Suspending Basal Insulin To Treat a Low BG

I have never been a fan of suspending basal insulin even when you are experiencing a low BG. Here’s why. A basal and a bolus are both deliveries of insulin and although a basal is a very small dose of insulin delivered every few minutes, it takes hours for that drop to be fully absorbed. That is the same for a bolus which is a much larger dose but is usually given for a meal. It takes hours for the bolus to be fully absorbed although it begins its absorption in about 15 minutes. So, when you suspend insulin (basal) you are suspending very small portions for a period of time but it does very little to increase your BG immediately. Rather it will tend to increase you BG for hours later. In my opinion it is much better to eat a fast-acting carb than to suspend your basal. And you won’t be going higher later for no apparent reason. It is surprising to me that pumps are now automatically suspending basal insulin to help with a projected low. I understanding the marketing appeal to this but not so much a real-life appeal. Am I looking at this incorrectly?


No you aren’t looking at it wrong. In short form, I mentioned this very thing on a thread and got zero “likes”. I’m perplexed that people don’t agree. oh well, at least I know better, as do you. :slight_smile: ie, I treat a low with CARBS–not reducing my basal in hopes that’s going to magically increase my bg’s from the 40’s or 50’s back up to 100. It ain’t happening.


Let me start by agreeing with your idea that treating a low with fast acting carbs is a tactic that works. I’m here to tell you, however, that modulating basal delivery with an automated insulin dosing system works well, too.

And it works more quickly than you would think. While the peak effect of analog insulin may not arrive for 60-90 minutes, its onset is in 15-20 minutes. If your glucose metabolism is well balanced at the time, this onset of action is enough to tip the glucose level down or to slow down a rise.

When I first heard this idea proposed, I was skeptical, too. But after living with Loop, a system that alters basal delivery based on active insulin, carbs on board, insulin sensitivity and other factors, I am a firm believer that this basal manipulation does indeed work.

Here’s a Nightscout report from today that shows my glucose level as well as the basal profile. The basal profile is the blue “cityscape” trace at the bottom of the report. Loop makes a basal dosing decision every five minutes. It adds or subtracts or remains with the pump-programmed basal rate. You can see how the blood sugar rise starting around 5:00 a.m. is countered by the rise in the basal rate. The glucose level responds nicely but it does take some time.



That’s (reducing/stopping basal) all fine and dandy if you are just dropping a little bit down towards a hypo, but it’s of no use to fix what one generally thinks of as a true hypo. For that you need CARBS.


I agree that the quality of the hypo matters. Steeply diving glucose levels with insulin on board will not be held back with stopping a basal rate. You need to bring on the power of fast-acting carbs.

Diabetes is a Goldilocks disease. It’s very easy to overdo treatment and buy a seat on the gluco-coaster. Assessing the timing and intensity of counter-moves makes diabetes management challenging. Sometimes you need forceful intervention, sometimes finesse works best.


I’m also a proponent of cutting basal. As Terry mentioned, as long as you’re dealing with more or less steady state metabolism, putting the brakes on basal delivery for short periods is every bit as effective as ingesting quick acting carbs. And some of us avoid carbs except for emergency situations.

I’m in the last day of a 48 hour fast (no food since Fri 5pm) hence the only glycogen I have stored is in my liver. I noticed at midnight my BG was getting low, so cut my basal from 0.400Units/hr to zero for 30 minutes. Approximately 0.2Units was cut, which is exactly what’s needed to raise my BG by 1 mmol/L (18mg/dl).

As Terry also mention, the onset was within 30 minutes, and as planned my BG rose from 3.7 to 4.7 in 40 minutes.

Easy as all get out. BTW after I set my 30 minute temp basal to zero, I rolled over and went back to sleep


Agreed with overdoing things! I learned about a decade ago to bolus for 1/2 of the excess carbs that I would consume when pigging out big time because a low was so severe I’d eat “everything in sight”. By bolusing 1/2 of a normal bolus for carbs eaten in excess of what I should have eaten, I can prevent a high rebound that gets way out of hand. I suggest those that have a hard time holding back from overeating when low, they consider doing the bolus thing.


