You might think you're doing your bosses a favor by coming into work when you're poorly, or demonstrating a commendable commitment to your job. But presenteeism – that's attending work when you're sick – comes with a high cost in terms of productivity loss and the risk of employee burnout.

New research identifies one of the key reasons staff work when they're not well enough: they haven't met their daily work goals. The study also found that working when sick has a negative effect on work performance the following day.

That's based on an analysis of diaries kept for 15 days by 126 employees working remotely. The researchers behind the study say that it's important to manage expectations and workloads in order to protect against presenteeism, and ensure that overall productivity doesn't take a hit.

"While it may seem a good idea to work despite ill health to deliver on work goals, our research shows that this has a knock-on effect for remote workers' performance on the next day as presenteeism drains employees' psychological energy, which cannot be fully recovered after work," says psychologist Wladislaw Rivkin from Trinity College Dublin in Ireland.

Study participants were gathered from a variety of professions, covering IT, teaching, finance, and other sections, and a total of 995 data points were gathered that measured physical health, work goals, and working hours. The data revealed a link between having work to finish and carrying on while sick.

Overcoming the signals being broadcast by our bodies when we're sick in order to keep on working causes ego depletion, the researchers say – a gradual sapping of our willpower and mental strength that then takes time to recover.

Considering the subsequent negative impact on work performance, as well as the risk of prolonging illnesses through a lack of rest, the study authors suggest managers should actively discourage presenteeism – and avoid it themselves. One approach could be to reduce workloads or switch tasks assigned to staff.

"If employees engage in presenteeism they should work on tasks that are inherently pleasant rather than tedious tasks that further drain their energy," says Rivkin.

Of course, wanting to keep up with workloads isn't the only reason people don't take sick days. For many, carrying on working is simply an economic necessity – they need the money, and risk losing their positions if they don't show up.

It also seems clear from this and other research that the shift towards working at home seen in some industries and businesses puts presenteeism in a different light: with no commute, no physical contact with others, and an always-on internet connection, the considerations around whether to keep on working when sick are different.

This was one of the first studies to look at presenteeism in the COVID-19 pandemic which has blurred the lines between work and leisure time even further – whether or not employees are feeling unwell.

"It is crucial to tackle daily presenteeism, especially for remote workers," says Rivkin.

"Managers should openly discourage presenteeism by reassuring team members that if they feel unwell it is acceptable to reduce their daily work goals and instead tend to their health."

The research has been published in the Journal of Occupational Health Psychology.