Researchers at Pennington Biomedical Research center in Baton Rouge looked at five prior studies of 167,00 people in several countries.
They estimate a person could add two years to their life by reducing sitting to less than 3 hours a day.
Researchers did not prove that sitting more is the cause of earlier death, but they examined evidence that sitting appears to have detrimental effects on lifestyle.
The study appears in the British medical journal open.
