That's according to a new study that revealed many people feel work pressures make them drink and smoke more, put on weight and do less exercise.
A survey of almost 1,400 workers revealed that almost a third believed work-related stress could lead to high blood pressure, while one in five feared it could cause a heart attack.
The British Heart Foundation urged employers to encourage workers to spend at least 10 minutes a day improving their lifestyle.
Lisa Young, Project Manager for the BHF's Health at Work programme, said: "This survey is a stark reminder of just what happens when we don't take our health at work seriously enough.
"Millions of people say they are smoking more, exercising less and putting on weight because they're not considering the impact their job is having on their health and wellbeing.
"Behaviours like these can be extremely damaging, not just to your heart health but also to businesses. From working with over 9,500 organisations we know that the pay-offs of making health at work a top businesses priority are too great to ignore."
A third of those polled said they had put on weight because of work, half ate more unhealthily, a quarter drink more and 43% believe work has caused them to exercise less.
TUC general secretary Frances O'Grady said: "The BHF report is a shocking indictment of the modern world of work.
"Long hours, the insecurity of jobs on zero-hours contracts and the stress associated with them are all taking a toll on people's health.
"The report's findings show just how bad some workplaces have become. However, the answer is not just for employers to encourage their staff to change their lifestyle - it is for employers to improve working conditions, provide secure jobs and treat their workers like human beings rather than machines."