Dawn Phenomenon and the CGM

I recently was able to borrow a FreeStyle Libre from my endo for 13 days, and thus was able to see some things about my DP. Apparently my DP is less consistent than I thought it was in both the time it starts and how many points my BG climbs. And that makes me curious . . .

So for those of you who have CGMs and have had a much better opportunity to observe this, I’m wondering if you have been able to reach any conclusions about what things might influence your own DP. Please share.

During my trial with the Libre, a lot of days I either had a late snack that might have influenced results or had an early breakfast - like 3:30 or 4 AM. So I had too few consistent days to reach any conclusions.

I’ve seen a consistent rise in my BG from 4:30am on; however, the rise is slow at first and speeds up after I wake. “First foot on the floor” phenomenon :slight_smile: The problem that makes it hard to track in my case is that my house is generally on the dry side and I dehydrate to some degree overnight most of the time. If I wake at 3am, or so, and take a big drink of water, I get more reliable numbers at “dawn,” but many nights - and lately, most nights, I sleep through that point or, even when I do wake, I forget to take that water, in which case, my CGM slowly goes out of sync with my BG at around the same time that my BG is rising. When I wake somewhat dehydrated, I see as much as a 40pt difference between my BG on the meter and the CGM.

Sorry I can’t give a better answer. What I can say, though is that my ‘DP’ is still somewhat inconsistent, though more in magnitude than in timing. I rarely have nighttime snacks anymore. What I have seen that affects it is NOT eating enough carbs at dinner (I need at least 15-25g carbs at dinner to get better morning numbers), and an evening ‘low-carb’ alcoholic drink - which usually results in less DP.

I find it has nothing to do with what I’ve eaten the night before. I have the feet on the floor syndrome as well. My blood sugar could be perfect when I wake and could stay that way if I stay in bed for an hour, but the minute I get out of bed it starts shooting up like mad and is difficult to stop unless I bolus immediately or set a temp basal increase. It is much worse for me if I am in court, even if it is for something not very serious. It is much less pronounced if I am just going to the office or on weekends. The only way I’ve been able to deal with it is to dose/adjust based on what my CGM says. I know every morning will be different and expect every morning to be now. There is little I can do before the fact that makes a difference.

My situation might be a little different than most because I have postprandial hypotension. My blood pressure drops between 20 and 50 points after a full meal. So ideally for my BP I eat many times a day, just a smaller amount each time. That avoids the extremes of BP. But that does make things a bit complicated for a diabetic on insulin.

One of the things I frequently eat at bedtime is a dessert that contains 10 g carb, 18 g protein and 15 g fat. From what I’ve read a food with that much fat and protein could take five hours or more to show its effects in the BG. So whenever I eat that late, its theoretically possible to affect the early hours of DP with BG increases being due to late digesting protein. And if I have to bolus specifically for the snack, since some of my boluses seem to keep lowering BG for over five hours, that, too, could go into the DP hours. That’s why I tried to discount the results of mornings following such a substantial bedtime snack.

I’ve read that food digestion slows even further than normal when one is sleeping. Has anyone seen any CGM evidence of this?

I have a Dexcom. When I was on Levemir, I would consistently see a rise starting at 2-3am, which then accelerated when I got out of bed, not stopping until about 11am. I would wake up high, take a big dose to handle my current BG and to cover the “feet on the floor” effect. It didn’t matter what I ate (LCHF vs. 100g/day vs. night time snacks, etc). Sure some days it went higher than others but the pattern was always there.

After switching to a pump, I’ve gotten it mostly under control and never need to correct upon waking, or in anticipation of “feet on the floor”. Being able to use a higher basal during the early morning made all the difference.

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After forty years of DP what @Scott_Eric just said is me to the letter on an insulin pump. It’s when I get up and start moving my liver ‘helps’ me by kicking sugar into my blood. It doesn’t matter what time I get up it will ‘help’ me out with energy to start the day. When pumping it has started to throw my a1c out so to settle this effect down I have been experimenting with a very very small amount of long acting insulin at 11:30 at night ( while still using my insulin pump) and so far it is working. Most of my basal is via the pump but the tiny amount of lantus seems to create stability if you will with my pump. My corrections also work much better than they were. Like Scott said it is impossible to plan for it because it happens at really odd times and I was setting all sorts of temp basal rates and bolusing that it felt really unstable even though the basal rates were good if say I just stayed in bed all day. With the lantus ( or levemir) I have to make it as small as possible so I don’t get surprise hypos, as I said the one very small dose at night make my insulin pump less erratic, I can’t pull the pump off like the untethered method suggests as most of the basal is still coming from the pump, I have about 10% basal from long acting and 90% basal from the pump.So far it has removed the very temperamental effects that Scott mentioned. When on MDI I used split dosing of lantus to rid myself of DP but as I got older the long acting (lantus) started working at strange times and the result was bad hypos so I got back onto the pump but due to DP (foot on floor phenomenon) it has been very erratic until now. If your reading this and thinking of doing same keep in mind that the swings I was getting sometimes would be from 4.5 (81)up to 10 (180)or 9 (162) so they were not drastic I just didn’t like having to set so many temp basals and bolusing at differing times, I wanted the pump to be alot more stable.

