Sweating is an extremely complex symptom. It can be caused by a number of things, including heat sensitivity and anxiety. But in fibromyalgia patients, this symptom can seem to come out of nowhere.

For people with fibromyalgia, the body has trouble maintaining its internal temperature. When it rises, the body begins to feel overheated and starts to sweat. Doctors don't know exactly why this happens, but some suggest a connection with the thyroid. Some others suggest that blood flow might be restricted due to nerve damage.