April 7, 2014 -- The studies just keep coming. Sitting our life away, it seems, may be very bad for our health and even our life expectancy.

Just since January, researchers have reported that sitting for long hours is linked to:

Worse mental health

A higher risk of death from heart disease and other causes

A higher risk of being disabled

The new studies add even more weight to earlier research suggesting that too much sitting is bad -- even if you get regular exercise.

Experts say they still don't know for sure which comes first. Does too much sitting trigger poor health, or is it the other way around?

They also say we may need to think about sitting and exercise as two separate behaviors, each contributing on its own to our health. So while that 1-hour jog is great for you, it may not undo the 8 hours sitting at your desk.

WebMD asked three experts to weigh in on what we know about sitting and how we can reduce our sitting time.