Keeping blood glucose levels within normal range can be a frustrating challenge for someone with diabetes. Many patients wonder: Why do my blood glucose levels sometimes go up for seemingly no reason? Here are some insights from Johns Hopkins.
Blood glucose levels naturally fluctuate, so don't get exceptionally worried if they go up for no apparent reason -- we can never explain every rise and fall. But when looking for the culprit, food and drink are an obvious starting point. "Harmless" energy drinks, for instance, often have more sugar or caffeine than you realize and can cause a spike in blood glucose. Bagels, which contain 60 g or even 90 g of carbohydrate, are a well-known offender. Stress or an illness can also provoke a temporary jump, and a cortisone injection (into a knee or shoulder, for instance) will predictably raise blood glucose a lot.
Your average blood glucose level (HbA1c) is the best indication of how well you are managing your diabetes over time. That doesn't mean you shouldn't monitor your blood glucose levels at various points in the day. Finger-stick tests can give an early indication that your glucose is rising faster than it should.
The HbA1c test measures the amount of glucose attached to hemoglobin -- the oxygen-carrying protein in red blood cells that gives blood its color. As blood glucose levels rise, so does the amount of glucose attached to hemoglobin. Since hemoglobin circulates in the blood until the red blood cells die (half of red blood cells are replaced every 120 days), the HbA1c test measures average blood glucose levels over the previous two to three months.
The American Diabetes Association recommends keeping your HbA1c levels at less than 7%, which is equivalent to an average blood glucose level of about 170 mg/dL or less. Your doctor may give you a different level to aim for, depending on your age, weight, and other factors. HbA1c tests are usually performed every three months to see if you are maintaining your blood glucose within the target range. If you have stable blood glucose levels and are meeting your treatment goals, you may need less frequent HbA1c testing.
Bottom line: Keep in mind that blood glucose naturally goes up and down, and sometimes the fluctuations are unpredictable. No matter how hard you try, your levels will not be normal every time you test. As long as they don't stay too high, you should be in good shape.
