Dawn Phenomenon: How to Identify and Manage It

woman with dawn phenomenon

What Is the Dawn Phenomenon?

The dawn phenomenon is a well-characterized problem that is common in people with and without diabetes. People without diabetes commonly need more insulin in the early hours of the morning to keep their blood glucose levels from rising. This need for more insulin is thought to be due to the natural circadian (biologic cycle of the body) elevations in anti-insulin hormones such as the growth hormone. If you do not have diabetes, the pancreas merely secretes a little more insulin during this time period, which is normally between the hours of 3 a.m. and 7 a.m. However, if your pancreas does not secrete enough insulin because you have diabetes, your glucose level will go up during this time unless you compensate for it. If no extra insulin is provided, the glucose will rise and be high when you wake up. As a person approaches middle age, the dawn phenomenon often declines or disappears entirely. The dawn phenomenon may vary from day to day, making controlling the glucose levels very difficult.

How Do You Manage It?

In order to combat the problem, many teens and adults with type 1 may require a higher basal rate in the predawn hours to counteract the natural increase in growth hormone production. If you have a continuous glucose monitor, you can determine exactly at what time in the early morning your blood sugar starts increasing. People using insulin pumps can take this information and adjust their basal rate appropriately to counteract the issue. Pumps provide temporary basal rates that can be increased or decreased in 1% to 10% increments for 1 to 72 hours as needed for illness, exercise, or other situations like the dawn phenomenon. Having an increased basal rate during the time of the dawn phenomenon is normally very effective at preventing the rise in glucose during those early morning hours. If you are on multiple daily injections and taking a long acting basal insulin, it is very difficult to target and control the dawn phenomenon.

How Do You Know If You Have It?

Testing for the dawn phenomenon is typically done overnight. Have an early dinner and make sure your post meal glucose value is between 120 and 180 at bedtime, with a horizontal trend arrow if you’re on a CGM. This makes it much easier to test your basal dose of insulin. If your glucose values go up overnight to more than 30 mg/dl from your bedtime value, the basal dose my need to be adjusted upward. If your glucose values stay flat until around 3am and then rise, the dawn phenomenon may be present.

It should be noted that not everyone experiences the dawn phenomenon, and on the flip side, in some cases the dawn phenomenon is so strong, no basal insulin at any dose can control it. This is when an insulin pump is truly needed.

The bottom line is that the dawn phenomenon is very common and can be easily treated with insulin pumps that can be programed to increase the basal rate during the early morning hours. If you are on multiple daily injections, the timing of the basal insulin may be important to counteract the issue.

 

Additional Resources:

Overbasalization in Type 1 and Type 2 Diabetes: You Can Have Too Much of a Good Thing!

How to Treat Foot to Floor Phenomenon

The Many Reasons for High and Low Blood Sugars (and why we need a LOT of compassion for ourselves!)

Lifesaving Tools to Prevent and Treat Hypoglycemia

37 Comments
  1. Hello Dr. Edelman, I am a Type 2 and there are times that I wake up in the morning and my reading are over 130. I take one tablet Metformin Hydrochloride 1,000 Mg Tab with my evening meal and I still have highs on some morning not all. Is there any remedies for my problems.

    • Hi Venus,
      130 is not too shabby, but if you go higher on a regular basis, believe it or not you can take the maximum daily amount of metformin all at night as it may reduce your morning highs. There are lots of other choices as well. PLEASE CHECK WITH YOUR DOCTOR FIRST BEFORE MAKING ANY CHANGES! Good luck, and we’d love for you to join our online conference on Nov 7th: https://tcoyd.org/tcoyd-nov-2020/

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        Hi, I have had gestational diabetes with both of my pregnancies diet controlled. I had normal numbers after my baby this time around but I checked my fasting number this morning and it was at 102 but an hour later it went down to 94. Is that normal? I read anything above 100 for fasting is abnormal. My post prandial after that have been normal. I’m currently 3 months postpartum.

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    Any thoughts on other ways to treat or combat morning highs for Type 2s than taking all the metformin at night? Most patients I educate don’t have a pump or CGM and may not even be prescribed insulin. I hear this a lot from my patients when I am assessing their daily challenges in managing their diabetes. I work in an acute care setting and also see out patients for education.

