If the increase was rapid and intense, you may have inadvertently pressed the button. This can sometimes happen if you have your legs crossed or are resting your legs against an object, like a
piece of furniture or the car door while driving. App users can disable the button to prevent unintentional changes.
If intensity is increasing on its own and waterfall pattern is shown, calibration is running. Pressing the button 4x in a row will stop calibration. If this was accidental, the device will remember your previous calibration settings.
If the increase was noted toward the latter half of the therapy session, the habituation ramp is too steep for you. The device is designed to increase intensity throughout a therapy session to compensate for nerve habituation. For some people, this ramp is too steep, in which case the therapeutic intensity should be decreased during the therapy session. If you allow therapy to run the full 60 minutes, the device will remember the adjustment for future therapy sessions.