations and getting back to the active life you want!” Or feedback regarding step count may take the form of: “It looks like you’re getting about 3,900 steps a day right now. For someone about your age, even with the kinds of health conditions you have, getting about 7,500 steps a day can improve your overall health and increase longevity. So we can aim for 4,500 steps a day--just a little bump to start out with, and build from there a bit at a time until you’re getting the amount of steps you need to reap all these wonderful benefits.”

The ultimate objective is to design an exercise prescription that will facilitate sufficient exposure (approach behavior) to physical activity itself and the feared exercise sensations while also increasing the total amount of daily physical activity. The exercise prescription is the foundation of exposure practice in the BE-FIT intervention and is augmented by additional physical activities and interoceptive exposures to fully target feared exercise sensations (see “Interoceptive Exposure Practice” below) and to achieve specific behavioral goals that are aligned to patients’ values (see “Values Clarification and Committed Action” below).

Values Clarification and Committed Action

Identification and clarification of personal values related to increased physical activity, and the expected improvements in strength, stamina, and functional capacity, can be a compelling source of motivation for facing feared exercise sensations and persisting in challenging physical activities. This focus on personal values clarification in BE-FIT provides the rationale for exposure practice in acceptance-based approaches (Arch et al., 2015; Twohig et al., 2018). While many patients will articulate “longer life” as the ultimate reason for participation in lifestyle physical activity and structured exercise, the values clarification discussion with the BE-FIT interventionist probes further to ask, “And what do you want to do with that longer life afforded by increased physical activity? What will your life look like? What will you be doing, and who will you be doing it with, that will make your life meaningful and rich and rewarding?”

BE-FIT interventionists listen carefully for indications of patients’ personal values and ask follow-up questions to increase the salience of those values. For example, in response to “John”‘s discussion of his physical activity, the interventionist followed up, “Wow. It sounds like walking the golf course was part of what made playing so enjoyable for you. What did it feel like to spend the day on the links and walk from hole to hole? How did you feel about yourself and your vitality after a long day on the golf course? What would it mean to you to get that back in your life?” This probing helped to bring additional clarity, so that “John” was able to identify vitality and zest for life as two qualities that represented his personal values. In response to “Jane”, the interventionist said, “Your sister is really important to you, and you’re missing out on an opportunity to take part in a big step in her life--looking at potential new homes. Why would you like to be able to do that with her? What is so important to you about doing that together rather than her having to do it without you there for company? … And what about just being able to go out to the grocery store alone and bring home your own groceries? What would it be like for you to have that independence back?” As a result, “Jane” identified being actively engaged and supportive in her relationship with her sister and regaining self-reliance and independence as values-consistent outcomes that she hoped to achieve by embracing a more physically active lifestyle. Taking the time in the earliest sessions to clarify the importance of these values in “Jane”‘s life provided excellent motivation for practicing the exposure trials when “Jane” reached that point in the intervention.

Intentionally probing for more information with this values-oriented filter allows the interventionist to prompt patients to provide their own nuanced and compelling rationale for bravely facing exposure practice and fulfilling their physical activity prescription. Achieving their physical activity goals is in this way directly tied to reclaiming participation in meaningful, valued activities that can only be facilitated by embracing a more active lifestyle. For example, one BE-FIT patient “Joseph”, who called himself former “navy man” assured his interventionist he was “used to tolerating a little discomfort”, however was worried that his arthritis pain paired with being deconditioned after a newly placed stent would prevent him from being able to attend his grandchildren’s sporting events. While it was a source of pride for him to watch his grandchildren play and doing so helped him to feel connected and engaged in their lives in a meaningful way, he was not sure if he would be able to walk the distance from his parked vehicle to the baseball field. This dialogue provided a rich source of information about “Joseph”‘s personal values, which the interventionist leveraged for sustained motivation to build his tolerance and courage for walking longer distances. “Joseph”‘s step count prescription and the duration for his prescribed bouts of walking (2 bouts of first 10 and then 15 minutes each) were explicitly tied to his values-consistent functional goal of walking the length from his parked car to the ball field (walking a distance to and from his car that took him about 15 minutes to cover each way). Clearly establishing this synergy between the objective goals of established physical activity guidelines and the patient’s values-based functional capacity goals is an integral facet of the collaboration between interventionist and patient and sets a strong motivational foundation for the guided exposure practice.