A 2-day fast? OMG. It’s tough for me to go 18 hours. I recently had surgery–at 7:30AM, and around noon I was so happy to see my meal come up to the room–very tasty chicken with mashed potatoes, poultry gravy, veggies, and a roll. I wolfed it down and had a nearly identical meal at supper time. Only downside was my bg’s, thanks to the stress of surgery, had me up around 300–a level that I just don’t ever get to for many years. If I were to go without food for 2 days, I think I’d eat anything not nailed down. :slight_smile:

Glad to hear this works on a closed loop system. I considered it to be it more of a marketing gimmick which targeted hypo victims. I am not on a closed loop system so for me, I will continue to treat a low with quick acting carbs. I have gone from low to high after treating for lows but have learned how many carbs it takes to move my BG 20 or 50 points. I don’t want to be too dependent on a closed loop system as there are too many independent variables that even a closed loop system cannot predict. I do think that it is better to treat a super low with quick acting carbs and maybe the marginal low with turning off a basal rate temporarily.

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I believe you meant to say carb rather than insulin


I have been treating moderate lows by turning off basal ever since I first went on an insulin pump. By moderate I mean something between a 72 (when I know it is on its way down) and 62. Anything under that I do treat with carbs in the form of Skittles (1g each). If I find myself down in the 40s or 30s (which has happened), I then have faster acting juice. But turning off basal has served me well for many years. I don’t have a CGM.

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When the automatic stopping of basal insulin is activated because of a pending low really is great is during the night while you are sleeping.

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I suspend the basal if I think I might go unconscious in the next hour or two, otherwise I dont find much value. I think that can help. Primarily, if my basals are set way too high, this is valuable. Sometimes I turn it off for a couple hours - if the trends are bad.

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I do most times use glucose tablets when dealing with a low. But I have cut off insulin overnight quite a few times when dealing with multiple surgeries during a trial. Since I couldn’t eat, I had the CGM set a little higher the night before and I would cut off the insulin before it got too low. While some nights took a little longer for the blood sugars to come up, it worked very well for the no food before surgery rules. I don’t think I would use it to deal with true lows.
But my new Tandem IQ does this but in a predictive low situation. I love it! Can’t tell you how happy this pump and the G6 makes me! The numbers I am running are so much better than what I was able to do with my old pump! Technology is my friend.


I’m looking forward to my first tandem pump but can’t get it now thanks to some technicality with Medicare and the upcoming feature, Control IQ. The issue is so preposterous, I can’t even explain it. Suffice it to say the sales rep said I have to wait until this summer (hopefully that timeframe isn’t extended) for Medicare to bless the Control IQ feature, because according to the Tandem sales rep AND her boss, if I buy the t:slim now, i may be locked out forever for the upgrade to Control IQ. I KNOW that makes zero sense, but that have told me that repeatedly. I’m getting aggravated about it to tell the truth, as it seems like an arbitrary rule of sorts, that they referenced from Medicare. So my wife and I both want to get t:slims (since a month ago) but are being denied for months, thanks to Tandem’s extreme caution in selling a pump that they think may not be allowed to be upgraded to Control IQ. If anyone here has real, intimate knowledge of such a potential issue with Medicare and pump upgrades, I’d love to hear it.

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My application for a t-slim x2 and the G6 has been postponed for a Catch 22 reason that my Animas Ping warranty does not expire until 2021 and, theoretically, I can’t get another pump until my warranty expires. This is preposterous as everyone knows that Animas is out of business in the U.S. and has shuttled its clientele to Medtronics for service and supplies. Tandem claims it has something to do with Medicare. Medicare says it is not them so must be Tandem. Hope to sort things out after the holidays. Could these reasons all be manufactured to stave off the avalanche of orders that Tandem can’t fill right now, postponing Medicare purchases because they are of lower dollar? I am very confused at this point.


I don’t think it’s a conspiracy, Willow–it’s just RIGID rules that government entities such as Medicare (or other medical insurance companies) adhere to. Hang in there.


I’m in the same situation here in Alberta Canada @Willow4

My Animas Vibe coverage doesn’t run out until Nov 2019, and the only option for a trade / new pump is Medtronic (ugh)

Problem 2 in Canada is that while the T-Slim finally received Health Canada federal approval in Nov '18, we need provincial approval prior to getting funding approved. I hope and pray that’s taken care of in eleven months

I share your sentiments. I never thought I’d want to get away from MM pumps, but the 670, is, in my opinion a very very poor replacement for my trusty, simple, 551 (530G).

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If you were trying to do the $1000 offer that Tandem has (offer expires 12/31/2018), that is not allowed for people on traditional Medicare. I don’t understand the Advantage aspect to be able to comment on Advantage plans.

The issue is any company/provider which accepts Medicare is not allowed to bill the customer anything above that which Medicare has already contracted. That would be illegal on the part of the company/provider with potentially very large consequences.

Or were you @Willow4 not trying to use the $1000 offer from Tandem but rather attempting a different route for a pump?