Mine is 36.5 degrees Celsius on average, sometimes lower. My doctor told me it is a symptom of POTS (body has problems with regulation) That's why I find it very hard to keep warm and I tend to 'hibernate' in winter. I can sleep up to 16 a day. Or in really bad cases I have had times where I slept 48 hours in a row. But that's extreme. Is there any literature on low body temperature and causes and what it does to the body?