Interoceptive Exposure Practice

Guided exposure is introduced as the regular and systematic practice of avoided activities as well as activities that intentionally elicit feared bodily sensations. The goal of exposure is to facilitate interoceptive tolerance and learning that feared exercise sensations and the accompanying anxious thoughts can be experienced without avoidance (Craske et al., 2008). Concerns about safety and patient tolerability are common barriers to use of interoceptive exposure, especially in patients with comorbid medical conditions. Patients are reminded that sensations are normal reactions and that while they are uncomfortable, experiencing them during exposure will help them build tolerance and help to facilitate exercise and physical activity in the long term. It is also important for both clinicians and patients to recognize that patients have not only been medically cleared for MVPA in CR, but that MVPA is recommended. As in CR, the BE-FIT intervention follows the proverb, “Start low and go slow” to inform safety. In addition, patients are taught how to use the Rating of Perceived Exertion scale (RPE; range 6–20) to monitor subjective effort during exposure, with a target RPE rage of moderate-vigorous intensity (12–16 range). The interventionist also has access to heart rate (HR) data recorded from the activity watch which can be used as an additional index of exertion during exposure. In the absence of a baseline graded exercise test, the resting heart rate (RHR)+30bpm can be used as a target for moderate-vigorous intensity; with a graded exercise test, target intensity can be based on 40–80% of heart rate reserve (HRR) (American College of Sports Medicine, 2017; Mytinger et al., 2020).

Given the high degree of medical comorbidity in this patient population, as well as a varied array of feared sensations which contribute to avoidance of exercise, the exposure practices are designed to target a range of exercise sensations. Any exercise sensations, whether cardiopulmonary in nature or otherwise (e.g., pain, weakness, instability), are relevant to older adults with a variety of cardiovascular and other health issues, thus are targeted in BE-FIT. Exposures are planned by the interventionist in collaboration with the patient and an exercise physiologist (if needed). The exposures are tailored to the needs of each patient based on the nature of their fear-avoidance behaviors. Exposures are practiced with the guidance of the interventionist during session and are also assigned for homework (unsupervised) practice to facilitate generalizability of learning. Examples of interoceptive exposures include bouted moderate-vigorous intensity walking (prescribed distance, duration, and/or pace, depending on the target), hill-climbing, jumping jacks, straw breathing, breath holding, balancing exercises, and specific weight/resistance exercises that patients report elicit feared sensations. Exposures can also be combined to enhance effectiveness. Gradually increasing duration and intensity of physical activity according to personally-tailored exercise goals and adding targeted interoceptive exposures (e.g., jumping jacks or straw-breathing) to intentionally elicit feared sensations while exercising provide the building blocks for collaboratively developing the exposure plan.

In keeping with the acceptance-based exposure framework, patients learn that they can persist in exposure practice whether feared sensations and worrisome thoughts come along for the journey or not, rather than seeking to eliminate/mitigate sensations or challenge the accuracy of fears about the sensations (Meuret et al., 2012). Interventionists promote non-judgmental awareness and acknowledgement of bodily states through mindful, curious attention to experience (as opposed to avoidance or distraction from distressing internal experiences), as well as defusion from fearful thoughts (e.g., “Oh, look, there goes my uncertainty kicking in with all the ‘what ifs?’ Well, I don’t have to let that stop me from walking up this hill because that’s just gonna make me stronger.”) Patients are encouraged to “walk past worrisome thoughts” or allow the thoughts to drift freely by like clouds in the sky or leaves on a stream, as they just keep moving toward their physical activity goals, and the active lifestyle which will give them greater access to engaging in values-consistent activities.

For example, “Andrew”, the taxicab driver, while he was accustomed to taking long, low-intensity walks in between jobs, believed that he would be “paralyzed with fear” if he felt the combination of symptoms that he experienced prior to his emergency surgery (i.e., shortness of breath with racing heart). In session, “Andrew” and his interventionist completed jumping jacks together to elicit the sensation; it required 50 jumping jacks to elicit sufficient sensations to trigger anxiety. To his surprise, rather than being paralyzed by fear, he was pleased, “I haven’t done that in decades!… I didn’t think I could do so many jumping jacks at my age!” For his at-home exposure prescription, he completed a set of jumping jacks immediately prior to a brisk moderate-intensity walk and repeated the jumping jacks every five minutes during walking to sustain a moderately-elevated heart rate and heavy breathing for the prescribed 30 minutes. After completing his homework, he was thrilled that he was able to face these sensations independently, without supervision, and that he was fit enough to complete such an ambitious exercise goal at his age after recovering from emergency percutaneous coronary intervention.

