Mental health

Checking emails out of work 'can reduce wellbeing'

"Checking your emails outside of work really IS bad for your health," the Mail Online reports. A German study recruited a sample of 132 workers and aimed to look at how extended working outside normal hours influenced people's mood the next day.

It found working outside normal working hours limits the sense of detachment from work, and these factors are linked to feeling more tired and less relaxed and content the next day. It was also linked to higher morning levels of the stress hormone cortisol.

This issue is very relevant to today's working culture, where remote working and smartphones allow many of us to be continually engaged with work outside normal working hours.

However, the study gives limited representation of UK workers in general. It assessed the effect of formal "on-call" duties, compared with days when people didn't have these duties. This means it isn't as relevant as it first appears to be for the many UK workers who don't have formal arrangements like this, but who do respond to emails and calls at home outside normal working hours.

If you are not contractually obliged to respond to emails or phone calls outside your normal working hours, we recommend you don't. Creating a clear split between your working life and home life could make you less stressed and, ultimately, improve your performance at work.  

Where did the story come from?

The study was carried out by researchers from the University of Hamburg and supported by the German Federal Ministry of Education and Research.

It was published in the peer-reviewed Journal of Occupational Health Psychology.

The Mail's coverage implies the findings apply to all workers, when in fact the study was focused on formal on-call arrangements. The effects of being officially on-call may be different from more informal out-of-hours work, such as checking emails on your smartphone in the evening.   

What kind of research was this?

This was an experimental study exploring the relationship between the extended availability of employees outside work hours and the physical and psychological effect this can have on the body by looking at mood and stress hormones.

The researchers discuss today's mobile technology environment of smartphones and easy access to the internet, and remote communication with co-workers and customers at any time and place.

Previous studies observed how this technical opportunity to continue working outside normal hours and beyond the normal workplace has led to larger workloads and greater employer expectations. It also intrudes on home and family life, crossing the "work-family border".

The researchers define extended work availability as "a condition in which employees formally have off-job time, but are flexibly accessible to supervisors, co-workers or customers, and are explicitly or implicitly required to respond to work requests". The expectation is that recovery from work is limited under such conditions and this may impair wellbeing.

Three main hypotheses were investigated by this study:

  • extended work availability the previous day has negative effects on mood at the start of the following day, and is associated with higher levels of the stress hormone cortisol when waking up
  • extended work availability has negative effects on psychological detachment on the same day and limits control over out-of-work activities
  • the effect extended work availability has on mood at the start of the next day is influenced by the amount of psychological detachment the previous evening and how much control the person felt they had over out-of-work activities

What did the researchers do?

The study recruited 132 participants from 13 organisations. Participants were 91% male with an average age of 42 years, and the majority had worked at the same organisation for more than five years. The organisations were involved in transport and logistics, water supply, IT and technical services, trade, nurseries and hospitals.

The participants completed daily surveys during four days when they were on on-call duty (defined as being expected to be available during non-working hours) and four days when they were not on call. These were both composed of two weekday and two weekend days.

Participants completed the surveys using handheld computers that had an alarm to prompt them to complete them at set times of the day – for example, the start of the day and the afternoon.

The surveys contained questions on work and covered components from different psychological assessment scales. For example, to assess extended availability they would be asked, "How many calls from work did you receive in the last 24 hours?".

Recovery would be assessed using a scale where participants had to assess how much they agreed with statements such as, "This evening, I didn't think about work at all".

Mood at the start of the day was assessed by choosing from options such as, "At this moment, I feel discontent/content and unwell/well (valence), tired/awake and without energy/full of energy (energetic arousal), agitated/calm and tense/relaxed (calmness)."

A sub-sample of 51 participants gave consent to provide saliva samples so cortisol levels could be measured. Cortisol is a hormone the body releases in response to stress.

The researchers were mainly examining the effects of on-call duties for individuals, rather than between individuals. Potential confounding factors adjusted for in the analyses were age, gender, normal working hours, and the day of the week of the assessment. Cortisol measures were also adjusted for individual factors such as body mass index (BMI), smoking status, and subjective physical and mental health. 

What were the basic results?

In support of the researchers' first hypothesis, the results suggested extended work availability had negative effects on the three core mood components the following morning: energetic arousal, calmness and valence. It also increased cortisol levels the next morning.

In support of the second hypothesis, there was also a negative effect of extended work availability on recovery from work – that is, feeling detached from work and having a sense of control over one's out-of-work activities.

Lastly, they found the amount of recovery a person felt mediated the effect extended working hours had on their mood the next day. However, recovery experiences of control and detachment did not mitigate the effect extended working hours had on cortisol levels.  

How did the researchers interpret the results?

The researchers concluded that their study "provides evidence that extended work availability during non-work hours negatively affects employee wellbeing and recovery".

By this, they mean being expected to respond to work issues outside work restricts employees' crucial leisure time, which allows them to recover from work.  


This study explored the effects of extended working hours on an individual's mood and cortisol levels the next day. Perhaps unsurprisingly, it found working outside normal working hours limits a person's sense of detachment from work, and these factors are linked to feeling more tired and less relaxed and content the next day. The study will be of interest to sociologists, psychologists and the general public – being very relevant to today's 24/7 working culture.

However, a key limitation of this study is whether its findings apply to workers in the UK in general. The study involved a fairly small sample of predominantly male middle-aged workers, who will not be representative of the general UK population.

They had all responded to an advertisement saying this was a study aiming to optimise on-call work. It is possible the people who are most impacted by extended working hours may not respond to such an advertisement, as they may have thought they were too busy or had no time to take part in a study on top of all their other commitments.

This study looked at the impact of formal on-call days, when people were expected to be available during non-working hours, compared with days without this requirement. The formal on-call duty may be applicable in some professions – hospital workers, for example – but is this really representative of the general work culture the study aimed to assess? 

We live in an environment centred in mobile technology, where people have continued access to colleagues, clients and work projects. Many professionals won't have formal "on-call" days, but they may be in an environment where every working day has the potential to encroach on what should be their out-of-work recovery time. This environment of non-formal extended working hours – through emails, calls, at-home working, etc – may have an even greater effect on general health and wellbeing.

Even for this specific sample, the study's results may not be concrete. The study used surveys making use of valid psychological assessment scales, but these may not be able to capture all of the person's thoughts and feelings and other factors that may be involved beyond just the influence of working hours.

Also, the researchers only assessed this on a sample of days within a two-week period, which may not necessarily be representative of long-term working patterns.

What's more, this study was conducted in Germany, which may have a different work culture and environment from other countries.

Overall, the study is undoubtedly of topical interest, but because of the limitations of its small sample size, it can't provide definitive answers.

Most occupational psychologists would agree with the principle that you need to create a clear divide between your work life and your home and family life. If you are not on call, try to resist the temptation to check your work emails in the evening, or even worse, on holiday.

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