Now what else can cause a low besides just some "unsolved mystery".

If you start seeing a pattern of low blood sugar, are not taking insulin or a sulfonylurea, are not taking some (other) medication even for another condition that lists low blood sugar as a side effect - are eating mostly regularly, not climbing Mt. Everest or doing an Iron Man workout on an empty stomach...

So you have ruled out meds, environment, lack of food then there are three "unrelated to diabetes" conditions that can cause that low blood sugar (or unexplained high blood sugar as well).

A defective Thyroid Gland can cause the release of hormones that will result in insulin release thus burning up our sugar or inhibit it leaving us high.

A defective Pituitary Gland can have exactly the same effect.

And lastly, the presence of Cushing's Syndrome or Disease which messes with the Adrenal Glands can really mess with blood sugar levels as well.

In fact any three of those conditions could also explain "wild swings" between quite low and quite high blood sugars.

Fortunately an Endocrinologist can detect, diagnose and treat any of those conditions - so in some "very few cases" your Low or High may have nothing to do with Diabetes.

The last reason you might see extreme lows (again, for no reason) or extreme highs or swings in between is a condition called Labile or "brittle diabetes".

While this effects Type 1's more often (but is still super rare in them) it can also effect Type 2's - it is diagnosed by determining that your Thyroid, Pituitary and Adrenals are "fine", it is not drug or environmental induced and there is literally no other reason.

If you are diagnosed with Labile/Brittle Diabetes then that "really sucks" - they have no idea what causes it, no way to treat it and those "with the condition" ARE considered the experts in it.

So just to wrap up -

don't freak out if you go "a little low" particularly if it's a rare occurrence for you

don't wolf down a ton of carbs which can just launch you into a high - if you are simply down into the high 3's/60's, get about 15 carbs worth of (sugar/juice) into you and retest at 30 to 60 minutes

IF you regularly experience lows, particularly drug induced, keep your glucose tablets on hand and instruct others around you what to watch for - but this is not really the "lows" I'm trying to address here

If your lows start to become common, don't sit on the information, talk to your Doc and if they don't seem to listen, insist on seeing a specialist - it may not even be your Diabetes that is messing with your sugar levels...

I am not worried about my sugar lows. I eat a healthy granola bar with mixed nuts, milk and water too. I do testy sugar afterwards too. I also sometimes eat a small amount of dried fruits like dates cranberries figs and milk too when my sugar is low too.

One low 3.5 to 4.0 does not kill us. Maybe you missed insulin, forgot to take medication, or did not eat, so many to consider and correct. Immediately to correct drink some juice or take sugar tablet and check after 15 minutes, if still low like 3 mmole/L then again repeat and check. these are a few things that can be done. If somebody can help you quickly with these steps, that will be the best. It is most difficult for a senior living alone because he might get dizzy or can lose unconsciousness. It happened to me once in the morning. I quickly ate some oats porridge with some honey, I was OK. Keep the functional meter READY. The reason I write, I learned the Lesson.

It has been a very rare experience for me. I was running around getting ready to go out or go to work and thought I'll stop get a biscuit on the way. I started seeing big yellow spots and extremely dizzy. SO, okay that stopped me in my tracks. I sat down and took my blood sugar. It was 36. I got a chair so I didn't have to move around; parked in it front of the refrigerator. I'M VERY TALL. And sometimes my height can give me a problem. I began with a protein like a cold chicken leg, a bite of cheese, and 1/2 an apple. I didn't gobble and I felt better within about 15 to 20 minutes.
Next I called my doctor and reported the incident. They said come in NOW. So I called work and took care of me.
End of the story was I can't be late or skip meals. I was a "newly" diagnosed at the time. My lows now might be around 66. I also carry glucose tablets with me in my purse. I'm never without them.

I am on 5 anti diabetic meds as my a1c and sugars were running very high, when they started to normalize I felt like I was dying, shaky all the time and just blah. Now I am ok with lower sugars but have had periods where my sugars have dropped to below 58 and I do tend to over react. I need to learn to calm down. It becomes a vicious cycle. I need to lose weight, but I sabotage myself as if the sugars are low I run for the nearest high carb or high sugar item.