A comprehensive meta-analysis by Ekelund et al. [11] reported a dose-response association between the risk of all-cause mortality and increased sitting time in combination with lower levels of activity. High levels of moderate-intensity physical activity (i.e., approximately 60–75 minutes per day) attenuate but do not eliminate the increased risk associated with high TV viewing time. The Korea National Health and Nutrition Examination Survey (KNHANES) revealed a concerning trend: a significant proportion of the adult population fails to meet the recommended levels of physical activity. In 2021, Korean adults aged 19 years and older spent an average of 8.9 hours per day on sedentary behavior, with 63.7% spending more than 8 hours per day on sedentary behavior [12]. The overall prevalence of adults in Korea meeting the World Health Organization (WHO) physical activity recommendations [4] was 44.9%. This included 18.8% who engaged in at least 150 minutes of moderate-intensity aerobic physical activity per week and an additional 26.1% who achieved higher levels of activity for additional health benefits–300 minutes or more of moderate-intensity or vigorous-intensity aerobic physical activity in a week, or 150 minutes or more of vigorous-intensity aerobic physical activity, or an equivalent combination of both [12]. A total of 24.8% of adults in Korea performed muscle-strengthening activities at least 2 days a week. The decline in physical activity levels was accentuated during the coronavirus disease 2019 pandemic, with the prevalence of adequate physical activity decreasing significantly from 36.0% in 2017–2019 to 30.0% in 2020, and further to 29.7% in 2021, according to data from the Korea Community Health Survey, which was conducted by the Korea Disease Control Agency [13]. This decrease underscores the impact of pandemic-related restrictions and lifestyle changes on physical activity habits.

Similarly, in the United States, 46.9% of adults met the guidelines for aerobic physical activity, and 24.2% adhered to the guidelines for both aerobic and muscle-strengthening activities [14]. Among European adults, 33.2% attain the recommended level of physical activity [15]. These worldwide trends highlight the critical need for public health strategies to promote physical activity and reduce sedentary behavior as preventive measures against CVD. In 2018, the World Health Assembly approved the Global Action Plan on Physical Activity 2018–2030 [16], setting a voluntary global target to reduce physical inactivity by 15% by 2030. The WHO urges all countries to establish national guidelines and set targets for physical activity. To support populations in achieving these goals and maintaining healthy physical activity levels, countries are encouraged to develop and implement policies and programs at both national and subnational levels.

Regular physical activity, particularly aerobic exercise, enhances cardiorespiratory fitness (CRF) by increasing oxygen consumption and cardiac output, leading to beneficial exercise-induced cardiac remodeling such as increased left ventricular mass, improved diastolic filling, and augmented stroke volume [17-19]. Aerobic exercise also improves vascular health by increasing capillary density and nitric oxide availability, enhancing endothelial function and blood flow [20,21]. It may protect against life-threatening arrhythmias by enhancing the cardiac autonomic balance, increasing the parasympathetic tone, and reducing sympathetic activity [22-24]. Resistance exercise complements these effects by improving muscle strength, bone density, and left ventricular hypertrophy, while lowering blood pressure [25-27].

Physical activity exerts anti-inflammatory effects by reducing systemic markers such as C-reactive protein and interleukin-6 [28-31]. Skeletal muscle also acts as an endocrine organ, releasing myokines during contractions, which help reduce inflammation and insulin resistance, protecting against atherosclerosis progression and promoting plaque stability [21,32,33].

A recent 18 F-fluorodeoxyglucose positron emission tomography/computed tomography study showed that regular physical activity reduces CVD risk by lowering stress-related brain activity, particularly in the amygdala, with notable benefits in individuals with depression [34]. This finding indicates both the direct cardiovascular and indirect psychological benefits of physical activity.

