Hypo while sleeping

First off I would like to say what a great site. I have become more knowledgeable on diabetes and related stuff since I found this site and my doctor is impressed with how much I have learned from you all. Because I live in small town Alberta and my doc only sees me every three months to discuss my A1C results and I don’t get to see a doctor that specializes in diabetes untill Feb. of 2017 this place has become a gold mine of information for me. With that being said here is my question that I keep forgetting to ask my doc.
I have read about people having hypos while sleeping and how bad that can be, but when you are sleeping how would you know if your BG is to low. I take 32u of Levimir in the morning and at bed time around 11:00pm - 2:00am. Durring the day I take anywhere from 10u to 15u of Novorapid of Novo quick what ever it is called about 3 to 4 times aday. When I know that the Novo crud will be to quick to start I will take Humulin R. My BG’s are usually around 7.4 to sometimes 18.0 mmol but mostly from 7.4 to 12.0. I could only dream about getting them lower, and when they are lower around 4.3 or 3.5 it is because I skip a meal or two or I have taken a gliclazide pill which I was told to stop but I want my numbers lower.
I also take Metformin 1000 morning 500 noon 1000 dinner, victoza and a statin for cholesterol. Maybe my initial question got lost in all my yabbering, how does one know if they are having a hypo moment when they are asleep, and being asleep how does one correct it.

Lows while sleeping are difficult for many of us to detect. Some people naturally wake up, so they can test and treat as appropriate. One of the body’s defenses is the release of adrenaline in response to a low. A raised heart rate and sweating are typical symptoms when adrenaline’s in play.

Before I started on a continuous glucose monitor (CGM), I experienced many lows while sleeping. For me, one of the symptoms of low blood glucose is increased sleepiness – the exact opposite of what would be helpful. My CGM is my most reliable defense for overnight lows. I also have a hypo-alert dog who can wake me up when I’m low. But he’s not 100%, either. Between these two systems, however, I rarely miss an overnight low.

If I didn’t have a CGM or a dog, I would set an alarm to wake me up around 3:00 a.m. so I could test and treat as necessary. Your test kit and fast acting glucose should be on your night stand.

One of the biggest consequences of undetected lows while sleeping is that your body will experience a full counter-regulatory response. This leads to strong insulin resistance and 4-6 hours or more of high blood sugar (200+ mg/dL or 11+ mmol/L) after waking.

I can’t say enough about the benefit of a well calibrated CGM. It’s a bit pricey to maintain but I would pay out of pocket if I had to. I wouldn’t want to live without one.

Good luck.

I’d like to add, one of the best ways to minimize overnight lows is to decrease how much your blood sugar swings – in other words, decrease blood glucose variability. Alcohol can also cause your blood glucose to drop during sleeping.


Unless you wake up while you are having a low and test then to confirm, you won’t know. However, you could tell if you wake up sweaty and/or with a much higher than expected BG, that there is a suspicion that you had one and that your liver decided to rescue you by dumping extra glucose. That happens to some with a low, but not to all. I’ve never had it happen to me. But I’m a septuagenarian, and I understand that the elderly are less apt to respond to lows in that way.

I’ve been on insulin about 3.5 years. I don’t have either pump or CGM. Yet I’m reasonably sure that in that time I’ve only had two lows in the night, the lowest of which was a 52 and woke me up. Here is what I’ve done to prevent night time lows that you might be able to do, too.

(1) I’ve tested my basal rate to make sure that it keeps me quite level through the night. Like most people my age, I tend to wake up during the night most nights, so periodically I check my BG when I’m awake anyway to see that there are no surprises with my BG being lower than I’d expect.

(2) I always wait at least four hours and sometimes five hours after my dinner bolus to take my bedtime reading, then make any corrections necessary. If I take a bedtime snack, I always choose something for which I am sure how much insulin it requires. And I target a BG of 100, which gives me 30 BG points of leeway for error.

(3) On those rare days that I have done so much exercise that it might increase my insulin sensitivity into the night with a potential for a night time hypo, I target a BG of 120 instead, thus giving me 50 points of leeway.

By following this pattern, I’ve managed an A1c of between 5.5 and 5.9 for over 3 years and only two night time hypos. If one can keep a good night time BG, one is one-third of the way to a good A1c.

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Simple answer: Continuous Glucose Monitor (CGM). My son, 2, had many hypoglycemic events before getting on a CGM and that kept me up every night, mostly all night. With a CGM, it’s easy to see when there’s a down-trend heading for dangerous territory. When a threshold is passed, the CGM will sound an alarm which is very audible…I just can’t speak highly enough about CGM’s. If you’re not on one, I would recommend that to be your next mission.

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I echo the recommendations for a CGM if you are someone who is prone to lows at night. It’s really the only way to know for sure whether lows are occurring. I’ve had diabetes since I was a kid, and so my body has become so used to lows that when I’m sleeping I usually will not wake up until I’m around 2.2 mmol/L (40 mg/dl), and before I got a CGM sometimes I wouldn’t wake up even then. There are clues that you may have that cause suspicion of an overnight low, as others have mentioned, but unless you wake up and catch it, they can be very hard to confirm. Before I got a CGM I had a suspicion that I spent hours at dangerously low levels some nights, but it wasn’t until I was able to see my CGM graph that I could confirm that this was occurring.