Hmmm that’s interesting, I never thought of it as a pump vs. injected basal insulin effect, but I was only on Levemir/MDI for 3-4 months after diagnosis (and barely needed any basal since I was honeymooning) so everything I know is from using a pump. It sounds like an interesting idea what you are doing, but I’ve gotten pretty good at taming the phenomenon using my CGM and as long as I remember to up my basal 40-50% right before I get out of bed (and bolus for breakfast if I’m going to eat soon). If it ever gets out of hand I’ll try what you’re saying for sure. The biggest problem with the pump is site problems, so while it usually works well, I may have an unstable or bad night sometimes if I have a bad site and didn’t realize earlier. I’m wondering if what you’re doing helps with that.

@Scott_Eric It is early days for this experiment Scott but the Dr who coined the term untethered uses the idea so it does protect him from bad sites and even disconnecting for long periods like several hours and makes a big point of saying that it stops DKA from any pump failure, but he uses a very high basal rate of 75% from lantus. I think as I am doing it, it definitely seems already to give a little longer than normal for reaction time to things like bad sites but only time will tell how well. Again though I am trying to do it with as small as possible amount of lantus to give my pump just a little more stability from the problems we have discussed, I could always raise the lantus but then I don’t like the idea of having a high dose of lantus or levemir and being hooked up to continuous quick acting insulin infusion (sounds like playing with fire ) . I will post back here though as I don’t think it will take long to find out how this is going to pan out. The original article is here

I have to admit that I’m fascinated by those macros! I’m imagining eating candied chicken thighs with the skin on, or something equally horrible. Just out of curiosity, but what dessert has that much protein and fat while having a modest amount of carbs? :smile:

Ah, just combine peanuts, peanut butter, gelatin, milk and cottage cheese for a high protein dish, add some chocolate or cocoa and artificial sweetener, and you’ve got a winner. This is my diabetic substitute for my mothers chocolate cake with peanut butter frosting or my favorite pre-diabetic candy, Reese’s peanut butter cups. Initially, I developed the recipe with cream cheese, but after getting my last cholesterol numbers, I changed that to cottage cheese.


I have the same problem but my DSN have never heard of this before. I have been saying i have this many times but yet been able to convince them that it exists let alone i have it. I find whenever i relax for too long or drop off watching tv on the sofa and wake up i have to bolus to counteract the rise i am about to get the same as every morning. If wake during the night i have to get up and bolus to counteract the high i am about to have.

Does anyone have any new updates regarding this please?

I have specifically seen this (on CGM). Unexpected wake in the night quickly followed by significant unexpected BG rise.

My assumption was the BG rise was due to the wake but being only once (nighttime waking is quite unusual) didn’t think much on it. Interesting however…

We have the pump programmed (basal) for the typical wakeup time to counter the DP.

That seems quite strange. Never even heard of it???

Yeah snap if i wake up anytime during the night i have to get up and bolus. My DSN has never heard of it. I have just seen my DSN and i think she is looking in to it. I only notice since starting the Libre so god knows how long this has actually been going on for. Its like DP but no set time. Be good to know how you set up your pump as I’ve just started my omnipod pump??

Hi, Uff_Da, from Minnesota. I have my pump set to combat DP. However, it is more pronounced when I wake up early. This week I woke up at 4:30 AM and couldn’t go back to sleep, due to the fact that I went to bed early and when I bent over to pet my fluffy, little kitty, it had a mouse in its mouth and I started screaming bloody murder. My CGM showed a very pronounced DP at 4:30. It was also more pronounced when my schedule dictated that I get up at 5 AM. I think that I release more stress hormones, upon waking, when I get up early. But, it is consistently connected to the time I start to wake up - whatever time that is.

It’s called “feet on the floor” phenomenon, I have it too. If you wake up at the same time everyday you can program your pump basal rate to increase an hour or 2 before it to stop the spike. If not (I don’t), you can bolus or set a temporary basal increase the moment you wake up for about an hour to deal with it.

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I suffer from sleep problems and it can make my overnight readings crazy. If things go wonderfully and I sleep well my CGM shows I am totally flat overnight. But disturbed sleep and I can end up at 250 mg/dl in the middle of the night or have much higher rising readings from my Darn Phenomenon. At least with the CGM you can be alerted and treating early can avoid the most egregious swings.

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@Wassy, I muddle my way through it. It depends on my schedule. If I get up during the week at 5am, and 10am on the weekends, then its challenging. I might set a temporary basal increase, upon waking, everyday during the week. So, maybe I increase my basal by 50% when I wake up everyday, for 3 hours and then re-evaluate at the 3 hour point after waking up whether I need to continue a basal increase. I’m on an Omnipod pump.

We are similar and use a 40% basal increase for 4 hrs to counter the DP.