Determinants of Sedentary Behaviour in Individuals with COPD: A Qualitative Exploration Guided by the Theoretical Domains Framework

Abstract

In people with chronic obstructive pulmonary disease (COPD), there is increasing recognition that the prolonged accumulation of sedentary time (ST) is associated with adverse cardio-metabolic health outcomes. Nevertheless, changing this lifestyle, which has evolved over several decades, is likely to be challenging. This study reports the determinants, perceived by individuals with COPD, as being important for reducing ST. An in-depth understanding of this information is essential when planning an intervention to reduce ST. Fourteen individuals with COPD completed semi-structured one-on-one interviews, which were audio recorded and transcribed verbatim. Both the interview schedule and mapping of data items extracted from the interview transcripts were informed by the Theoretical Domains Framework (TDF). A total of 867 quotes were mapped to the 14 TDF domains. Seven of the fourteen domains were identified as being important determinants for reducing ST: knowledge, beliefs about consequences, beliefs about capabilities, environmental context and resources, social influences, social/professional role and identity, and behavioural regulation. There was a lack of knowledge regarding the meaning of sedentary behaviour. Participants’ desire to be educated by knowledgeable health professionals in a formal programme was a dominant theme across multiple domains. The most frequently reported barriers to reducing ST related to the domains of social/professional role and identity and environmental context and resources, while the most frequently reported enablers were related to the domains pertaining to beliefs about consequences and social influences. Potential strategies to reduce ST among people with COPD include education and other determinants identified in this research.

Keywords:

• Sedentary behaviour
• theoretical domains framework
• chronic obstructive pulmonary disease
• health promotion
• behaviour change

Introduction

Sedentary behaviour (SB), which has been defined as “any waking behaviour characterized by an energy expenditure ≤1.5 METs while in a sitting, reclining or lying posture”, [1] is associated with detrimental health effects [2–5]. In the general population, the time spent in SB has been linked with an increased risk of developing diabetes and cardiovascular diseases, as well as an increased risk of all-cause mortality [4–8]. Physical activity has been defined as “any bodily movement produced by skeletal muscles that results in energy expenditure” [9]. Of interest, the health risks associated with SB are largely independent of the time spent in moderate to vigorous physical activity and as such, SB has emerged as an independent target for interventions [10–12]. Given the strong inverse correlation reported between sedentary time and time spent in light intensity physical activity [13], substituting sedentary time for activities undertaken in an upright posture at low intensity may be an achievable goal. Isotemporal substitution modelling suggests that replacing 30 min/day of SB with light intensity physical activity may produce a significant decrease in the risk of all-cause mortality in general population [14,15]. Of note, light physical activity is associated with cardiac and metabolic benefits, even if the intensity of this activity does not meet the recommendations for moderate or vigorous physical activity [16–20].

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disease, characterised by dyspnoea, fatigue and exercise intolerance [21]. Individuals with COPD are more likely to spend prolonged time sitting and less in a standing position or walking, compared with healthy individuals [22,23]. They spend most of their time in SB and engage in little physical activity due to their marked dyspnoea and fatigue [24,25]. Hartman and colleagues [26] suggested that in this population, SB was associated with lower exercise capacity, lower motivation to exercise and increased number of exacerbations in the past year.

Replacing time spent in SB with light intensity physical activities may be a feasible goal to improve health of people with COPD given their reduced exercise capacity and fatigue [24,27]. Information on interventions aimed to reduce SB in individuals with COPD is scarce with only few behaviour change interventions to reduce SB in this population have been developed [28]. Exercise training, the cornerstone of pulmonary rehabilitation (PR), is associated with significant improvements in dyspnoea, fatigue, emotional function and mastery as well as exercise tolerance [29,30], but the impact of exercise training on physical activity is very small [24,31,32]. This likely reflects the lack of behaviour change strategies during PR programmes that are directed at increasing habitual physical activity [24].

