Three in five (57%) workplaces do not offer benefits or programmes to encourage employees to exercise, according to Opinium research.
Two online surveys of 2,007 and 2,000 UK adults, in August and September respectively, also revealed that one in five (22%) of organisations offer a cycle-to-work scheme, while 14% provide subsidised gym memberships.
Some 13% of employers organise exercise classes such as a running club or yoga sessions. Only 8% of workplaces have after-work sports teams and just 5% encourage employees to exercise during their lunch break.
Sophie Holland, research executive at Opinium, said: "Whether we like it or not, the majority of our time is spent in the workplace. Our employers expect a lot from us and the pressure to perform is always there.
"Our research shows that the majority of workplaces do not encourage or incentivise their employees to exercise, be it by subsidising gym memberships or other benefits, and this could be unwise in the long term given the links between exercise and mental health."
In the regional breakdown, three-quarters (76%) of those living in the East of England said their workplaces do not offer employees anything to be more active, while the same was true for 72% in the East Midlands and 64% in the South East.
Londoners have the highest number of workplace exercise options available to them, with 26% having access to a cycle-to-work scheme, 24% provided with a subsidised gym membership and 24% offered exercise classes through work.
According to the Short Warwick-Edinburgh mental wellbeing scale, published by NHS Health Scotland, University of Warwick and University of Edinburgh in 2007, those who exercise at least once during a typical week have a higher mental wellbeing than those who do not tend to exercise.
The research also found that 38% of those who exercise as part of a group feel happy as opposed to 22% who exercise alone, and 35% of group exercisers feel energised compared with 24% of those exercising alone.
The reasons given for feeling more motivated when exercising as a group include having more fun (43%), socialising (40%) and the activity feeling less of a chore (38%).
Sarah Stewart-Brown, professor of public health from Warwick University, said: "The relationship between mental health and exercise is likely a bidirectional one, with exercise improving mental health, as well as good mental health driving increased exercise.
"It would be a wise move for more employers to encourage exercise among their workforce. Not only would employees that exercise find themselves more motivated and with better mental wellbeing, but they would also likely increase their productivity at work."
