The Evolution of Biochemical Storm of Circadian Rhythm and Circadian Dysfunction in Relation to Vascular Disease and Diabetes

The earth rotates around its axis (and around the sun); hence our physiology has adapted to coordinate functions according to circadian (and circannual) rhythms. Homo erectus used to go to river banks or lakesides in the forest in the early morning for hunting when animals emerged from the forest to drink water, which was associated with marked physical exertion and mental stress with underlying biochemical storm of increase in catecholamines, and cortisol. It is possible that this habit of the ancient men causing increased sympathetic activity in the morning (6.00-12.00 hours) became a circadian rhythm which has an adverse effects in modern men. The increased sympathetic activity may be also associated with rise in thyroid hormones which are known to cause increase in basal metabolic rate resulting in to increased energy expenditure in the morning compared to other times of the day. A disturbance in sleep wake cycles may cause increased cardiometabolic risk in the modern society. It is proposed that disturbances in circadian rhythms and diet and lifestyle factors may be associated with glucose variability disorder which may be the first event in the pathogenesis of diabetes. Halberg was first to propose circadian rhythm in biological functions and demonstrate vascular variability disorders. Guidelines from various agencies for the management of CVDs and diabetes emphasize that the necessity, choice and intensity of treatment should be determined by the individual’s probability of an event (risk) within a given time span predisposing to complications. There is little consideration for chronotherapy, diet and exercise. Optimization of treatment by timing, however, in relation to the time of awakening, has already demonstrated that higher efficacy with fewer side effects can be reached with a reduced dosage, a practice that should enter mainstream medicine. Knowledge of circadian functions and utility of chronotherapy may be used in clinical trials, in reducing the dose of the agent as well as its adverse effects while providing several-fold greater benefit, thereby optimising therapeutic efficacy. Keywords: Drug therapy; Lifestyle; Chronobiology; Circadian therap