There is increasing interest in implementing behaviour change interventions to decrease SB among people with COPD, especially the prolonged and uninterrupted bouts during the day [24,27]. However, information pertaining to how individuals with COPD perceive SB is lacking. A better understanding of the determinants of SB from the perspective of individuals with COPD as well as the identification of the barriers and facilitators to decreasing SB may provide important information that will help inform new interventions to reduce SB in this population.

This study utilises the Theoretical Domains Framework (TDF) to understand determinants of SB as perceived by individuals with COPD. The TDF is a widely used comprehensive framework that covers 84 theoretical constructs and adapted from 33 psychological theories [33]. The TDF consists of 14 domains addressing the potential range of personal and institutional factors that influence changing behaviours [33]. These domains are: ‘Knowledge’, ‘Skills’, ‘Social/Professional Role and Identity’, ‘Beliefs about Capabilities’, ‘Optimism’, ‘Beliefs about Consequences’, ‘Reinforcement’, ‘Intentions’, ‘Goals’, ‘Memory, Attention and Decision Processes’, ‘Environmental Context and Resources’, ‘Social Influences’, ‘Emotions’, and ‘Behavioural Regulation’. The TDF is an advanced version of the Capability Opportunity Motivation-Behaviour (COM-B) model, which can be linked to the Behaviour Change Wheel (BCW) to help healthcare providers and researchers in the selection of intervention functions and behaviour change strategies for the design and delivery of new interventions [34,35].

The aim of this study was to explore the determinants of SB among individuals with COPD using the TDF.

Methods

Study design

This study used an established qualitative methodology [35,36]. Approval was obtained from the Joint West Park Healthcare Centre -Toronto Central Community Care Access Centre - Toronto Grace Health Centre Research Ethics Board (JREB) (JREB Number: 18-02-WP), with all the participants providing informed consent. Thereafter, between February and May 2018, the first author [AW] conducted semi-structured one-on-one interviews with individuals with COPD. The consolidated criteria for reporting qualitative research (COREQ) is used to report the study findings [37] (online supplement 1).

Framework

The first author [AW] used the TDF to create the interview schedule (online supplement 2), which was then revised by [KH], who is a researcher with expertise in the field of SB and COPD. The interview schedule was piloted with two persons with COPD at West Park Healthcare Centre (WPHC) and then, it was refined accordingly (e.g. minor wording changes, removing repetitive questions). A coding manual was constructed prior to and updated during data collection by two researchers [AW, AS] to guide the coding process (online supplement 3).

Participants and recruitment

Participants were recruited from the maintenance programme provided by WPHC, in Toronto, Canada. This programme is attended by those who have completed PR and comprises a weekly session during which people perform supervised exercise training and are provided psychosocial support. The first author [AW], who is a physiotherapist and a PhD candidate, was responsible for approaching potential participants in person and explaining the consent form to those interested. He was not involved in the participants’ clinical care. The inclusion criteria were a diagnosis of COPD confirmed by spirometry (ratio of forced expiratory volume in the first second forced vital capacity [FEV₁/FVC] < 0.7), an ability to ambulate and have functional limitation resulting from dyspnoea, defined as a modified Medical Research Council scale [mMRC] ≥ 2. Individuals who were unable to provide informed consent and those unable to communicate due to language barriers or cognitive impairments were excluded.

Data collection

All interviews were conducted in a quiet area at WPHC between March and May 2018, and lasted between 20 min and 101 min. Participants were asked standardised questions informed by the TDF, with prompt questions being asked for further clarification (online supplement 2). Transcripts were not returned to the participants for comments or corrections. Field notes were taken during the interviews by the interviewer. Recruitment was completed once the point of saturation (the point at which no new insights have been gained) had been reached [38], which occurred following the twelfth interview and was confirmed in a further two interviews.

