To address your question directly, yes, it is very safe to use. We have not had any reports of people complaining of such incidents. As for the heating, yes it heats up to provide more relaxation. The heat helps to soothe tired muscles and sore feet brought about by standing on your feet for a very long time or walking long distances. I think you can opt for other massagers that don’t heat up if you feel uncomfortable about the heating features of this brand. There are a lot of other options for you so you can enjoy the benefits of foot massagers.