Aerobic exercise lowers both systolic and diastolic blood pressure, with effects comparable to antihypertensive medications [35,36], through improved endothelial function, greater nitric oxide bioavailability, and reduced arterial stiffness [37]. It improves lipid profiles by raising high-density lipoprotein cholesterol levels and lowering triglyceride levels, though effects on low-density lipoprotein cholesterol are less consistent [38]. Regular activity enhances insulin sensitivity, glucose uptake, and skeletal muscle capillarization, partly via GLUT4 translocation [39,40], reducing glycated hemoglobin (HbA1c) by 0.6–0.8%—a benefit similar to some oral antiglycemic agents [18,41]. These effects occur even without weight loss and are particularly beneficial in those with high baseline insulin resistance. When combined with calorie restriction, high physical activity supports weight loss, long-term weight maintenance, and the prevention of gradual weight gain, thereby lowering the risk of overweight and obesity [42-45].

Physical activity is categorized into four main domains (Table 1): occupation, transportation, household, and leisure time [46]. Physical activity can occur at any time of the day and provides health benefits, regardless of its purpose. This includes non-leisure activities, such as transport-related physical activities (e.g., cycling to work), which are now acknowledged as valuable ways to promote physical activity. However, in a recent meta-analysis, occupational physical activity showed a non-significant trend in reducing the risk of coronary heart disease and stroke [53].

Exercise can be categorized into aerobic and anaerobic metabolic categories. Aerobic exercise, which is well-documented to improve CRF, uses the metabolism of stored energy through aerobic glycolysis, meaning that the body needs to deliver oxygen to the muscles, which allows the muscles to perform the activity [18,58]. In contrast, anaerobic exercise uses the metabolism of stored energy to be largely processed by anaerobic glycolysis. It requires short bursts of exercise and is not dependent on oxygen delivery alone [18,58]. Research suggests that combining resistance exercise with aerobic exercise provides enhanced benefits for CRF, muscle strength, and body composition compared to aerobic exercise alone [59]. This combination approach is also more effective than aerobic exercise alone in cardiac rehabilitation, serving as both a secondary prevention and treatment strategy for coronary artery disease [59,60].

The exercises can be performed at different intensities (Table 1). Intensity can be measured in different ways but can generally be determined using a talk test, which is commonly used in clinical settings. During moderate-intensity activity, a person can talk but not sing. During a vigorous-intensity activity, a person cannot say more than a few words without pausing for a breath.

Internationally, organizations such as the WHO and the American College of Cardiology/American Heart Association (ACC/AHA) have provided clear guidelines on the recommended physical activity levels (Table 2) [4,61]. The recommendations for the general adult population in these guidelines are based on a scientific report [46] of the Physical Activity Guidelines for Americans, second edition (Table 2) [62]. Both organizations advocate at least 150–300 minutes of moderate-intensity aerobic activity per week or 75–150 minutes of vigorous-intensity activity supplemented with muscle-strengthening activities of moderate or greater intensity on at least 2 days per week. For additional health benefits, especially in managing weight, it is recommended that physical activity exceed 300 minutes per week [4,62,63].

When adapting these guidelines to the Korean context, it is crucial to consider cultural and environmental factors that may influence physical activity levels. The Korean Society of Lipid and Atherosclerosis, Korean Society of Hypertension, Korean Society for the Study of Obesity, and Korean Diabetes Association recommend physical activity based on principles similar to international guidelines, emphasizing at least 150 minutes/week of moderate-intensity aerobic activity or 75 minutes/week of vigorous activity, combined with muscle-strengthening activities on ≥ 2 days/week. However, their specific recommendations differed slightly in terms of type, duration, intensity, and frequency of physical activity, such as greater emphasis on minimizing sedentary time, the inclusion of high-intensity interval training (HIIT) for selected T2DM patients, and tailored strength or balance training for older adults (Table 3).

The impact of sedentary behavior on cardiovascular health has been a focus since the WHO released its recommendations on physical activity in 2020 [4]. Prolonged sedentary time, generally considered to be in the range of 8–10 hours per day, has been associated with an increased risk of CVD [64-66]. In general, all individuals should be encouraged to “move more and sit less” throughout the day, regardless of the type of physical activity, as even small movements contribute to health benefits [4]. Interrupting sedentary time every 30–60 minutes with light-intensity activity has been linked to improvements in cardiometabolic health indicators [67].

