Too much time spent sitting after the age of 60 is linked to major disability, irrespective of how much exercise a person gets, a new study suggests.

According to US researchers, this is the first study to show that sedentary behaviour is a standalone risk factor for disability, separate from a lack of exercise.

In fact, being sedentary is almost as strong a risk factor for disability as a lack of exercise.

Disability refers to limitations in being able to do basic activities, such as dressing yourself, washing yourself and eating. It also includes mobility issues, such as getting into and out of bed or a chair and walking.

The study found that after the age of 60, every additional hour you spend sitting each day doubles your risk of being disabled.

In other words, if you take two men in their 60s - one who is sedentary for 12 hours per day and one who is sedentary for 13 hours per day, the second one is 50% more likely to be disabled.

"This is the first time we've shown sedentary behavior was related to increased disability regardless of the amount of moderate exercise. Being sedentary is not just a synonym for inadequate physical activity," commented the study's lead author, Prof Dorothy Dunlop, of Northwestern University in Chicago.

The study involved almost 2,300 adults aged 60 and older. It compared people who were in similar health and who undertook the same amount of moderate vigorous exercise, such as brisk walking.

For three years, the participants also wore accelerometers - small devices which measure both exercise levels and sedentary time.

The researchers said that they were surprised that sedentary behaviour was nearly as strong a risk factor for disability as a lack of exercise.

"It means older adults need to reduce the amount of time they spend sitting, whether in front of the TV or at the computer, regardless of their participation in moderate or vigorous activity," they noted.

They made the following suggestions to reduce sedentary behaviour:
-Stand up if you are talking on the phone
-If you are going shopping, park in the space furthest away
-If you get up to have a tea break, walk around your house or office
-Avoid taking the car if you have a nearby errand
-If you are able to, always take the stairs rather than the elevator or lift.

Details of these findings are published in the Journal of Physical Activity & Health.