Data analysis

All interviews were audio recorded and transcribed verbatim by a professional transcriber. The data were stored and managed using Microsoft Excel. Data analysis was undertaken in a two-stage process. Deductive directed content analysis was utilised, where the transcripts were coded into the relevant TDF domain(s). Then, domain summary themes were reported to provide descriptive summaries of the responses pertaining to SB to capture the diversity of meaning in relation to each TDF domain. This approach was recommended by Atkins and colleagues [35] and was previously used by Weatherson et al. [39]. It allows for an in-depth understanding of both pre-determined (TDF domains) and emergent (specific participants’ beliefs) factors that affect the targeted behaviour. Following the coding manual, transcripts were coded independently into the relevant TDF domain(s) by two researchers [AW, AS]. The researchers met after coding each transcript to discuss any discrepancies and adjust the coding manual as necessary. Generating domains summary themes and beliefs statements as well as barriers and facilitators extraction was undertaken by the first investigator [AW], and subsequently revised by [AS]. Discrepancies were solved through discussions until a consensus was reached. We applied three criteria to identify the relevant domains that influence SB as follows: high frequent coded domains; conflicting beliefs within domains; and evidence of strong beliefs that could affect SB judged by the authors.

Results

Participants

Fourteen individuals (17 approached, 3 declined) participated in the study. Their characteristics are shown in Table 1. The mean age (SD) of the participants was 75.6 (8.4) years, 10 (71%) were females, 7 (50%) were on oxygen therapy, 9 (64%) used walking aids for ambulation, and 10 (71%) lived alone.

Table 1. Characteristics of participants (n = 14).

	Mean (Max, Min) or n [percentage]
Age, years	75.6 (87, 60)
Gender
Females	10 [71]
Males	4 [29]
BMI, kg/m^2	30.5 (38.7, 20)
Pulmonary function
FEV1, L	1.2 (3, 0.6)
FEV1, %predicted	52 (91, 24)
FEV1/FVC, %	45 (68, 24)
FVC, L	2.6 (4.2, 1.5)
FVC, %predicted	86 (120, 62)
TLC, L	5.6 (8.2, 3.6)
TLC, % predicted	111 (157, 72)
Diffusion, ml/min/mmHg	10.9 (19.8, 5.9)
Diffusion, % predicted	59 (105, 40)
mMRC*	3 (2, 3)
Smoking history
Pack-years	50.4 (120, 8)
Former smokers	14 [100]
Current smokers	0 [0]
O2 therapy	7 [50]
6MWD, m	344 (547, 120)
Living alone	10 [71]

Abbreviations: BMI, body mass index, FEV₁, forced expiratory volume in 1 s, FVC, forced vital capacity, Max, maximum, Min, minimum, mMRC, modified Medical Research Council scale, O₂, oxygen, TLC, total lung capacity, 6MWD, six-minute walk distance.

*Data reported as median (Q1, Q3).

Barriers and facilitators

Of a total of 867 quotes mapped to the TDF domains, we identified 247 barrier and 505 facilitator codes (total = 752). The other 115 quotes were coded items that were neither facilitators nor barriers. Table 2 summarises the number of quotes mapped to each TDF domain per participant as well as the numbers of facilitators and barriers. The most frequently coded barriers related to domains of; (i) social/professional role and identity (14/14 participants, 6% of mapped items) and predominantly concerned the sensation of breathlessness, fatigue and presence of comorbidities, (ii) environmental context and resources (12/14 participants, 4% of mapped items) which predominantly concerned difficulties associated with humid or cold weather and, (iii) beliefs about capabilities (10/14 participants, 3% of mapped items) which predominantly concerned the perceived difficulty of changing SB. Less common barriers related to domains of skills (0.5% of mapped items), beliefs about consequences (0.9% of mapped items), optimism (0.5% of mapped items), goals (0.2% of mapped items), memory, attention and decision processes (0.3% of mapped items), behavioural regulation (0.2% of mapped items) and reinforcement (0.1% of mapped items).

Table 2. Frequency counts of quotes mapped to TDF domains for each participant.

