Mental stress is the answer of our body to uncomfortable and possibly harmful situations to temporarily improve performance by triggering several mechanisms. One key actor within these changes caused by stress is the heart. The heart activity can provide several insights into the human body. Doctors have used electrocardiograms for decades for pathological reasons. Thanks to their rise in popularity, wearable devices to monitor the heart have become affordable and offer a convenient way to collect heart data without the use of expensive medical devices. The analysis of the heart rate variability (HRV) can provide insights into the activity of the autonomic nervous system, which plays an important role in regulating mental stress. This master’s thesis describes a newly developed app for the OEFAST test, which is a yearly test for each smoke diver of Austrian fire brigades. Three requirements were set for the app: documentation of the test, physical monitoring, and mental monitoring of the research participant. The main focus was given to mental monitoring in order to detect high levels of mental stress. Mental stress detection is a field with a lot of uncertainties. To provide a stress detecting algorithm, knowledge about the HRV and mental stress had to be gathered before. Based on the findings in the literature, several studies were made to find potential correlations between stressors and the parameters of the HRV. The results show that stress coping and the human reaction to stressors differ among individuals. Therefore, the presence of good stress data is essential to make good predictions.
