Body temperature
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.
Core temperature is regulated and stabilized primarily by the hypothalamus, a region of the brain linking the endocrine system to the nervous system.
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.[1]
- Katrina Berne reports a prevalence of 75-80% for heat/cold intolerance.[2]
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.[3]
References[edit | edit source]
- ↑ De Becker, P; McGregor, N; De Meirleir, K (September 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 (December 1, 1995), Running on Empty: The Complete Guide to Chronic Fatigue Syndrome (CFIDS), 2nd ed., Hunter House, p. 58, ISBN 978-0897931915
- ↑ London Criteria