Question sparked by another post - hypoglycemic seizures

So, someone mentioned having a seizure at 40. Is there a formal number range where we might expect seizures? I always imagined hypoglycemic seizures occurring at much lower numbers. But, I suppose it varies individual to individual. Can someone reply back if your medics actually got a reading during or shortly after a seizure? Anybody ever read, in a book, at what BG value hypoglycemic seizures might occur? I guess I never really thought about it before…

I’ve never had a seizure, been unconscious or gone into DKA. I’ve been down to 26 and up to around 500…and I’ve never had ketones (and I have tested).

None of that precludes it happening in the future.

There is no number at which you would expect to have a seizure, but I imagine being in the teens is not conducive to brain function and/or consciousness.

Strangely enough, my sister (who is not a diabetic) had a low blood sugar episode a few years back. Her youngest came out to ask her something in the back yard and he ran to his Dad inside.

“Something’s wrong with Mom. She’s babbling and not making any sense.”

Seems she hadn’t eaten all day. When the EMTs arrived, they gave her a juice box and told her not to skip meals.

After that, my sister had the strange idea that the Glucagon pen I have at her place was appropriate for her use (which is ridiculous).

Treat your lows right away and you’ll be fine. And make sure you have a Glucagon pen at hand and others around you know how to use it.

(I actually had my pharmacists ask me, “Do you know how to use it?”

To which I replied, “the important question is do YOU know how to use it?”)


I can’t answer that for a seizure, but I can for a coma. A relative of my friend was found by her BF in the morning unresponsive. He assumed it might be a hypo so took her BG to find it at 31. He called the ambulance and the paramedics also took her BG with the same result. She was in a coma from which she never recovered.

By contrast, several years ago I was slightly suspicious that I might be having a low in the last few blocks as I drove home from an out of town trip. I took my BG as soon as I got in the house. It was 31. It had been 85 before I left for home less than two hours earlier after I had just eaten. Obviously, I had over-bolused for what I ate.

I’ve been in the low thirties a couple of times since, too, and though I was incapable of doing complex math, didn’t really act strangely, walk or talk strangely or anything and was certainly able to get my own glucose to treat.

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I was told sometime that any time sugars drop below 40 seizures or coma could result. I have been as low as 28 and know of others with similar readings. Still, it is best to avoid those numbers if possible.

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I had seizures. At no time was BG brought up. Long time ago and far away but now that I am diabetic I wonder about the correlation.

I’ve been into the twenties and was still conscious and able to ski a double black diamond to the bottom to get food, but I’ve also skied through partial seizures. If I can stand, I can ski. Plus, skiing is strange because super high energy sports over the course of days or a week might make me ‘adapt’ to low BG quickly. So, that might be some strange exception.

I feel suspicious about claims of type 1 seizure at BG = 40. I’m sure its possible, but it feels suspect somehow. Especially if someone is not accustomed to running high (runs a low A1C).

Thanks for input.


There is always the possibility of additional medical complications in play and and not strictly a T1 issue.

I don’t get overly concerned over a 40. Treat - sure - obvious. And check to make sure the BG comes up and stays up. Although I do tend to get more aggressive with multiple lows during the same 24-hr period.

Clearly everybody is different and the degree to which a particular person is impacted by a low BG and what exactly that person considers “low BG” has quite the variability.

Your question is a classic example of YDMV. For many cursed with diabetes, a 40ish BG is gonna be a seizure or worse. For others, particularly members of the DOC, it’s likely to be a m’eh(!) event that gets treated (and maybe overtreated) - let’s move on, nothing to see here.

I know when I first started with an Endo after years of not paying attention to numbers, I might’ve been in seizure @ 80. When she told me that I should start trying to get my post-prandial numbers down to :100:, I was adamant that I couldn’t be expected to get below 120, LOL.

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I have been completely unconscious and unwakeable when the EMT’s measure my bg at 40 on their meter. No seizures at that point.

I have been conscious but having my arms and legs jerk around seizure-like with my bg in the 40’s.

I have also been walking around but unable to get my eyes to point in the same direction. BG in the 40’s.

