This overnight basal test was to confirm a previous test run to confirm my overnight profile. The test was successful, with two annoying exeptions:
Dexcom STS woke me up with a low alarm (DexCom alarm set to 80) at 5 am (ultra = 136). I re-calibrated, went back to sleep, and an hour later, received another low alarm (ultra = 132). The low alarms occurred even though DexCom was showing my BG trend was essentially flat during the evening, hovering around 100 +/- 15. As can be seen from the following nine-hour trend screen. Note the false noise dipping below the dashed line in the middle of the screen(the low alarms), circled in red. I have no idea what caused this. This particular sensor is on day 8 Ignore the 228 BG reading, that's the dawn phenomenon I'm now working to correct:
Normally I wouldn't mind a false low at this hour since I'm an early riser during the week, but hey, it's labor day weekend and I wanted to sleep in a little later.
Anyway, I re-calibrated a second time, and DexCom is now tracking my dawn phenomenon quite well. I consider the test successful since it confirmed my new overnight basal rate, although I did wake up a couple of times. I have my low alarm set at 80, perhaps I need to consider setting it to 70 if this pattern is too frequent, although these are the first false lows I've encountered overnight. Back to some more experimenting!