For the golfer, “John”, he had a fear of walking the hill on the back-nine which is where he first felt dyspnea and fatigue related to his heart disease. The final exposure prescription that “John” was assigned was to play golf and bravely walk up that hill (instead of riding in the golf cart). He told his interventionist, “If I can make it up that hill, I’ll know I’m back to the man I used to be.”

The personally-tailored nature of the exposure prescription is designed to maximize the impact of the brief treatment and ensure that new learning successfully targets the most feared sensations and generalizes to the patient’s everyday life. When patients gain a more flexible behavioral repertoire, it can also result in a renewed sense of what is possible in terms of day-to-day living for older adults recovering from a serious medical setback.

Addressing Safety Behaviors

Cognitive-behavioral models of health anxiety emphasize the role of avoidance and safety behaviors in the development and maintenance of anxiety (Helbig-Lang & Petermann, 2010; Rachman et al., 2008; Salkovskis et al., 1999) including in older adults (Boston & Merrick, 2010). Avoidance and safety behaviors are anxiety-motivated actions that temporarily relieve anxiety yet maintain and exacerbate anxiety long-term. The appropriateness of the anxiety-motivated behavior is context-dependent on the context: in case of real threat (e.g., chest pain), an anxiety-motivated behavior (e.g., going to the emergency room) is adaptive, as it serves survival; whereas maladaptive behaviors are used in the absence of real threat or used to prevent or reduce anxiety (e.g., checking pulse regularly or avoiding activities that increase heart rate, like public speaking, exercise, sex, amusement rides). Through repeated use of maladaptive anxiety-behaviors, individuals learn to attribute “safety” (i.e., reduction in anxiety) to their avoidance and safety aids and develop false beliefs that safety is contingent upon certain actions. Many aspects of CR can reinforce use of false safety aids and behaviors. For example, patients typically wear an electrocardiographic telemetry monitor that connects to a centralized system that is monitored by a CR staff member during exercise sessions. The use of telemetry monitoring during exercise may inadvertently contribute to the development of (false) beliefs that exercise is safe only because of the monitoring and supervision, which can maintain exercise fear-avoidance outside of CR or when not monitored. Avoidance behaviors related to exercise (e.g., avoidance of activities that increase heart rate and respiration) are targeted in the PATCHD protocol (Tully et al., 2017). The BE-FIT intervention similarly addresses avoidance behaviors but also focuses on teaching patients to recognize common safety behaviors (e.g., checking heart rate) and identifying and addressing their own false safety behaviors.

Naturalistic observation of patients during CR activities can help to inform interventionists about specific targets. For example, the interventionist observed that “Jane”, the supportive-sister, exclusively selected to use the recumbent bike during CR. When asked, “Jane” explained that she avoided the treadmill because of concerns about balance. In addition, despite having no gait problems or history of falls, she described that she only felt safe walking with a balance aid, even though it made her “feel old”. The interventionist consulted with the exercise physiologist and found that there was no medical cause for “Jane” to be concerned about falling—she was physically capable of walking without support and had no conditions that would cause her strength, balance, or coordination to be compromised. After supervised exposure practice with treadmill walking during CR, the interventionist worked with “Jane” to gradually reduce her reliance on balance aids while walking outside of the clinic. For example, she practiced walking in the grocery store with only one hand on the shopping cart or pulling the cart (instead of pushing it). A patient may also report informative details about their physical activity practice at home that can inform presence of avoidance behavior. For example, the golfer “John” described, “I always walk the loop around the block in my neighborhood in this one direction so that I can go down the hill at the beginning, otherwise I’d have to climb the hill at the end of my walk when I’m tired, and I just don’t know what that would do to my heart.” While patients may be under the impression that such behaviors are a common sense ‘safety-first’ approach, psychoeducation is used to illuminate the role of such behaviors in the maintenance of fear and narrowing the behavioral repertoire. Patients are taught to recognize and increase awareness of anxiety-motivated behaviors and identify patterns or themes of avoidance.

