Workplace Interruptions Lead to Physical Stress

Summary: Study reveals the body produces more cortisol when people are interrupted during work.

Source: ETH Zurich

ETH researchers have used an experiment in a simulated group office environment to show for the first time that the body produces more stress hormones when people are repeatedly interrupted at work. And yet the subjects did not experience an equal rise in their consciously perceived sense of psychological stress.

According to the Job Stress Index 2020 compiled by Stiftung Gesundheitsförderung Schweiz, a Swiss health foundation, almost one-​third of the Swiss workforce experience work-​related stress. Should this stress become chronic, it can lead to states of exhaustion that have a negative impact on public health and carry a significant economic cost.

The goal: a digital early warning system

At the Mobiliar Lab for Analytics at ETH Zurich, an interdisciplinary team is working to pre-​empt such states of exhaustion by developing a digital early warning system that uses machine learning to detect stress in the workplace in real time. “Our first step was to find out how to measure the effects of social pressure and interruptions – two of the most common causes of stress in the workplace,” says psychologist Jasmine Kerr. Kerr is driving the project forward together with mathematician Mara Nägelin and computer scientist Raphael Weibel.

The three doctoral students are all lead authors on a recent study, details of which appeared in the journal Psychoneuroendocrinology. They used a university platform to recruit 90 participants, who agreed to take part in an experiment lasting just under two hours. To conduct their experiment, Kerr, Nägelin and Weibel transformed the Decision Science Laboratory at ETH Zurich into three group office environments. Each workstation was equipped with a chair, a computer with monitor and kits for collecting samples of saliva.

Playing the parts of employees at a fictional insurance company, the participants were asked to perform typical office tasks, such as typing up information from hand-​written forms and arranging appointments with clients. While they did so, the researchers observed their psychobiological responses. At a total of six points during the experiment, the participants rated their mood on questionnaires, while a portable ECG device continuously measured their heartbeat. The researchers used the saliva samples to measure the concentration of the stress hormone cortisol.

In line for a promotion

For their experiment, the researchers divided the participants into three groups and exposed each group to a different level of stress. All groups were given the same workload. In the middle of the experiment, all participants were visited by two actors masquerading as representatives of the insurance company’s HR department. For participants in the control group, the actors staged a sales pitch dialogue, while in the two stress groups they pretended to be looking for the most suitable candidates for a promotion.

The difference between the two stress groups was that participants in the first group stopped work only to have samples of their saliva taken. But the participants in the second stress group had to contend with additional interruptions in the form of chat messages from their superiors urgently requesting information.

Almost twice the level of cortisol

Upon evaluation, the data indicated that asking participants to compete for a fictional promotion was enough to raise their heart rate and trigger the release of cortisol. “But participants in the second stress group released almost twice the level of cortisol as those in the first stress group,” Nägelin says. Weibel adds: “Most research into workplace interruptions carried out to date focused only on their effect on performance and productivity. Our study shows for the first time that they also affect the level of cortisol a person releases, in other words they actually influence a person’s biological stress response.”

This shows a stressed woman at a laptop
Interruptions by work colleagues can also increase stress levels. Image is in the public domain

What surprised the researchers were participants’ subjective responses in terms of how they perceived psychological stress. They observed that participants in the second stress group, who were interrupted by chat messages, reported being less stressed and in a better mood than the participants in the first stress group, who didn’t have these interruptions. Interestingly, although the two groups rated the situation as equally challenging, the second group found it less threatening.

The researchers inferred that the release of cortisol triggered by the additional interruptions mobilised more physical resources, which in turn led to a better emotional and cognitive response to stress. It is also possible that the interruptions distracted the participants from the impending social stress situation, meaning that they felt less threatened and thus less stressed.

About this stress research news

Source: ETH Zurich
Contact: Press Office – ETH Zurich
Image: The image is in the public domain

Original Research: Open access.
The effects of acute work stress and appraisal on psychobiological stress responses in a group office environment” by Kerr JI, Naegelin M, Weibel RP, Ferrario A, La Marca R, von Wangenheim F, Hoelscher C, Schinazi VC. Psychoneuroendocrinology


The effects of acute work stress and appraisal on psychobiological stress responses in a group office environment


The high prevalence of office stress and its detrimental health consequences are of concern to individuals, employers and society at large. Laboratory studies investigating office stress have mostly relied on data from participants that were tested individually on abstract tasks. In this study, we examined the effect of psychosocial office stress and work interruptions on the psychobiological stress response in a realistic but controlled group office environment. We also explored the role of cognitive stress appraisal as an underlying mechanism mediating the relationship between work stressors and the stress response.

Methods and Materials

Ninety participants (44 female; mean age 23.11 ± 3.80) were randomly assigned to either a control condition or one of two experimental conditions in which they were exposed to psychosocial stress with or without prior work interruptions in a realistic multi-participant laboratory setting. To induce psychosocial stress, we adapted the Trier Social Stress Test for Groups to an office environment. Throughout the experiment, we continuously monitored heart rate and heart rate variability. Participants repeatedly reported on their current mood, calmness, wakefulness and perceived stress and gave saliva samples to assess changes in salivary cortisol and salivary alpha-amylase. Additionally, cognitive appraisal of the psychosocial stress test was evaluated.


Our analyses revealed significant group differences for most outcomes during or immediately after the stress test (i.e., mood, calmness, perceived stress, salivary cortisol, heart rate, heart rate variability) and during recovery (i.e., salivary cortisol and heart rate). Interestingly, the condition that experienced work interruptions showed a higher increase of cortisol levels but appraised the stress test as less threatening than individuals that experienced only psychosocial stress. Exploratory mediation analyses revealed a blunted response in subjective measures of stress, which was partially explained by the differences in threat appraisal.


The results showed that experimentally induced work stress led to significant responses of subjective measures of stress, the hypothalamic-pituitary-adrenal axis and the autonomic nervous system. However, there appears to be a discrepancy between the psychological and biological responses to preceding work interruptions. Appraising psychosocial stress as less threatening but still as challenging could be an adaptive way of coping and reflect a state of engagement and eustress.

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