The influence of circadian rhythms on carbohydrate metabolism in health and in diabetes mellitus

Most processes in the human body and other living organisms are governed by biorhythms. The term biorhythms refers to periodically recurring changes in biological processes. Biological rhythms are genetically fixed and are crucial factors in natural selection and adaptation of organisms. In humans, circadian rhythms are regulated by central and peripheral clocks. The central clock is located in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus, while peripheral clocks are found in various tissues and organs of the human body, including the brain, pancreas, liver, adipose tissue, gastrointestinal tract, and muscles. External and internal signals are in constant synchronization, ensuring homeostasis. A mismatch between internal biological clocks and external signals can lead to desynchronization of circadian rhythms. Desynchronization of the circadian rhythm may result in the onset of metabolically associated diseases, including the development of type 2 diabetes, obesity, and poorer glycemic control. This article examines the impact of circadian rhythms on biological processes and hormone secretion, as well as the relationship between circadian rhythms and glucose metabolism in individuals with type 2 diabetes and normoglycemia.