Business leaders are being urged to help employees engage with health and wellbeing initiatives available to them at work.
The call followed Vitality research that found three quarters of ill-health related absence and presenteeism (working while sick) came from factors such as depression, poor lifestyle choices and stress.
The data, which was developed by Vitality, Rand Europe, and the University of Cambridge, found that businesses lost the equivalent of £81bn as a result of ill-health related absence and presenteeism in 2018.
This was a £4bn increase when compared with 2017.
Mental health, a significant driver of productivity loss, accounted for £38bn of the total cost to businesses in 2018, with £17.2bn stemming specifically from workplace stress.
In terms of time, employers now lose an average of 35.6 working days per employee per year due to health-related absence and working while sick.
Neville Koopowitz, CEO at VitalityHealth, said: "For the sixth year in a row, Vitality’s Britain’s Healthiest Workplace data illustrates the huge cost of absence and presenteeism to British businesses.
"With this data showing that employees lose, on average, over 35 days each a year, it is becoming impossible for businesses to ignore the link between ill health and productivity.
"Simply implementing intervention programmes is no longer enough. By prioritising and elevating employee engagement in health and wellbeing within the business, ideally to board level, we can make a significant difference to productivity and the overall success of the business."
Christian van Stolk, vice president at Rand Europe, added: "Although it is encouraging to see an increase in the number of employees that have access to health and wellbeing initiatives in the workplace, the data from this year’s study also shows that businesses are still failing to properly engage employees, and get their participation, with such initiatives.
"We know from the Britain’s Healthiest Workplace findings that employees report a significant improvement to physical and mental health as a result of workplace interventions year on year.
"As such, businesses need to do more to drive effective employee engagement - this is critical to addressing the issue of productivity loss across our nation."
According to the Britain’s Healthiest Workplace study, those with the best results demonstrated a 30-40 per cent reduction in productivity loss linked to ill health.
However, the research showed that awareness and engagement of interventions was low.
While 67 per cent of employees had access to interventions in the mental health space, only 26 per cent of them claimed to have knowledge and awareness of what is on offer.
In addition, once aware, just 18 per cent of employees participated in any of the programmes.
Paul Fairclough, scheduling coordinator at United Utilities, who has suffered from mental health issues in the past, said: "As someone who kept their battle with mental health issues a secret for over a decade, it’s positive to see the conversation around mental health becoming more open, and employers – like mine – engaging actively in the discussion.