Biological connection of circadian rhythm and insulin resistance: a review

Circadian rhythm interrelates with insulin mechanism of action; any disruption in the circadian rhythm can cause insulin resistance, ultimately impacting health significantly. Due to its directly proportional relationship between circadian rhythm and insulin resistance, any disruption in the normal physiology of circadian patterns leads to the impairment of insulin sensitivity. The dysregulation in these two mechanisms is mediated by alteration of the clock genes (CLOCK, BAML1, PER, CRY) and hormonal cycles, which is evidenced by various research in the review. Furthermore, insulin resistance has a significant impact on the functioning of circadian rhythm as various studies have demonstrated that insulin resistance simultaneously affected circadian rhythm by modifying gene expression, particularly in melatonin receptors (MTNR1B) and clock-controlled genes. These complex interactions can transverse into significant metabolic dysregulation, compromising glucose metabolism and potentially contributing to type 2 diabetes. In this review, the bidirectional relationship between disruptions in the circadian rhythm and insulin resistance is systematically examined.