I wore a holter for 24 hours. As I can home a huncch- don't know what. I called in and said I saw nothing on the screen and wondered if it was really on. They said the screen fades after a while. As I returned it the doc looked at it, called back and said the monitor had turned off after I wore it for 15 minutes!! That was such a BUMMER- especially since I happened to have some of my worst and significant events as I wore it! I just banged my head in the wall,,,,LOL! Love my doc and his nurses, but I don't like his monitor! It would be like winning the lottery to have such a 24 hour period again ( with my most significant symptoms present)as I have to wear it again next week. Please pat me on the back, I need it,,,,LOL!