Close to a quarter of employees in the UK went into work in January despite feeling ill.
That is according to a YouGov poll commissioned by the TUC, which revealed that staff went to work because they were concerned about letting colleagues down.
The research also revealed that over the last year more than half of British workers admitted to going into work when they were ill.
Commenting on the findings of the survey, TUC general secretary Brendan Barber said: "Too often we are told that British workers are always taking bogus sickies or taking time off at the first sign of a sniffle.
"But the truth is that we are a nation of mucus-troopers who struggle into work even when we are too ill because we do not want to let colleagues, clients or our employer down."
The survey results also suggested that people may be concerned about their job security as 29 per cent admitted that the recession would make them more determined to go to work if they were unwell.
According to the Chartered Institute of Personnel and Development, if employees have a good manager they are "less likely to take time off sick unnecessarily".