Why Everyday Stress Still Isn't Fully Understood

Most of what we know about stress research comes from carefully controlled experiments on animal models and humans in the laboratory.

In 1993, Clemens Kirschbaum and his colleagues revolutionized stress research when they presented their safe and highly reliable stress paradigm called the Trier Social Stress Test (TSST, Kirschbaum et al., 1993).

The TSST is now used for the majority of studies on stress. In its traditional form, it asks participants to stand in front of two people in lab coats who look a bit grim and offer no encouragement as you explain why you and only you are the right candidate for your dream job.

Their non-smiling faces are usually accompanied by a video camera to make the impression of being judged even stronger. After this self-presentation, participants have to do a pretty hard arithmetic task such as counting backwards in steps of 17 from 2043 and starting over whenever they make a mistake.

The TSST gets people’s heart rate up and raises their cortisol levels. Following its publication in 1993, the TSST has become the default stress paradigm, with hundreds of studies using it (Campbell and Ehlert, 2012). Since then, we've learned that men’s cortisol levels react stronger than women’s to the TSST (up to twice as strong, see Kudielka et al., 2009), that hormonal contraceptives change the cortisol response (Gu et al., 2022), that mindfulness makes people more resilient to stress (Brown et al., 2012), and more.

Another current branch of modern stress research can be found in organizational psychology. In this branch, stress is part of the research on burnout. Stress and burnout have a complex relationship (Pines & Keinan, 2005), but, generally, stressors such as tight deadlines, role conflict, or a difficult supervisor can lead to low work engagement and high emotional exhaustion, which are seen as the main components of burnout (Demerouti et al., 2002).

The lab and the workplace are important locations to study the causes, processes, and effects of stress in animals and humans. However, these areas are hardly comprehensive for all of human activity.

Where is the research on stress in the real world, outside of the workplace?

It’s easy to come up with examples when people are exceptionally stressed in their day-to-day lives: Visits at the doctor’s office, waiting (and missing) a train connection on the way to an important appointment, and, my personal favorite, moving to another country with a 9-month-old baby (I’ll publish a report on this further down the road if Psychology Today will allow it).

If we want to study and understand stress, we must eventually conduct studies outside the lab so we can achieve ecological validity. Ecological validity tells us how the conclusions we have arrived at in the lab perform in everyday life.

This comes with a number of challenges on its own, as it’s much harder to conduct carefully controlled studies in the real world than in the lab. There are simply too many third variables that can influence results. Nevertheless, we have to try if we want to understand stress and how it affects humans in their everyday lives.

To address this problem, Urs Nater and a group of other senior scientists at University of Vienna recently founded a research platform called “The Stress of Life” (SOLE), which I just joined as a postdoc. We want to understand the processes and mechanisms of everyday life stress and see how they might be different from stress under controlled conditions.

Other groups are working on stress in everyday life as well, using technology such as ecological momentary assessment, which asks people to report on their perceived stress in real time (EMA, see Can et al., 2020; Fabes & Eisenberg, 1997).

The American Institute of Stress (2013) estimates that diseases and injury related to stress costs the U.S. economy $300 billion per year. Too much stress, experienced over long periods of time, can make people sick and unhappy.

Understanding stress better, in the lab and in the real world, is a vital task in solving the problem of how to handle the stressors of modern life.