September 1, 2006
Daily Care, Type 2
Question from Canton, Michigan, USA:
My most recent A1c was 7.2. I am on metformin 500 mg extended release, two at night and two in the morning. I have also been taking Actos, one a day for the last couple of weeks. After the high A1c report, I got serious with my diet. I am now restricting my carbohydrates to mostly complex carbohydrates and no sugar. I am taking long aerobic walks every day now, too. My goal is to lose at least 20 pounds in the next three to four months. I am 5 feet, 10 inches and weigh 225 pounds. On most days, I seem to get my blood sugar readings down to the 115 to 125 mg/dl [6.4 to 6.9 mmol/L] two hours after eating or after exercise, so I think I am on the right track. HOWEVER, my morning blood sugar before eating is usually around 140 mg/dl [7.8 mmol/L] even though it was 115 mg/dl [6.4 mmol/L] at bedtime. Why does my blood sugar go up when I am sleeping? My doctor says my body "makes sugar." What do you think?
This is one of the most common questions that I get asked by patients. Overnight, you are not eating, but your brain still requires glucose as its only fuel. Man has developed a way to make glucose continually available by storing glucose in the liver and then liberating it during times of fasting. Your liver will break down the stored glucose and export it into the blood overnight. One of the key metabolic abnormalities in diabetes is the inability to suppress the output of glucose by the liver. That is why your blood sugar goes up over night without having eaten anything.