Interventionists discuss how anxiety can affect avoidance in an overt manner (e.g., choosing not to engage in exercise when unsupervised, skipping CR because of anxiety) and subtle forms (e.g., riding the bike rather than using the treadmill or keeping a death grip on the shopping cart in “Jane” case). See Table 2 for a list of common exercise avoidance and safety behaviors. Because excessive heart rate checking is a common safety behavior in CR, it is proactively targeted as a ‘teachable moment’. Patients are taught how checking heart rate during exercise (e.g., via activity watch) can provide reassuring feedback in the moment but can also contribute to hypervigilance and preoccupation with heart rate data, and ultimately creates a reliance on such data (and intolerance to uncertainty in the absence of such data). Fading safety behaviors/aids and increasing acceptance of anxious cognitions (e.g., increase tolerance for uncertainty) is encouraged during exercise

Table 2.

Common exercise avoidance and safety behaviors

Behaviors that occur during CR	Behaviors that occur outside of CR
Avoidance: Skip CR sessions when the exercise program involves high-intensity interval training; Avoid certain exercise equipment that produce feared sensations; Refuse to increase intensity or resistance on machines to avoid feared sensations.	Avoidance: Avoid exercise or activity when alone, too far from home, or in areas that are not populated because “no one will be there to help me if something happens”; Refrain from using home equipment because lack of supervision.
Escape/Abandoning: Terminate exercise early/reduce intensity, incline, or resistance on machines when feeling feared sensations	Escape/Abandoning: Terminate activity earlier than planned when anxious (“I’m too far from home, what if something happens?”)
Reliance on “safety” cues: Tightly grip machines during exercise because of the belief that ‘it’s the only safe way to use it’; Select exercise machines based on presence of other patients/staff nearby because “it’s safer… someone will help me if needed”.	Reliance on “safety” cues: Choose to exercise or activities only when accompanied by friend/family, because “it’s safer in case something happens”; Keep phone and/or rescue medication on person during exercise because “it’s the only way to be safe”.
Reassurance Seeking: Ask CR staff for reassurance during exercise when feeling sensations (“Am I okay?”).	Reassurance Seeking: Call doctor, research symptoms online when feeling sensations to make sure they are not harmful
Checking: Checking heart rate monitors before, during, and after exercise; Checking balance to confirm safety.	Checking: Checking blood pressure or heart rate to decide whether it is safe to start/continue physical activity.

To highlight one example, the navy man “Joseph” reported that whenever he went for a very brief walk in his neighborhood, he would stop and turn around to “come on home before the pain got too bad and left me stranded,” which meant that he never allowed himself to walk farther than a specific, short distance. “Joseph” was reminded of one of his core values – to be connected and engaged in his grandchildren’s lives – and recognized that the distance he was willing to walk was much shorter than the distance he would need to cover if he was going to walk from his parked car to the ballpark to watch his grandson’s baseball game. His therapist explained staying just close enough to home to avoid feared pain sensations was keeping him from building the strength and stamina that would be required to sustain him on a longer walk; by contrast, gradually walking farther with each exposure practice would allow him to both bravely approach his fear of pain and increase his physical capacity. When this patient had to drive out of state the next week, he reported to his interventionist that he completed his exposure practice on the side of the highway at a roadside rest stop (quite a long way from home!) just to make sure he was working toward his goal of walking to the ballpark when the baseball season started.

Feasibility and Safety Outcomes

The overall study retention rate was 100%. All 12 patients in the BE-FIT intervention cohort completed each of the six BE-FIT intervention sessions (100% treatment completion). Compliance with the activity watch was very high. Overall, patients met wear compliance on 97.7 % ± 4.9% of days: with compliance of 98.1% ± 4.9% of days in the active BE-FIT cohort and 97.0% ± 5.3% of days in the monitoring-only control cohort. BE-FIT patients were prescribed exposure practice on an average of 10.9 days (SD = 1.00; minimum = 9, maximum = 12), with an average of 12.7 exposure trials (SD = 3.14, min = 9, max = 19). The modal number of exposure practices prescribed was one exposure trial per day (max = 3 per day). Exposure compliance was high. On average, BE-FIT patients completed 86.3% of the prescribed exposures (SD = 16.4%; min = 55.56%, max = 100%), which reflected an average of 11.1 completed exposure trials (SD = 3.34, min = 5, max = 17). Five of the twelve patients in the BE-FIT cohort completed 100% of prescribed exposure trials. RPE and HR were recorded in 80.5% and 87.2% of all completed exposures. BE-FIT patients reported an average peak RPE of 14.5 (range = 11.5 – 17.0) during exposure. Peak HR during exposure increased by a mean of 29.1 BPM (SD = 10.37; range = 11 – 46) above RHR. There were no adverse events reported during the study period among patients in either of the two cohorts.

