Does the body temperature change in older people?

Abstract

Aim: The aim of this study was to determine the mean body temperatures in older people using mercury-in-glass thermometer.

Background: Older people are unable to regulate their body temperatures to the same degree as young adults because their responses to changes in body temperature are altered. Several published reports suggest that body temperature decreases with advancing age and has a greater variability in older populations. The aim of this study was to determine the mean body temperatures in older people.

Design: Non-experimental.

Methods: Axillary body temperatures were taken in 133 older subjects in a nursing home for older people using mercury-in-glass thermometer. Temperatures were measured at 8 a.m., 2 p.m., and 6 p.m., over three consecutive days. Each subject had all three measurements taken on the same day.

Results: The mean age of the subjects was 77.2, SD 7.3. In the 133 older subjects, the mean axillary temperatures ranged from 35.1 to 36.4 degrees C (95.3-97.6 degrees F). The mean temperatures for those aged 65-74 was higher than in those aged 75-84 (p < 0.001) and those aged 85 and older (p < 0.001) at 6 p.m. but not at 8 a.m. or 2 p.m. We concluded that older people have mean axillary body temperatures lower than the reference point of 36.5 degrees C (97.7 degrees F).

Relevance to clinical practice: When assessing body temperature, it is important to take the age of the patient into consideration. Also, the reference point of 36.5 degrees C is inappropriate in older people, especially when diagnosing a febrile illness.