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.
Here is the method I use. It helps to use really cold water, from the fridge.
1. Soak two large facecloths in cold water. [If we are going through a heatwave I make sure to soak them, wring them out, put them in a plastic bag, and put them in the fridge an hour or two before bedtime.]
2. Lie naked on the bed on top of a towel. Have the facecloths handy in a bowl (which will also serve as a place to dump them after use).
3. Wring out one facecloth, if you haven't already done this, and spread it out over your abdomen &/or chest (your choice depending on how large you are and where you feel hottest). After about 10 minutes it will have reached body temperature.
4. Dump the used facecloth in the bowl and replace it with the second.
This method has always worked for me, & I hope it does for you. I lose control of my temperature easily, esp. when tired. Going through menopause was very hard. But sometimes I have fallen asleep with facecloth #2 still on me and then woken up a bit later shivering!
I think it's important to note that scientists are now revising a single "normal" body temperature to a range, recognizing that it varies during the day and with sex, age, etc., while there is also evidence that the modern normal is lower than it was in the 19th c.