Despite considerable progress in prevention, diagnosis and management strategies, coronary artery disease (CAD) is still the leading cause of death in developed countries.1 Three decades ago, it was believed that physical activity (PA) was hazardous in patients with CAD.2 Today, we know that it is well tolerated and safe, and that even severely symptomatic patients can benefit from exercise.3–5 It is strongly recommended that individuals with stable ischemic heart disease should engage in 30-60 min of moderate intensity aerobic activity on at least five and preferably seven days a week.6 Regular PA decreases neurohumoral activation, reduces sympathetic tone, increases vagal tone and improves myocardial perfusion.7,8 It also increases endothelial nitric oxide (NO) synthase expression and protein phosphorylation, raising nitric oxide levels. Additionally, exercise reduces the expression of inflammatory substances such as interleukin-6, interferon-gamma and toll-like receptor (TLR), as well as platelet aggregation.9

Clinically, PA helps to regulate blood pressure, control body weight and lipid profile, and decrease insulin resistance.10,11 Studies have shown that the favorable effects of exercise improve anaerobic threshold and aerobic capacity, functional status and quality of life.12 A meta-analysis of 51 randomized controlled trials showed that exercise training reduced the primary composite outcome of all-cause mortality or all-cause hospitalization by 27%.13

As a result of these complementary findings, exercise training has become a standard non-pharmacological treatment modality in the management of cardiovascular diseases.14 In recent European guidelines on cardiovascular disease prevention in clinical practice, regular aerobic exercise is recommended in patients with coronary disease to improve functional capacity and symptoms.15

Despite its widely known favorable effects, regular exercise is not prevalent among patients with CAD. Although there are many studies showing the beneficial effects of PA in primary and secondary prevention of cardiovascular disease, there is little information about patients’ adherence to exercise training and parameters that can improve adherence rates. In this study, we aimed to investigate factors which may influence regular PA in patients with a history of coronary revascularization.

The mean age of patients who met the inclusion criteria was 61.3±11.2 years, with males comprising 73% of the cohort. Of the total population, 121 (60%) patients had hypertension, 59 (29%) had diabetes, 85 (42%) had previous infarction and 26 (13%) had heart failure; 104 (51%) patients had previous percutaneous coronary intervention (PCI), 67 (33%) had coronary bypass graft surgery (CABG), and 31 (15%) had both revascularization procedures. The median time after coronary artery revascularization was 60 months.

A total of 46 (23%) patients engaged in regular exercise, of which walking (83%, n=42) was the most common PA. Study patients exercised on a median of two days per week, with a median of one hour's exercise on each of these days.

The PA status of the study population and their demographic and anthropometric characteristics are shown in Table 1 and their clinical characteristics, laboratory findings, and medications are summarized in Table 2. Patients’ PA status according to marital status, employment status and education level is shown in Figure 1 and according to comorbidities in Figure 2. There were no significant differences between the groups in terms of age, anthropometric characteristics, comorbidities, functional status, revascularization procedures or medications. Female gender, low education level, unemployment, low household income, implantation of bare-metal stents (vs. drug-eluting stents) and absence of regular follow-up visits were more common in the inactive group.

Figure 1.

Patients’ physical activity status according to marital status, employment status and education level.

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Figure 2.

Patients’ physical activity status according to comorbidities.

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The results of univariate and multivariate logistic regression analysis are listed in Table 3. In multivariate regression analysis, low education level (p=0.01, odds ratio [OR] 3.26, 95% confidence interval [CI]: 1.31-8.11), and lack of regular follow-up (p=0.04, OR 2.95, 95% CI: 1.01-8.61) were found to be independent predictors of absence of regular PA in study subjects after adjusting for other confounders.

The present study examined the parameters that influence PA in patients with a history of coronary revascularization. Low education level and lack of regular follow-up were identified as independent predictors of absence of regular PA.

In our study, the majority of the patient population were inactive. In the inactive group, female gender, low education level, unemployment, and low household income were common, while follow-up visit rates were lower. In patients with a history of previous PCI, bare-metal stents were more commonly used in the inactive group than in the active group.

