Oral temperatures of the elderly in nursing homes in summer and winter in relation to activities of daily living

This study was conducted to clarify the seasonal difference in body temperature in summer and winter, and to document the thermal environment of the elderly living in nursing homes. The subjects were 57 healthy elderly people aged greater than or equal to 63 years living in two nursing homes in Japan. One of the homes was characterized by subjects with low levels of activities of daily living (ADL). Oral temperatures were measured in the morning and afternoon, with simultaneous recording of ambient temperature and relative humidity. Oral temperatures in summer were higher than in winter, with statistically significant differences (P<0.05) of 0.25 (SD 0.61) degrees C in the morning and 0.24 (SD 0.50) degrees C in the afternoon. Differences between oral temperatures in summer and winter tended to be greater in subjects with low ADL scores, even when their room temperature was well-controlled. In conclusion, the oral temperatures of the elderly are lower in winter than summer, particularly in physically inactive people. It appears that those with low levels of ADL are more vulnerable to large changes in ambient temperature.