Thanks for the info all. I have looked into a CGM but the cost for one of those in Canada is outrageous. I have med coverage through my wife’s work plan (sunlife) but they told me they do not cover CGM’S. If anyone knows a way I can get them to I’m all ears. I don’t worry about sleep lows right now because at bed time i well take 32u of levimir and my bg may be 6.8 to 7.9 when i wake up it is usually around 12 to 15 mmol/l. I was told by my doc to keep increasing by 2u every three days untill my fasting is at 7. Now say i have to take it to 40 or 50 u a night is that to much?

There is no such thing as “too much” insulin unless you are so insulin resistant that you have to take hundreds of units per shot. Otherwise, you need as much as you need, and everyone’s needs are different.

I’m also in Canada and I self-fund the CGM. It is very expensive, but it’s possible to decrease the cost to about 1/3rd by stretching supplies as long as they will possibly last. If you can, I would recommend appealing your insurance’s decision. I’m with Pacific Blue Cross and initially they said a flat-out no, we never cover these, period. Now they are saying it’s “under evaluation” so I am trying again, and I will try again next year as well if they continue to say no.

Before my daughter got her Dexcom CGM, I got up every 2 to 3 hours and tested her BG to make sure she wasn’t low. I can’t imagine running high in order to avoid overnight lows… Not worth the risk of complications down the road.

What I can’t imagine is that I (and most others) back in the R and NPH days (a far more dangerous insulin regimen than today’s MDIs and pumps) went through our childhoods rarely or never testing at night unless we woke up low (or our parents couldn’t wake us up in the morning…). Heck, that’s probably the reason I don’t wake up now until I’m dangerously low; I probably spent half my childhood sleeping through lows…

You need what you need. Your doctor’s advice was right on - keep increasing the dose gradually every several days until you stay approximately level through the night.

You are apparently quite new to insulin use. My recommendation is to get either the book Think Like a Pancreas by Gary Scheiner or Using Insulin by John Walsh. Both give a lot of hints of how to become something of your own expert on insulin use. I used the second of these to basically get all my own doses adjusted after my endo gave me initial starting doses, then was going to turn me back over to my PCP. I knew from past experience that she had very little knowledge about how to manage insulin, so in the interest of self-protection, I got everything all adjusted before I even went back to her. The books really do give one that much information, particularly if one is fairly good at analyzing things and reasonably good with numbers. It sounds as though you have a good doctor, but long range it is best if you can manage your diabetes largely yourself. The doctor won’t be there 24/7, so the more you are able to do on your own, the better.

I see that your doctor suggested you stop the sulfonylurea. I was on one, too, before I went on insulin. It was my experience that the action of insulin was far more predictable than that of the sulfonylurea, so I quit mine immediately, as my endo, too, recommended. I can understand that you might want to keep it up for a while as you are adjusting up your insulin dosage, but I really think you’ll have fewer chances of unpredictable lows after you get off the sulfonylurea.

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I am on Sunlife and on my plan Sunlife covers both CGM sensors and transmitters (where medically nessecary).

I have no idea what medically nessecary means. I am Type 1 on MDI and apparently that qualifies.

I have T2 and tightly control my diabetes with insulin and have done as your doctor suggested adjusting my basal insulin up. The goal of basal insulin is to enable you to go to bed with a normal blood sugar and awake to a normal blood sugar. But for many of us, the overnight road can be a little rocky. For a long time my endo kept telling me that I must be having overnight lows and wanted to wake up all the time and test. I already have sleep apnea so the last thing I need is an alarm going off every two hours. My efforts to “catch” a hypo were never successful.

In June I got a CGM. First, I would say that it did catch some lows overnight. But for me these have been mild lows. The real concern is a sharp drop, especially to a low value that impairs my ability to think, harms me or requires assistance. I’ve never had one of those. The lows have all been what I term “basal lows” that are a slow drift over time to the 60s. With the CGM I am alerted to them and treat them, but actually I could probably survive just fine ignoring them.

That being said, I have always taken special care to try to avoid circumstances that lead to variability overnight as @Uff_Da suggests. Don’t eat and dose rapid insulin before bed, hopefully going to sleep 3-5 hours after any meal. Be careful correcting a high blood sugar before bed. Be aware of major changes in activity levels and drop some of your basal dose if to account for very active days. Etc.

Although you may have trouble getting coverage for a CGM you might find that your endo will be able to support using a “clinical CGM” that is loaned to you so that you can adjust your insulin upwards to a proper level and monitor for hypos.

ps. And remember you need the amount of insulin that you need. If you consistent awake with high blood sugars that will throw you off for the day. Starting the day with a blood sugar of like 5-7 mmol/L would be ideal.


One thing you may want to be cautious about - the possibility that you have dawn phenomenon (DP). You may want to do a search on that to become more familiar with it. It is the liver giving the body extra glucose in the wee hours of the morning, basically to wake us up and help us to get going. A non-diabetic’s system can handle it, but many diabetics find that their BG climbs at that time. Mine starts between the hours of 3 and 4 AM. I think that’s a pretty common time.

So while we say the ideal basal insulin level is to be able to get up at about the same level as you went to bed, for a person who has a very strong DP, that could mean a hypo shortly before the DP starts. To avoid that problem, I set my basal dose as one that keeps my BG level only until about 3 or 4:00. If I happen to wake up then, I bolus for breakfast, eat, and go back to bed. But I’m retired and can do that. If I then sleep until 9 or 10, it is no problem for me. Most working folks can’t do that. On days that I happen to sleep in much later, my BG will be much higher on awakening, up to 40 points higher if I sleep very late. So to avoid hypos in the night, it might be a good idea check to see that your BG isn’t a lot lower at around 3 or 4 than it is when you usually arise. If you can’t borrow a CGM, set the alarm for that hour a few times.

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