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You may know that wildly fluctuating blood sugars can negatively affect your autoimmune disease -making it worse and exacerbating symptoms – but HOW do you know if your blood sugar is fluctuating? Learn how in this post.

In the last post, I explained why blood sugar fluctuations can be bad for your autoimmune disease health and long-lasting freedom from symptoms. If you haven't read that, I highly recommend doing so before reading this: Read How Blood Sugar Affects Autoimmune Disease

Once you've got an understanding of how detrimental fluctuating blood sugars can be, you might have a desire to know if that's happening to you, right? I mean, that's what I'd want to know!

In this post, I'll go over the “normal” ranges of blood sugars, some tests you can do at your doctor's office to determine if you're outside of these ranges a lot, and then some tests you can do at home that will help you determine if specific meals or foods are causing you to go outside of these ranges.

If you'd rather WATCH all of this instead of read it, you can do so by watching this video below!

What is normal?

To start off, you need to know what is considered to be normal.

This can actually vary quite a bit depending on the source you are referring to – a functional medicine practitioner uses tighter ranges than a conventional doctor, for instance, and even between the various diabetes organizations and conventional doctor groups, there are discrepancies.

So for simplicity, we'll take a number that is close to most of these and say that 70 – 100 mg/dL is a “normal” range. This is 70 – 100 milligrams of glucose to each deciliter of blood.

In non-US countries, you'll probably be using millimoles instead – so that would be around 4-5.4 mmol/dL.

Anything outside of this range would be considered either high or low.

a graph showing arrows pointing to blood sugars outside the normal range

What happens when you're outside of these ranges?

Now to be clear, if you go outside of these ranges, especially slightly higher (some say 120, some say up to 149) than the normal amount, it's not going to be much of a problem, especially if it's for a short period of time and you come right back into the normal range.

What's more of a problem is if you go really high out of the range, go higher than the normal range quite frequently, or spend a lot of time out of the range. This is where your body is going to be producing cortisol and other detrimental effects I talked about in the last post.

Alternatively, your body almost always produces cortisol when you go lower than the ranges – this is a stressful situation for your body.

Either way, you might feel specific symptoms when you go outside of the ranges as your body deals with a higher or lower amount of glucose than normal.

Using symptoms to determine blood sugar fluctuations

One of the easiest, least invasive, and no-cost ways to determine if you're having blood sugar fluctuations is to go off of the symptoms you have after a meal.

Typically you should NOT have any symptoms after a meal, but if you do have any, it may indicate a blood sugar going higher or lower than normal. (Though it also could be a reaction to the food if you have an intolerance to it)

This method is the vaguest and hardest to know whether you are high vs. low, but it will help you to know that at least something is going on and you might want to dig deeper.

Low blood sugar symptoms (hypoglycemia)

hypoglycemia symptoms

When you're experiencing a blood sugar lower than 70 mg/dL (4 mmol/dL), you may experience one or more of the following symptoms. (Do note that for some people who tend to be at higher overall blood sugar for an extended period of time may feel these symptoms at 85 mg/dL or lower):

  • Cravings for sweets
  • Desire to eat EVERYTHING in sight.
  • Irritability and grouchiness, especially if it’s meal time and you’re not eating (Hangry)
  • NEED coffee for energy
  • Lightheadedness between meals, esp if it’s meal time
  • Fatigue is eased if you eat
  • Feeling shaky, jittery, faint, weak
  • Feeling agitated, like something is off and you just can’t figure out why
  • Easily become upset
  • Memory is bad, you forget things easily
  • Blurred vision
  • You might be cold – or your extremities might get cold (and this is different than a Hashimoto's kind of cold – it's more acute and goes away once your blood sugar is normalized)

High blood sugar symptoms (hyperglycemia)

hyperglycemia symptoms
Alternatively, these are the symptoms you might feel if you're higher than 100 mg/dL (5.4 mmol/dL):
  • Tired after meals – you really feel like you want to take a nap
  • Constantly hungry
  • Sugar cravings – including ones that don’t seem to be relieved by eating carbs and you feel like you HAVE to have carbs/sugar – and I will say the difference for me with low vs high sugar cravings is that I’m low I feel faint, weak, and almost instinctually know I need sugar but don’t have actual “cravings”. It’s just this need. But when high I feel like my body is buzzing with energy and I really want sugar. Like I can’t stop thinking about it kind of craving. It took me a while to figure out this distinction but it’s really helpful.
  • Dizziness 
  • Anger (I find this to be beyond grouchiness and irritability – it’s like you just are angry at everything and people know to stay away from you when you’re like this kind of thing)
  • Longer term – if you have some insulin resistance and get higher blood sugars often you might notice an increased need to pee, more thirst than usual, inability to lose weight, and migrating aches and pains