	Knowledge	Social Influences	Social/Professional Role and Identity	Beliefs about Consequences	Environmental Context and Resources	Behavioural Regulation	Beliefs about Capabilities	Intentions	Emotions	Goals	Memory, Attention and Decision Processes	Reinforcement	Optimism	Skills
P1	12	5	4	5	7	4	0	1	4	0	2	0	1	1
P2	4	21	11	8	13	5	5	5	4	4	1	3	2	4
P3	3	17	7	4	16	4	6	2	2	1	2	0	0	0
P4	12	16	14	11	3	6	8	9	2	1	2	0	0	0
P5	5	4	3	5	11	6	2	3	4	5	3	3	1	1
P6	10	6	3	6	0	1	2	3	2	2	2	5	1	1
P7	8	10	20	6	2	1	10	4	1	0	2	0	2	1
P8	16	2	7	7	2	7	6	3	1	2	2	1	0	1
P9	17	9	7	18	12	12	2	5	1	2	2	5	1	2
P10	10	9	5	5	3	2 (	0	3	5	11	2	1	1	0
P11	11	6	8	5	8	2	2	3	13	0	2	1	3	0
P12	11	7	5	6	4	6	5	3	5	1	2	3	1	1
P13	5	2	2	5	4	0	3	5	0	3	2	0	1	0
P14	8	9	5	5	4	5	5	1	2	3	2	1	1	0
Total	132 F = 40 B = 37  U = 55	123 F = 78 B = 25  U = 20	101 F= 12 B = 55  U = 34	96 F = 88 B= 8 U = 0	89 F= 51 B=28 U = 1 Both= 9	61 F = 58 B = 2  U = 1	56 F = 18 B = 29  U = 9	50 F = 24 B = 26  U = 0	46 F= 30 B = 14  U = 2	35 F = 33 B = 2  U = 0	28 F = 25 B = 3  U = 0	23 F = 21 B = 0  U = 1 Both = 1	15 F = 10 B = 4  U = 1	12 F = 6 B = 4  U = 2

Abbreviations: F = facilitator, B = barrier, U = undetermined (neither barrier nor facilitator), BOTH = item can be perceived as a barrier and/or facilitator (e.g. weather).

The most frequently coded facilitators related to the domains of; (i) beliefs about consequences (14/14 participants, 10% of mapped items) which mainly concerned beliefs of the positive benefits of reducing SB and being more physically active, (ii) social influences (13/14 participants, 9% of mapped items) which mainly concerned support from family and loved ones and being surrounded by people, (iii) behavioural regulation (13/14 participants, 7% of mapped items) and mainly concerned self-monitoring and action planning; (iv) environmental context and resources (12/14 participants, 7% of mapped items) which mainly concerned home and neighbourhood designs, access to programmes and equipment such as oxygen tanks and rollators. Less common facilitators related to the domains of skills (0.7% of mapped items), optimism (1% of mapped items) and social/professional role and identity (n = 1% of mapped items).

Domain summary themes

The most frequently reported domains of the TDF were knowledge, social influences, social/professional role and identity, beliefs about consequences, environmental context and resources, behavioural regulation and beliefs about capabilities, while the least reported domains were intentions, emotions, goals, memory, attention and decision processes, reinforcement, optimism and skills (Table 2). The deductive content analysis is shown below and the domain summary themes with sample quotations are presented in online supplement 4.

Knowledge and perception of sedentary behaviour

There was a lack of knowledge pertaining to the meaning and what constitutes SB among individuals with COPD. It was described as “idle time” or “doing nothing”. They often reported low estimates of the total amount of time they spent in SB during the day and many of them thought that a reduction in SB reflected a requirement for more exercise. Respondents were unaware that reducing SB could be achieved by replacing it with light physical activity or by replacing prolonged periods of sitting with transitioning to upright positions (barrier).

Some participants indicated that they spent more time in SB in the evening compared to the morning, because of fatigue and lack of energy or watching their favourite TV show. Most indicated that there was no difference in their SB over weekends compared to weekdays as they were all retired. The majority of participants expressed their desire to be educated on how to reduce and break up their sitting time (facilitator).

Skills

Reduced fitness and limited physical skills were barriers to reducing SB. Participants pointed out that learning how to manage their shortness of breath was important for increasing their physical activity (facilitator).

