The normal human body temperature range is typically stated as 36.5–37.5 °C (97.7–99.5 °F). The average internal temperature is 37.0 °C (98.6 °F). It is typically maintained within this range by thermoregulation. Body temperature normally fluctuates over the day following circadian rhythms, with the lowest levels around 4 a.m. and the highest in the late afternoon.
Pathophysiology[edit | edit source]
- Hyperthyroidism, the overproduction of thyroid hormones, can cause heat intolerance
- Hypothyroidism, the underproduction or poor utilization of thyroid hormones, can cause cold intolerance
ME/CFS[edit | edit source]
Temperature dysregulation[edit | edit source]
- 53.9% - 58.7% of the 2073 patients in a Belgian study of 2001 reported symptom exacerbation in extremes of temperature.
- Katrina Berne reports a prevalence of 75-80% for heat/cold intolerance.
Temperature instability[edit | edit source]
Loss of thermostatic stability and intolerance of extremes of temperatures are separate diagnostic criteria in the International Consensus Criteria for ME. Indicators of temperature instability are listed as subnormal body temperature, marked fluctuations of temperature throughout the day; sweating episodes, recurrent feelings of feverishness with or without low grade fever, and cold extremities, e.g. fingers and toes.
References[edit | edit source]
- De Becker, P; McGregor, N; De Meirleir, K (Sep 2001), "A definition-based analysis of symptoms in a large cohort of patients with chronic fatigue syndrome.", Journal of Internal Medicine, 250 (3): 234-240, PMID 11555128
- Berne, Katrina (Dec 1, 1995), Running on Empty: The Complete Guide to Chronic Fatigue Syndrome (CFIDS), 2nd ed., Hunter House, p. 58, ISBN 978-0897931915
- London Criteria (2014)
- Carruthers, BM; van de Sande, MI; De Meirleir, KL; Klimas, NG; Broderick, G; Mitchell, T; Staines, D; Powles, ACP; Speight, N; Vallings, R; Bateman, L; Bell, DS; Carlo-Stella, N; Chia, J; Darragh, A; Gerken, A; Jo, D; Lewis, DP; Light, AR; Light, KC; Marshall-Gradisnik, S; McLaren-Howard, J; Mena, I; Miwa, K; Murovska, M; Stevens, SR (2012), Myalgic encephalomyelitis: Adult & Paediatric: International Consensus Primer for Medical Practitioners (PDF), ISBN 978-0-9739335-3-6
myalgic encephalomyelitis (ME) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.