Life that is. A recent study published in the May 2009 issue of Medicine & Science in Sports & Exercise
found that there is a strong relationship between time spent sitting and mortality from cardiovascular disease and all causes, except cancer - despite participation in exercise at recommended levels.
The researchers set out to investigate a different twist on the relationship between sedentary behaviors and mortality. It is well documented that getting at least 30 minutes of physical activity a day reduces your risk for morbidity and mortality. But, little is known about the effects of prolonged periods of sitting during the day independent of physical activity levels.
Over a period of approximately 12 years, researchers followed 7,278 men and 9,735 women ages 18-90 years who were participants in the 1981 Canada Fitness Survey. During household visits, participants were asked to rate the amount of time they spent sitting during the day on a scale from "almost none of the time" to "almost all of the time." Leisure time physical activity levels were recorded, as well as Body Mass Index (BMI) profiles.
During the time of the study there were 1,832 deaths - 759 from cardiovascular disease, 547 from cancer, and 526 from other causes such as respiratory disease, injuries, violence, mental disorders, nervous system disorders, and digestive system disorders. The study found that those individuals who died during the study had a higher BMI, were less physically active, and were older compared to the survivors.
Furthermore, after controlling for factors such as age, gender, smoking status, alcohol consumption, and physical activity levels, a dose-response relationship between sitting time and mortality of all causes, except cancer, was observed. That is, length of sitting time has an independent effect on mortality; and, the greater the period of time you spend sitting during daily activities (such as working at your desk or computer and watching television) the greater your mortality risk.
These findings reveal that participation in physical activity, even if it exceeds recommended levels, cannot compensate for extended periods of sitting. This does not mean, however, to discontinue participation in regular exercise; rather, you should limit time spent sitting throughout the day during sedentary tasks/pursuits. Break-up long periods of sitting at work by hand delivering a memo instead of sending an email, perform calisthenics during commercials while watching television, and walk around the house instead of sitting while talking on the phone.
Labels: 1981 Canada Fitness Survey, prolonged sitting