A study by research group OnePulse also found that a third of workers said they were not able to take all their holiday entitlement.
A survey of 2,000 employees revealed that most felt forced to work through their lunch break and four out of five do not leave the office on time most days.
The report, to mark National Work Life Week, said half of people felt stressed and tired at work.
Nick Walter, OnePulse chief marketing officer, said: “The real issue is the taboo nature of working overtime today.
“Since the start of the UK financial crisis in 2008, there was a nervousness amongst employees, who were urged to up their game to keep their jobs. This is the hangover - who is going to speak out?
“Simultaneously, the rise of ‘bring your own device’ into the workplace and innovations in digital technology and improved access to high speed internet, ‘work’ is no longer only possible in the office - work is everywhere we turn.”
Seven out of 10 of those polled said they worked an extra day each week because of overtime, with 43% saying it was unpaid