A Closer Look at Night Glucose Testing

Insulin-dependent diabetics frequently ask if they should wake up in the middle of the night to test their blood sugar. Parents of juvenile diabetics often wake themselves up to test their child’s blood sugar. However, should the patient and/or the parent(s) disrupt their sleep patterns to perform this task? 

The data obtained from middle of the night testing can be vital to tight blood sugar control, reaching target A1C levels and all of the corresponding benefits. The additional testing provides patients and parents the ability to analyze the accumulated date in order to:

• Observe and adjust basal (long-acting) insulin requirements
• Define the effects of and adjust insulin requirements in order to better align and time dosages with late-digesting food
• Identify when dawn phenomenon begins and adjust insulin requirements
• Avoid middle of the night hypoglycemia
• Awaken with controlled blood sugar and start the day in target range

There are some potential risks to regularly waking to check blood sugar in the middle of the night. Some cons to consider are:

 

In addition to the potential cons listed above, some studies show that long-term sleep deprivation causes chemical changes that may lead to insulin resistance and weight gain. However, to an insulin-dependent diabetic, the potential benefits may outweigh the potential risk.

 

Both high and low blood sugars can disrupt sleep. Many patients find their bodies are good indicators of blood sugar swings and awaken as a result. This is a good signal for patients to listen to their bodies and test their blood sugar. Assuming (without testing blood sugar) that waking to a symptom of sweating, for example, always means low blood sugar can lead to treating blood sugar that is actually high or over treating a moderate low blood sugar event. Incorrect treatment can then lead to waking in the morning with high blood sugar and all the corresponding side effects. Therefore, many patients find it helpful to at least test if they wake up in the middle of the night.

 

Other patients find that middle of the night testing assists in adjusting basal or long-acting insulin requirements. Some products, especially in larger doses, cause low blood sugar several hours after dosing. The test data in conjunction with associated basal dose adjustments can reduce or eliminate hypoglycemic events. Other patients discover that their long-acting dose does not last the entire anticipated duration. From testing, they may learn they need to take two doses.

 

Many patients identify that digestion of their dinner takes far longer than the basal (rapid-acting) insulin dose they took with their meal. Middle of the night testing identifies the resulting highs for which the patient can take a correction dose so that they do not leave their blood sugar in a hyperglycemic state until morning. In addition, patients can learn how to better predict secondary post-meal insulin requirements to avoid late night high blood sugar.

 

Due to the random fluctuations of blood sugar levels in young children, parents often fear their child will not awaken to hypoglycemia. Therefore, they are comforted and reassured of their safety by waking up to test their child’s blood sugar. 

 

Middle of the night glucose testing is one of the tools insulin-dependent diabetics have at their disposal to control blood sugar. Some patients have replaced or supplemented individual glucose testing with a continuous glucose monitoring system (CGMS). Patients should weigh the pros and cons of middle of the night glucose testing and discuss them with their medical team if necessary. In the end, whether patients choose a CGMS or traditional glucose monitoring, the data can be invaluable if judiciously used, properly analyzed and applied to their diabetes care.