Background
Noncardiac chest pain (NCCP) is one of the leading reasons for emergency department visits, accounting for 2 to 5% of all visits [
1]. Furthermore, a large proportion of patients with NCCP repeatedly consult various physicians and medical specialists [
2,
3]. In the United States, the annual costs associated with these visits are estimated between $8 and $13 billion [
3‐
6].
NCCP poses a heavy burden on patients, which is compounded by the fact that the symptoms become recurrent in the long term in up to 90% of cases [
7‐
10]. Although the cardiovascular prognosis of NCCP following an emergency department visit is generally favourable, this symptom significantly and persistently limits the daily functioning, quality of life and ability to engage in physical activity for 20 to 60% of patients [
3,
8,
10,
11].
Patients with NCCP are more than twice as likely to be physically inactive during their leisure time than the general population (23% vs. 10%; 13). However, the picture of these patients’ level of activity is incomplete as the rate of transportation- and work-related physical activity has yet to be documented in this population. The observed high level of physical inactivity in adult with NCCP is potentially fraught with biopsychosocial consequences, since, in addition to being a risk factor for the development of a number of serious health problems, it may contribute to the maintenance of NCCP and of the resulting disability [
12,
13]. Indeed, a lower pain tolerance threshold has been reported in physically inactive individuals [
14], which could contribute to the development and maintenance of NCCP. Furthermore, inactivity may result in physical deconditioning that increases the likelihood of experiencing physical symptoms, such as NCCP [
15,
16]. Lastly, for many patients with NCCP, physical inactivity results from a fear of triggering a heart problem, despite the absence of a diagnosis to justify such a fear [
17,
18]. Being inactive, they do not have the opportunity to confront these fears, which could contribute to their maintenance [
19]. Yet, these fears are associated with the perpetuation and exacerbation of NCCP and of the resulting disability [
20,
21].
On the other hand, physical activity appears to have a protective and potentially therapeutic effect in a number of pain problems [
22‐
28]. Indeed, it can raise the pain tolerance threshold through gradual habituation to pain symptoms [
12,
29]. It also reduces anxiety sensitivity [
30,
31], the fear of anxiety-related physical sensations and their consequences [
32], a factor associated with NCCP-related disability [
33]. Physical activity is also associated with a 35% reduction in heart-focused anxiety, defined as the fear of cardiovascular sensations and their anticipated negative consequences [
34,
35]. This is highly relevant to NCCP as heart-focused anxiety explains much of the efficacy of interventions for NCCP [
36,
37]. By acting on several biopsychosocial mechanisms associated with the exacerbation and maintenance of NCCP, physical activity might lower the risk of experiencing NCCP-related disability.
A better understanding of this link would make it possible to determine if increased physical activity can limit the development of NCCP-related disability. In order to fully understand the role of physical activity, it is essential to consider the influence of biopsychosocial factors that have been associated with the development and maintenance of NCCP and the related disability. The main biological factors associated with NCCP are sex, age and medical conditions [
10,
20,
38]. Studies and biopsychosocial models of NCCP or unexplained medical symptoms link social support and heart-focused anxiety with the development and maintenance of NCCP and its consequences [
20,
34,
36,
39]. While psychological distress and anxiety sensitivity are also relevant constructs, it appears to be through their association with heart-focused anxiety [
33,
36,
40,
41]. This goal of this study was to deepen our knowledge of the link between physical activity and NCCP-related disability.
Objectives and hypotheses
The first objective of this study was to document the level of physical activity in patients with NCCP. The second objective consisted in exploring the association between patients with NCCP level of physical activity at the time of an emergency department visit with NCCP and NCCP-related disability in the following 6 months.
As previously reported in the literature, it was expected that the level of physical activity in patients with NCCP would be lower than in the general population. It was also expected that a higher level of physical activity would be associated with a lower likelihood of NCCP-related disability at six-month follow-up.
Discussion
This study assessed the global physical activity level in patients with NCCP and prospectively assessed its potential protective effect on NCCP related disability. Overall, during the year preceding their emergency department visit with NCCP, half (48%) of the sample had not reached the minimum level of physical activity required to achieve health benefits, based on the Actimètre questionnaire criteria (i.e. active, moderately active, somewhat active or inactive; 51). Over one fifth of the sample (21.9%) was considered inactive, which is consistent with results from a previous study [
59]. The proportion of participants who were physically active in their leisure time according to the Actimètre questionnaire was 34% lower than in the general population of the same age and region (22.0% vs. 33.3% [
60];). Substantial differences were also observed in transportation-related physical activity, as the percentage of inactive study participants for this category was 26% higher than in the general population (78.9% vs. 62.8% [
60];). Thus, patients with NCCP are less active than the general population, which confirms the first hypothesis.