    • Hello Nicole,
      Believe it or not, some patients respond to a small alcoholic drink at or near bedtime that suppresses the liver from producing glucose, also a small snack as the glucose elevation leads to insulin release that suppresses the liver as well. This can work in patients who still have endogenous insulin production. When someone fasts like overnight, the liver starts to pump out glucose which leads to elevated fasting levels.

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        Hi. Im having a problem I eat at night by 10pm my glucose reading is 90 and when I wake my reading is 120. Readings all day the day before were bellow 150 150 being an hour after eating. I basically stay about 110 as an average all day dropping yo 90 twice between meals. Do I have diabetes?

        • From those numbers it does not look like it, but possible that you may have pre-diabetes. You should get an A1c test.

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    I Love what you are doing. We will donate to your organization because of the good work you are doing.

    My question is:
    I am on loop with the Omnipod. My problem is, that as soon as I bolus my blood sugar goes up without eating because I followed your advice about blousing 30 minutes in advance, so why is my blood sugar rising without eating???

    • That is unusual. See what’s going on 2-4 hours before you bolus. Were you snacking with no bolus, or exercising at a reduced basal rate and then stopped exercising soon before you were going to eat? The rise in the blood sugar could be from prior snacks with gastroparesis, and/or after exercise, when you get the rebound high. But please get back us. I’m curious what it’s from. It may have something to do with your settings on your loop as well.

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    Hello, I have been having a similar issue however I am not a diagnosed diabetic and I have no common risk factors (weight, BP, cholesterol) all normal. I’m 39 years old, I am a vegetarian and eat healthy. I do have a family Hx of both type 1 and 2 diabetes though.
    My morning fasting BS is consistently between 130-160 for about an hour give or take upon and after waking and then suddenly plummets to 80-90 sometimes within a time period of 10-15 mins with no interventions. Which I feel as a very lightheaded and dizzy shaky feeling so I know exactly when it happens.
    Neither of the 2 medications I take for anxiety cause raised blood sugar (I’ve checked) and 1 is PRN.
    I’ve been monitoring this for a period of months and have been refer to endo however my A1c and all type 1 markers are normal.
    I do however often have keytones present in my urine but I have no idea if that is related to this very frustrating issue.
    Do you possibly have any idea on what this could be?
    I’m pretty much healthy in every other way except for battling after effects of Covid back in September (they call it long Covid syndrome?) however the BS issue was present prior to the onset of Covid.
    Thanks for your help.

    • Anything above 126 on two occasions in the morning is abnormal. Above 140 is diabetes and between those two numbers is prediabetes. At minimum, you most likely have prediabetes. Not sure where the keytones are coming from unless you’re on a very low carb diet. The A1c is just an average, so for people with prediabetes, they sometimes wake up high but then are normal the rest of the day so their A1c isn’t necessarily reflective. It would be ideal for you to get a CGM (you can do a free trial with the FreeStyle Libre) to see what happens to your blood sugars before and after eating and throughout the day.

      https://www.freestyle.abbott/us-en/myfreestyle.html

    • Anything above 126 on two occasions in the morning is abnormal. Above 140 is diabetes and between those two numbers is prediabetes. At minimum, you most likely have prediabetes. Not sure where the keytones are coming from unless you’re on a very low carb diet. The A1c is just an average, so for people with prediabetes they sometimes wake up high but then are normal the rest of the day so their A1c isn’t necessarily reflective. It would be ideal for you to get a CGM (you can do a free trial with the FreeStyle Libre) to see what happens to your blood sugars before and after eating and throughout the day.

      https://www.freestyle.abbott/us-en/myfreestyle.html

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    Hello . A recent laboratory blood test revealed my glucose level 115 and AI3 at 6.3. I moved to monitor purchase a monitor to test blood at home . I noticed that if I continue to fast through 10am levels lower to 90’s and after lunch I have dinner and at 2 hours my glucose is between 90-120. Is this typical pre diabetes or dawn effect

    • Let me first say that everybody (with or without diabetes) has the dawn phenomenon, but blood sugars go up in the morning if your body cannot accommodate for all the reasons that cause them, so it’s possible you have a mild case of dawn phenomenon.

