New York, Feb 18 (IANS): Spending a lot of time sitting may increase heart disease risk among overweight and obese post-menopausal women, warns a study.

"Reducing sitting time improves glucose control and blood flow, and engaging in physical activities, even light-intensity daily life activities like cooking and shopping, show favourable associations with reduced mortality risk and prevention of heart disease and stroke," said lead study author Dorothy Sears, Professor of Nutrition at the Arizona State University College of Health Solutions in Phoenix, US.

In this study, published in the Journal of the American Heart Association, the researchers measured the sitting habits of older women and who were overweight or obese.

The study included a total of 518 women with an average age of 63 years and an average body mass index (BMI) of 31 kg/m2.

Study participants wore accelerometers on their right hip for up to 14 days, removing the devices only to sleep, shower or swim.

The accelerometers were used to track and record sitting and physical activity of the study participants throughout the day.

A single blood test, concurrent with accelerometer wear, measured blood sugar and insulin resistance.

Each additional hour of sitting time per day was linked with a more than 6 per cent higher fasting insulin and a more than 7 per cent increase in insulin resistance, the results showed.

Each additional 15 minutes in average sitting period was associated with a greater than 7 per cent higher fasting insulin and an almost 9 per cent increase in insulin resistance.

"We were surprised to observe such a strong negative link between the amount of time spent sitting and insulin resistance, and that this association was still strong after we accounted for exercise and obesity," Sears said.