What’s Normal Blood Sugar?

blood sugar ranges






The first thing we have to define when we speak of normal blood sugar is how we're going to define normal.  We could speak of the mean among all people, regardless of what condition they are in, for instance we're taking people with so called normal blood sugar and including people who have impaired blood sugar, and also throwing in diabetics in there as well, because all these people are part of the set of human beings if we're looking to figure out what the average is.

This is basically how labs determine normal results by the way, they take all the data they have and then do a statistical analysis on it, and the extremes get tagged.  So if you are extremely high or extremely low than you fall outside the normal range.

So it's not hard to imagine that this approach has its issues, and in fact normal itself, perfectly normal, might not be healthy.  There are nutrients that the majority of people are deficient in for instance and just because you aren't super deficient, falling outside the range, which by the way generally is the top 5% or the bottom 5%, the two standard deviations statistical model, in other words you are in the 90% of people who don't fall outside this range, then you are OK.

This model basically requires that 90% of people are healthy as far as the variable you are measuring, and health doesn't quite work that way, it just doesn't conform to all of this, and there are cases where most of the people in the 90% normal range may be suffering from a condition but they are all told that they are fine.

So when we say normal, what we really are looking for is normal blood sugar in healthy individuals, and that's not necessarily the same thing.  Normal blood sugar is actually rising each year, but this doesn't mean that what's healthy goes up.

With all this said though, the standards for normal blood sugar that we use isn't like that, at least not too much anyway, at least from a diagnostic perspective.  So we have three ranges here, normal, impaired, which is used to diagnose prediabetes, and diabetes itself.

That's not what we're after here though, we instead want to know what blood sugar is in healthy subjects, which is different than saying, well there's a healthy range and then as it starts to get more and more unhealthy until you get to the point where you've crossed this line and we're going to call it something else now, like impaired glucose tolerance.

I do want to point out though that while we may measure normal blood sugar in healthy individuals, that doesn't mean that blood sugar that falls outside this range is unhealthy, that's going to depend, and when we say unhealthy this is going to have to be by a meaningful degree, and this is actually something that a lot of diabetics get confused about.

However it is educational at least to know what the normal reference ranges are here among healthy subjects, those who don't have any glucose tolerance or any other manifestations of metabolic disorders, including elevated insulin levels as well, something we tend to neglect a lot.

So this particular study sought to do just that, and you can click here if you want to watch the video presentation on it, although I will warn you that it's on the dry side, but interesting nonetheless.

So what they did is take a group of subjects who were screened for various things such as BMI, A1C, insulin levels, and so on, and were determined to be fit in all these categories.  The BMI average was 22 by the way, so we're talking people that are pretty lean, and that's what we want.  Average A1C was 5, a very healthy number, prediabetes is 5.7 to 6.4 to give you an idea, and diabetes is 6.5 and up.

So these subjects aren't anywhere near prediabetic, which is what we want, we want the standard for people who don't have any issues.  Insulin levels were not just normal but on the low end of normal, the optimal end.

So they used continuous glucose monitoring for several days under controlled conditions, and fed them at regular times with snacking not allowed, and measured the results.  Post prandial spikes were almost all under 125, and what was noteworthy here is the brief time that the subjects stayed at this level, a matter of a few minutes, and then their blood sugar was on the way down, although the drop was slow and steady, bringing them down to a fasting baseline of around 80.

Throughout the night, their blood sugar remained remarkably stable at the same baseline of 80, only showing very slight variations during the hours that they slept.

Breakfast was the meal that produced the biggest spike, but this is understandable, and this was significantly higher than the other two meals of the day, however they are under the influence of morning elevated cortisol and this does show us that even these people get a little liver dumping, as the meal itself would not have produced this higher reading.

We also see insulin levels spiking within a half hour of meals, and glucose levels spiking a little before the one hour mark, which is very distinct from diabetics, with both taking a lot longer to peak and much longer to come down to normal.

After two hours, both glucose and insulin levels are almost all the way down to normal, where with diabetics they often are still rising.

They also did a study where they took diabetics and measured their average glucose with and without feeding them breakfast, with total caloric intake the same, and they found that average blood sugar was 7.06 mmol/l without, and 7.42 with, so that's super interesting.  This might cause us to think twice about having breakfast, they say it does keep your energy up, but it does that by keeping your blood sugar up it seems, something we may not want as diabetics.

This might also make a case for eating less often as diabetics, as you are subjecting yourself to additional periods of postprandial (after meal) peaks, and eating less often also leads to less overall insulin secretion, a desirable trait as well.

So this is all good information to have, including how our glucose metabolism is supposed to work when not under stress or dysfunction, this doesn't mean by the way that this is something we need to demand of ourselves as diabetics or even strive for, as that may involve paying a price where the costs and risks exceed the benefits, but it's still good to know what this is all supposed to look like.

