Endocrinology, Sleep, and Circadian Rhythms

Hormonal signalling is a central component of the regulation of sleep, behaviour, and multiple other physiological processes aligned with external time cues through endogenous circadian clocks. Endocrine feedback to the circadian clock is exerted via key systems and supports the robustness of endogenous rhythmicity. It is challenged by multiple modern lifestyle factors such as shift work, light pollution, or high-calorie diets which may alter this delicate balance and shift physiological set points. The following chapter summarizes current knowledge on the underlying mechanisms controlling this interregulation of circadian timing, sleep, and the endocrine system, and what disorders may be caused by its imbalance.