Is the Mat is designed for overnight sleeping? How long can the automatic shut off be set for?

Unlike some 30-60-90 minute pads, MediCrystal mats can be programmed for up to 12 hours of uninterrupted use. 

You can sleep on it all night long on the lower heat levels in the winter or on negative ion mode in summer.

You can set the mat to turn off after 3, 6, or 8 hours for some models or after 4, 8, or 12 hours for other models. 

You can also use an A/C powered timer, with options to set a more exact time and for additional safety, if you fall asleep with it on.