Long Lost Member
Total Posts: 7
Registered on: ‎03-11-2011

So....what blood glucose number starts the "danger zone"

I've asked my dr., my mother (a former diabetes educator), and my current diabetes educator and not gotten a firm answer to this.  Mom gave the closest thing to answer and I'll tell you what she said after I ask my question and you have a moment to think about it.

There are two facets to this question: 1) What blood glucose number begins the "danger zone" for causing danger to the body; and 2) if my A1c is below 6 and my 2-hr post-meal sugars are rarely above 150 (say twice in 6 months) then why do I need to get so worried about a 135 fasting blood sugar?  If 135 isn't dangerous for a post-meal sugar why is it dangerous for a fasting sugar?

I'm seriously not trying to be difficult.  I just come up with these types of questions (the kind that give my husband a headache) and, usually, if I can find a real answer, then I end up understanding things better and am able to make better decisions about things.

Okay, now that you've seen the question(s), and had a moment to think, this is what mother said when I asked her this 3 years ago:  "The severity of damage caused by elevated blood glucose is on a continuum.  The lower the blood sugar, the less damage you will have; and the more concentrated the glucose is the more damage you will have in a given amount of time."  But that doesn't really answer the question of at what point we consider blood glucose to be excess enough to cause damage.  If it's 135 for fasting, why would 135 for post-meal be any different?  Same concentration of sugar: one causes damage and the other doesn't?  And if it's not 135, if it's something like 180, or 200, why is 135 considered dangerous for someone like me?

Okay, tell me what you know or think or hypothesize or deduce.  I'm interested to know what people who have varied experience and knowledge of diabetes have to say about this.  I know some answers I expect to hear, but I'm interested to see if anything else pops up that I haven't thought about.
Total Posts: 7,049
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Registered on: ‎10-31-2009

So....what blood glucose number starts the "danger zone"

Forget about blood glucose numbers for a minute.  Let me tell you a parable.  Let's dye some fabric instead.  Just pour some dye in the water and add the white tee-shirt and dye the shirt.  How much dye, you ask?  What is the proper concentration?  At what point does the dying process become effective?

Okay, in that illustration, the dye is like glucose.  The tee-shirt fabric is like our red blood cells, and the color of the tee-shirt is a matter of how much dye gets attached to the fibers in the fabric, sort of like an A1C result show how much our red blood cells have been permanently altered by exposure glucose.

If we add just a little dye, the color will never get very intense.  With a lot of dye, the color will get more intense.  If we move the shirt back and forth between the dye bath and a tub of clear water, the color will depend on both the concentration of the dye and the time spend in the dye.

How much dye is the optimum amount?  There may be guidelines that can help us decide, but ultimately, the right answer depends on looking at the results to see if we get what we want.  Too little dye and the color will never move beyond pastel.  Too much dye and we may get a dark color even with minimum exposure.  In between, and we start to use judgement, and a lot of other factors can come into play, like the kind of fiber, the temperature, timing....

Each of us is different and there are probably a number of factors that determine how many carbs we can handle   We can give each other some guidelines, and pick ones that work well for most people, but the real answers come in looking at the results.

"Molly" (aka mollythed)
Type 2 diabetes diagnosed in 1995, now managed with Lantus, Novolog and Metformin; diet and exercise.
My late husband had diabetes. My three adult sons also have type 2 diabetes.

Long Lost Member
Total Posts: 7
Registered on: ‎03-11-2011

So....what blood glucose number starts the "danger zone"

Good analogy, Molly.  I'm going to keep that picture in my head.  It does kind of help explain a little -- esp. the part about alternating the fabric between the dye bath and the clear water.  Like maybe 150 isn't so bad for a post-meal as long as I am having some good low numbers at other times of the day, like overnight.  Good one!  Thank you for replying!
Trusted Contributor
Total Posts: 11,418
Registered on: ‎11-28-2009

So....what blood glucose number starts the "danger zone"

Is this a hypothetical question, or does it describe your situation?

Fair question, and I think there are 2 aspects.

One is that as a peak number 135 is the max, the number you approach and then leave after a short while--maybe 15 minutes, maybe half an hour. As a fasting number, you could be there for many hours in the morning or night, and then getting back there before each meal perhaps. In essence if it is a fasting number, you are there a whole lot longer so it would have more of a chance to work its damage...

The second aspect is one that your question sort of rules out in theory, but which is a lot less likely to be ruled out in practice. If you are at 135 fasting then at some point you will be going a lot higher.  It is possible that 135 might be your peak all day long, that eating in the morning forestalls the dawn phenomenon, and then you never get up there again,  I suppose this is why sometimes CDEs tell people with dawn phenomenon not to worry about it,  but this situation would not be the usual one. So the 135 is an indicator that at some point you are getting into more of a danger zone.

Diagnosed Type 2, with an A1c of 11.4 in 2003; averaging a 5.0 A1c since then with diet, exercise and Glipizide XL + meds for blood pressure and cholesterol. 
A bit dated, but scroll down on this page if you want to know more ...

Super Advisor
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Registered on: ‎01-10-2010

So....what blood glucose number starts the "danger zone"


Every time I hear the dirty word 'exercise', I wash my mouth out with chocolate.

dx 12/2009 a1c7.4  3/2011  aic 6.6 long way to goto 5% club next a1c oct. 2011