Dawn effect or I'm a just a freak of nature? ;-)

[BigDogz]

I'm really confused by what is meant by "the dawn effect". Initially, I understood it to be that sugars were high upon rising but normalize (at least to some degree) the further into the day a person goes. Recently, though, I've seen some references to sugars that are lowest upon awakening and rise prior to breakfast as being the definition of the "dawn effect". What is the real definition of that phenomenon?

Two nights ago, I went to bed with a BG of 106. Immediately upon waking (I test before I even get out of bed), my BG was 136!!! It totally confused me that it went up during the night! I made certain that the bedtime BG was at least 2 hours since my bedtime snack.

As an experiment, I made sure to hit the sack the following night with a higher BG. Upon going to bed, the BG was 133. When I tested the next morning, my BG was at 106!! Why would it go from low to "high" one night and then "high" to low the next? Was this the "dawn effect" at work or is my body just a freak of nature?:D Logic seems to dictate that if the dawn effect is making my sugars go up at night that I should have had an AM BG of 150 or 160 that second morning. Perhaps my pre-diabetic pancreas is just having fun trying to psych me out. LOL.

Both tests were performed on the same meter and at the same interval (8 hour fast). The only difference, and it was out of my control because of work hours, was that the first test (106/136) was performed on a 9P-5A sleep schedule and the second test (133/106) was done on an 11P-7A sleep schedule.

As I said, I've not had a sugar as high as 136 upon waking before so I triple-checked the result, twice on the same meter and once on a back-up meter, and they all agreed. One interesting side note, by the time I got dressed, walked to the front of the house and took our 5 dogs out (one at a time) to potty on their leashes (about 20 min. total time), I was feeling REALLY bad - shaky, hot, weak - like my sugar was low. I checked it again and, in that short time, my BG had dropped to 91. Why would it plummet 45 "points" in such a short time, especially since I wasn't doing anything at all strenuous? Once I ate breakfast it recovered to the 120's range and I felt better.

In an effort to gather more data, I'm going to do another experiment tonight going to bed with a higher sugar on the 11P-7A sleep schedule and see if the "high" to low effect occurs again. Since this whole pre-D thing has come about, I absolutely LOVE collecting data, trying to figure out what my body is doing and trying to understand it. I enjoy learning about new things so I guess I consider that to be the silver lining of my diagnosis.

[genie86333]

Possibly, the fact that you went to bed with a higher level on the second night meant your bs did not drop as low as the previous night. The previous night, your blood sugar may have dropped a little too low during the night & then rose when your liver dumped glucose into your system, causing a higher # when you woke up in the morning.

Plus, don't forget that time isn't the only factor - what you ate the night before (did one night have more fat than the other? more carbs? etc), exercise you did on one day but not the other, illness, the "aliens" (aka unknown factors.)

[Subby]

I'm really confused by what is meant by "the dawn effect". Initially, I understood it to be that sugars were high upon rising but normalize (at least to some degree) the further into the day a person goes. Recently, though, I've seen some references to sugars that are lowest upon awakening and rise prior to breakfast as being the definition of the "dawn effect". What is the real definition of that phenomenon?


A rise of hormones in the early morning, usually between 4 - 8. This leads to more insulin required, and more resistances (so often, higher BGs through these issues). It's just part of the 24 hour biological rhythms we have as organisms - everyone is likely to have this release to some degree. It just becomes noticed when it has an impact on BGs.

Bearing in mind it is different between people, and that people rise at different times, it's quite plausible for some to wake high and some to notice it kick in when they are awake.

Your DP may essentially be at the same time each day, regardless of temporary sleep pattern. (Sleep patterns can over time of course change your biological rhythms, but they usually take some long term shifting to do so). It would partly explain why you've gotten these disparities. Look instead, for the time of day your background insulin requirements change.

As for normalising, that depends on the amount and effectiveness of insulin in the system, to counter the effect in the short (at the time) and longer (over proceeding hours) term. The normalisation part is not part of the definition: DP occurs in everyone, but different diabetics have different abilities (or lack of ability) to combat highs, in different ways. In the context of pre-diabetes, I would imagine normalisation may often occur without further help.


As I said, I've not had a sugar as high as 136 upon waking before so I triple-checked the result, twice on the same meter and once on a back-up meter, and they all agreed. One interesting side note, by the time I got dressed, walked to the front of the house and took our 5 dogs out (one at a time) to potty on their leashes (about 20 min. total time), I was feeling REALLY bad - shaky, hot, weak - like my sugar was low. I checked it again and, in that short time, my BG had dropped to 91. Why would it plummet 45 "points" in such a short time, especially since I wasn't doing anything at all strenuous? Once I ate breakfast it recovered to the 120's range and I felt better.

First, it's important to realise that non-diabetics BG goes all over the shop (within tolerance) all the time. So while you might be a more extreme case, it's not like a non-D will likely have a rock steady 100 all that time.
As to why the exacerbated plummet, firstly, although you've mentioned you double check some tests, most testers have an innacuracy of 20%, which has to be kept in mind at all times. It may or may not have been as much, just needs to be remembered. Secondly, it may well have been your pancreas overcompensating for your high, or your DP coming to an end (so resistance falls away), or a combination.


In an effort to gather more data, I'm going to do another experiment tonight going to bed with a higher sugar on the 11P-7A sleep schedule and see if the "high" to low effect occurs again. Since this whole pre-D thing has come about, I absolutely LOVE collecting data, trying to figure out what my body is doing and trying to understand it. I enjoy learning about new things so I guess I consider that to be the silver lining of my diagnosis.

That's great, enjoying collecting data about your BG is something that will stand you in wonderful stead if with whatever BG issues you have now and in the future.

[BigDogz]

OK, so now I'm going to throw another monkey wrench into the fire.

During the day, even if I'm sedentary, I'm usually able, with careful diet considerations, to maintain BG's in the upper 80's & 90's.

I've taken a daytime nap probably a half dozen times since my diagnosis. Each time my BG was in that 80's-90's range before lying down sometime between 3P & 4P. And each time, my BG upon waking an hour or so later has been mid-120's and up. Am I causing an "artificial" DP by napping in the afternoon?

[Subby]

I understand what you mean, it's probably more useful just to consider this another activity that causes a background fluctuation. Useful to observe such trends. There may be some striking kind of similarities in the mechanics going on, then again, there may not. While there is the common factor of sleep, DP is again not directly tied to actual sleep except in the overall biological habits and rhythms of your body. Nor does DP come on from going to sleep for a short time, like a nap. There's no real call to name it an artificial DP in my book, then again, you can call it what you like :)

[LizR]

Would this liver dump cause the heartbeat to rise? I've had instances where I am awakened at night by a fast heartbeat. I'm exhausted but the fast beat prevents me from sleeping. Sometimes I'm hot, cold, have a dry mouth - no doctor yet has been able to figure it out. Have had a cardio workup - EKG, Echocardiogram, Holter monitor, stress test - no idea. I'm presently on a beta blocker and go to sleep with a heartbeat of about 50 and then waken about 4 or 5am with a pronounced, faster beat in the 80's. I know that it isn't fast, but when I'm sleeping it is for me. I see an endo tomorrow and will ask, but what is the opinion of forum members? And if it is sugar related, is there a way to control that with food?