Businesses in the UK could lose an estimated £790 million as a result of staff hangovers, according to new figures.
Research by the hotel chain Travelodge found that lost productivity as a result of festive partying the night before could be worth hundreds of millions of pounds.
Travelodge carried out a survey of 4,500 workers and discovered that workers reported spending two hours and 18 minutes "staring into space" at their desks when suffering from the effects of the night before.
A third of respondents said they called in sick because they could not face a day in the office after the Christmas party.
But 34 per cent of these said their boss could probably see through their excuses.
Leigh McCarron of Travelodge said: "It's not just sleep that can cure the effects of a big night out, it's also what you do before and after.
"Always drink plenty of water before going to bed, and first thing in the morning eat a healthy breakfast."