The aim of the present study was therefore to map the condition of the sympatho-vagal balance with the help of non-invasively measurable heart rate variability (HRV). In subsequent steps, a parameter derived from the HRV should be identified later, which is suitable for announcing an imminent IDH. The reliability of the HRV measurement should be checked by intraindividual comparison over time. In a total of 34 dialysis patients (age 56 ± 14.4, m / w = 23/11) continuous ECGs were derived during dialysis and beyond the end of dialysis. In a timely manner, a repeat measurement was performed on the same patient collective to test the stability of the method. The course and appearance of the tachograms indicate the cardiovascular risk profile of the patients. The reliability test showed the reliability of the method. There was no IDH during the study. The proven good measurement stability of HRV long-term measurements means that the method is suitable for regular measurements in dialysis mode. Looking ahead, by incorporating an ECG chip into the dialysis technique, the HRV could complement the patient's parameters, such as blood pressure, blood volume, heart rate, to approximate a physiological dialysis, to minimize the risk of IDH.