Social/professional role and identity

Participants’ self-image as an active person may facilitate reducing SB. However, individuals’ experiences of their disease seems to place constraints on how they perceive themselves and the activities they consider appropriate for them (barrier). Comorbidities (e.g. osteoarthritis) were frequently reported by the participants, which seemed to increase the time the participants spent in SB (barrier). Most participants suggested that it is up to the individual to change their SB.

Beliefs about capabilities

Some participants thought that changing SB was a difficult task (barrier). They suggested that confidence is important to decrease SB and increase physical activity. However, many participants expressed a lack of confidence for performing physical tasks that were easily accomplished earlier in life (barrier), which limits what activities they engage in. Overall, the participants suggested that there should be a balance between sitting and being active, because of their limitations.

Optimism

While participants had a generally optimistic perspective, the reduction of SB depended on their motivation and personal beliefs (barrier or facilitator).

Beliefs about consequences

Most participants recognised the positive benefits of reducing SB and the negative consequences of sitting for long periods. Only a few participants (two of them) indicated that reducing SB was associated with increased breathlessness (barrier). Notwithstanding that, the majority of the participants had the desire to be educated regarding the benefits of reducing it (facilitator).

Reinforcement

Many participants reported receiving useful encouragement by healthcare providers working in the pulmonary rehabilitation field on the importance of being physically active, but there had been little or no emphasis on reducing SB (barrier). Many participants expressed their willingness to be educated, encouraged and followed up by healthcare providers concerning reducing SB (facilitator).

Intentions

Participants were ambivalent about reducing SB (barrier). They were willing to try (facilitator) to reduce their SB although many were unsure how and did not think that it was possible (barrier). When asked whether they intended to participate in an intervention to reduce it, they were generally willing to be involved in such an intervention, if it were made available (facilitator). Most of the participants suggested education as a main component of the intervention, which reflects their desire to be educated by a knowledgeable healthcare provider (facilitator).

Goals

Many participants perceived reducing SB as an important goal for improving their functionality (facilitator). They had no explicit or detailed plans on how to reduce it, but they tended to prefer to break up prolonged periods of SB, instead of reducing the total sitting time. Many participants indicated that having purpose or reason to move was important for reducing SB (facilitator). They suggested that an intervention to reduce SB should include setting goals that have to be followed up by themselves or a healthcare provider.

Memory, attention and decision processes

All participants were able to remember previous information provided by the interviewer (facilitator). Comments coded into this domain were responses to questions related to previous information provided to or discussed with the participants (e.g. meaning of SB, health consequences of SB).

Environmental context and resources

Most participants reported that home spaciousness helped in reducing their SB (facilitator). They wanted to get out of their homes in order to reduce it. Accordingly, access to transportation and nice weather were perceived as facilitators to reducing SB as they would facilitate getting them out of their homes. They also preferred structured programmes including educational classes. Moreover, access to activities programmes (e.g. community-based programmes) seems to be a facilitator to reducing SB. Some suggested that having gym equipment at home (e.g. treadmill) was not enough to motivate them to reduce their sitting time, thus reflecting the lack of knowledge of the difference between reducing SB and being physically active (i.e. they think that reducing SB means doing exercise). Those participants who were on portable oxygen therapy and those who used mobility aids (e.g. rollator, wheelchair) indicated that the use of such equipment could hinder or facilitate reducing SB.

Social influences

Participants indicated that support from family, loved ones and peers were important to changing their SB and that inclusion of family members and/or loved ones in an intervention to reduce SB may be beneficial. Being accountable seems to facilitate SB (e.g. being responsible for someone or a pet or having someone to report to). However, being surrounded by people was identified as both a barrier and a facilitator to reducing SB. For example, some participants reported that having someone around versus living alone facilitated more active behaviour even without direct verbal contact, while others indicated that when surrounded by people, everything would be done for them, which increased their SB and dependency. Modelling and comparison of self to others (observational learning) as well as comparison of the former self to current self were perceived as a facilitator and barrier, respectively.

