In a glut of new research on the subject, experts are warning that we should 'beware our chair', as spending too long in it can raise the risk of high blood pressure, a sluggish metabolism and weight gain.
With the average person sitting down for just under nine hours a day at the office, at home or in the car, even a daily workout is unlikely to offset the risks of being seated for too long.
Sit ups: Being chair-bound for too long can raise the risk of high blood pressure, a sluggish metabolism and weight gain.
According to Swedish scientists, quoted in the British Journal of Sports Medicine recently, prolonged sitting should carry a public health warning.
So why is the humble chair being blacklisted? As the most passive activity behind lying down, being seated burns a bare minimum of calories - even eating an apple or fidgeting uses more energy than parking your bottom on a chair.
While standing engages muscles in your back, shoulders and legs, sitting presents no positive physical challenge to the body, forcing it instead into an inactive state.
It is almost inevitable, researchers say, that long-term sitters find their waistline expanding.
While the action of standing up only burns a few calories, do it enough times a day and it makes a real difference.
It's easy to burn 30 to 50 extra calories a day, which is enough to prevent a weight gain of 2lb to 3lb a year. Spend your time sitting down and the pounds will creep on unnoticed.