A study of more than 4,000 civil servants found that those who spend less than 12 hours sitting down a week can decrease their risk of diabetes by 75%, and that those who sit more than 25 hours per week increase the chance developing metabolic risk factors like “bad” cholesterol and insulin resistance. The study was published by the British Journal of Sports Medicine.

Taking into consideration smoking, waist circumference, dietary quality, exercise habits and other variables, the scientists were able to isolate the specific effect that the hours of sitting seemed to be having on people’s life spans: Every single hour of television watched after the age of 25 reduces the viewer’s life expectancy by 21.8 minutes.

By comparison, smoking a single cigarette reduces life expectancy by about 11 minutes, the authors said.

Dr John Buckley from the University of Chester, found that if you stand for three hours a day for five days you burn around 750 calories more than you would sitting. Over the course of a year it would add up to about 30,000 extra calories, or around 8lb of fat.

“If you want to put that into activity levels," Dr Buckley says, “then that would be the equivalent of running about 10 marathons a year. Just by standing up three or four hours in your day at work.”

We’re sold.

Off the clock: four scientific reasons why you should always leave work on time, no matter what