Circadian rhythms: charting oral temperatures to spot abnormalities

1. A normal daily variation in body temperature is found in the elderly. Normal oral temperature in an older person is lower than in a younger person, and the temperature peaks in the early afternoon and is lowest in the early morning hours before awakening. 2. Elderly subjects may be more prone to hypothermia in the early morning hours when their body temperature is naturally lower. Bathing may cause the body temperature to drop up to 1 degree C and add to this risk. 3. Many factors should be considered when analyzing temperature data for the determination of fever. Time of day, as well as symptoms of infection, should be considered. 4. Disturbances in circadian temperature rhythms accompany central nervous system dysfunction and may be an early indicator of other illnesses.