ClinicSpeak: body temperature and fatigue

Will lowering your body temperature help your fatigue? #ClinicSpeak #MSBlog #MSResearch

“The study below is very interesting. Its findings are in line with some of my own anecdotal observations in MSers and has potentially major implications for all MSers. In short RRMSers have a higher body temperature than controls and this is associated with worse fatigue.”

“Why would RRMSers have a higher body temperature? Maybe they have MS lesions in the area of the brain that controls body temperature; i.e. the hypothalamus. This is unlikely as this should be a greater problem in SPMSers who generally have a higher lesion load and are therefore more likely to have lesions in the hypothalamus; in this study SPMSers did not have a raised body  temperature. In fact hypothermia, or a low body temperature, does occur in MSers from lesions in the brain’s temperature control center or hypothalamus and I have only ever seen this rare complication of MS in SPMSers. I suspect the most likely explanation for the raised body temperature in MSers is that it is due to active inflammation in the brain. Inflammatory MS lesions produce chemical signals called cytokines that may explain the raised body temperature. Interleukin-1 (IL-1) and TNF-alpha are the main cytokine culprits when it comes to raising your body temperature. These cytokines bind to nerve cells in the hypothalamus and stimulate the so called sickness behaviour refelex; this includes fatigue, hypersomnalence (tiredness), a rise in body temperature and a change in your metabolism to conserve energy. If this is the case then MSers could use their body temperature as a way to monitor if their MS is active or not? A corollary to this would be if that if you went on to a highly-effective DMT that shut down inflammation in the brain it should lower your body temperature. I think this would be an interesting and cool study to do. May be we could crowd source this and do the study via the web? I have some ideas how it can be done.”

“Some of my clinical anecdotes that are congruent with the results of the study below are: (1) I have several MSers I look after who take anti-pyretics (medication to lower your temperature) as a means of treating their fatigue. Some use paracetamol or acetaminophen and others ibuprofen; they swear by it. (2) Women with MS often complain of worse fatigue during menstruation; a period in  their menstrual cycle associated with a slight higher body temperature. (3) Flu-like symptoms associated with interferon-beta therapy, which cause a mild pyrexia, exacerbates fatigue. (4) Warm environments, exercise and infections all of which raise body temperature exacerbate fatigue. (5) Despite the poor evidence-base a large number of MSers swear that cooling improves their fatigue; one of my patients has had a walk-in butchers fridge installed in her home; it easily takes her wheelchair. She spend 4 to 5 half-hour sessions in the fridge every day; she claims this is the only way she can cope with her fatigue.”

“There are some small trials supporting these observations; i.e. that aspirin, a widely used anti-pyretic helps MS-related fatigue. Could the latter be due to effect of aspirin on body temperature?”

“How could a raised body temperature cause fatigue? I have discussed this in many previous posts; the one on Uhthoff’s phenomenon explains it best.”

“Have any of you noticed that anti-pyretics helps your fatigue? I would be interested in finding out.”

Sumowski & Leavitt Body temperature is elevated and linked to fatigue in relapsing-remitting multiple sclerosis, even without heat exposure. Arch Phys Med Rehabil. 2014 Feb. pii: S0003-9993(14)00126-9.

OBJECTIVE: To investigate whether resting body temperature is elevated and linked to fatigue in RRMSer.

DESIGN: Cross-sectional study investigating (a) differences in resting body temperature across RRMS, SPMS, and healthy groups, and (b) the relationship between body temperature and fatigue in RRMSers.

SETTING: Climate-controlled laboratory (∼22°C) within a non-profit medical rehabilitation research center.

PARTICIPANTS: Fifty RRMSers, 40 matched healthy controls, and 22 SPMSers.


MAIN OUTCOME MEASURE(S): Body temperature was measured with an aural infrared thermometer (normal body temperature for this thermometer is 36.75°C), and differences were compared across RRMS, SPMS, and healthy persons. RRMSers completed measures of general fatigue (Fatigue Severity Scale; FSS), as well as physical and cognitive fatigue (Modified Fatigue Impact Scale; MFIS).

RESULTS: There was a large effect of group (p<.001, ηp2=.132) whereby body temperature was higher in RRMSers (37.04°C±0.27) relative to healthy controls (36.83 ± 0.33; p = .009) and SPMSers (36.75°C±0.39; p=.001). Warmer body temperature in RRMSer was associated with worse general fatigue (FSS; rp=.315, p=.028) and physical fatigue (pMFIS; rp=.318, p=.026), but not cognitive fatigue (cMIFS; rp=-.017, p=.909).

CONCLUSIONS: These are the first-ever demonstrations that body temperature is elevated endogenously in RRMSers and linked to worse fatigue. We discuss these findings in the context of failed treatments for fatigue in RRMS, including several failed randomized controlled trials (RCTs) of stimulants (modafinil). In contrast, our findings may help explain how RCTs of cooling garments and antipyretics (aspirin) have effectively reduced MS fatigue, and encourage further research on cooling/antipyretic treatments of fatigue in RRMS.

About the author

Prof G

Professor of Neurology, Barts & The London. MS & Preventive Neurology thinker, blogger, runner, vegetable gardener, husband, father, cook and wine & food lover.

1 comment

  • I know this is an 'older' blog post but I'm quite interested in the 'temperature thing' with MS. My 'normal' body temperature seems to be around 94.6F to 95.9F. When it goes above this, I know I'm always headed for a relapse.

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