Inclusion Criteria:  All participants:  BMI 17 to 35 kg/m2 Diagnosis of Graves' disease (matching one of the following criteria: elevated TRAb and/or ultrasonography and functional imaging consistent with Graves' disease) In possession of a smart phone Able to use a wearable device and willing to regularly upload their biometric data Informed consent as documented by signature (Appendix Informed Consent Form)  Group "treatment":  TSH < 0.2 mIU/l and fT4 > 25 pM or fT3 > 8 pM ATD planned, additional treatment with propranolol allowed  Group "surveillance":  TSH within the reference range between 0.3 and 4.5 mlU/l Cessation of ATD is planned within the next 2-4 weeks  Exclusion Criteria:  Chronic treatment with beta blocker or verapamil-type calcium antagonist for other reason than symptomatic treatment of hyperthyroidism (propranolol) Treatment with amiodarone Pacemaker with continuous stimulation. Severe concomitant diseases: chronic heart failure, liver cirrhosis, kidney failure, active cancer Abuse of alcohol or illicit drugs Allergic to nickel or silicone Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant