Resistant low - puzzling?

I was up about 2 hours last night with a resistant low that I couldn’t get to come up.
The night before I had 3 homemade tacos for dinner and took 4u Humalog for the 30 carbs (taco shells and beans) and everything was fine. Last night I did the same and was awakened with a 75 which progressed to a 44 (confirmed by meter). Over about 2 hours I ended up taking 3 Smarties (18 g carbs), 15 g apple juice, 18 g graham cracker , and a tablespoon of peanut butter. before I got it above 80. It would go up slightly and then dive again. It looks like it peaked about 200 eventually and then I woke up this morning with a 125. And I feel like crap. Anyone else have this experience and is it normal to feel crappy the next morning?


That sounds like your glucagon response. For me it kicks in around the 30’s, if you saw a 44 it may have gone down enough to provoke the glucagon response. However:

It sounds like you weren’t adsorbing any of that. Maybe you have an infection? (That would also explain the crappy feeling of course). The only time I’ve seen a “sticky” low was after a number of hours of strenuous walking on MDI, my blood sugar dropped through the floor and I had to eat everything we had (must have been about 100g of sugars) and it still wasn’t fixed, of course my glucagon response kicked in then.

I have had milder versions of what you experienced. Normally for me this is a result of more exercise on the prior days, this puts my body chemistry into a mode where I have to eat much more.


Do 3 smarties really contain 18 g of carbs?

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I have had a respiratory virus off and on for the last two weeks, but I feel better and thought I was coming out of it.

We’re pretty much snowed in here, with a 50 mph wind, so I haven’t had much exercise other than some walking in the house.
I thought that maybe I took 2 shots instead of 1 at dinner, but my routine is I calculate the dose, write it down, then write down the time I take it so I know how long to wait for the “prebolus.” If I came back and took another shot, I would think I would have noticed that it was already written down. I suppose I could have taken a larger dose than I calculated, not paying attention when I drew it up.
I took the shot about 7:15 pm, ate 20 min later, and the low occurred around 10:30 pm. You’d think most of the insulin would have been gone (3+ hours).

Sorry, three rolls of Smarties. Each roll has 15 little candies for a total of 6 g carb.


Have you tried cross country skiing? We do that when we get snowed in and it is really good exercise because we aren’t very good at it :grin:

I find I adsorb grain products very rapidly, I don’t normally eat them because of that but when I do I can count on a high after about 1 hour which then comes down over the next two hours as the insulin (I use Fiasp) catches up. If I were to double dose then I could probably avoid the high. I don’t normally per-bolus; mealtimes aren’t planned that well, and I could probably do better with grains if I did.

The low would correspond to significantly reduced insulin activity, but not stopped. The insulin tails off and the “fast acting” stuff has almost the same tail as regular insulin however the paper insert for humalog compares humalog with humulin-R and the graphs only run to 4 hours, suggesting negligible activity from either after that time.

All the same, I think there are only two reasonable explanations; either too much insulin or too little carb adsorption. Of course those aren’t really explanations because the question for either is, “What caused that?


Hi @Jan,

How long after dinner was your low?

If it was more than four hours after eating, I wouldn’t suspect either your meal or your shot for your meal.

Prolonged lows that aren’t terribly soon after a meal tend to relate to your basal or long acting insulin.

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I took the shot about 7:15 pm, ate 20 min later, and the low occurred around 10:30 pm.

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For a low to last two hours starting at 3+15 after your meal injection, and a low that requires multiple treatments before it turns around for good…in my book that says it was most likely caused by long-acting insulin rather than the meal insulin.

I wouldn’t suspect infection or poor absorption of your food based on one event. And definitely not based on these circumstances. If you get another stubborn low at that time of night, I’d look at your long-acting insulin first. One thing you could eventually try (if you want) is moving up your dinner time so that you go into bedtime with as few variables as possible. If you’re still going low at that time, basal is a safe bet.

And of course it could have just been a one-off occurrence and you might not need to adjust anything.


I also don’t know that we can definitively state that your eventual high was from an internal glucagon response. It could have been from the treatment carbs finally catching up with you. And if your long-acting insulin was too high, that could explain how it eventually came back down to 120ish on its own.


Sounds like basal to me as well. Are you using Lantus? I had middle of the night lows much more commonly on Lantus than with Levemir


For a lot of T1’s (myself included), their body no longer responds to a low with glucagon. Glucagon still works, which is why we have glucagon injections, but their body no longer releases glucagon on it’s own from low BG.

Some maintain this counter-regulatory response, but most T1’s lose it after many years. (Reference here - one of a million you can find on this…)

Chances are you did not see a high from glucagon, but from the carbs catching up to you.

The tablespoon of peanut butter, that will generally slow down carb absorption, which might be why you saw the spike later.


Yes, I use Lantus.
I’m beginning to suspect that it is the Lantus, as I tend to have a low several times a day, and my BG tends to drift down during the day and all night.

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When I was on MDI, which was from 1971 to, I think, sometime in 2014 I periodically had the same problem. This was particularly true at the start where I was on a mixed (PZI and regular) injection a day; the equivalent of just injecting NPH once a day.

When I started using the Omnipod I did the calibration steps to establish my basal and bolus requirements. Since then I hardly ever go low and when I do it is because of something obvious, typically over-bolusing. I also tend to go less high, though I’m not in the ideal range; I count ‘high’ as 180mg/dl and that still happens on a daily basis.

I do meet the medical profession expectation of basal==bolus, but that is only true because my diet is somewhere in the range 100-150g of carbohydrate a day. If I hit 100g I end up with 12IU/day basal plus 12IU/day bolus (for the 100g). If I have to eat out (e.g. on vacation) my bolus requirements go up a lot but the basal remains the same.

IMO it is certainly important to test the basal setting on MDI; it is actually less important with a pump because we can simply switch off the basal. This is impossible with MDI; typically a basal change will take at least 8 hours to even start showing through. This also makes accurate basal requirement measurement quite difficult; with a pump you just tweak the settings after at least 6 hours without food and that gets pretty close to the exact answer pretty fast.

Even for MDI the basal test is easy; get up one morning and don’t eat. If you start going low then reduce your basal, wait at least 24 hours with the same basal (so don’t try again the next day, wait 'til the day after) then try again.

Lantus was always peaky for me; it was no where near as flat as Novotard, which I used until it was discontinued. I ended up doing Lantus twice a day although that dose was still a little high (8IU times 2; when it should have been 6IU times two). These days when I swap back I use 6IU twice a day, exactly matching my pump basal.

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I always had stubborn lows on lantus approximately every 6 hours and resorted to cereal and unsweetened vanilla almond milk (to avoid the extra 13 grams of sugar from cow milk) I’ve used tresiba for about a year and it solved the issue, but I know its not always easy to switch…


forgive me for asking, Jan, but how did you feel during the low? Did it feel like a low or were you relying on your meter to tell you it was a low?

I ask because the CGM that I use will routinely lag in recording lows, and I’ll notice the low before it shows up on my instrument.

[and I second the comment on cross-country skiing - it makes it fun to be outdoors on (moderately) cold days, and great exercise!]


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Well, I was asleep so the Dexcom woke me up. I was sleepy so I didn’t feel the more subtle signs of a low, but I did have my major sign which is vision, black spots etc. From that point on I was depending on the CGM especially the arrow. I got a double down arrow which I very rarely have ever had. And I was using my meter to confirm the Dexcom’s numbers.

For me that delay is about 5 minutes, I’m using the Dexcom G6. If I do a fingerstick in the intervening period I seem to get a lower result, but not as low as my bg eventually goes, so I think the fingerstick is delayed by maybe 2-3 minutes from the level in the blood going to my brain.

For me vision disturbance happens somewhere in the range 30-40mg/dl, certainly under 50. I’ll let a sub-80 figure hover without immediate treatment if the CGM shows a flat line and I’m at home with my wife, but if it hits 70 I will always treat. This is pretty rare these days because I start doing something when I notice my BG heading down below 100 unless it is descending really slowly. I don’t always use the arrow; I prefer looking at the graph. On my phone if I “squeeze” the Dexcom G6 display it overrides the autorotate-lock and gives me a longer horizontal graph which I find easier to read because the base display is only 4 hours; the horizontal display allows 24 hours.

With the graph I can normally guesstimate where the CGM will be in a few minutes. I figure this is a more accurate estimate of where my blood glucose is now than the current CGM reading. The Dexcom prediction of a low doesn’t really work; i.e. the “Urgent Low Soon” setting doesn’t tell me soon enough that something is about to go wrong.

I also use SugarMate, but it’s predictve low alert requires a downward trend of at least an hour. Yesterday I got a down trend that hit 80 in 45 minutes; this was caused by an overbolus which itself seems to have been caused by the G6 reading maybe 40mg/dl high, at least the downwards trend started with what looks like a G6 transmittter reset from about 180mg/dl at 13:00 to 130mg/dl in maybe 10 minutes:

The grey bar on the SugarMate graph covers the range 80-120mg/dl, so Dexcom alerted me when I went below 80 but SugarMate didn’t say anything until later. I started minor corrections at around 14:20 (I didn’t enter that into SugarMate) then bobbed around just below 80 until I ate (then I think I overbolused slightly again!) Ironically this low was also resistant to what I was doing, but then I think that was because I overbolused twice.

Getting the exact data is very difficult on an iPhone with the apps I’m using. I have to get it from Apple Health, but the G6 delays updates to Apple Health by 3 hours, so basically Dexcom lock me out of the record until three hours have elapsed :unamused:

Anyway, the data in Apple Health doesn’t quite match the data recorded by SugarMate; the G6 appears to have adjused one point. Previously I thought it was adjusting more, but the I discovered my line up of the two screen shots was off by one measurement. Here is what UnderMyFork shows from the Apple Health data:

Superimposing the SugarMate graph (direct from the Dexcom app) over the SugarMate (from Apple Health data published by the G6 after three hours editorial review) gives this (I just updated this with the correct alignment):

You can see from the full displays that both apps report a “before” bg of 163 and an “after” of 79. The 6 unit bolus was given as 4.35IU immediate plus 1.65IU with a half hour delay. When I line up the right dots the only ones that seem different are the two either side of the sudden drop around 13:20. The change in the Apple Health recoding (UnderMyFork, the colored dots) makes the drop less precipitous.


I just use the Dexcom G6 Receiver. I have the Clarity app on my phone, but it’s not much use because I have to upload the data from the receiver via my computer to the clarity program.

I think the sight of me on Cross country skis out in one of the pastures would scare the shxt out of the cows (literally!). A person on a horse or a 4-wheeler or in a truck or tractor, no problem, but a person “gliding” along on skis, we’d have a major stampede. :laughing: