Why Is My Blood Glucose So High in the Morning?
I am puzzled by my blood sugar pattern. I am not on any medications. My morning fasting blood sugar is always the highest of the day—between 120 and 140 mg/dl. The rest of the day it is in the normal range. Why does this occur? Ruth Reynolds, Elk Grove, California
Christy Parkin, MSN, RN, CDE, responds:
In the early morning hours, hormonal changes in your body will naturally cause blood glucose to rise. For people who don't have diabetes, the increase in blood glucose is offset by increased insulin production. For people with diabetes, this can be a problem.
There are a couple of things going on that make your glucose rise in the morning. One of these is insulin resistance—a condition that means your body's muscle and fat cells are unable to use insulin effectively to lower blood glucose. However, insulin resistance also affects how your liver processes, stores, and releases sugar, particularly at night. The liver is supposed to release small amounts of glucose when you're not eating. But in type 2 diabetes, the liver dumps more glucose than is needed into the bloodstream, especially at night. So, while your hormones are causing a natural rise in blood glucose, your liver is releasing even more sugar into your system. And because your insulin resistance prevents your muscle and fat cells from using the sugar, your blood glucose level rises.
Unlike mealtime blood glucose, which can be somewhat controlled by diet and exercise, high fasting blood glucose usually needs to be treated with medication. You should talk to your doctor about medications that can help you obtain good control. You may also want to read our September 2008 story "Rocky Morning Highs."