Emotions

Mood appears to contribute to SB and vice versa as both a barrier and a facilitator. Most participants reported that low mood might increase their SB and decrease their motivation to move around. Enjoyment of physical activity seems to have facilitated reducing SB as participants wanted to be engaged in activities that were interesting/fun to them. In contrast, a few participants expressed their enjoyment of sitting, which is perceived as a barrier.

Behavioural regulation

Due to their illness, participants suggested that there should be a balance between sitting and being active. Pacing themselves to be more physically active (e.g. taking frequent rests to alleviate dyspnoea while walking) seems to have been a facilitator in reducing participants’ SB. Self-monitoring of the time spent in SB and keeping records as well as generating alternatives (e.g. finding different things to do in different circumstances) were reported as beneficial in reducing it. Further, positive self-talk could play an important role in changing SB as participants suggested that talking to themselves into being more active could be helpful. Trying to break habits by linking changing SB with certain stimuli (e.g. getting up every commercial) seems to be a good strategy to reduce SB as suggested by participants.

Discussion

This is the first study that has utilised the TDF to explore the determinants of SB as perceived by individuals with COPD. Participants perceived their SB to be mostly influenced by factors relating to knowledge, beliefs about consequences, beliefs about capabilities, environmental context and resources, social influences, social/professional role and identity and behavioural regulation domains of the TDF.

Participants lacked knowledge about the meaning of SB and many were unable to describe it. This is in keeping with observations among adults with stroke and obesity [40,41]. Of interest, participants were recruited from a maintenance programme which followed participation in a PR programme. Educational materials of PR do not include information on SB apart from physical activity [42]. Importantly, knowledge regarding behaviour and its health consequences is an important step in promoting health [41]. If individuals with COPD are unaware of this concept or their patterns of sedentary time accumulation throughout the day then motivation to change this behaviour would not develop. Moreover, knowledge that reducing sitting time does not necessarily require exercise or moderate intensity physical tasks, and can be achieved by replacing it with standing or light physical activity, may encourage individuals with COPD to engage in more light physical activities. Participants indicated their interest in a structured SB programme led by healthcare providers which offers the opportunity to be included as part of pulmonary rehabilitation (PR). However, knowledge and information should be joined with other behaviour change determinants to be effective [43].

The most commonly reported barriers to reducing SB were related to social/professional role and identity domain. These included the severity of symptoms including dyspnoea and fatigue, and the presence of co-existing conditions. Previous research suggests that exertional dyspnoea contributes to increased SB [44] and a reduction in physical activity in persons with COPD [45]. Moreover, comorbidities such as heart disease and osteoarthritis, are frequently reported in people with COPD [46–48] and have been found to negatively related to physical activity (49,50) and positively related to SB (51). Adopting slower pace and/or taking frequent short rests to undertake more physical tasks were suggested to reduce SB, in keeping with the report by Kosteli and colleagues [52].

Participants were generally aware of the potential health benefits of being physically active. They were also aware that being too sedentary had negative health consequences. Hartman and colleagues found that awareness of benefits of being physically active was not associated with high physical activity among people with COPD [53]. In contrast, they found that illness was associated with low physical activity and argued that perceptions of limitations was more influential than awareness of benefits [53]. This finding implies that in order to reduce SB and increase physical activity, perceptions about the extent their illness hinders physical activity should be mitigated (e.g. by verbal persuasion) before increasing awareness of the many potential health benefits of being physically active and less sedentary [53]. Changing patients’ perceptions and awareness can be done by healthcare providers within PR programmes. In this study, participants frequently indicated that encouragement from healthcare providers would be important to help them to reduce their SB and increase physical activity. Encouragement from healthcare providers was one of the recommendations of COPD clinical practice guidelines to promote physical activity and reduce SB [54].

In the present study, factors related to environmental context and resources domain were frequently mentioned by participants as barriers or facilitators to reducing their sitting time including weather and home design and space. Poor weather (e.g. humid, cold) was perceived by participants as a factor that leads to increased SB as they preferred to get out of their homes to reduce their sitting time. Adverse weather has previously been shown to be a common reason why individuals with COPD as well as older adults are sedentary [52,53,55,56,]. Indoor activities, such as walking in a mall or activities in a community centre, are potential solutions to improve SB in poor weather conditions. Nonetheless, people with COPD should be educated that SB can be reduced without the need to go out of home. Environmental restructuring is a promising intervention technique to reduce SB among older adults [57]. For example, simple tips such as leaving the remote control out of reach so that one has to get up to change the channel may help reducing SB.