As for the second objective, being physically active at the first time point was associated with a 46% reduction in the risk of reporting NCCP-related disability in the following 6 months. This association remained significant, with a 38% reduction of this risk, when potential biopsychosocial confounding variables (age, sex, a history of gastrointestinal or cardiovascular disease, social support education level, smoking status, number of NCCP episodes in previous 6 months, average NCCP intensity and heart-focused anxiety) were introduced into the model, which confirms our hypothesis. Of note, in the final model, a history of cardiovascular or gastrointestinal disease appears to increase the risk of reporting NCCP-related disability in the following 6 months by 60 and 93%, respectively. The observed role of gastrointestinal disease in the increased risk of NCCP-related disability might be explained by its association with general sensitization, a mechanism common to both conditions [
38,
61]. Furthermore, several gastrointestinal conditions can cause NCCP, among which gastrointestinal reflux disease is the most frequent [
62]. Accordingly, this condition may contribute to the maintenance and increased intensity of NCCP over time which, in turn, could result in NCCP-related disability.
Coherent with a biopsychosocial conceptualization of the effect of physical activity, the absence of heart-focused anxiety in the final model, although surprising, can possibly be explained by its inverse correlation with the level of physical activity [
35]. Along the same line, the presence of a history of cardiovascular disease in the final model may play a role in increasing the risk of presenting NCCP-related disability by its association with heart-focused anxiety, a factor known to be central in this condition [
63,
64]. In addition, in some cases, pathological mechanisms such as microvascular angina could contribute to the maintenance of NCCP [
65] and explain the associations between cardiovascular disease and NCCP-related disability.
Physical activity appears to play a protective role in reducing the risk to suffer from NCCP-related disability. This finding highlights the importance of examining the biopsychosocial factors that can influence participation in physical activity in this population, which is already less active than the general population, and looking into ways to promote physical activity for this population. Promoting physical activity appears a promising biopsychosocial intervention because of its effect on key psychological (e.g. heart-focused anxiety) [
32,
33], and biological factors (e.g. cardiovascular disease) [
35,
66] associated with the development of NCCP-related disability. In order to globally improve the level of physical activity, the literature on the promotion of physical activity stresses the need to intervene at both the population and individual level through several strategies, based mainly on the cognitive-behavioral approach [
67,
68]. These strategies include providing information about health linked with physical activity, goal setting, reinforcement of efforts, self-monitoring of physical activity, etc. [
68].
Limitations
Certain limitations inherent in this study should be borne in mind when interpreting its results. Most of the data were collected by means of self-report questionnaires, which leaves open the possibility of recall and social desirability bias [
69]. Ascertaining the level of physical activity retrospectively over the previous year leaves open the possibility of potential fluctuation in the level engaged in at the time of the emergency department visit. However, having data that was gathered for a one-year period enabled us to better account for the seasonal variations and provided an estimate of the general physical activity level. In addition, the possibility of an inverse relationship between the variables of interest, that is the impact of NCCP-related disability on physical activity practice in the following 6 months, cannot be eliminated. Moreover, participants in the final sample differed from those who did not complete the main measures in terms of education level and smoking status. These differences may limit the generalizability of the results and influence the level of physical activity reported. A higher education level is associated with increased rates of moderate-to-vigorous physical activity practice compared to lower education level [
70]. The lower proportion of smokers in the final sample indicate that the number of patients considered active may have been overestimated in our sample [
71]. However, these variables did not contribute to the explanation of NCCP-related disability in the final model.
Conclusions
In conclusion, being physically active is associated with a lower probability to suffer from NCCP-related disability in the 6 months following an emergency department visit. These findings point to the importance of further investigating the protective role of physical activity in the course of NCCP. Meanwhile, health care providers involved in the care of NCCP could enhance the benefits of exercise for these patients who otherwise tend to suffer persistently.
Acknowledgements
We wish to acknowledge the contribution of Pierre Beaupré, MD, Julie Carrier, MD and Mario Côté, MD for their support in the implementation of the research project in both recruitment sites. Our team also wishes to thank the patients as well as the emergency staff and physicians who collaborated in this study and made this work possible.
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