The actual current amount of a temp basal

Does anyone do anything to calculate their actual temp basal amounts to figure out what they are really getting at the present time?

I don’t think any pumps do this.

If you lower your basal, it takes a while for that amount to actually be in play. I am not sure the best way to describe this, but I will try an example:

Suppose your duration is 4 hours (and also suppose you have not eaten anything for a while so you can totally disregard IOB).

If you completely turn off your basal at 1:00 pm, you know at 1:01 pm you are not really at 0% yet. If you have a 4 hour duration, in actuality it will be 5:00 pm before you are truly at 0%. So even though the pump says 0%, it’s not really 0% for a while. It comes down from 100% to 0% over several hours.

This isn’t too difficult to calculate in your head for a 0% temp basal. But if you are doing temp basals like 40% or whatever, it becomes challenging to calculate.

Is this something that would be useful to see on a pump? The “effective” current temp basal amount you have? Or would that be too confusing?

Am I making any sense here?

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A bit but I am also confused. On some pumps, they do call the Insulin on Board (IOB) by the term Bolus on Board (BOB). I forget where I saw this. But point being, AFAIK, (which I think you also are saying?) the basal is always ignored by the IOB or BOB. The IOB or BOB only takes into account the bolus and never the basal.

So if I did not understand, then your question remains the same as:
Would it be useful to see the current Basal in your system.

I would think this would only be useful if you were going to use this to influence actions. For most people - not likely. For yourself - nothing would be surprising. What are your thoughts on how this would influence what actions you would take over the next few hours?

To confuse the issue even further, on a pump there really is no difference between basal and bolus other than amount given. It’s the same insulin, doing exactly the same thing.

So why on earth would a pump calculate IOB or BOB and ignore basal? That makes zero sense.

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I would disagree. The difference (in my thinking) is what action are you going to take based on the information.

With basal in the system, is that going to influence our next bolus or are we going to ignore that as background information and would this additional information only serve to confuse the issue?

With bolus on board (IOB/BOB) - we definitely need to use this to influence our actions under certain circumstances. The classic case being bolus for food with BG included in less then 3 hrs after the original bolus. I do not always trust the calculator/wizard within 3 hrs of the previous bolus - quite potentially as I may not have the Duration of Insulin (DIA) properly set but also I am not confident the carbs from the food have hit and the BG impact and all that.

My preference for multiple food bolus in short order (grazing, desert, second helping, whatever) is to use the Calculator/Wizard for the first one (and adjust as seems appropriate to you - we don’t blindly follow it) including your BG. For subsequent bolus in short order, just bolus the food. Ignore the IOB, ignore the BG. Just bolus the additional food.

I almost always run with no IOB, so throw IOB out for this discussion.

For me, I turn my basal off or down for exercise. Not all of the time, but certain runs of sufficient length.

So I may go to zero basal anywhere from 0 to 30 minutes before my run. Usually I don’t do longer than that before I start, so I don’t spike. But I can keep it off for hours while running.

I would like to look at my pump and see an actual basal number for that moment. For example, if I have been off for 45 minutes, rather than the pump kind of dumbly saying “zero”, I know there is still basal insulin floating around from the previous hours. So I would like the pump to give me a value that is correct.

At 45 minutes of zero basal, I guess I am at about ~60% still. Doing crap like that in your head sucks when you are running.

@Eric - Your explanation totally makes sense for you.

However I think you are far from the average pump user. (In a good way of course!!!)

For the vast majority of the pump users, I do not think this information would be helpful and in fact would likely serve to confuse them and negatively impact their decision making process.

As I have learned it, and as @Thomas stated…basal is really irrelevant once it’s dialed in correctly. It is the slow, level, and gradual insulin that the body needs to receive all the time in order to remain level in the absence of any other event (such as eating.) So, there are no decisions being made off of that insulin. It’s just running in the background, doing it’s thing.

IOB on the other hand is very important to know because it helps prevent stacking, it advises you how much current active, fast-acting insulin (bolus) is on board so that you know whether a correction is needed, etc., If you knew BOB, what would you do with that information?

I use temporary basals a lot, but I mostly think of them in terms of percentage and “offset”—if I set a temporary basal now, it’s not going to “kick in” for an hour or so. But my temporary basal rates are usually pretty short, 30-45 minutes for reduced or zero basal and an hour or two for increased basal. Even with exercise, I can’t turn my pump off for more than about 45 minutes without skyrocketing (and that may be even worse with Fiasp, I’ve noticed my blood sugar responds much more to even 30-minute zero basals, and at times even that’s caused my blood sugar to rise too high).

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So that sounds kind of like what I am thinking of, right? You just know you are not really at the temp basal level right away. Do you just mentally process that with some formula in your head?

I just look at the amount of time I have been on a temp basal and try to come up with my current basal level. Sometimes it’s easy to do in my head, and sometimes not so much…

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My basal changes, especially zero ones, are usually very brief and related to “exercise” (activity that isn’t really exercise but still lowers me, like walking to the store for groceries). In those cases I’ll just do a temporary basal rate an hour or 30 minutes before I plan to leave, and then just make a mental note that I want to leave at a certain time. The other times I use temporary basal rates are to help with running high or low. If I do a lot of exercise, then I do a -10% or -20% basal rate overnight. These I don’t really calculate, I just know that they usually work. And then I’m stuck high, I’ll do a +100% basal rate for the default four hours and just cancel it when my blood sugar starts to drop.

