Why Does Blood Glucose Go Up Some Days and Not Others?
Why does my wife's blood sugar go up to 230 mg/dl at dinnertime (5 p.m.) on some days, while on other days that doesn't happen even though she eats about the same food? My wife has type 2 diabetes. Name Withheld
Janis McWilliams, RN, MSN, CDE, BC-ADM, responds:
Even minor changes in meals, physical activity, and overall health can affect blood glucose.
Carbohydrates in food all cause a person's blood glucose to rise. However, different types of carbohydrates can have varying impacts on how quickly and how much blood glucose goes up. In addition, the amount of fat and fiber in these foods can slow your body's absorption of the carbs, making your number appear lower after eating than it typically would, but higher a few hours later.
What you eat is only one factor that can affect blood glucose. Medications can have an effect on your glucose. Some medications, such as steroids, can raise it. If you are using insulin, your injection site can affect how the insulin is absorbed. That can change the action of the insulin in bringing down your blood glucose. And if you take your medications late or not at all, that can also have an effect.
Stress can contribute to high blood glucose. The body's normal response to stress—both physical and emotional—is to release glucose stored in the liver into the bloodstream. In people with diabetes, this response is exaggerated, and blood glucose levels rise even higher. High blood glucose can also be caused by infection, and you can have an infection without experiencing any other symptoms.
Sometimes, people with diabetes and their health care providers just can't determine the cause of high blood glucose. This is frustrating for everyone, and you need to remember to not get too upset about one high number, but to focus on your overall control. Look for patterns and try to determine what might be causing your high blood glucose. You can use a logbook, a feature on a blood glucose meter, or diabetes management software to help you look for trends. Consider not just your blood glucose values in your record keeping, but also the time you tested, what you ate, when you took your medications, and any other notes from the day. Review your log regularly with your doctor or diabetes educator.