July 26, 2007

Type 2s: Understanding False Hypos

Here's a piece of very important information that doctors rarely give people with Type 2 diabetes which can make a huge difference in the success you have controlling your blood sugar.

If you are not injecting insulin or taking a sulfonylurea drug you do NOT have to worry about hypos!

The word "hypo" is short for "hypoglycemia", which in tern is mangled medical-Greek for "low sugar". A true hypo is an emergency when it strikes someone who is injecting insulin or using a sulfonylurea drug because too much insulin, whether injected or provoked by a drug that overstimulates your beta cell, can make your blood sugar drop so low that your brain cannot function.

But if you are not using insulin or insulin stimulating drugs, you are not at risk for dangerous hypos. Neither Metformin, Byetta, Januvia, Precose, Avandia nor Actos provoke hypos nor can you experience a true hypo if you cut way back on your carbs. What you are likely to encounter if you use these drugs or carb restriction to bring your blood sugar down to normal levels, is a "false hypo."

The false hypo is the feeling of being hypo, which, while it is uncomfortable, is not a crisis, and is, in fact, a well-understood phenomenon that can happen if your fasting blood sugar has been more than 20 mg/dl over true normal levels for any period of time.

To understand the difference between a real hypo and a false hypo, you need to understand that a truly normal fasting blood sugar may range from 70 mg/dl (3.9 mmol/L) up to the low 90s (5 mmol/L). In fact, doctors recommend that pregnant women keep their blood sugars between 60 mg/dl (3.3 mmol/) and 90 (5 mmol/L) mg/dl and consider any blood sugar over 95 mg/dl (5.3 mmol/L) dangerous to the baby.

Clearly, then, a blood sugar in the 60-70 range is not a life-threatening emergency!

Hypos do become dangerous when blood sugar starts to drop into the 40s or lower and if your blood sugar drops into the 20s for any extended period of time you can become unconscious. This kind of hypo can be a huge problem for people who inject too much insulin or take too much of an insulin-stimulating drug, but the only time it will happen to anyone else is if they have a very rare kind of tumor that causes uncontrolled insulin secretion.

The reason people not on insulin don't have to fear real hypos is that your body has an exquisitely sensitive feedback system whose job is to push blood sugar back up as soon as it senses that the blood sugar has dropped to more than 20 or 30 mg/dl (1.7-2.2 mmol/L) below your usual fasting blood sugar level. When this happens, this system kicks in with dramatic effect.

It does this by secreting "counter-regulatory hormones" which are your old friends the stress hormones. One good burst of counter-regulatory hormone and your blood sugar will surge back into the safe zone. Unfortunately, the burst of counter-regulatory hormone may also get your pulse pounding, your sweat pouring, and your body feeling as if you'd just narrowly escaped becoming a predator's lunch.

What makes the counter-regulatory response so hard to deal with for Type 2s--and what adds to the confusion about the danger of hypos--is that the body does not have a set, absolute threshold for responding to perceived hypos. It does not say to itself, "Uh-oh, blood sugar approaching 55, time to do Hypo Repair!".

Instead, it uses a relative threshold based on the fasting blood sugar level it is used to. If you've been running a fasting blood sugar of 180 mg/dl (10 mmol/L) for a while, and cut back on your carbs for a few days, when your blood sugar drifts down to 120 mg/dl (6.7 mmol/L), your body may scream, "Blood sugar 60 mg/dl below normal! Hypo! Hypo!" even though your blood sugar is now, for the first time in months, barely approaching a normal level.

When your heart is pounding and you are feeling shaky and faint, it is very tough to do nothing, especially since your body is helpfully suggesting that all would be well if you'd just scarf down some nice, high carb food to "fix" the problem.

It is not unusual to experience the symptoms of a false hypo, rush to your blood sugar meter, test, and discover that your blood sugar is actually higher than your usual fasting level.

The reason this happens is that by the time you feel the impact of those stress hormones, they have already signaled your liver that it needs to dump a load of glucose into your blood stream to raise your blood sugar to correct the false hypo. And when this happens, you may find you are even more insulin resistant than usual for the next couple hours--to say nothing of feeling very jangled!

This response can be a major barrier on the road to achieving normal blood sugars. If you aren't prepared for it, you may end up sabotaging yourself by reacting to the symptoms of a false hypo by gobbling carbs in the belief that you are fighting a life threatening hypo.

