Because memory foam mattresses are designed to respond to body heat, a heated mattress pad can interfere with the material’s function. The pad will heat up a large portion of the mattress, which may lead to inadequate support for your body. If you’re planning to use a mattress pad with a memory foam mattress, it’s best to put a blanket or other barrier between your pad and the mattress.  Heated mattress pads should not affect the performance or longevity of other types of mattresses.