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    Dear Dr. Edelman – Just watched a TCOYD video by my former endocrinologist, the one and only Dr. Irl Hirsch! I’ve been struggling with getting an answer for how to handle my 13yo son’s significant dawn phenomenon for when we might need to go off pump (emergencies mostly, since he doesn’t want to go off pump and loves his 6.9 a1c):
    – His overnight rate is 0.38/hr
    – At 6am, the rate increases to 1.0u/hr, reducing to 0.5u/hr at 10pm

    I have been told repeatedly to “just give Degludec for basal.” As you know, that doesn’t match the curve of insulin needs at all, and takes over 24 hours to reach a steady active state.
    One of your videos with Dr. P mentioned taking 3 doses of NPH to substitute for basal, and I wanted to thank you for being the first voice to mention this approach, which has the potential for flexibility needed to match that curve. Now, to get some insight into potential dosages from his team… (I am not hopeful this can happen, alas)

    • Avatar

      Thank you for your kind words – glad it helped. If you still have questions after you confer with your medical team, let us know.

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    Hi Dr. for me also fasting sugar is around 115 & post around 125, but h1abc 6.7, shall I take the medicine for diabetics? Please suggest

    • At this point your A1c is at goal for a person with diabetes, and it sounds like your numbers are excellent. If you’re maintaining those numbers not on medication, then you don’t need medication, but if you were my patient I would have many more questions about your overall health before I would make that decision.

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    Hello~ found this thread while researching the Dawn Effect. I have a long history of gestation, T2, non, and PRE; also family history. I was 6.3 in January, down to 5.8 in May. I’m currently wearing a CGM ( Freestyle) through the NutriSense program. I control my numbers, generally, quite well with food and exercise, I take zero medications, I’m 56, fit, healthy, active, avid walker, etc… However…. This darn DE!!! As, let’s just say, a non or preduabetic, on no meds, what can I do to slow or stop this early morning spike?
    Is there something I should be doing at night? I do not drink alcohol. I’m experiment with different types of snacks upon waking at 5:30; all to no avail.
    Thoughts or book recommendations??
    Thanks~

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    Good morning Dr.Edelman.

    I really find your page very interesting. Early this month I went on my own for a routine test and found out that my Sugar was high. 14.0.

    I immediately cut down on some habits. ( stopped alcohol-beer, soft drinks, high carb food, late night food.

    Before now I will eat heavy food around 10pm and 11pm everyday.

    The first 2 days without medications, the Sugar dropped from 14.0 to 11.0. But the doctor insisted I have to commence medication to lower it the more. I did and the Sugar level dropped. Now I am managing with diet control.

    I have made it a point to eat dinner between 6pm and 7pm but I noticed that in some mornings, my Sugar will be elevated. That is between 125 and 132. This is with or without the medication. And especially when I take nuts like almond and cashew nuts around 10pm.

    Some other when I don’t take anything after 7pm, my morning readings will be between 115 and 120.

    What will be your opinion

    • Sounds like you’re doing everything right. You’re changing your life around, and doing a great job with your diagnosis.

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    I have just discovered you and am loving your You Tube videos. My 11 year old T1 son goes to bed in range, usually rises around midnight, and then consistently has fairly sharp drop at 3am and is then in range or borderline low until morning. As I read that the dawn phenomenon usually starts at 3am, I think this is something different. Spike in growth hormone increasing insulin resistance maybe? Grateful for any thoughts you have on it or advice to overcome it. Thank you very much in advance.

    • There are a lot of variables. One is what type of long-acting insulin he’s on and what time of day he takes it. Also, the dawn phenomenon can occur at other times, and unfortunately it’s not that consistent. Some days your son may experience it and other days he may not. The time he’s eating and what he’s eating may also have an effect. There are a lot of conditions, but there are lots of ways you can make adjustments to the insulin. He would be a great candidate for the hybrid closed loop system – the modulating basal rate would take care of it every night.

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    My fasting blood sugars are in around 115 in the mornings. I’m not diabetic so no meds, HGBA1C is normal at 5.6, abnormal glucose tolerance 2 hour test at 154. Dont know what fasting was because they didnt take it but was about 13 hours no food or sugar. Drank a bottle of water before test so not sure if that helped or made worse.

