Same question, none of the listed reasons apply. I thought it might be related to Type II diabetes; I get warm when BG is low, but have begun having very sudden cold spells with shivering. Not related to room temperature. I also have LOW blood pressure, thought that might cause them.
Sudden cold shivers often result from a rapid loss of body heat. This happens when a person experiences shock, fever, infection, etc. Exposure to extreme cold can also result in sudden onset of cold shivers.