A normal fasting blood sugar is less than100 milligrams per deciliter, or mg/dl, but many people, especially those with diabetes, experience much higher levels in the middle of the night. Even when you are trying to eat as few carbohydrates as possible, this spike often occurs around 3 a.m. This may occur because your body produces hormones that inhibit insulin's regulatory effects on blood sugar. Other causes include the rebound hypoglycemic effect, a poor diet or inadequate medication.
Blood Sugar
Your blood sugar rises and falls throughout the day, depending on the foods you eat and the amount of physical activity you engage in. When you eat foods containing carbohydrates, such as fruits, vegetables and sugary snacks and drinks, your blood sugar rises. Your pancreas then produces insulin, a hormone that regulates blood sugar, and your glucose levels decrease. Blood sugar is usually relatively low several hours after a meal, but in some people--such as diabetics--it may spike during the night. Diabetes is a condition in which either not enough insulin is produced by the pancreas or the body's cells have become insensitive to the insulin that is produced.
Inadequate Medication
Your blood sugar may spike in the middle of the night simply because your diabetes medication has lost its effectiveness at that time, according to the American Diabetes Association. When this is the case, the remedy is to change the time you take your medication, or change the type or delivery system of medication. Adding Metformin---a medication that keeps the liver from producing glucagon---may be the answer if this nightly release is causing your spike in blood sugar. Using an insulin pump can also keep your blood sugar under control if it is rising to dangerously high levels in the early morning hours.
Dawn Phenomenon
The "dawn phenomenon" occurs when blood sugar levels rise unexpectedly in the middle of the night due to natural hormonal changes, according to MayoClinic.com. These hormones---cortisol, growth hormone and epinephrine---counteract the regulating effects of insulin and allow blood sugar to rise. Not all blood sugar elevations at night are due to this normal hormonal production. Other factors include eating a bedtime snack that contains carbohydrates, skipping medication or routine exercise that day. Sometimes a medication change is necessary to counteract the "dawn phenomenon."
Somogyi Effect
Also known as "rebound hypoglycemic effect," the Somogyi Effect occurs when glucose is produced by the body in reaction to a nighttime low. This low blood sugar level can occur because the insulin injection or diabetes medication is too strong, you are consuming alcohol or your diet is too carbohydrate-restricted. If your blood sugar is spiking in the middle of the night, a decrease in medication or a bedtime snack may keep you from experiencing this rebound effect. A change in the type of medication you take may also resolve the problem.
Testing
The only way to discover the cause of nocturnal blood sugar elevations is to test blood glucose levels during the night. Charting the dosage and schedule of your diabetes medication, along with the foods you eat and when you eat them, can help your doctor determine whether you are experiencing blood sugar elevations due to ineffective medication, hormonal changes or a reaction to a low blood sugar episode.
