A new study finds that while young and healthy mice show clear differences between daytime and nighttime body temperature rhythms, in older and diseased animals the difference essentially disappeared.
In humans and other mammals, body temperature oscillates in a 24-hour rhythm. This daily rhythm in body temperature is a critical factor in regulating many physiological processes. The loss of this rhythm is an important marker of, and contributor to, disease.
In a study published in the journal Chronobiology International, UCLA Health researchers looked at body temperature rhythms in young and middle-aged mice, and in a mouse model of Huntington’s Disease. They found that in young healthy mice, there is a distinct difference between the nighttime rhythm and daytime mode. At night, the young and healthy mice had strong higher frequency oscillations, while in the daytime, these body temperature oscillations were absent. But in the older and diseased animals, the night/day difference disappeared.
“In these older and diseased mice, as the song says, ‘it’s hard to tell the nighttime from the day,’” said Alan Garfinkel, Research Professor of Medicine and Integrative Biology and Physiology. “This loss of the ability to segregate daytime from nighttime rhythms may be a general phenomenon in health vs. disease, since virtually all hormones in the body have a similar pattern of nighttime vs daytime rhythms.”
Article: "Circadian and ultradian rhythms in normal mice and in a mouse model of Huntington’s disease." Chronobiology International (2022): 1-12.
Authors: Christopher G. Griffis, Janki Mistry, Kendall Islam, Tamara Cutler, Christopher S. Colwell, and Alan Garfinkel.
The authors reported no conflict of interest and no funding associated with the work.