Why is blood sugar high in the morning?



DEAR DR. DONOHUE: I have type 2 diabetes and check my blood sugar every morning before breakfast. It's usually in the 125 mg/dl (6.9 mmol/L) to 150 (8.3) range. When I have my blood sugar checked at the lab, they tell me to fast before taking the test. My AIC is in the 6.2 to 6.5 range. My doctors are happy with these numbers. I take metformin and glyburide daily. I am 80 and have been doing this for many years.

Dr. Donohue

My question is that before retiring for the night my sugar reading is 110 (6.1) to 120 (6.7). Why does my sugar rise during the night when I'm asleep? No one gives me a satisfactory answer. Some say, "The body does strange things," and other nonsensical answers. Can you give me a common-sense answer? -- P.V.

ANSWER: It's not easy explaining why blood sugar rises when you have nothing to eat during sleep. I don't mean to offend you, but do you take a late-evening snack? It can take four hours for some food to exit the stomach. The carbohydrates taken from the snack might not raise blood sugar until four hours after you've eaten it.

A better explanation is that your diabetes medicines have been metabolized before you wake up in the morning. Metformin comes in two different preparations, an extended-release form and an immediate-release form. If you take the immediate release, the medicine might be long gone before you waken the next day.

The same goes for glyburide. It lasts from 12 to 24 hours. But if you are a person in whom it lasts on the shorter side of that span, it, too, may have been metabolized long before you wake in the morning.

A before-breakfast blood sugar is best when in the range of 70 (3.9) to 130 (7.2) Your highest reading is 150 (8.3), not all that far from the ideal high. Too-exact control can result in dangerously low readings.

Your hemoglobin A1C is perfect. It indicates blood sugar control for the prior three months. I see why your doctors are happy with your readings. You should be too.

TO READERS: The booklet on valvular heart disease explains things like aortic stenosis and mitral regurgitation. Readers can order a copy by writing: Dr. Donohue -- No. 105, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order for $4.75 U.S./$6 Can. with the recipient's printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I take 81 milligrams of aspirin daily. I will be taking a trip to the Far East, which includes a 14-hour plane ride. I am thinking of taking the higher aspirin dose, 325 milligrams. Is all I need the 81 milligrams? -- S.B.

ANSWER: The 81-milligram strength aspirin ought to afford you protection against forming clots. Stagnant blood tends to clot. If the legs are in a resting position, like sitting on airplane for 14 straight hours, the leg veins could develop clots.

You can add to the anti-clotting effect of aspirin by getting up and walking up and down the aisle every half hour. Or if the airplane crew takes a dim view of this, you can contract your leg muscles many times every 15 minutes when you are seated.

DEAR DR. DONOHUE: You wrote less-than-favorable comments on turmeric. I am 82 and have had severe leg pains in both legs. I could not make it to my grandson's graduation. I was told to try turmeric, and I started. After three days, I noticed improvement. After 21 days, the pain is gone. I walk much better. I referred it to a friend who has had the same success. Please do the world a favor and print this. -- R.S.

ANSWER: Turmeric comes from the roots of a plant related to the ginger plant. Curcumin is its most important constituent. It's used as a spice in curry. It's been used for a wide range of illnesses. The proof of its healing properties isn't extensive. However, I feel that a person who gets relief from symptoms with turmeric should continue with it and spread the word to others. I don't believe it will harm anyone. Medicines derived from plants are nothing new. Aspirin, perhaps the most widely used medicine in the world, was first derived from the bark of the willow tree.

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Dr. Donohue

Last modified: September 15, 2012