cosinuss° One was tested during activities such as slow and fast walking, slow and fast treadmill running and cycling on an ergometer with different intensities. In addition, talking, chewing, sitting and standing were examined. A total of 16 persons participated the study, which took place in the cosinuss° laboratory, under controlled conditions, to ensure the comparability of the results. A chest strap (Polar H7) was used as a reference. The cosinuss° LabClient served as a Bluetooth receiver for the °One and also for the chest strap, in order to record synchronized data from both measuring devices. The trigger function of the LabClient makes it possible to mark time points and periods in the recordings, so that we could differentiate between specific activities and phases.