Entrained body temperature rhythms are similar in mild Alzheimer's disease, geriatric onset depression, and normal aging.

Sleep-wake rhythms are known to be altered in Alzheimer's disease (AD) and in unipolar depression. Other evidence suggests that the circadian rhythm in body temperature may be altered as well. Entrained circadian temperature rhythms were measured in healthy elderly men and women, as well as in men and women suffering from unipolar depression or mild AD, to examine this possibility. There were no differences in the temperature rhythm characteristics of subjects with depression or AD compared with healthy control subjects. However, gender differences were observed. Female control subjects showed a larger amplitude, higher peak temperature, and earlier acrophase relative to male control subjects. Also, the mesor of female AD subjects was higher than for male AD subjects. These results are discussed in the context of the widely varying subject populations used in other studies.