80% of the tracked data had a signal quality from good to excellent. Meaning the cosinuss° One can monitor the vital signs of first-time untrained users reliably during regular work. The reason for the other 20% with a quality from moderate to bad were mostly the wrong placement of the sensor inside the ear or a bad Bluetooth connection between smartphone and the in-ear sensor.
The transmission between the cosinuss° One sensors and the personal smartphone of the employees worked excellent in general. 90% of all data transmissions were completed successfully. Only one test person had known issues with his smartphone model to keep a steady connection via Bluetooth Low Energy.
It is noticeable that the fatigue score is subject to fluctuations during the day. As expected, it indicates a high performance level at the beginning of the day and a reduced performance level at the end of the day. Furthermore, there is a noticeable correlation between the fatigue score and the location temperature. The average fatigue is decreasing with the decreasing of the location temperature.
The Physical Stress Index, too, is subject to fluctuations during the day, however this score could not indicate extreme conditions during our study. The highest PSI value measured in this pilot was at score 5 with 7 being the highest. Two test persons in the study had shown a strong correlation between their PSI and their location temperature. Their average PSI was decreasing with the decreasing of the location temperature.