Sedentary behavior is a known risk factor for heart disease, and a review article published in the American Journal of Lifestyle Medicine has shown that sitting is an independent risk factor for cardiovascular disease.
The article presented results from cross-sectional studies published in or after 2010 that measured sitting time and health outcomes. Measurement methods mostly included questionaries, accelerometers, or direct observations of participants, and the main contributors to sitting time during the day included occupational sitting, TV viewing, and sitting during transportation.
TV viewing is the most common leisure-time sedentary behavior. TV viewing time is strongly linked to diabetes, and it seems to have a dose-dependent relationship with heart disease; the more time spent watching TV, the higher the risk of developing cardiovascular disease. Occupational sedentary and sitting behavior, which have increased in recent years, appear to be linked to heart failure but not other forms of heart disease. While data is less available for active transportation (walking, biking, etc.) vs. sedentary transportation (riding in vehicles), active commuting appears to be better for improving risk factors such as hypertension and diabetes. Additionally, time spent in cars seems to be linked to cardiovascular disease, with one study reporting that men who spent 10 hours or more in cars per week had a 50% higher chance of developing heart disease compared to those who spent 4 or fewer hours per week in cars.
Exercise is well known to improve heart and overall health, and the Physical Activity Guidelines for Americans recommend that adults get at least 150 minutes of moderate-intensity exercise per week. Staying aware of our time spent sitting throughout daily activities is important for improving and maintaining heart health.
Sources: American Journal of Lifestyle Medicine, Physical Activity Guidelines for Americans