Half of workers never leave their office, while two thirds spend at least six hours a day sitting at their desk despite the risk to their health, a new study has revealed.
A survey of more than 1,000 office staff found that those in sales, media, marketing and finance were most likely to be desk-bound all day.
A third of those questioned by recruitment firm Office Angels regularly stayed late to finish off tasks, while one in five took work home with them.
Office Angels said the results showed that many workers were sacrificing their happiness, health and wellbeing by putting in such long office hours.
Steven Kirkpatrick, managing director of Office Angels, said: "Many workers feel pressurised in today's workplace and as a result work longer hours and spend more time at their desk in an attempt to prove their worth.
"Organisations must now take action to create a working environment which fosters a sense of wellbeing. Office workers need to take regular breaks, stretch their legs, and eat away from their desk if work demands allow. Failure to do so may result in an unhappy, over-worked and dissatisfied workforce, which in turn may result in a loss of productivity."
Half of people said they went into work if they were ill.
Dr Munther Sabarini, of the spinal clinic Avicenna, in Berlin, commented: "Sitting at your desk for hours on end can lead to very serious back complaints. It can lead to muscles weakening, pressure on the smaller joints, and a decrease in blood supply to the bones. The discs in the spine receive their nutrition from blood and oxygen - if they don't receive this, the discs can degenerate. This wear and tear can be very painful.
"To avoid this, office workers need to change their posture from time to time, and employers need to pay attention that the tables, chairs etc are suitable for the height and shape of their employees. I advise people to sit at their desk for no longer than an hour, after which a short five-minute walk or break is needed."