Treatment Acceptability

At an end-of-treatment assessment visit, patients in the active BE-FIT condition completed the 8-item Client Satisfaction Questionnaire (CSQ-8) (Attkisson & Zwick, 1982) to evaluate the acceptability of BE-FIT. Items on the CSQ-8 are rated on a 4-point Likert scale, with higher numbers reflecting greater satisfaction, and a total summed satisfaction score is derived (possible range 8–32). An additional question was included regarding the extent to which patients thought participating in the BE-FIT program would be helpful increasing physical activity in the long-term. Overall, patients reported high satisfaction with BE-FIT (CSQ-8: M = 29.5, Median = 30.5, SD = 2.71, min = 24, max = 32). Specifically, satisfaction ratings were reported as follows (M±SD): quality of program (3.75±0.45), the kind of program the patient wanted (3.75±0.45), program met the patient’s needs (3.50±0.67), would recommend to a friend (3.75±0.45), amount of help received (3.75±0.45), ability to stick to the program (3.58±0.51), overall satisfaction (3.75±0.45), and helped increase long-term physical activity (3.67±0.49).

Efficacy Outcome Data

See Table 3 for means and standard deviations at baseline and end-of-treatment, in addition to effect size estimates. Independent samples t-tests revealed that there were no significant differences on measures of outcome variables between patients in the active BE-FIT condition and the monitoring-only control group at baseline. Regarding changes in physical activity, the BE-FIT intervention produced an average increase of 2,003 steps/day from baseline to end-of-treatment, which was a significant, large-sized effect (t[11] = 4.35, p = .001, Hedge’s g = 1.211 [CI_95%= 0.46, 1.937]). BE-FIT also produced an average increase in MVPA by 28.2 minutes/day from baseline to end-of-treatment, which was a significant, large-sized effect (t[11] = 3.30, p = .007, Hedge’s g = 0.921 [CI_95% = 0.241, 1.572]). Notably, BE-FIT patients demonstrated increases in steps/day and MVPA min/day on days in which whey attended CR and on non-CR days. See Figure 2 for visual depiction. In contrast, the monitoring-only control cohort evidenced no change from baseline to end-of-treatment for either steps/day (t[6] = 0.05, p =.963) or MVPA minutes/day (t[6] = 0.46, p = .661).

Table 3.

BE-FIT Outcomes and effect sizes

	BEFIT (N=12)							Control (N=7)						Between
	Baseline M (SD)	End of Treatment M (SD)	t	p	Hedge’s g	CI		Baseline M (SD)	End of Treatment M (SD)	t	p	Hedge’s g	CI	Partial eta2
ESQ-Total	44.2 (11.5)	25.6 (15.6)	3.44	.005	0.960	0.271, 1.621		36.7 (10.5)	30.1 (14.7)	1.25	.257	0.443	−0.308, 1.162	0.113
ESQ-Pain/weakness	16.4 (8.1)	8.3 (6.6)	2.94	.013	0.820	0.164, 1.449		11.7 (7.2)	10.1 (7.0)	0.52	.619	0.185	−0.523, 0.879	0.121
ESQ-Cardiopulmonary	27.8 (5.1)	17.3 (9.3)	3.25	.008	0.907	0.231, 1.555		25.0 (5.0)	20.0 (8.0)	1.85	.114	0.653	−0.149, 1.414	0.072
Avg Steps/Day	5758.8 (2940.6)	7761.5 (3684.4)	−4.35	.001	−1.211	−1.937, −0.456		5979.7 (4795.7)	5936.2 (3369.5)	0.05	.963	0.017	−0.677, 0.71	0.229
Avg MVPA min/day	20.5 (16.9)	48.9 (35.2)	−3.32	.007	−0.926	−1.578, −0.245		30.2 (32.1)	27.7 (23.0)	0.46	.661	0.163	−0.543, 0.856	0.279

Note: M (SD) = mean (standard deviation); CI = confidence interval; ESQ = Exercise Sensitivity Questionnaire; MVPA = Moderate-vigorous physical activity.

