It sounds like you are experiencing dawn phenomenon (or a rise in blood sugar usually between 2 and 4 a.m.). This is a natural rise as your body gets ready for the day. Have you ever talked to your doctor or diabetes educator about an insulin pump? On a pump you can program a higher amount of basal insulin in the morning to prevent this. Please note that this is my opinion only. Have a wonderful day. CD
Yup, it sure sounds like "Dawn Phenomenon" that CD described. There's a much less common phenomenon called Somogyi effect where a waking high blood sugar results from our blood sugar having plummeted overnight -- then the liver causes glucose to be released to counteract that low.
Here is a good explanation offered by someone at UCSD:
http://www.faqs.org/faqs/diabetes/faq/part2/section-13.html
While I'm not a physician (no one here is), I've learned how to "test" what's going on. It does require at least one night of rather interrupted sleep. The test is to do several blood tests during the night & early morning to record the results.
Bedtime
Midnight
2am
4am
6am
wake up time
Do this test on a night when you've had a meal that's typical for you and not particular loaded with fats. It's ideal if you can go to bed with a fairly normal blood sugar. Record your results. If the results are not what you think is typical, then repeat the test a few days later after catching up on good sleep ;-)
Call your doc with the results and discuss treatment options. I'm assuming you're a Type 1, and so your doc's approach will likely involve adjusting dose & timing of your long-acting insulin -- finding the balance that won't drive you too low.
For Type 2s with a dawn phenomemon, a good strategey is to have a bedtime snack that includes a good dose of protein (metabolized more slowly than carbos). This snack seems to ease that dawn phenomenon. I was told that this approach does not work for us Type 1s.