Do you eat a snack to cover your BOB before bed?

That’s great advice, not to eat after 7:30, but easier said than done. I’m trying to figure out… when there’s insulin on board when I go to bed, and I enter a carb number into the bolus wizard to try and figure out what I need to eat in order to cover the leftover, the wizard number does not compute with my own calculation. If there’s .6 leftover, and my carb ratio is 1 unit to 15 carbs, shouldn’t I need to eat 7.5 carbs? But the wizard will tell me like one carb. Does that mean that the remaining insulin has already been spoken for even though I am at my goal already, that it needs to use that .6 to keep me at my goal? What am I not getting?

Can someone introduce me to BOB? I am not familiar with this term.

Hi Holger. It may be that I have the terminology skewed. I am referring to bolus on board, don’t know where I picked that one up and since you don’t know it, maybe I made it up myself! Anyway, leftover bolus insulin that is in play near the end of the five hour active period set in my pump (using humalog) is what I’m trying to understand. Woke up sweaty and heart racing at 4am with bg up at 127 and bg has been going up slowly since then. Usually doesn’t rise in the morning unless I wake up sweaty so think it’s from a low. Had .6 leftover before I went to sleep at midnight and ate 7 carbs with some cheese. Maybe I am just having a delayed spike from my midnight snack as it was high in fat and protein with the cheese. Anyway, went to bed at about 100, my target, with .6 left over, and now am at 167. And hungry. And tired. I think I’m going to stick to your suggestion of not bolusing after 7:00 or so and not having to deal with the insulin issue. Do most people set their duration at five hours? I’m new to diabetes and my medtronic trainer set the duration. Seems like you hit on an obvious answer to having good numbers, though, as one cannot control blood sugars while sleeping… so…

Now I got it.

The pump profile should always be neutral. This means when the active insulin is gone the pump profile should keep you steady. So there is no need for snacking. Too many variables involved I would say.

If you tend to go down at night: modify your pump profile until this is fixed. Do not try to fix the problem with snacking. For example you could set a Temporary Basal Rate of 90% for 4 hours to find the correct level. As far as I know this should happen 3 hours before the problematic phase begins (22:00 or 23:00). I would not set it longer than 4 hours because most people need insulin at dawn.

It seems that you have snacked because of BOB. But the BOB calculation depends on the duration that has been set. Actually I think that the way of calculating the BOB implemented in todays pumps is not correct. The duration depends on the type of insulin and the dosage used. The more insulin the longer the duration. Because of that and other factors the BOB calculation is just a helper for you. Furthermore if the carb factor is correct the active insulin will fit to the carbs you have eaten. Of course you should eat if the value before sleep is below your target. But just the amount to bring you to the target.

Most CDEs I know set active insulin at 3-4 hours. Humalog’s tail may go as far as 5 hours, but it’s rare and wouldn’t be too noticeable as far as affecting your blood sugar (unless you’re sensitive).

I do not eat food to cover insulin on board. Insulin on board is there to take care of the food I already ate. If I went to bed and I was 90 and I thought I might drop because I took too much insulin, yes, I would eat something. But if I was 120 or 160 or 200, the insulin on board is there to keep your blood sugar steady from your previous meal. You shouldn’t have to do anything with active insulin (which is the same thing as BOB, just a more common term). If you are having issues with going low later on after a meal or while sleeping, you will probably want to take a look at your bolus ratio or your basal rate, depending on how far after a meal you are dropping (or going high, as the case may be).

I only eat if my BG is at target and I still show insulin on board. So it sounds like I should set my duration of insulin back to four hours from five hours and see if that more closely matches my getting to my target BG. If I’m understanding, since I use relatively little insulin, two to four units per bolus, I’m absorbing it fairly quickly. So, I should be getting an in range reading about four hours after my bolus, given that all the settings are right. Seems like I still need to work on the settings. Just checked my BG and I’m up to 280. A big surprise. Says I have 2.5 units left after two hours and forty five minutes, and I gave a total of 3.3 for 40 carbs plus correction. Is this high a result of a nightime low? I eat the same breakfast every morning, same bolus, aaagh!

The only way to know if it’s a nighttime low is to either wake up and check throughout the night to see if you drop, or to wear a CGM. I wouldn’t change anything unless it’s consistent over 2-3 days. Your pump may be telling you that you have more insulin in your system than is actually present. The only way to know for sure is to wait and see if you continue to drop.

Your 280 is most likely a result of something else, not a nighttime low as you would have seen that at your fasting BG level, not your lunch level.