Office workers will stand at their desks rather than sit to see if it is better for their health.
In what has been described as the longest experiment of its kind, staff from Virgin Media in Sheffield will ditch their chairs for a minimum of two hours a day.
The trial is being conducted after increasingly sedentary lifestyles have been linked to serious health problems such as type 2 diabetes and cardiovascular illnesses.
Previous short-term studies calculated that around 30,000 extra calories could be burnt a year - equating to 3.6kg (8lbs) - simply by standing for two to three hours a day at work.
The experiment will see the first group use the special sit-stand desks for six months, and the second group for the following six months.
John Buckley, professor of applied exercise science at the University of Chester, who is leading the study, said: "The simple act of standing for even as little as two hours per day can increase muscle activity to have a significant impact on health and wellbeing.
"This unprecedented study with Virgin Media will allow us to gain a more comprehensive understanding of the benefits working on your feet can have on health and performance."