The only way to cure his problem is to know that the body resets its glucose "thermostat" over time and that if you don't treat a false hypo as if it were an emergency your body will eventually get used to a new, lower, fasting blood sugar and only give hypo signals when you are truly hypo--which if you are a Type 2 not using insulin or insulin-provoking medications will be never.

It may take a few weeks for this to happen, and it may happen even if your fasting blood sugar was not all that high. I was experiencing overwhelming "hypo" symptoms when I dropped my fasting blood sugar dropped from about the 110 mg/dl it had been permanently set to for many years to 85 mg/dl. The symptoms were so disturbing, I went to see a doctor who instead of explaining that my "hypos" were normal, took me off the drug that was "causing" the hypos!

I have heard from many people who have had similar experiences, including a few who visited nutritionists who warned them that blood sugars under 100 mg/dl (5.6 mg/dl) were "dangerous" and urged them to drink orange juice to bring up that "dangerous" blood sugar level, stat!

If you've been the victim of such advice, it helps to understand that the nutritionist or nurse who gave this poor advice it to you does not understand that the guidelines they were taught apply ONLY to people injecting insulin or overstimulating their beta cells.

A blood sugar of 100 mg/dl is only an "emergency" if you have injected or stimulated far too much insulin and that 100 mg/dl might be an early stop on the way to a blood sugar of 25!

But if you are controlling with diet or safe drugs, when you feel "hypo", grab your blood sugar meter and test your blood sugar. Unless you see a blood sugar level under 70 mg/dl, you need do nothing. If you feel like you need to do something to deal with the unpleasant symptoms you may experience when your blood sugar drops below 80 mg/dl, please visit Treating Mild Hypos without Creating Rebound High Blood Sugar.

Eventually, when your fasting blood sugar arrives at a normal level, you'll find you feel far better than you did in the past when it was high, and the only "problem" you may then encounter is that the very high blood sugar levels you got used to in the past may now start to feel horribly toxic, which is good, because that unpleasant feeling will help motivate you to keep yourself from experiencing those damaging highs.


Anonymous said...

I think this needs updating. There is no mention of Byetta or similar injectable drugs which can and do induce Hypo's.

cugila. Moderator.

Isaac W. said...

ACtually, it said this at the very top: "You are not injecting insulin or taking a sulfonylurea drug." Byetta is a sulfonylurea drug.

Jenny said...


You are dead wrong. Byetta is a GLP-1 analog. GLP-1 stimulates insulin secretion in a way very differnt from sulfonylureas and when blood sugar drops, GLP-1 stops stimulating insulin release. With sulfs, insulin secretion isn't coupled to blood sugar levels and will continue even if blood sugar is low.

Lucy said...

I just want to say thank you. I've browsed around your site a few times, learned a few things and just moved on.

So glad I came back. I'm sitting here in tears. You wrote EXACTLY how I have felt concerning these "False Hypos" (I didn't even know there was a word for them). You described to a "T" what happens and how one who doesn't understand what is happening responds. I have, in vain, tried to explain to my spouse (he's a wonderful support but is not diabetic so can only understand so much) and w/my doctor (she listens and all she's ever told me was I was normal, it was ok). But she never explained how I could be ok when it didn't feel o.k.

Again, when I read your words, I felt like they were my words...words I've not been able to say because I didn't know how.

Thank you. Thank you for helping me understand. This is going to help me in a big way!

Now I'm off to read "Treating Mild Hypos without Creating Rebound High Blood Sugar".

A little info: I'll be resuming my metformin. I cannot for the life of me get my fasting under control so I thought the "extra help" would help. I took met before but stopped bcs of the lower readings, thinking something was wrong.DUH! As you said, I think my body just wsn't used to regular numbers, so I freaked.

I think I'm going to be o.k this time around! Information is powerful. Thanks again!

Jenny said...


Glad you finally found some help. A lot of doctors don't understand this at all, just as they fail to understand so much else about the effects of blood sugar fluctuations.

Spike said...

Hi Jenny

I can think of one possible situation where the feedback mechanism might not protect people from False Hypos - if their liver's glycogen store was exhausted. This might happen after running a marathon or something similar. Do you agree? I don't want to frighten anyone though. This is a rare but scary situation for Type 1 diabetics though of course many Type 1 diabetics do run marathons, they just take appropriate precautions.