Social support from family and loved ones may be a facilitator to reducing their SB. Living alone was associated with increased SB in the elderly [58,59]. A systematic review by Thorpe and colleagues indicated that social support is a facilitator to physical activity participation in people with COPD [60]. Individuals with COPD who live with an active loved one have a higher likelihood of being active [61]. In the present study, participants suggested that being engaged in structured programmes with their COPD peers (e.g. walking groups) and involving family members and loved ones in a sedentary reduction intervention may be helpful.

The participants considered reducing their SB to be a challenging endeavour. They indicated their low sense of self-efficacy for being engaged in physical activities that were more easily accomplished earlier in life. Self-efficacy, which refers to “beliefs in one's capabilities to organize and execute the courses of action required to produce given attainments”, is an important determinant of a wide array of health behaviours including physical activity [62,63]. Low self-efficacy may be related to lower physical activity in people with COPD and therefore, improving self-efficacy is important to increase physical activity in sedentary individuals with COPD [26,45,53]. Liacos and colleagues [64] noted that better self-efficacy at baselines was associated with lower SB after PR suggesting that strategies to increase self-efficacy for sitting less and moving more should be emphasized in PR. Self-efficacy can be enhanced by vicarious experience (modelling), social persuasion and performance experience of success [53,62]. Vicarious experience and social persuasion can be enhanced by participants being engaged in physical activity with family or loved ones, or encouragement of a healthcare provider [26].

Encouraging individuals with COPD to find solutions or alternative options that work best for them to overcome their barriers may be beneficial to help them being less sedentary. Self-regulation skills are important to improve physical activity and reduce SB among adults [57,65]. In the present study, participants suggested a range of self-regulatory skills to manage their symptoms and motivate themselves to be less sedentary, including self-monitoring, problem-solving, generating alternatives and pacing themselves to accomplish more physical activity. These suggestions are consistent with previous research, which suggested that self-regulatory skills could facilitate physical activity in persons with COPD [52]. Despite being suggested as promising strategies to change activity behaviours [11,66,67], the use of technology such as mobile applications or real time feedback as a self-monitoring strategy may not be appropriate to our sample of people with COPD: the participants in this study were older adults (mean age [SD] = 75.6 [8.4] years) and unfamiliar with the use of technology.

Intentions, goals, reinforcement and emotions domains appear to be relevant to SB but less important than the aforementioned TDF domains. Skills, optimism and memory, attention and decision processes were the least coded domains and therefore the least relevant to SB.

One of the limitations of this study is that the participants were retired, thereby limiting the generalizability of our findings. Sedentary behaviours in the retired population may have different determinants from SB in those who continue to work and the barriers and facilitators will likely be influenced by the social frame around the setting in which it occurs [68]. Differences in gender roles have not been accounted for in the interview schedules and analysis. Gender roles for men and women may differ in some communities and gender differences were previously noted in the motivators for physical activity [69]. Despite being informed by a widely used and comprehensive framework, the use of the TDF itself has limitations. Some content was difficult to code into one specific domain (e.g. knowledge and beliefs about consequences) as there seems to be lack of independence between them, a limitation which has been previously noted [39,70].

Conclusion

There is limited knowledge of the concept of SB among individuals with COPD. Domains of the TDF likely to enable a reduction in SB relate to knowledge, beliefs about consequences, beliefs about capabilities, environmental context and resources, social influences, social/professional role and identity and behavioural regulation. Interventions to reduce SB will be informed by a better understanding of behavioural determinants, notwithstanding individual variations in emphasis.

Declaration of interest

The authors report no conflict of interest.

Additional information

Funding

This research was funded by the Canadian Lung Association through a Breathing as One Allied Health Research Grant.