Circadian Rhythm and the Diabetes Connection

The circadian rhythm is a cycle, 24 hours approximately, that is a bioglogical process in plants and animals. For us, the circadian clock is found in the brain. There are a cluster of cells found in the suprachiasmatic nucleus in a part of the brain. These cells are found in the hypothalamus section of the brain which controls sleeping, eating, heart rate, blood pressure, the body temperature, and levels of hormones, as well as our immune system.

Insulin levels and the counterregulatory hormones, that work against the actions of insulin are in turn, influenced by the circadian rhythm. These hormones which include glucagon, epinephrine, (adrenaline), cortisol, and growth hormones raise blood sugar levels when they need to be raised. During the middle of the nighttime hours, there is a surge in the amount of growth hormone the body will release, that is followed by a surge in cortisol. This increases blood glucose production by the liver. In a nondiabetic person, these processes are offset by the increase in insulin secretion by the pancreas. Blood glucose then, remains stable. In type 1 diabetics who don't make insulin at all, and in type 2 diabetics where the liver may not respond to insulin very well to stop glucose production, changes in blood sugar levels during rest can have a large effect on morning glucose levels. The dawn phenomenon occurs, and this is where sugar levels rise between 4 AM and 8AM.

Disordered sleeping in diabetics cause blood glucose to go out of control. If you are having type of sleep problems at all, it is best to see your doctor and work out the problems. Some conditions can interfere with a person's waking and sleeping cycles. Jet lag syndrome is the more common of these disorders, which means lack of daytime alertness and sleepiness when travelers cross time zones. There is also shift-work sleep disorder in people that work night shifts or shifts that rotate.