I check my blood sugar before going to bed and sometimes I go low later in the night for reasons unknown to me (maybe it's the dreams). Fortunately I wake up often and that's normal for me. If my sleep is more troubled than usual, I check my blood sugar. If I suspect I will go too low, I have 100 to 200 grams of fruit or carrots, without any covering insulin, and I eat it with plenty of cheese. The cheese slows the rate of digestion and consequently release of the carbs into the blood stream. So far that's worked for me to last out while I sleep.