Updated July 20, 2006

Blood Glucose Monitoring
What Do the Numbers Tell You?

by Virginia Peragallo-Dittko, A.P.R.N., M.A., B.C.-A.D.M., C.D.E.

My blood glucose is always higher in the morning when I get up and is lower during the day.

• Your liver might be sending a lot of glucose into the bloodstream because the signals telling it to shut off aren’t working. The drug metformin may be prescribed, because its main action is to signal the liver to shut off.
• Your dinner or bedtime snack choices might be raising your blood glucose the next morning. Try changing your food choices and portions to learn more about their effect on your blood glucose levels.
• Your body may be unable to handle the effect of the hormones secreted at dawn that work against insulin. This early-morning release of hormones is called the dawn phenomenon. High blood glucose that results from it can be managed with oral medicines or insulin.
• Your insulin or oral medicine dose may need to be adjusted.

My blood glucose is high all day.

• If you have Type 2 diabetes, your cells may be resisting your insulin. Exercise, weight loss, and certain medicines will help to make your body more sensitive to insulin and lower your blood glucose.
• If you have Type 2 diabetes, your pancreas may not be making enough insulin to meet your needs, and you may require oral medicines or insulin.
• If you have Type 1 diabetes, you may need an increase in your basal insulin doses. Basal insulin is the amount of insulin your body needs in the background all day long. Insulin glargine (brand name Lantus) or NPH can provide basal insulin. An insulin pump is also programmed to deliver basal insulin.

My blood glucose is within range before I eat but high two hours later.

• It is helpful to understand how the secretion of insulin changes in Type 2 diabetes. The pancreas secretes insulin in response to a meal in two phases. In the first 10 minutes after glucose enters the bloodstream, there is an early burst of insulin release called first-phase insulin secretion. This is followed by the second-phase insulin secretion, a sustained release of insulin that lasts for several hours. One of the early changes in Type 2 diabetes is the loss of first-phase insulin secretion following a meal. This means that not enough insulin enters the bloodstream as quickly as it is needed, resulting in high blood glucose after meals.
  

  Certain medicines taken at mealtimes can help. Nateglinide (Starlix) and repaglinide (Prandin) stimulate the pancreas to release more insulin when blood glucose levels are higher, while acarbose (Precose) and miglitol (Glyset) slow the rate at which certain carbohydrates are absorbed from the small intestine.
  

  The rapid-acting insulin analogs lispro (Humalog) and aspart (NovoLog) also work effectively to lower blood glucose after meals. Regular insulin peaks too slowly to completely lower blood glucose following meals although some people find Regular insulin is the best choice for them.
  

• What you eat makes a difference, too. Your blood glucose reading taken two hours after you start to eat should be about 30 mg/dl higher than before you eat. After-meal readings can tell you about the impact of food on your blood glucose levels. If your blood glucose reading was 111 mg/dl before eating two cups of pasta and 322 mg/dl two hours later, you’ve learned that two cups of pasta is too much for you. However, a reading of 157 mg/dl two hours after eating one cup of pasta tells you how much pasta you can eat to keep your after-meal readings within the target range.
  
  Many people are shocked by how high their readings are after meals. Ralph was convinced that his large restaurant meals every night didn’t really raise his blood glucose levels because his fasting readings weren’t elevated. But when he actually checked two hours after dinner and got readings over 400 mg/dl, he decided to make some changes.

Also in this article:
Blood Glucose Meter Averages: Don’t Be Fooled

Virginia Peragallo-Dittko is a Diabetes Nurse Specialist and Director of the Winthrop-University Hospital Diabetes Education Center in Mineola, New York.

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