I used to be a swimmer and for those sessions (usually an hour to an hour and a half), I did a -50% or so basal rate. I found I could not disconnect the pump because I’d end up really high with high ketones and feeling sick about an hour after finishing. I often did go low by the end, but weirdly also usually had to bolus right as I finished so that I wouldn’t go high later on. I haven’t been swimming recently because of my schedule and my pump is out of warranty and not waterproof anymore, but I’m hoping to get back into it soon. For that, I probably will have to calculate how much insulin I’ll miss so that I can bolus for 50% of it, and I’ll do half (so 25%) up front and the other half when I’m done. (If I recall, the old Cozmo pump 1800 version actually did calculate how much insulin you’d missed during a pump suspend after resuming delivery so that you could replace that lost basal if needed. I only have the 1700 version of the Cozmo, so missed out on this and some other great features.)


So, with openAPS we are tracking the reservoir volume…this tells you how much insulin you have delivered at any time. I think that’s the most reliable way to do it. We then have a little program that spits out how much insulin is in the reservoir with time, and I just manually subtract within a given time period to figure out how much basal was actually delivered.

Then, we have a second metric we calculate, which is insulin activity. This is basically a first derivative of the pump reservoir volume (i.e., the IOB + basal delivered) multiplied by some factor based on how long insulin is active in the blood stream, and it’s our rough proxy for how much insulin is currently working to lower blood sugar or ketones AT THAT TIME. What’s very interesting about this number is that it typically peaks about 60 minutes after the last insulin delivery, and it decays very slowly – typically going down to 0 many hours after you deliver the insulin. So even when your delivery looks spiky in terms of IOB (say you have a big meal bolus and then zero temp to create a super bolus), the actual insulin active in your bloodstream at any given time has a much smoother profile. While obviously we’re just making a guess here based on some past studies, in the end it does give us a pretty reliable sense of when his BG is likely to go up.

At the beginning my husband and I also realized there’s a lot of uncertainty about how much you insulin you’re actually delivering with systems like ours. For instance, each pump doesn’t actually provide a continuous, miniscule drip of insulin – they try to mimic the pancreas and either deliver “squirts” of basal anywhere from every 5 to 7 minutes to every fifteen minutes. So for us, with temp basals that are being shut on and off every minute or two it was actually sort of impossible to figure out how much was truly delivered at a time. When it switched from a high-temp basal to a low temp basal after 2 minutes, was it giving two squirts of the hourly basal rate or just one? And when it was zero temped and then goes back to a high temp, was that zero temp just equivalent to what it would have been anyways in between those two basal delivery points? Anyways, that’s why we use the reservoir volume as a more accurate gauge. That tells you what was actually put into the subcutaneous tissue.

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I totally agree with you because the assumption that basal needs stay constant through the day (and that basal and bolus are not actually fungible, based on what you eat) is, in my opinion, not accurate. I think it’s a really useful way to think of things when you don’t have a CGM and are only testing BGs intermittently throughout the day, or when you’re on MDI. But I think it makes things more confusing when you’re on a pump.

That sounds like quite the nice feature. I would really like that. This would be another one of the “basic” things that I think all the pumps should have. Like for a shower. Some days maybe 15 minutes some days maybe 45 minutes. Might be during a time of day with lower basal or maybe during a time of day with higher basal. Assuming the shower itself does not impact the BG then I would think putting the “missed” basal back in as a post-shower bolus would make sense.

Or when doing a site change. And you get distracted in the middle and it ends up actually being off for 30 mins.

The Cozmo had such nice features! The 1800 version also had a feature where if your glucose was below target it would tell you exactly how many grams of carbohydrates you needed to eat to raise it to target. So you didn’t have to think through that whole process when low. I don’t recall what other features it had, but man, I miss that pump.

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OMG !!! I would so totally have gotten this.

Yeah - I am always doing that manually. Nothing wrong with manual but some of the basic stuff is like … why doesn’t the pump just DO this?

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The Cozmo was by far the best pump (in terms of software) I have ever used. Kind of like how I’ve heard the Asante Snap had really nice features as well. It’s so unfortunate how these smaller, innovative companies go out of the pump business, meanwhile we’ve had the same Animas and Medtronic pump features for the past 15 years…

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Dang, I wish I could take a 45 minute shower. What kind of industrial strength water-heater do you have?!?

Yeah - I am always doing that manually. Nothing wrong with manual but some of the basic stuff is like … why doesn’t the pump just DO this?

THIS! i mean I love me some math and numbers but at some point it really does reduce your ability to make good decisions if you need to make thirty thousand calculations a day. Sometimes other life stuff just gets in the way and it’s like…hello, pump, you’re basically a computer. Can’t you just do this for me?


This is actually a feature in xDrip+. Also tells how much insulin to take to get back to target. Of course it can suffer from garbage in garbage out, but it’s right on if set correctly.


ha ha ha. Potentially my water heating system is like your insulin delivery system.

Solar fed into pellet fed into fuel oil fed into electric. Each one can be cut out of the system with a two valve turns if necessary. I don’t think we can run out of hot water.

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