The circadian rhythm of human body temperature – Clinical implications and review of the literature

Human body temperature remains an essential vital sign that had been used to judge our health given its strong correlation with human disease. Body temperature is also a manifestation of our circadian rhythm, with a predictable rise during the day peaking in the evenings and steady decrease during the night reaching a minimum around the time of awakening. Yet, the rhythm is believed to be endogenous and to exist independently of any external stimuli, including day light. Human illnesses such as infections, autoimmune conditions, and cancer had been associated with a disruption in the circadian rhythm. This is of significant clinical interest because measurements of the specific disruptions of the rhythm appear to carry diagnostic and prognostic value. This is a review of the literature with a focus on the determinants of human body temperature and the circadian rhythm of body temperature. The last section provides potential new research avenues in our search for chronotherapy clinical applications.