British people take an average of four days to fully adjust to work after the holiday period, according to a survey.
A study of 2,000 adults found most people will not begin functioning properly until almost a full working week has passed.
Re-adjusting to early mornings, the mountain of work piled up over the festive break and having to deal with challenging clients can take a toll in early January.
Others find it hard to get into the mood to exercise, knowing when they do go to the gym, it is likely to be packed with people on a New Year fitness kick.
The study, commissioned by working animal charity SPANA, found that for one in six Britons, the feeling of having nothing to look forward to also meant they struggle to get back into their normal routine.
The study found 44 per cent of adults believe they suffer from the January blues, and 52 per cent said that during the early part of the month, they would only be be at work in body, but not "in mind".
Three in 10 workers said they are expecting work to be awful in January because they know it will be some time before they get their next holiday, while a fifth said they are likely to return to a long list of tasks.
And a quarter are not looking forward to the likelihood that everyone else will be miserable about the return to work.
Perhaps unsurprisingly, more than a fifth of adults have considered calling in sick for the first few days back to work, while more than half are expecting to feel sad the evening before their first day.
Researchers also found almost half of those polled have no intentions of making any social arrangements in January.
When asked why, 12 per cent said they would be too grumpy, while a third said they would have no money.
Top 30 reasons Britons said they struggle to get back in the saddle
- The weather is horrible
- The days are still short and dark
- There are still months left of winter to go
- You feel tired and sluggish
- January feels like the longest month of the year
- The excitement of Christmas has passed
- Re-adjusting to the boring routine of everyday life / the daily grind
- It feels like you have to wait a long time before you can book more days off work
- You feel like there's nothing to look forward to
- You find it hard to motivate yourself to do any exercise
- You have eaten so much over Christmas you find it hard to stop
- The TV is rubbish
- You can't do anything of interest until January pay day
- You've picked up an illness after Christmas
- You can no longer blame 'the holidays' for eating/drinking too much
- All the work you said you'll get back to after Christmas is too much
- You can't be bothered to take the tree/decorations down
- January sales means you want to spend more money - but then you realise Christmas has left you broke, so you're depressed again
- You feel like you've socialised enough over the Christmas period to last a lifetime - hence seeing any more people is just effort
- Clients and customers are a challenge to work with
- The gym is packed with people on a new year fitness kick
- Children are also struggling to get back into routine
- Everyone else seems to be back on it, but you aren't quite ready
- Social media is full of weight loss plans and New Year's resolutions that you can't relate to
- No point in going out - as everyone is doing dry January
- Your house is full of Christmas presents - many of which are unwanted
- You start to experience chocolate withdrawal symptoms
- Children are a nightmare because they've been spoiled over Christmas
- Children have got used to late nights and late mornings which means getting them ready for school is even harder
- Having to face all the people you behaved badly in front of at the Christmas party
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