Scientists have said that the long holiday break of Christmas combined with the New Year will leave many suffering from a 'social jet lag'.
They said that the festive break wreaks havoc with our body clocks and leaves them with symptoms similar to having travelled to a different time zone.
Plus feeling down and out as the holiday gets over could leave many with negative emotions, and two weeks of irregular sleeping patterns could lead workers to feel tired and lacklustre.
'Social jet lag' manifests itself in the struggle to get up in the morning, feeling sluggish, finding it a difficult to fall asleep at night and feeling sleepy during the day.
Other symptoms include indigestion, loss of appetite, difficulty concentrating, memory problems, clumsiness, feeling generally unwell, lack of energy, fatigue and irritability.
"Over the Christmas period we will enjoy staying up late at night and staying in bed in the morning. However, this will allow our body clock to drift later in time similar to flying a couple of time zones west," the Daily Mail quoted Dr Victoria Revell, a researcher from the University of Surrey, as saying.
"This means that when we go back to work in the new year our body clock will be set later than we want it to be so we will really struggle to wake up, get up and get going in the mornings.
"One way to enjoy the festive season but not let our body clock drift too far is to ensure that we still get up at a reasonable time even when not going to work."