Jenny said...

Spike, It always amazes me that the marathon is a race that commemorates an original race where the man who completed it dropped dead at the end. Why this is considered a healthy thing to do now is mystifying.

And yes, one could burn through one's glycogen if one was doing that extreme a practice.

People who eat very low carb diets are advised to bring glucose along with them and take bits of it as they exercise too, but even low carbers have some glycogen stored in liver and muscles, just not anywhere near as much as others.

Gopikrishna said...

Dear Maam,

Grt post. I am educated on false hypo. I am going to try what u r advising. Will keep u posted about the efficacy.
Thanks and regards

James M. Crisp said...

Sorry if I am off topic, but what do you think about the science communities filip flop on coffee? Six months ago it prevented diabetes, a week ago they said it made it worse.

Jenny said...

James, The study design is different hence the studies come up with different results. Food research is of such poor quality I tend to ignore it. The only "research" any of us need pay attention to is the research we do with our meters after we eat. If a food (or drink) pushes up our blood sugar unacceptably, don't eat it. If it doesn't fine.

Gretchen Becker just blogged about coffee research HERE.

Dixhistory said...

There is no doubt in my mind at all that this lady gives sound advise. Please do read her whole site to understand all that she writes about.

This false hypo was me and well said by Lucy so ditto on her comments.

I read this about 5 months back. I had a check up last month with an A1C of 4.8 and lost another Two pounds.

Dear sweet Jenny, you have made me one happy camper!


Juanita said...

Hi.. I am researching both Type 2 and Hypoglymecia. I am NOT on any insulin, or any other diabeties drugs. I take vitamins, D3, and Iron, with Drs suppervision. I am also taking ViiBryd (have been now for 4 weeks). My previous medecine did not help my depression.
I do have a qlucose meter. My fasting level is usually between 89 and 94. My problem is (from my point of view, and now for many years, 20+, had a problem with very low blood sugar. I am talking mid 20s. I am sick, cannot think, blurs my vision, lips and tounge go numb. I read here that can be caused by a rare tumor. Assuming this is correct--20+ years? I find if I am not very carefull I begin bouncing up and then down very low again. I did read to use Smarties. I used to eat a half of baked potato, because even though it took a while 30 to 45 minutes to work, I did not bounce back down again within the next hr. Please direct me what to look for, who to talk to, how to make sure I do not have the tumor. Then if I do not, why the bounce? I have tried to back track and determine a cause when I have these lows, they seem to happen in a group of days, then I am fine for several days, sometimes even weeks. I guess I have talked enough, thank you for your time. Juanita

Jenny said...


I believe that the kind of insulin secreting tumor that causes hypoglycemia would make you hypo all the time and would not last 20 years.

Readings that were truly in the 20s would put you into a coma, so my guess is that your meter is not entirely accurate as many aren't.

What usually causes hypos is blood sugar that rises steeply and stimulates an insulin response that does not shut off when blood sugar drops into the normal range.

The simplest way to keep this from happening is to cut way down on the carbohydrates you eat so that you don't cause the spike that results in the reaction.

If that doesn't help, you really do need to consult with a good endocrinologist, especially if you are seeing 20s on your meter. Get someone to take a photo if you do and take it with you to the doctor. There are rare conditions out there with all kinds of odd symptoms that you won't find reading web sites. A well-trained endocrinologist should be aware of them. See one affiliated with a medical school if possible. Sometimes the local guys who work out of the community hospitals have lost interest in their jobs and haven't kept up.

JoinRats said...

Thank you so much for posting everything on your site, I'm finding it invaluable. I'm a type II on Metformin which is working. I have a friend whose diabetes is much worse, and who suffered a heart attack (not clear the cause). She becomes nauseous on metformin and as a result she's only on glyberide - but - she says her sugars remain somewhat high. Do you have a page that shows what medication can substitute for Metformin? For some reason she thinks she's stuck with diet control and glyberide and high-ish sugars. I think she should be pushing her doctors for additional drugs.

Jenny said...


Metformin is quite unique in how it works, and no other drug on the market does what it does. Other drugs are advertised as "reducing insulin resistance" but they do it by absorbing glucose into fat. So they really don't lower IR, but lower blood sugar. Metformin actually changes the way the muscles burn glucose and it also changes how the liver releases glucose into the blood stream (which it often does wrong for people with type 2.)

