BTW to save a new reader delving through the previous 5 pages here, body temperature is far more complicated than people think. The normally-quoted 98.6F/37C is highly-misleading as that will vary by time of day (I vary by 1.3F/0.7C), gender (particularly as a woman's temperature varies substantially over her menstrual cycle), and age, even before we consider the issue of what is a normal range around the average.
So, for the 296 people who have ME/CFS, joined this site, read this thread and answered the survey, their body temperature is normally lower than the accepted norm. Even allowing for the self-selection involved, this suggests to me that there is some link, either because people with a low body temperature are more vulnerable to ME/CFS or because ME/CFS produces a lower body temperature.
My waking oral body temperature is typically 96.7F/35.9C and averages 1.6F/0.9C lower than published detailed averages at any time of day, which seems to fit the pattern here. At one time I thought this was significant as a lot of articles suggested that low temperature was as sure sign of thyroid problems; however, my blood tests were well within accepted ranges, albeit away from the average (higher TSH, lower T3, lower T4), and I noticed no difference to how I felt and my body temperature after self-medicating with Thyroid S for 2 months.
For the want of any evidence to the contrary, I've pencilled in low body temperature as a symptom of ME/CFS rather than a symptom of something else that causes or contributes to it.
Most of the time I take my temperature, it runs from 94.5 to 97.4. I think this is part of the pattern of "low and slow" in this illness. In me (ME), everything seems to run low and slow--temperature, immune system, energy, thought and memory, recovery--you name it.
My body temperature was for years high around 37.6° and sometimes more, meanwhile it is dropping and mostly around ~36.8°.
I am surprised about the poll results. I was always thinking most CFS/ME sufferers have fever all the time, but it seems still a low percentage did have such issues.
First many years of illness, i had a rise in body temp. to 99.3 ; docs ignored it no matter what i said about how that was high for me. Then when i got autonomic problems starting 5 years ago, it plummeted along with my resting heart rate. body tmep went to 97.2 resting heart rate went from 88 to 62. Doctors ignored it.
I had a sauna last night, only ten minutes, another 10 mins afterwards I took my body temp 39.4 ( tongue)
This morning it was 35.9.
For me its the regulation that is missing and I suffer at both ends, headaches with mild exercise as body heats, raynauds with cold.