Figure 2.

Visualization of changes in steps/day and MVPA in BE-FIT compared to control.

Note: CR = Cardiac Rehabilitation; BE-FIT = Behavioral Exposure for Interoceptive Tolerance; PA = Physical Activity; MVPA = Moderate-vigorous physical activity.

In terms of target engagement, BE-FIT produced significant reductions in exercise sensitivity from baseline to EOT (MΔ = 18.6, SD = 18.69; t[11] = 3.44, p = .005, Hedge’s g = 0.960 [CI_95% = 0.271, 1.621]). In contrast, the monitoring-only control cohort evidenced small-sized, non-significant changes in exercise sensitivity from baseline to EOT (MΔ = 6.6, SD = 13.89; t[6] = 1.25, p = .257, Hedge’s g = 0.443 [CI_95%= −0.308, 1.162]).

Interventionist Feedback and Lessons Learned

An audio-recorded interactive, unstructured group interview was conducted with the study interventionists as a debriefing to further inform feasibility and areas for protocol refinement. All study interventionists responded to open-ended questions about their experiences with training, supervision, and delivery of the manualized intervention. Debriefing take-aways included the following: (1) Thorough assessment of feared sensations and cognitions is essential in order to understand the complex and nuanced nature between feared bodily sensations and medical symptoms/conditions; (2) Personalized tailoring of interoceptive exposure prescription (i.e., type of exposure, frequency, duration, intensity, location) is especially important in this population given the significant heterogeneity in medical symptoms/conditions between patients; (3) Interoceptive exposure is not only acceptable but, indeed, it is welcomed by patients who are eager to bravely approach physical activity; and (4) With sufficient assessment, monitoring, and exposure tailoring, interventionists can feel confident that exposure to feared interoceptive sensations is both safe and effective.

Study Limitations and Future Directions

Given the preliminary nature of this pilot investigation, limitations include a small sample size, collecting data from cohorts assigned in two subsequent waves (active BE-FIT condition followed by monitoring-only control condition) rather than true randomization, and the lack of longer term follow-up. These limitations should be considered when interpreting the results of this study. Our Stage II randomized controlled trial (R01-AG070136) will allow for a true time- and attention-matched comparison control with blinded randomization and assessment as well as longer-term follow-up in a larger sample of patients enrolled in cardiac rehabilitation at a large academic medical center. We will test the effects of BE-FIT on daily physical activity and cardiac rehabilitation adherence at end-of-treatment and follow-ups (total = 24 weeks), and evaluate mechanisms of change. We expect that the results of this study will produce valuable scientific knowledge regarding the efficacy of BE-FIT and mechanisms of action. The public health significance of this work is the potential for adapting BE-FIT for future dissemination to cardiac rehabilitation and for other patient populations, with the goal of promoting lifestyle physical activity, and in turn, more successful aging.

Summary and Conclusions

Our preliminary work established the feasibility, acceptability and safety of BE-FIT. We also found evidence of target engagement (large-sized reductions in exercise anxiety) and initial evidence for the effect of BE-FIT on exercise outcomes, including significant increases in steps/day and MVPA minutes/day at the end of treatment. Heterogeneity and medical comorbidity in this population necessitates thorough assessment and a high-degree of personalized tailoring of interoceptive exposure practices. With a well-informed, individually-tailored approach and careful psychoeducation, interoceptive exposure can be used successfully and safely in older adults with complex cardiovascular conditions, even when completed independently (unsupervised). Exposure practice during CR may provide a window-of-opportunity for aging patients to regain physical activity abilities, mobility, and independent functioning during a stage in life when capacity might otherwise be diminished. If the efficacy of the BE-FIT can be established in a subsequent Stage II randomized controlled trial, this intervention could serve as an adjunctive treatment to CR and be adapted for other patient populations and treatment settings, for physical activity promotion in support of successful aging.

Data Availability Statement

The data that support the findings are archived with the university and are available from the corresponding author upon reasonable request.