A medical blood-treating apparatus for the extra-corporeal treatment of blood has an extra-corporeal blood circuit. An arrangement for the extra-corporeal treatment of blood and an arrangement for electrical muscle stimulation (EMS) with which muscles of the patient can be stimulated in a targeted fashion during the dialysis treatment are provided. For this purpose, the arrangement for EMS has a means of generating electrical pulses, and has one or more electrodes connected to the means of generating electrical pulses. To enable targeted stimulation, the electrodes are applied to the patients skin, e.g., the legs, during the blood treatment. Muscle stimulation during blood treatment may result in the dialysis treatment being more tolerable for the patient and increase the efficiency of the blood treatment. The blood-treating apparatus according to the invention allows an improvement in the efficiency of the blood treatment without any active sporting activity or exercise by the patient.
