Any ideas?

After 10 years of T2 which I control at pretty much non-diabetic levels A1c in the 5s always with VLCdiet and 2 x Metformin 500 per day, I thought nothing was likely to surprise me. Was I WRONG?
I only check my blood sugar first thing in the morning.
Just this last week, my fasting level has been 2.4 mmol/l[43.2mg/dl] three mornings.
I have felt perfectly normal each time, so not bothered to "correct" until this morning, when I thought I'd better, before driving to the gym.
I can understand not feeling hypo, because i wasn't aware of the dropping process.
I'm going to do an overnight monitoring tonight, because I need to walk 5 miles tomorrow morning and wouldn't like to cause a kefuffle anywhere en route.
Although I feel absolutely fine and today I've gone up to 5.6mmol/l [100.8mg/dl] after I biscuit[cookie] for breakfast and about 2 hours in the pool and the gym, I'm puzzled.
I have been careful with carbs recently. I'm aiming for an A1c in the 4s next time. Anyone got an explanation? It's not supposed to be possible with Metformin

Just curious; does your doctor want you to have such low BG or do you? What you're aiming for is lower BG than many non diabetics. Some of us diabetics develop the mindset that the lower the blood sugar, the better. That's only true up to a certain point. Trying to always have non diabetic numbers will inevitably result in dangerous lows. We should remember that low blood sugar is more dangerous than high blood sugar.

I am aiming for non-diabetic numbers. My doctor generally just goes along with what I'm doing. Except he won't prescribe test strips for me, because they cost too much and the NHS doesn't want stablw t2s to have them.

Low blood sugar, when NOT caused by medication, isn't dangerous. Persistent high blood sugar IS!
much of the danger in diabetes, is down to the medication NOT the disease.

Agree nothing you are doing, or drugs you are taking should cause this in a T2. I would guess it's some type of reactive hypoglycemia. Perhaps your insulin resistance is decreasing or your beta cells have regenerated to the extent that it makes something like this possible. It seems that reactive hypoglycemia is more a symptom of very early stage diabetes, and is not typical for a veteran such as yourself. About all you can do is test during the night and amass some data. Sad your doc won't prescribe test strips, that would make this so much easier to troubleshoot. Do they think an excellent A1c, such as yours, just happens?

I applaud your desire to get into the 4's, it's a worthy goal, and hope this problem won't derail you!

Hmm... I'm taking the same dose of metformin right now but it's half tabs 3 or 4 times a day depending on A1C. I had my first low reading over the Christmas season. 3.2 so not too low. My lips were numb and I felt scattered. I was wrapping presents so I added a little Baileys to my black coffee and carried on. Are you sure it's not dangerousto go low? I'd rather not treat if it's no problem.
Well.. I did enjoy the Baileys... first time in 9 years... and I did take a chance and "treat" again when I saw a 4.0. :) Cheers! Joanne

Metformin by itself should not cause bg lows. I take 2550 mg per day and I am quite petite. I rarely go below 90. If I were you I would do some after meal testing. It definitely sounds like Insulin Resistance that may cause you to spike and then crash. You could also be getting hormone spikes over night that do the same thing. Are you sure your meter is accurate. When was the last time you changed the battery? I got a super low reading one time that freaked me out. I rewashed my hands and did another reading and it was 100.

I'd have to respectfully disagree that low blood sugar, when not caused by medication isn't dangerous. I'm 59. When I was around 10, I started having hypoglycemia episodes if I skipped a meal (no medication). I rode my bike to school & barely made it to class before passing out & I was unconscious for at least 25 minutes. Since my diabetes diagnosis in 2009, I've had three lows - without any medication or insulin; the worst low was 57. For me, a low is anything 100 or less. I'm not able to function, drive safely, etc. unless I'm over 100. That's when I start having symptoms & it goes downhill quickly from there. Some research has shown at each hypoglycemic episode causes some brain damage.

If the test strips are so hard to come by and, as BadMoon said "nothing should cause this..." I would probably test again? My senses for hypos are a bit dull after years of skating along the edge but at 42, I can usually feel the symptoms pretty strongly?

This has now happened on 3 separate mornings in one week, so I don't suspect either the srips or the meter. Anyway I have great faith in my Freestyle lite.
Strip are not hard to get, but i save them, becausee I have to pay. The NHS in its wisdom has decreed that stable T2s need only test once a week. Apparently we don't have any ways of responding to our results!!!!!
Ps if it keeps happening, I might get a chance at some strips from the doctor.

I function perfectly normally at 2.5mmol [45mg/dl] I didn't say that lows not caused by medication don't happen, just that they are not dangerous. Lows caused by insulin become dangerous, because the bg continues to drop and the system may not be able to restore itself. Theoretically this could cause death although I've never found a case recorded of this kind of fatality.
Non-diabetics may suffer low bg if they miss meals, but they are not generally thought to be at risk of life and limb.
I did "correct" this morning, because I was going to drive to the gym. Tomorrow I plan to walk to the local catering college to have lunch with friends in their restaurant. It's almost 5 miles, so I'll need to be careful. If I feel off, I'll get the bus. I don't use the car if I don't have to. There's no bus from my home area to the gym.
I've done some digging and the only useful bit of info I've found on Metformin mediated hypoglycaemia is that it may be due to depletion of hepatic glycogen. That would tally with my VLC diet, so maybe I found my answer.
I will keep checking though.

I haven't paid that much attention to which meters are more or less accurate than any other meters as my main criteria are size and "acceptable" (to me, ha ha!) accuracy.

In the USA, I believe that they are supposed to be +/- 20% of "lab" results (although I haven't see a lot that questions how accurate those are? I gave up on one lab recently because I went in to drop off some blood and, while there was no one there, they said "you have to go make an appointment online" which, of course, I didn't because the other lab will take me on a walk-in basis). Still, if the BG test result is out of the normal range that much and not consistent with how you feel, I'd wonder about the result of the test and probably not believe it. If the test *was* correct, OTOH, there's not a huge margin of error?

Maybe the plan you've come up with for yourself is pretty safe. I've had some interesting insulin-fueled running experiences, where for one reason or another my BG ran lower than I anticipated and being out on a 5 mile hike and running out of glucose is not too much fun either.

I looked this up too Hana and it seems you are right that it isn’t dangerous but actually normal. If you have normal numbers, you apparently wouldn’t feel the low. I feel a lower number because my body is used to high numbers while yours is not. Jenny does have some tips about treating these lows without spikes and as usual, her advice appears to be the best.
I think I got my first prescription for scripts this fall because my logs showed too many 4’s. With your recent numbers, it should be a done deal. Best of luck to you.
Cheers! Joanne

From the Mayo clinic:

"Metformin can cause low blood sugar (hypoglycemia). However, this can also occur if you delay or miss a meal or snack, drink alcohol, exercise more than usual, cannot eat because of nausea or vomiting, take certain medicines, or take metformin with another type of diabetes medicine."

That does not seem like a normal low that someone might have. Keep in mind that there are other conditions not related to diabetes that can cause excessive secretion of insulin by the pancreas, such as pancreatic tumors.

Hana, did you know that you can pose this question directly to Jenny through her Bloodsugar101 site? I shared an article with her in the winter and I asked for her input and she responded right away. I did it through her Facebook page but you can also contact her through her site. Joanne