Is there a recommended amount of time, after taking insulin at bedtime, that is recommended before checking glucose levels in the morning? 8 hours? 6 hours? For example, I was up far too late and didn't take my insulin until 11:30 at night. I checked at 5:30 in the morning and was very high. I checked again another hour and half later (still fasting) and had come down to 127. I'm just wondering if I'm checking too early (I'm clearly not getting enough sleep!)
You are wondering if checking your blood glucose too soon after taking your bedtime insulin will affect your reading the next morning. The answer is, it depends on what type of insulin you take. If you are on a long-acting insulin, such as Levemir or Lantus, the timing of the morning blood glucose check should not matter. These insulins usually have a steady glucose-lowering effect for up to 24 hours. However, if you take NPH, an intermediate-acting insulin, which peaks 4 to 12 hours after injection, then 6 hours may not have given the insulin enough time to work. You may want to experiment to see if your blood glucose is high every morning in the early morning hours and then drops as the morning progresses. Check your blood glucose at bedtime, at 4 am and at 7 am for 3 days. If the pattern repeats itself, make an appointment to see your doctor or educator to discuss the results. Sometimes a high-fat meal or late-night snack can cause a bump in blood glucose levels in the early morning hours. There is also the “dawn phenomenon” that can cause this. The dawn phenomenon is a normal rise in blood glucose caused by a release of stress hormones by the body in the early morning hours. These hormones help the body wake up, and, for some people, can cause blood glucose levels to increase. By looking more closely at the patterns, you and your healthcare team should be able to figure out why it is happening.