My friend, who has type 2 diabetes, has observed that her sugar level comes down to normal levels (90-110 mg/dl [5-6.1 mmol/L] ) at night, about three to four after a low carb dinner, but by morning it rises up to 140-160 mg/dl [7.8-8.9 mmol/L]. Any idea why blood sugar rises during night?

It is not uncommon to observe this elevated morning blood sugar (“fasting hyperglycemia”) pattern in type 2 diabetes. The rise in blood sugar during the pre-dawn and early morning hours is a result of increased insulin resistance due to circulating hormones and hence an elevated release of liver glycogen stores.

In other words, the very hormones that help us to awake in the morning stimulate the liver to release a supply of stored glucose, thereby raising blood sugar levels. This is often termed a dawn phenomenon and can occur in type 1 diabetes as well.

Oral agents exist for type 2 diabetes that directly address this fasting hyperglycemia. Glucophage [metformin] does this best by reducing hepatic (liver) glucose production. Often an improvement in fasting blood sugar is noted as a result. Weight loss and regular exercise in combination can help as well by reducing insulin resistance.

DMW