If psychologists wanted to find out about stress perception of test subjects and the consequences of mental stress, until now they had to rely on classic questionnaires or experiments. But an artificial laboratory situation influences the validity of the results, and in case of surveys, looking back over a week at work, for example, is susceptible to memory distortions. Regina Schmid, however, now studies stress and stress reactions as they arise – in the everyday work of hospital staff, teachers or police officers: “We use ambulatory methods that allow us to collect data over a longer period of time. The test subjects are equipped with a chest strap that continuously records their heart activity over several days.” In addition, they receive a smartphone with an app that briefly surveys them several times a day: What type of activity have you been carrying out for the past two hours? Was time pressure involved? How does the current load in your job feel? “We can thus collect subjective information over a long period of time and then combine it with physiological data of the ECG in the evaluation”, Schmid explains.
The so-called heart rate variability (HRV) is of particular interest to her. It describes differences of milliseconds between two heartbeats. Contrary to common belief, a healthy heart does not beat like a metronome. “Quite the opposite: A large variability between heartbeats is a sign of the organ’s adaptability to different demands”, says Schmid.
To avoid misinterpretation of the heartbeats, various influences are taken into account, for example, whether a participant practices an intensive sport or has any pre-existing conditions. The study participants – most recently over 100 teachers – are also asked about personal characteristics, behaviors and attitudes: Is work an important purpose in their lives? Are they easily upset?
“The evaluation of the smartphone survey and the HRV values shows that some participants don’t even notice how tense they are. They subjectively assess their well-being differently than the heart activity would suggest. In such people, mindfulness in the literal sense is less pronounced”, says Schmid. Participants who, in turn, are more attentive to themselves have greater convergence between the HRV data and the subjective feelings reported in the daily survey.
Those who also have a high heart rate variability over a longer period of time are less likely to be affected by stress, as Schmid’s results show: “These individuals have a strong ability to self-regulate and don’t perceive the demands of their work as draining as those with low heart rate variability.”
However, neither mindfulness nor heart rate variability are fixed variables that cannot be changed. The psychologist’s findings so far rather show possible starting points for occupational health care, for example. “In the long term, heart rate variability can be positively influenced by a healthy lifestyle and physical exercise. Awareness for a more mindful approach to things, on the other hand, can be increased through targeted training”, says Schmid. After all, not all requirements of a professional field can be changed fundamentally: Teachers will always be confronted with the expectations of parents and pupils, and hospital staff experiences time pressure and bears responsibility for the lives of others. That is why it is important to strengthen resources that people can use in their own initiative to reduce stress.