The result remained even after researchers factored out obesity or the level of daily physical activity people were engaged in, according to an MSN news report.
The authors of the study analyzed responses from questionnaires filled out by 123,216 people (53,440 men and 69,776 women) with no history of disease who were participating in the Cancer Prevention II study conducted by the American Cancer Society. Participants were followed for 14 years, from 1993 to 2006.
After adjusting for a number of risk factors, including body mass index (BMI) and smoking, women who spent six hours a day sitting had a 37% increased risk of dying versus those who spent less than three hours a day sitting. For men the increased risk was 17%.
Exercise, even a little per day, did tend to lower the mortality risk tied to sitting, but sitting’s influence on death risk remained significant even when activity was factored in.
However, people who sat a lot and did not exercise or stay active had an even higher mortality risk: 94% for women and 48% for men.
According to the news report, study lead author Dr. Alpa Patel, an epidemiologist with the American Cancer Society, said the obvious reason for the connection is that “the more time you spend sitting, the less total energy expended and you can have consequences such as weight gain and increased obesity.”
But, Patel also noted there’s a burgeoning literature evolving around “inactivity physiology.” When muscles, especially those in the legs, are “sitting,” they stimulate or suppress various hormones which then affect triglycerides, cholesterol and other markers for heart and other diseases, she explained.