A systematic review of body temperature variations in older people

Aim. The purpose of this systematic review was to determine the extent to which the research literature indicates body temperature norms in the geriatric population. Objectives. The specific questions addressed were to examine normal body temperature values in persons 60 years of age and older; determine differences in temperature values depending on non‐invasive measurement site and measurement device used; and, examine the degree and extent of temperature variability according to time of day and time of year. Background. The traditional ‘normal’ temperature of 98·6 °F/37 °C may in fact be lower in older people due to the ageing process. Age‐associated changes in vasomotor sweating function, skeletal muscle response, temperature perception and physical behaviours may influence the ability to maintain optimum temperature. Design. A systematic literature review. Methods. A search of multiple databases yielded 22 papers which met inclusion criteria. Studies were included which focused on temperature measurement, sampled persons 60 years of age and older, collected data from non‐invasive temperature measurement sites and which used a prospective study design. Studies were independently appraised using a structured appraisal format. Results. Temperature normal values by site were rectal 98·8 °F/37·1 °C, ear‐based 98·3 °F/36·8 °C, urine 97·6 °F/36·5 °C, oral 97·4 °F/36·3 °C and axillary 97·1 °F/36·2 °C. Temperature exhibited a 0·7 °F/0·4 °C diurnal and 0·2 °F/0·1 °C circannual variation. Conclusions. Synthesis of data indicated that normal body temperature values in older people by sites were rectal 0·7 °F/0·4 °C, ear‐based 0·3 °F/0·2 °C, oral 1·2 °F/0·7 °C, axillary 0·6 °F/0·3 °C lower than adults’ acceptable value from those traditionally found in nursing textbooks. Relevance to clinical practice. Given the fact that normal body temperature values were consistently lower than values reported in the literature, clinicians may need to re‐evaluate the point at which interventions for abnormal temperatures are initiated.