Seven out of 10 UK workers have dragged themselves into the office when they were unwell and should have taken a day off, a report said.
The study by insurer Aviva said 69% of private sector workers felt pressured into coming into the office partly to avoid work piling up. This percentage is equivalent to 18 million people nationally.
This compares with 23% of those surveyed admitting to taking a sick day off work when perfectly healthy.
The survey comes after official figures showed fewer days were lost to sickness last year than any year on record.
The Office for National Statistics said that sickness absence totalled 137 million working days last year, the equivalent of 4.3 days per worker. When records began in 1993, the equivalent of 7.2 days were lost.
But more than two in five of 2,000 employees surveyed for the report said they feel their employer prioritises the performance of the company over the workforce's health and wellbeing.
Aviva's Working Lives study said this widespread presenteeism – forcing yourself to come into work when unwell – is counterproductive.
Aviva UK Health medical director Dr Doug Wright said: "While every business wants the right level of resource in place, having employees who are unwell at work is a false economy.
"Businesses need to ensure they create a working culture whereby people do not feel pressurised into coming to work when they are unwell, safe in the knowledge their absence can be effectively managed."
He added: "Presenteeism, driven in part by an increased 'always-on' culture, poses a genuine threat to overall business performance through the adverse impact on productivity and morale in the workplace."