Stress is unavoidable in today’s fast-paced life, and its management significantly impacts physical and mental health and quality of life [1]. Interest in and the importance of managing mental and physical health are increasing worldwide. Psychological stress has been reported to be detrimental to engagement in healthy behaviors [2-5]. Further, prolonged sitting can diminish the anxiety- or stress-reducing effects of physical activity, leading individuals to perceive tremendous stress [6,7].

Sitting is an inactive behavior that consumes less than 1.5 metabolic equivalents of task of energy while awake [8]. Screen time, such as watching television or using a computer, playing board games, sitting, lying down, or leaning, is representative of inactive behaviors. The time involved in these sitting actions is called sitting time [9]. Sitting time has negative effects on mental health, making individuals prone to anxiety [10], depression [11], and poor emotional well-being [12,13], which are often associated with mental health problems [14]. Several studies have associated long sitting times with high levels of perceived stress [15,16].

Smoking is a risk factor for diseases that threaten multiple aspects of life by causing severe complications, such as lung cancer and other cancers, and cardiovascular diseases [17]. Smokers often perceive smoking as an easy way to relieve stress. According to the American Psychological Association, smoking directly causes stress rather than reducing it, contrary to the arguments of smokers [18]. Thus, the effect of smoking on stress, with an emphasis on smoking cessation to improve the quality of life, is an object of interest.

People who smoke are more likely to be physically inactive or have unhealthy habits [19]. Recent studies have noted that sitting is an unhealthy behavior comparable to smoking and that smokers are less likely to be physically active than non-smokers; however, little is known about the interaction between smoking status and sitting behavior [20].

The World Health Organization suggests physical inactivity as a risk factor for non-infectious diseases, including heart disease, cancer, chronic respiratory disease, and diabetes [21]. According to the Korea Centers for Disease Control and Prevention (KCDC), sedentary behavior is one of the factors that reduces physical activity [22]. As a disease risk factor, it is also recognized as a major health assessment indicator [23]. Previous studies examining stress-related factors in adults have found associations between perceived stress and age group, depression diagnosis, health checkups, non-metropolitan medical care, eating frequency, physical activity, drinking frequency, and smoking [24]. Based on the results of previous studies, this study was intended to analyze it as a correction factor that can be effectively confirmed in the primary medical environment using sitting time and smoking, is expected to be used as structured data for systematic stress treatment.

Previous studies conducted univariate analyses of the relationships between sitting time, smoking, and stress [25-29]. Nonetheless, few studies have examined the relationship between sitting time, smoking, and perceived stress. Therefore, this study aimed to identify and analyze the relationship between sitting time, smoking, and perceived stress using data from the 7th National Health and Nutrition Survey (2016-2018). Moreover, it aimed to provide primary data for developing interventions to manage stress in daily life and improve health and quality of life by considering individuals with high sitting and smoking habits.

This study attempted to provide primary data and suggestions for reducing stress in adults aged < 65 years by confirming the relationship between sitting time, smoking, and perceived stress using data from the 7th National Health and Nutrition Survey (2016-2018). This study found that people who spent a lot of time sitting and currently smoked received 1.987 times higher perceived stress in Model 1, 2.042 times in Model 2 after adjusting for significant gender, education, and 1.883 times in Model 3 after adjusting for significant gender, education, BMI, subjective health status, and sleep time compared to those with less than 8 hours sitting times and who were not smoking. The study also found that young and middle-aged adults who spent less time sitting and were nonsmokers were less likely to experience stress. These results highlight the importance of physical activity and smoking cessation in reducing stress risk.

A previous study examined the relationship between sitting time and mental health [33]; however, no study has identified a connection between smoking, sitting time, and perceived stress. Thus, it is difficult to make accurate comparisons with previous studies. The study found that stress levels increased significantly with sitting time. Existing studies on the relationship between stress and sitting time do not have consistent results. According to a study analyzing the sitting time and perceived stress of adults over 50 years of age in six low- and middle-income countries, the longer the sitting time, the higher the perceived stress [25]. In a 6-year prospective cohort study of Spanish university graduates, the Seguimiento Universidad de Navarra (University of Navarra Follow-up) study reported a vital link between physical activity and sedentary behavior in the development of mental illness [26]. A study with Australian adults conducted by Rebar et al. [27] found no association between overall sitting time and stress. Furthermore there are studies on the beneficial effects of physical activity on stress [34], however people may think that sedentary behavior is more beneficial in the short term [35]. Prospective studies are limited, and further confirmation of the temporal nature of these associations is needed through longitudinal studies.

This study found that stress levels increased significantly with current smoking. A study of 41 countries that provided data for the World Health Survey reported that perceived stress was significantly associated with increased smoking rates. Among daily smokers, higher levels of self-smoking stress were associated with an increased likelihood of smoking [28]. Furthermore, a study by Han et al. [29] examined the smoking status of professionals and found that smoking provided stress reduction, with stress serving as a motivation to continue smoking. Relieving stress or smoking due to stress is meaningful because it negatively affects mental health as a result. However, although stress and smoking appear to be closely related, there is a limit to explaining the causal relationship in that most studies, including this study, are cross-sectional studies.

In the modern world, individuals spend more than half of their days sitting. Owing to their current form of transportation, work, and automation, they spend most of their lives in a sedentary manner, sitting down for a long time and pursuing sedentary leisure time on days without work, resulting in many negative effects on the human body [36]. Therefore, promoting mild physical activity may be a reasonable strategy to reduce perceived stress and increase smokers’ long-term participation in physical activity. This can help prevent the occurrence of numerous comorbidities associated with physical inactivity. Furthermore, promoting physical activity can help promote smoking cessation, because regular physical activity has been shown to reduce nicotine dependence through reduced smoking needs, increased smoking cessation attempts, and successful smoking cessation [37,38]. Moreover, even if sitting time is extended, exercising regularly [daily] is considered suitable for health. However, individuals who sit down most of the day do not have a lower risk of developing diabetes or cardiovascular diseases, even if they exercise regularly. Therefore, an intervention program that involves light exercise every 30 min, rather than walking and getting up every 60 min, is suggested [39].

To the best of our knowledge, this is the first study to reveal the relationship between sitting time and perceived stress according to smoking status in Koreans. It can represent Koreans based on the Korean national health and nutrition survey data. Furthermore, this study lays the foundation for developing a stress reduction and health promotion program for those who sit for a long time and currently smoke. However, several limitations of this study should be considered when interpreting the results. First, a retrospective study should supplement this cross-sectional study [40]. Otherwise, engaging in data collection and inferring the causal relationship between the data is challenging. Second, all the variables were self-reported and susceptible to response bias.

This study aimed to determine the correlation between sitting time, smoking, and perceived stress in Koreans. This study demonstrated that perceived stress positively correlates with sitting for more than 8 hours and smoking. Furthermore, people who do not currently smoke, men, those who think their subjective health is not bad, those who sleep for more than 6 hours, and those who have a normal BMI say they are less stressed. However, those who graduated from college or higher and smoked reported being stressed. Therefore, we suggest that Koreans’ long-term sedentary lifestyles and smoking are closely related to stress and that regular physical activity interventions will help mitigate stress.