A wearable treatment device for treatment of a subject, comprising: a plurality of cardiac sensing electrodes configured to be positioned outside a body of the subject and to detect cardiac information of the subject; a treatment electrode configured to be positioned outside the body of the subject and to apply an electric current to the subject upon detection of when the cardiac information is indicative of a treatable cardiac arrhythmia condition; an activity sensor configured to be positioned outside the body of the subject and to detect activity information of the subject; an alarm module configured to alert the subject that the electric current will be applied to the subject. a user interface configured to receive user instructions to abort administration of the electric current to the subject; and a controller communicatively coupled to the plurality of cardiac sensing electrodes, the treatment electrode, the user interface, and the activity sensor, the controller configured to guide or prompt the subject throughout a predetermined test comprising a physical activity to be performed by the subject and to record activity information reflecting progress of the subject through the predetermined test based on signals from the activity sensor, wherein the controller is configured to record the cardiac information detected by the plurality of cardiac sensing electrodes during the predetermined test, wherein the controller is configured to determine whether the treatable arrhythmia condition exists based on data received from the plurality of cardiac sensing electrodes, data received from the activity sensor, and the user instructions received from the user interface, and wherein the controller is configured to adjust the timing of administration of the electric current when the activity sensor indicates that the subject is moving. a plurality of cardiac sensing electrodes configured to be positioned outside a body of the subject and to detect cardiac information of the subject; a treatment electrode configured to be positioned outside the body of the subject and to apply an electric current to the subject upon detection of when the cardiac information is indicative of a treatable cardiac arrhythmia condition; an activity sensor configured to be positioned outside the body of the subject and to detect activity information of the subject; an alarm module configured to alert the subject that the electric current will be applied to the subject. a user interface configured to receive user instructions to abort administration of the electric current to the subject; and a controller communicatively coupled to the plurality of cardiac sensing electrodes, the treatment electrode, the user interface, and the activity sensor, the controller configured to guide or prompt the subject throughout a predetermined test comprising a physical activity to be performed by the subject and to record activity information reflecting progress of the subject through the predetermined test based on signals from the activity sensor, wherein the controller is configured to record the cardiac information detected by the plurality of cardiac sensing electrodes during the predetermined test, wherein the controller is configured to determine whether the treatable arrhythmia condition exists based on data received from the plurality of cardiac sensing electrodes, data received from the activity sensor, and the user instructions received from the user interface, and wherein the controller is configured to adjust the timing of administration of the electric current when the activity sensor indicates that the subject is moving.