Sitting for extended period raises early death risk and cannot be reversed by exercise.
The study said women who sit for more than six hours daily are around 40 per cent more likely to die than those sitting for less than three hours a day, reports the Daily Mail.
The figure was about 20 percent for men, according to American Cancer Society researchers who looked at 123,000 people's health over 14 years.
Extended periods of sitting down increases risks of cardiovascular disease, diabetes, depression and obesity, the study said.
It also stated sitting for extending periods of time can do significant damage to your health that cannot be countered by exercising.
This result puts sitting down for extended periods of time in the same bracket as smoking.
The study was reported in the American Journal of Epidemiology.