UK reaches 5 million mental health sick days by March, highlighting growing workplace challenge 

More than five million working days have already been lost to mental ill-health in the UK in 2026, underlining the scale of the issue facing employers and workforce wellbeing strategies. 

New analysis from Simplyhealth shows the milestone was reached on 24 March – the 58th working day of the year – with an estimated 5,066,403 days lost to conditions such as anxiety, depression, stress and burnout. 

Mental ill-health is now the leading cause of long-term absence and the second leading cause of short-term absence, reinforcing its growing impact on productivity and business performance across UK workplaces. 

Alongside this milestone, new research reveals how widespread mental health challenges have become among employees. Nearly a third (30 per cent) report experiencing anxiety or depression in the past year, while one in four (25 per cent) report stress or burnout. 

The data also highlights how mental ill-health is affecting different age groups in distinct ways, with implications for how employers design support. 

Younger workers are more likely to take time off for mental health reasons, but typically in shorter periods. Around one in five employees aged 18 to 34 report taking time off for anxiety or depression (20 per cent) and stress or burnout (21 per cent) in the past year. 

On average, younger employees who took time off for anxiety or depression were absent for 5.5 days, while those experiencing stress and burnout took 3.8 days. 

In contrast, older workers are less likely to take time off, but when they do, absences tend to be significantly longer. Employees aged 55 and over who took sick leave for anxiety or depression were absent for an average of 9.7 days, rising to 10.3 days for stress and burnout. 

A similar pattern is seen among those aged 35 to 54, who took an average of 8.3 days off for anxiety or depression and 8.5 days for stress and burnout. 

This suggests that while younger employees may be more open to taking time off earlier, older workers may delay absence until symptoms become more severe, resulting in longer recovery periods. 

Paul Schreier, CEO at Simplyhealth, said: “Poor mental health is having a profound impact on workers of all ages in the UK. We have already seen 5 million working days lost to poor mental health this year, with millions more to come. 

“While younger workers are more likely to take time off for mental health, they tend to take shorter periods of leave, whereas older generations take longer but fewer periods of leave when needed. The findings underline how mental health does not have a ‘one-size fits all’ solution, with symptoms presenting differently and often in conjunction with other conditions. It’s a reminder for the need to offer a range of support options that are flexible and tailored to employees’ different life stages.” 

The findings come as employers continue to invest in mental health support, with previous research showing 64 per cent of organisations are taking steps to reduce workplace stress. However, only half believe their current approaches are effective. 

Experts say this points to the need for more targeted and preventative strategies, particularly as mental health continues to drive absence and impact workforce performance. 

Mark Rowland, Chief Executive of the Mental Health Foundation, said: “Creating conditions for people to thrive at work is good for everyone. Tackling mental health problems early with a preventative approach is one of the best ways to support employees to be healthy and happy in the workplace and reduce periods of absence. Workplaces can be stressful environments, but they can also give us much needed meaning and connection that is vital for our mental health.” 

The data highlights a clear link between mental health and workplace outcomes, reinforcing the need for employers to embed flexible, preventative and inclusive approaches to support employees across different life stages.