We all know that irresistible feeling of wanting to faceplant our sofa after a long, strenuous day at the office.

But it can often feel like a bit of a cheat to be so exhausted after a day filled almost entirely with sitting – after all, our sedate office jobs rarely demand anything physical of us.

Happily, however, science seems to have found an explanation for that weary, bone-tired feeling that often accompanies a stressful day spent sitting at our desks – and it’s all down to a phenomenon called “mental fatigue”.

Just as exhausting as exercise, mental fatigue can wipe us out entirely, with overworking our brains for an extended period of time often being just as draining as going for a long run.

Science finally reveals why sitting at a computer all day is exhausting