I don’t think meters have to be super-accurate much below 50 or so. So I’m not sure meters have to be able to distinguish 40 from 30 with accuracy. Both are way too low.

Different people behave differently when they’re low. Not everyone gets shaky or sweats. I remember as a kid at summer camp, whenever this one girl went low, she would scream and wail hysterically and thrash about and fight people off. It was scary and entertaining at the same time. I hope that went way as she got older. But it just goes to show we’re a varied bunch.

I was diagnosed in 1945, when I was 6. Very little was known about diabetes back then. I had several seizures each year, but my parents were good at taking care of them. When I started using a meter for testing blood at home, in the mid 1980’s, I saw highs most of the time. I felt awful in the 80-100 range. My body was accustomed to highs, nit lows, so 80-100 was very low for me. I had feelings like I did with seizures in that range. My control kept improving, and I stopped having seizures in the early 1990’s. My body adjusted to moderate lows, and I was not having seizures unless I was in the 20’s and very low 30’s in the late 1980’s.

Interesting. Thanks, guys. Its good to be reminded about how much we all vary. Sometimes we are so different that I can hardly believe it. It makes sense, it’s just counter-intuitive for me. I know that we get ketoacidosis symptoms at different numbers, as well. I have to remember that hypoglycemic is similarly variable.

Brian Bsc said it the VERY VERY best!

It’s when you change consistency of variable blood sugars that cause seizures. Imo. For example-when I stayed on Atkin’s Diet, bs of 48 would cause symptoms. But when I started eating more carbs, bs of 48 caused extremely embarrassing grand mal seizure that sent me to ER.

(Btw, my lowest bs was 28-no seizure, able to self treat).

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Completely agree. I think it gets easy to think that what you see is everything. Whereas the reality is (quite apparently) far more varied.

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My experience mirrors that of @Timbeak48—been as low as the 20s but never had a seizure or been unconscious. Every physiology is individual and distinct.

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Certainly a possibility. Certainly a measurement to treat for before it drops that far. Before CGM I would start feeling symptoms of hypo, test and meter would read LOW. Not sure what the lowest BG the meter would report. I am still fully functional with CGM reading LOW but would not drive or operate power tools (what is lowest that Dexcom reports?).

I am T2 and I’ve been down in the 20’s several times and just felt really slow, hot and somewhat anxious as I knew something was going on. When ever I feel funny, I check my BS. I have never had a seizure that I know of, I live and work by myself. I use a G5 CGM and it has helped me head off the lows and the highs. I work at a job where sometimes I burn a LOT of energy and other times I just sit behind the desk most of the day. One day I was discussing severe lows with my pharmacist who is a T1, he told me that if you are coherent enough to know that something is wrong, if you know what to do you should have enough sense to counter-act it.

I know that me and my Doc went over and over the medic reading, wondering if adrenaline or something had bumped BG higher during the seizure (which could be interpreted as anaerobic exercise, depending on how long your seizing, I suppose). In the end, the neurologist confirmed a cause, other than hypoglycemia, but we really thought about it a lot.

Sorry dannonebr, but mine dropped so fast I couldnt help myself. Husband brought me juice, but by then all I could do was spill it all over myself & my surroundings b4 going into full grand mal.

Sure-if you’re aware one would think one could help oneself. But when it happens to me I go from aware enough to ask for help-to seizure -within a minute or two. I’m T1-don’t know if that matters.

Paramedic bs reading on arrival=46. (Had 7 oz jc b4 seizure-not enough apparently).
Lowest = 28…self treated, no seizure.

But the problem was my meter.

Enough ‘SENSE’ to counteract it? That is insulting!

I had enough ‘SENSE’ to ask for help-just not enough time.

Happened @ 4:58 a.m.

1st seizure was unwitnessed. I only know it happened b/c I awoke w/tongue severely bitten & blood all over pillow. Confusion. Remember having a juice shortly b4-but it wasn’t (apparently) enough. Body so sore I could hardly walk for 3 days.

Tim35-said it well.

Thank you David