A report from the Women's Health Initiative (WHI) showed that women who sat for 10 or more hours a day were 18% more likely to have had a heart attack or stroke over a 12-year period than women who sat for five hours or fewer.
"The findings come from a 12-year study of postmenopausal women enrolled in the Women's Health Initiative (WHI). Although there were no men or young women in the study, "there is no reason to believe that prolonged sitting would not increase risk in all adults. Previous studies in other populations support this," says Andrea K. Chomistek, a research fellow at the Harvard School of Public Health. Dr. Chomistek is first author of the multicenter study, published in the Journal of the American College of Cardiology."
The risk for cardiovascular problems was increased even among women who sat a lot but got recommended levels of daily physical activity. However, the research subjects in the highest activity category (who exercised more often than the recommended levels) appeared not to have a higher risk of cardiovascular disease if they engaged in a lot of sitting.
"Although the WHI study included only women, other studies have explored the link between sitting and heart disease in men and mixed groups, with the same general results.
Earlier this year, a study of more than 63,000 Australian men found those who sat four or more hours per day were more likely to have developed heart disease, diabetes or another chronic disease than those who sat less than four hours a day, regardless of how active they were.
And a Canadian study of men and women found those who sat for most of the day were 54 percent more likely to die over the next 11 years than those who sat less than half the time. This study, too, found that too much sitting can be harmful even for those who exercise regularly"
Read more about the study here.