The survey from the BHF also found two thirds (67%) do no think their organisation offers any opportunities to get fit and healthy
More than 2,000 workers from bankers to healthcare professionals were surveyed for Health at Work which is sponsored by Legal & General.
Almost a fifth (18%) of employees rated their daily stress levels as seven out of ten or above. Respondents reported that stress from work spilled over into their home life and free time. Over a third (39%) claimed stress from work made them feel more tired than usual, and more than a quarter (29%) said they find it difficult to sleep.
The survey also found that more than one in 10 (11%) workers fail to do any exercise on an average working day and over a third of workers (34%) also admit to taking one or more sick days during an average month.
As part of National Heart Month the BHF is now urging employers to think more about workplace health and join their its Health at Work programme.
Lisa Purcell, project manager for health at work at the BHF said: "These survey results paint a worrying picture of workplace health. Workers seem to be suffering a toxic combination of unhealthy foods, lack of exercise and high levels of stress. Many of us spend 60% of our waking hours at work and the daily grind can have a serious impact on the health of workers across the UK.
"In the current financial climate it's clear that the focus must be on productivity in the workplace. But employers must realise that a healthy workforce is key to less stress, better team work and improved motivation, which results in increased productivity and fewer sick days.
"This National Heart Month we're calling on the bosses of Britain to help get their employees fit and healthy. When it comes to thinking about your health, your heart is the best place to start and a few small changes can make a huge difference."
The BHF's Health at Work programme is free to join. To help employers get their workforce fit and healthy the BHF has launched its Mission Very Possible resources. The free resources include a quick start guide, posters, keep fit guides and more.