Five years, and I'm still trying to figure this out. Empirically, it looks like I go through two- or three-month cycles, where one month all my numbers will be high regardless of what I do, the next month they'll be low, and the third month they'll be normal, and then the cycle will start again.
Unfortunately, it's not an exact cycle and it's not an exact science. Sometimes it's two months, sometimes it's four. Any relation to my monthly cycle is purely coincidental: one month, I'll drop two or three days before menses, and another month, I'll rise at the same time of the cycle.
Weather also seems to be an issue. I think I have more lows in the winter than in the summer, but then I'm paralyzed enough by cold that in summer I'll get lows from dehydration or extra activity.
After a month of running high enough that I was about to go to the doctor for an out-of-sequence check of my high numbers, today I can't seem to keep them high enough to be "normal people normal".
Now, for those who are on insulin, it's a matter of adjusting your injections or your basal rates and boluses. I'm Type 2, on diet-and-exercise, and getting precious little of the latter (something about having to be home until The Other Half leaves for his swing-shift and having to stay near the phone in case a potential employer calls with a potential offer for me)... leaving the Scylla and Charbydis of healthy eating versus unhealthy, and follow-the-bouncing-glucometer; trying to get back to a healthy weight or increasing my level of obesity... and trying not to stress my blood pressure into the realm of having to have my doctor up the dose of Cozaar.
This odd, can't-pin-it-down cycle reminds me of the "polar wobble" responsible for the Earth's occasional Ice Ages and interglacial periods. Am I the only one with "BG Wobble", or are there others? Has anyone figured out what might be behind it?
Answers, or maybe even better questions, would be useful.