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
In ME/CFS[edit | edit source]
Temperature sensitivity, or intolerance to the heat or cold, occurs commonly as a symptom in ME/CFS.
- 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 intolerance is featured as a symptom in the International Consensus Criteria. In the London criteria, sensitivity to both heat and cold is mentioned under the criteria of periods of impaired circulation compatible with autonomic dysfunction.
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
Myalgic encephalomyelitis or chronic fatigue syndrome, often used when both illnesses are considered the same.