Physical inactivity is a modifiable risk factor.16 Current guidelines recommend a minimum of 30-60 min of moderate PA four to five times a week, coupled with an increase in daily lifestyle activities, in order to prevent heart attack and death among patients with coronary heart disease.17 PA has been associated with a 25-30% reduction in CAD-related mortality, attributed to improvements in major risk factors and reduction of inflammation.9,18 In addition to mortality reduction, PA reduces recurrent of ischemia and improves quality of life.19 Kavanagh et al. reported that high aerobic capacity was associated with lower mortality rates in patients with CAD who had well-controlled diabetes.20,21

Despite these beneficial effects of PA, many studies including patients with CAD have found that most patients do not comply with recommendations for regular PA.22 Less than 25% of patients on cardiac rehabilitation programs do regular exercise and during follow-up most fail to complete the program.19 Recommendations for PA in patients with coronary revascularization are mainly made by physicians following the patients, and these proposals tend not to be detailed, due to their heavy workload. In some countries these programs are determined by some individual based training programs. Despite these efforts, adherence rates of cardiac rehabilitation programs are reported to be 41%.23

It is clear that the most important aspect of PA in patients with CAD is compliance, and so it is important to investigate parameters that influence dropout rates from recommended PA.

Patients with chronic diseases are able to improve their condition with adequate information and education and PA improves quality of life, as shown in previous studies.24,25 Social, economic and cultural factors play a role in the maintenance of sedentary life styles.26

Patient adherence is determined by multiple factors such as education level, employment status and household income. In our study women were generally inactive, only seven (12% of women in the study population) being physically active. Stewart et al. showed that advanced age, male gender and obesity were associated with less PA.27 In their study, most women were housewives and reported more PA because of housework.27 In our study, the majority of females were housewives, but they were significantly less active than men; we did not define housework as PA. It should also be noted that women account for only a small number of subjects in studies on PA and cardiac rehabilitation.9,28 Another study reported that obese patients were less likely to complete exercise programs, but found no difference between female and male patients, as well as the interesting result that young patients were more likely to drop out of the exercise program.29 In agreement with our study, Reid et al. found that males were more active than females and that educational level was associated with PA.30

Most studies on PA have been performed on the general population, but CAD patients differ in various aspects.27 Patients with CAD may experience more adverse events when they perform intense exercise,15 and are more likely to feel symptoms that cause premature interruption of exercise.7,27 Mood disorders that could affect PA adherence are also more frequent in patients with CAD.27

The results of our study indicate that socioeconomic status also affects adherence to regular PA.27 In previous studies, lower socioeconomic status and educational level were associated with increased morbidity and mortality in patients with CAD.31–33 Educational level and employment status were particularly associated with CAD.34 The WISE trial showed that low household income, smoking, higher BMI and greater waist circumference were associated with lower PA.35

Some trials have shown that patients treated by CABG are more active than those treated by PCI, however we found no difference in PA between types of coronary intervention. A possible explanation may be that CABG patients are encouraged to exercise by doctors and nurses to reduce pulmonary complications after surgery. Interestingly, we found that patients receiving drug-eluting stents were more active than those receiving bare-metal stents.

During hospital stay, encouragement to perform PA should be part of patient management. Educational programs can be prepared for patients with CAD and their relatives, and the value of cardiac rehabilitation should be emphasized at each hospital visit in order to raise awareness of the importance of PA.

The present study has some limitations, of which the most important is the use of self-reporting instead of objective measures to characterize adherence to exercise. The study was conducted in a single tertiary center, and so the patients may not represent real-world populations. Cognitive status and physical factors that may have affected PA were not assessed.

Regular PA is inadequate in outpatients with a history of previous coronary revascularization. Education level and regular follow-up visits can potentially influence PA adherence. Educational programs or telephone contact should be used to achieve more physically active lifestyles in these patients.

The authors have no conflicts of interest to declare.