Introduction

Around 805,000 myocardial infarctions (MIs), also known as heart attacks, occur in the US annually, with disproportionately higher MI mortality rates found in rural (251.4 deaths/100,000 people) versus urban areas (208.6 deaths/100,000 people) [1–3]. Higher MI mortality rates in US rural areas may be attributed to significantly higher rates of cardiovascular disease risk factors such as physical inactivity, hypertension, diabetes, and obesity among rural versus nonrural populations [4]. Individuals with continued cardiovascular disease risk factors following the first MI face an increased risk of recurrent MI which is associated with 200–400% greater risk of mortality than the index MI [5, 6].

A jointly-issued American Heart Association and American College of Cardiology guideline for MI survivors recommends physical activity to aid recovery and prevent recurrent MI with the guideline specifying that clinicians treating MI survivors “should encourage 30 to 60 minutes of moderate-intensity aerobic activity, such as brisk walking, at least 5 days and preferably 7 days per week” [7]. Centers for Disease Control and Prevention (CDC) data from 2017 indicate that, among the general US adult population, a significantly lower percentage of rural (19.6%, 95% CI: 18.0%-23.1%) compared to urban residents (25.3%, 95% CI: 24.5%-26.2%) were physically active [8]. The limited research on rural/urban differences in physical activity levels following a cardiovascular disease (CVD) event has yielded conflicting results [9]. In addition, the existing literature focuses solely on stroke survivors whose health behaviors may differ from that of individuals affected by heart diseases such as MI [9, 10].

Accordingly, we used national US surveys to examine whether post-MI physical activity levels differed between rural and urban residents prior to and following adjustment for MI-related sociodemographic factors.

Methods

Results

The study included 22,732 BRFSS survey respondents who had MI (Table 1). Of these MI survivors, 37.3% were rural residents. Rural MI survivors were more likely to be White, have a lower income, and completed fewer years of education compared to those in urban areas.

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Table 1. Characteristics of myocardial infarction survivors in the 2017 and 2019 Behavioral Risk Factor Surveillance System (BRFSS) surveys by rural residence status (N = 22,732).

https://doi.org/10.1371/journal.pone.0293343.t001

The percentage of rural MI survivors meeting physical activity guidelines (37.4%, 95% CI: 35.1%-39.7%) was significantly less than that of urban MI survivors (45.6%, 95% CI: 44.0%-47.2%) (Table 1). Among MI survivors, rural residence was significantly associated with a 28.8% (95% CI: 20.0%-36.7%) lower odds of meeting physical activity guidelines (Fig 1). Although this association became slightly attenuated following adjustment for sociodemographic factors, rural residence was still significantly associated with a 19.3% (95% CI: 9.3%-28.3%) lower odds of meeting physical activity guidelines.

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Fig 1. Associations between rural residence and meeting physical activity guidelines among US myocardial infarction survivors.

https://doi.org/10.1371/journal.pone.0293343.g001

Other significant predictors of meeting physical activity guidelines included age, sex, income, education, and insurance. Independent of rural residence, being male, having higher income, and completing more years of education corresponded with greater odds of meeting physical activity guidelines. The relationship between age and meeting physical activity guidelines was more mixed with individuals aged 18–44 years being more likely to meet guidelines than those 65 years and up and those 45–64 years less likely to meet guidelines than those 65 years and up. Our supplemental analyses indicated that neither the age and physical activity, sex and physical activity, nor race/ethnicity and physical activity interaction terms were significant. However, supplemental analyses did show that intensity and duration of physical activity was significantly less among rural versus urban MI survivors, results that are in line with our findings on meeting physical activity guidelines.

Discussion

We conducted a nationally representative study examining differences in contemporary post-MI physical activity levels between US rural and urban residents. Less than 40% of rural MI survivors met physical activity guidelines. In addition, rural residence was significantly linked with lower odds of MI survivors meeting physical activity guidelines prior to and following adjustment.

Prior research examining rural/urban differences in physical activity levels after a CVD event has been limited [9, 10]. In a study of Canadian individuals enrolled in the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) cohort between 2008–2012, investigators found that stroke survivors in rural areas were more likely to be physically active (48%) than those in urban areas (33%) [10]. In contrast, the sole US study of rural/urban differences in post-CVD physical activity levels reported that, among 2019 BRFSS survey respondents, rural stroke survivors were less likely to be physically active (29.8%, 95% CI: 25.4%-34.2%) than their urban counterparts (32.5%, 95% CI: 29.8%- 35.2%) [9]. Regarding the sociodemographic factors that were considered, our findings generally align with those from a integrative review of physical activity among CVD patients that reported male sex and higher income to be significant predictors of higher physical activity levels [22]. Our findings expand on previous work by providing physical activity level estimates specific to US rural and urban MI survivors, and further evidence of a US rural/urban disparity in physical activity levels following a CVD event.

Although we found slightly higher post-MI physical activity levels than what has been previously documented for stroke, the percentage of US MI survivors meeting physical activity guidelines remains particularly low with a rural-urban divide in post-MI physical activity levels evident. Rural areas lack public features such as parks and sidewalks that would make it easier for residents to engage in physical activity. One study found that the median distance to a park in US rural and urban areas was 6.2 miles and 0.5 miles respectively [23]. According to the US Health Resources and Services Administration, the lack of parks and sidewalks in US rural areas may be partly attributed to these regions having a smaller tax base to fund this public feature [24]. Conversely, the influence of rural areas’ limited parks and sidewalks availability on post-MI physical activity may be mitigated by the fact US rural areas have a higher median percentage of green space (54.9%) than US urban areas (2.8%) [23].

Furthermore, the few available rural specific physical activity interventions may be a contributor to the rural-urban physical activity divide. With regard to rural-specific physical activity interventions conducted in the US, a 2019 review identified only 29 coming from distinct studies [25]. Identified interventions included incentivized physical activity programs, mobile health delivered exercise reminders, goal setting, and self-monitoring [25]. None of the identified interventions were tailored to CVD survivors [25]. With that being said, increased availability of rural public features (i.e., parks, sidewalks) conducive to physical activity through governmental investment and development of interventions specific to CVD survivors may assist more rural MI survivors to incorporate physical activity into their secondary prevention strategies.

We consider study limitations below. As the physical activity outcome is self-reported, there is the potential for self-report and non-response bias to be present. While these types of biases cannot be fully excluded from self-reported data, there has been extensive research from the CDC and non-CDC affiliated investigators documenting good correlation between BRFSS responses and measurements collected in-person [26]. Due to BRFSS being cross-sectional, questions related to timing of health conditions or health behaviors cannot be addressed. Despite the cross-sectional nature of the BRFSS, this dataset allows for examination of nationally representative patterns of post-MI physical activity with questions on timing of post-MI physical activity initiation to be explored in future longitudinal studies. Our study does not include MI survivors aged <18 years or those that are institutionalized. However, as MIs in children are rare and the majority of US individuals are not institutionalized, our findings should be applicable to most US MI survivors.

Conclusion

This study showed that a large proportion of US rural MI survivors are not meeting physical activity guidelines even after accounting for sociodemographic factors, an area of concern relating to successful secondary MI prevention. This research expands understanding of US rural/urban differences in post-CVD physical activity levels, providing knowledge supporting the need for further physical activity-related secondary prevention efforts in high-MI burden rural areas across the country.

Supporting information