The safest way to lower blood sugar w/o metformin is to use insulin which has far fewer scary side effects than any of the other oral drugs. But it takes some education. Read up about it in the book, Dr. Bernstein's Diabetes Solution or in John Walsh's Using Insulin. Then she needs to find a doctor who will give her the prescriptions she needs.

Another option is to try Metformin ER, in a low dose, and see if she can build up a tolerance. The ER isn't as hard on the stomach as the regular and starting with a small dose might work. The heart- and cancer-prevention qualities of metformin make it a very valuable drug.

Also your friend can lower her blood sugars by cutting back on her carbs using the strategy she'll find HERE.

TenToHealth said...

Hi, Jenny, your blogs have been very helpful. I believe I have MODY, based on reading books and your blog, and I can currently control it with diet. I've been feeling "hungry" a lot, but not necessarily low blood sugars. Just extrapolating from this article--should I always test and wait 'til my blood sugar is 70 or lower before eating? That sounds really difficult!

Jenny said...

No need to wait until you drop that low! Just don't think of it as a hypo. And don't eat to correct it. Use the 'two gram cure' described at http://www.phlaunt.com/lowcarb/19058561.php"

v/vmary said...

how can a woman differentiate a nightime hot flash and rapid heartbeat caused by a false hypo from the same symptom caused byperimenopause?

Jenny said...

v/vmary, The rapid heart beat from a false hypo (or a real one) isn't usually accompanied by the dramatic change in perceived body temperature that comes with a hot flash. If you aren't throwing off the covers to cool yourself down--even on a January night with the heat turned down low--it isn't a menopausal hot flash.

Unknown said...

Hi Jenny,

I am 47 yrs old and weight 140lbs and I started taking metformin at night and experienced the following patterns every night for a while

3:00am -> 82mg/dl
4:00am -> 77mg/dl
5:00am -> 84mg/dl
6:00am -> 86mg/dl (liver starts producing sugar?
7:30am -> 88-108mg/dl
9:00am -> 140mg/dl

my fasting glucose before diagnostic is 125mg/dl
Does this pattern look like a "false hypo" to you and when do you think this pattern go away or I have to keep using this "2g sugar" technique to fix it around 6:00am in the morning in my case.

I found your post very helpful to me and others and it helps explaining thing better for me.

Thank so much for your help,

Jenny said...

Those look like completely normal numbers unless that high number at 9 AM is NOT caused by eating a meal.

I wouldn't do anything to raise those early morning numbers. You might try eating a breakfast with mostly protein and fat when you wake up. That should keep the blood sugar from rising so much at 9AM but that level isn't really bad.

But you shouldn't correct anything that is over 70 mg/dl unless you are using insulin or an insulin stimulating drug like glipizide/glibenclamide/glyburide.

Unknown said...

Hi Jenny,

at 9:00AM I do not start breakfast yet and monitor the blood sugar and i see it keeps going up until I take breakfast and it goes back to normal 2 hrs later.
Does it sound like "false hypo" to you at 9:00AM
My fasting glucose is 125mg/dl when I was diagnosed with type2 and with a1c=7.1%
I started metformin and see this issue lately.

I never use insulin or insulin drug at all. The doctor prescribed me to take metformin 500mg twice per day and I followed. I suspect if I do not take breakfast; it will keep going up .... but I don't know to what number.


Jenny said...

Tri Tran, This is not false hypo. This is Dawn Phenomenon, described HERE . Eat something as soon as you awaken and that will knock down the blood sugar.

This is a common reaction for people with diabetes. It is also why fasting is not a good idea for many people with diabetes.

Unknown said...

Hi Jenny,
What a great post, Jenny!

I read your post on the link and it makes the whole thing clearer for me.
My Fasting Glucose for an 8-9hrs window of fasting is almost < 110mg/dl ever since I started Metformin as I tracked the past couple of months. If I wait one more hour, then it will go to > 125mg/dl @9:00am and I have to start eating breakfast right away to help blood sugar.
Looks like, starting a medication will help restore beta cell before it is long gone.

From your experience, When do you think a person with type 2 can get off medications and what factors can determine that.

or they have to be on medications the rest of life.


Jenny said...


If you read the main Blood Sugar 101 web site, following the links listed on the "read this first" page, you will get a lot of the answers to your questions.