Next: Prediabetes

Previous: Is High Insulin A Good Predictor Of Diabetes?

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5 Comments on “What’s Normal Blood Sugar?

  1. When I had t2 diabetes (1993-4) I remember that it was times when I felt particularly stressed and there was high blood glucose, that I experiences the symptoms of thirst and frequent urination. But there were also times when there were high blood sugars and there was no thirst and frequent urination. I suspect that the difference was in the liver dumping. So while a reading might be high one has to also think that this high number may be being continually pushed high by liver dumping or it might be simply static owing to insulin resistance. I could see that my readings did not necessarily tell me the whole problem but only a part of it. Both were outside the normal range, which I would rather think of outside the range of resting metabolism. However the one condition posed a problem, especially for the kidney but the static high did not seem to be problematic in that my body still functioned properly and tolerated the high blood sugar.

  2. It actually might be that glucose from liver dumping might produce less symptoms as the body is in a sense putting in a request for it, or this might be the case sometimes anyway. The other side of this though isn’t insulin resistance though it’s high glucose consumption, which generally produces bigger peaks and it’s the peaks that can do you in. I’m not sure that knowing this helps us though.

    1. The body is putting in a request for more sugar in liver dumping but that is due to the either the fight or flight response (threats –> fear) and in some cases also anger if the person is violated. This means that the body does not assess “how much sugar have I got in the blood stream and do I need more”. When the metabolism is abruptly raised the liver is put into motion. So a person who is being repeatedly stressed, and I found that this can be done covertly, then their metabolism goes into overdrive.

      High glucose consumption, IMO isn’t going to produce the sort of problem that drives sugars in the blood high because all of the digested nutrient goes to the liver and the liver decides what to release into the bloodstream as sugars and how much to covert to triglycerides and hence to fat storage. Plus there is a decay factor. After eating there is normally higher sugars until all the digested nutrient is either taken up by muscles, nerves etc or stored and then the levels return to what is normal for what is happening to the individual. If they are resting or not working hard AND not stressed then the levels will return to a range that is considered normal. The problem that I see is that the medical industry wants to define the blood sugar only with respect to digestion and not in terms of stress. And consider too that the person that eats all the time is a person stressed. Eating is a way of self medicating. If you eat something the body tries to lower the metabolism to just above resting metabolism from some higher state. So if they are stressed in a way that has caused them to become agitated or angry then eating will help bring this down. Of course the price is high blood sugars and triglycerides as the nutrient is being moved through the blood stream.

      The real question is what constitutes disease? Is all high blood sugars disease? They are diagnosing on one symptom without taking into account what is going on in a person’s life. And on that basis they seek to push drugs. The diet doctor there on stage giving a talk measured his blood glucose and it was a staggering 900 according to some one on diabetes UK. He’s not diabetic. If he goes on stage and is stressed does that make him diabetic? I question the criteria being used to diagnose diabetes.

  3. Well the fight or flight response is one of the drivers behind liver dumping, most of this actually comes from the alpha cells in the pancreas though. It’s true though that these mechanisms, when broken, don’t care what your blood sugar is. If you overdose on insulin for instance you can inject glucagon and this will bring your blood sugar up even if you have a very dangerous amount of insulin in you, it simply works.

    With ingested glucose though, it does go into the bloodstream, the liver doesn’t really have a say in this although with type 2 it often will just keep churning glucose, and this is something a lot of diabetics don’t understand, the liver just doesn’t dump when we don’t eat, when we eat it tends to dump even more.

  4. I think that the diabetic who finds that their liver is dumping sugar while they are eating, ie they end up with more sugar than just what they eat, then I would say that it may be due to a person’s concerns about what they are eating. A person who becomes anxious about what they eat will ignite the fight or flight response and thus cause liver dumping. I did not have this problem. Once I moved away from where I was working and returned to Sydney I found, even on he way down to Sydney that my excessive thirst and frequent urination had stopped. I still had still some diabetes in Sydney but it lessened once I resolved some issues that had caused me episodic anger. I did not believe that the food I ate had any effect, probably because I was eating Greek food and the doctor approved of my diet so I had no concerns about what I ate. Only the Chinese herbalist wanted me to stop eating “a lot of sweets”, he did not say no sweets and he wanted me to stop eating prawn. Within 12 months I had normal numbers. But I could also see that once I resolved emotional issues the number dropped dramatically. So my experience tells me that the idea of glucose intolerance is suspect. If you listen to the neuroscientist Antonio Damasio you find that he says we experience emotion in all of our daily life and it is very important in decision making. He made me realize that there is nothing in a sense broken in the body. It is a matter of how we react to various situation and circumstances and bad relationships need to be avoided for good health.

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