There is no lower limit to the benefits of physical activity in reducing the risk of CVD. Unlike earlier guidelines, all physical activities contribute to the total recommended weekly amount regardless of the duration of each session [4]. Therefore, the ACC/AHA and European Society of Cardiology guidelines specifically state that even if individuals cannot meet the minimum recommended physical activity levels, engaging in some moderate- or vigorous-intensity physical activity or being as active as possible can still be beneficial in reducing the risk of CVD [58,61,68]. Even a few minutes of activity, such as parking farther away from the store or walking up the stairs instead of using the elevator, contributes to overall benefits [69]. The 150-minute target was based on obtaining benefits for the greatest outcomes. On the other end of the spectrum, additional physical activity confers additional benefits, and health risks are reduced with high amounts of physical activity, even beyond three to five times the 150-minute target weekly recommendation [46]. However, it should be noted that extremely high levels of physical activity, such as exceeding 10 times the minimum recommended amount, are relevant to only a small subset of the population and may carry potential cardiac risks, including myocardial fibrosis and atrial fibrillation, especially in those who are unfit or have underlying conditions [70]. While regular physical activity is beneficial for most individuals, very high volumes should be approached with caution, particularly in older adults and those with known structural heart disease, with intensity and workload gradually increased according to individual fitness and health status. For individuals with significant functional impairment, personalized recommendations should be provided by adjusting the type, duration, and intensity of physical activity to ensure safety and maximize health benefits, beginning at low levels and progressing gradually [61].

The total volume of moderate-to-vigorous physical activity was more critical than the specific number of days per week it is performed [71]. However, for certain benefits such as reduced anxiety, better sleep and executive function, lower blood pressure, and improved insulin sensitivity, engaging in physical activity regularly throughout the week may provide more sustained benefits [72].

For older adults (65 years and above), the general adult physical activity recommendations apply, with additional emphasis on balance, muscle strength, endurance, and functional training at moderate intensity for at least 3 days per week to enhance functional capacity and reduce falls [4,73]. Evidence shows a clear inverse relationship between aerobic activity volume and the risk of functional limitations [74-76]. Balance training significantly lowers fall rates, and multi-component activities reduce the risk of fall-related injuries [73]. Such physical activities also improve bone health and prevent osteoporosis. The same sedentary behavior recommendations for adults apply to this age group, given that the evidence includes those over 65 years of age [4]. In addition to physical activity, integrating supervised exercise interventions into healthcare services for older adults is crucial as these programs have proven effective in preventing functional decline and should be more widely implemented in primary and geriatric care settings to promote healthy aging [77].

Engaging in physical activity is associated with reduced gestational weight gain and a lower risk of gestational diabetes in pregnant and postpartum women, especially in those with overweight or obesity. Exercise does not increase the risk of gestational hypertension, low birth weight, or small/large for gestational-age babies [46]. Regular moderate-intensity aerobic and muscle-strengthening activity is recommended for this group, and these activities should be continued throughout pregnancy unless medically contraindicated. General adult guidelines for sedentary behavior apply to pregnant and postpartum women.

For individuals with CVD, a thorough risk assessment is essential and should include physical examination, electrocardiography, and comprehensive clinical history. Low-risk patients (e.g., those with stable heart conditions or asymptomatic valvular disease) generally require no exercise restrictions [58]. However, high-risk patients should undergo further evaluation, including echocardiography, exercise stress testing, and potentially advanced imaging before starting physical activity. Screening is especially important for detecting conditions that may lead to sudden cardiac death. High-risk patients require individualized exercise plans and more frequent counseling as recommended by the guidelines [18,58]. Muscle-strengthening activities can be included as tolerated under professional guidance.

A concise summary of physical activity recommendations for specific population groups—including older adults, pregnant and postpartum women, individuals with CVD, and those with significant functional impairment—is presented in Table 4 for practical reference.

Despite the well-documented benefits of physical activity, several barriers hinder its adoption. Perceived time constraints, motivational deficits, and functional limitations have been consistently identified as individual-level barriers in epidemiologic surveys. Societal barriers include limited access to safe and convenient spaces for exercise and socioeconomic factors that may restrict participation in physical activities [82].

Addressing these barriers requires targeted interventions; for instance, workplace wellness programs can provide opportunities for employees to engage in physical activity during their workdays. Community initiatives should focus on making physical activity accessible and inclusive, particularly for underserved populations.