    Weight is not an issue. I need to achieve a 110 or below for fasting. Feel like blood sugar doesn’t go down until I eat in the morning so guessing it is that pre dawn thing so the longer I fast, the longer I stay in the 115 range. How can I achieve the 110 FSBS in morning?

    Wonder if I stay up all night and eat at midnight LOL. Timing of or snacks at bedtime or later help and if so, what?

    HELP. I have to pass fasting at 110 or lower or GTT 2 hour at 140 or lower.

    • You definitely do not have diabetes. Some individuals just have higher fastings than others. If you have to pass a test, just eat something small before you go in for the test, because when you eat anything it causes insulin release which will bring your blood sugar down.

  12. What is small that will stimulate insulin and not raise blood sugar level. I had a FSBS of 93 at 600 am and at 650 am, the venus draw was 112.

    • I would say half of a small sandwich, or crackers with or without cheese, just a little snack with some carbs.

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    When I was pregnant in 2018 I was diagnosed with Gestation Diabetes. I have had regular A1C tests that are all within the normal range since. However, when I test myself my fasting blood sugar is pretty consistently between 100-115. My numbers 1-2 hours after eating are usually below 140, but I did have recorded a 167 spike after an especially sugary treat. I have tried lowering my fasting numbers to under 100 with all the tricks I can find, but it doesn’t seem to help. It will randomly be under 100 here and there, but my actions don’t seem to correlate at all. Am I prediabetic or is this normal?

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    Good morning,

    In Feb, 2022 my A1c was 6 then I made some changes to my diet and lifestyle and in May, 2022 went down to 5.6.

    I wake up at 5 in the morning, do my morning routine in the bathroom, drink a glass of room temperature water then practice yoga and breathing exercise. Around 7a.m I have breakfast which is boiled eggs, avocado with olive oil/Himalayan pink salt and pepper sprinkled and may be a toast at times before heading to work. That is my morning routine on weekdays.

    I always wake up hungry and it has been that way for as far as I remember and no matter what I may have eaten for dinner, so it is not a new thing, is this normal?
    I have been checking my blood sugar in last few days and my fasting or morning blood sugar before breakfast has been between 107-114, then it is 120s after 2 ours. Then before lunch around 1 it is between 96-110 and post meal 2 hours later it is below 140. Is this normal?

    I am 46 female, and I eat as healthy as one could (no fast food, no processed foods, no soft drinks or sweets, no canned food) all home cooked from scratch food with lots of spices and herbs because I am from Nepal. I am very active, I jog/walk, practice Yoga, a school nurse and have no significant medical history, may be undiagnosed PCOS?

    What are your thoughts? Thank you!

    • Hi Nisha,
      To answer your first question, yes it’s absolutely normal to wake up hungry. To address your second question, it sounds like you’re doing really well. Regarding your last question, based on what you’ve told me, I can’t tell if you have PCOS or not. I would look it up in Google and see if your signs and symptoms match.

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    Hello my son is 4 years old I smelled acetone on his breath a couple times when he was sick so decided to check his blood sugar which was 208 I took him to the dr they checked his a1c it was normal
    I have checked his sugars in the mornings and it was as follows
    Monday 208 and then a few hours later at the doctors office it was 104
    Tuesday 191
    Thursday 178
    Friday 168 and then an hour later 107
    I’m so confused as his sugar seems to be up right when he wakes up but goes down an hour after he wakes up what could this mean what should I do

    • You need to see a good pediatric endocrinologist. For sure he needs to be checked for the antibodies that lead to type 1 diabetes. He could be in stage 2 which is positive antibodies with dysglycemia (abnormal glucose values but not in the “diabetic range”) with normal A1c values. Putting on a CGM would be very instructive as well. Let me know what comes out of your visits.

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    Hi. My early morning glucose levels are about 6.5 mmol/l. I tested at 3, 5 and 7 am. I’m not diabetic, could you tell me why they are not coming down over that time please? Thanks

    • I would make sure that your A1c is normal, and that your two-hour post-meal blood sugars are below 140, and if they are, then you are totally fine, within the level of “normal” glucose tolerance. Some people just run a little higher in the morning than others.

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