Using these symptoms as a tool

high carb foods with arrows pointing to yes or no and the text "Do you feel symptoms?"

Next time you eat a high-carb meal or food, pay attention and see if you get any of these symptoms.

At the same time, pay attention next time you have a low or no-carb meal as well.

If you're getting symptoms from carby meals and not from low or no-carb meals, this also is an indicator to dig deeper.

Testing from a doctor

The following tests are going to be something you can get from your doctor, and they'll typically show more that you have an overall trend towards high sugars rather than helping you to know if a particular meal is affecting you. These will be helpful to know if you're having a lot of high blood sugars and/or spending a lot of time in a higher range.

If you feel any of the above symptoms and get one of these test results out of range, it's an indicator that your autoimmune disease most likely won't be helped on a long-term basis until you can balance your blood sugars.

HbA1c (Hemoglobin A1c)

red blood cells with sugar attached
On the left, a lot of sugar attached to a red blood cell, on the right, just a little sugar attached

The HbA1c test is a 3 month “average” of your glucose levels. When sugar circulates throughout your bloodstream, it attaches to hemoglobin, a protein in your red blood cells.

Everyone has some sugar attached to their hemoglobin, but people with a lot of sugar circulating throughout their bloodstream (so those with higher blood sugars) have more attached.

The HbA1c test measures the percentage of your red blood cells that have this sugar-coated hemoglobin.

The normal amount is under 5.7%.

The problems with this test are that it doesn’t necessarily show if you’re having fluctuations of high blood sugar and coming right back down into the normal range, rather than just spending a lot of time with high blood sugars. Either one isn't great for autoimmune disease though, so there is that…

And it also doesn’t show if you go low often. It's called an average, but it’s only essentially showing the amount of time you’re higher than usual. Sugars don't get removed from the hemoglobin if you have a low, so if you spend 70% of your time higher than the normal blood sugar ranges and 15% of the time lower, it will just reflect that 70% of the time you're high. So it's not the best diagnostic tool to determine if you get a lot of low blood sugars.

But it's a good test to see if your blood sugars have been higher than normal for the last 3 months.

Fasting Glucose

The next test is fasting glucose. This test is performed after you have not taken in any calories for at least 8 hours.

This test again is helpful for knowing if you have a metabolic issue where you're blood sugars are probably out of range for a large portion of time. Theoretically, if you are chronically high, your fasting glucose will be out of range as well.

If you ARE out of range (high) it could indicate insulin resistance, pre-diabetes, or diabetes, but from an autoimmune disease standpoint, it means your body is probably pumping out more cortisol than you need to be, exacerbating symptoms and causing immune system dysregulation (plus organ damage can happen as well).

So this is a good one to take in conjunction with the HbA1c just to find out if you're within the normal range.

Oral Glucose Test

The Oral Glucose Test is usually 2 parts – the Fasting Glucose test and then you drink a solution of 75 g of sugar and get your blood sugars tested at 1, 2, and sometimes 3 hours after. (Some labs will only do 2 hours)

A blood glucose at 2 hours post-drink of 140 mg/dL (7.8 mmol/dL) would be considered normal and anything above that could potentially indicate insulin resistance, pre-diabetes, or diabetes, but also exacerbation of autoimmune disease issues.

However, sometimes these tests can also be off if you say, had a bad night of sleep, are sick, in the middle of a flare-up of autoimmune disease symptoms, really stressed, etc – so it is something to maybe do more than once if you get a result higher than 140 the first time.

But more than one test of 140 does seem to point to the cumulative effect of high blood sugars and an inability for your body to process the glucose in your blood. Again, best used in conjunction with an HbA1c to get a longer-term picture.

At-home blood sugar testing

The following are two ways you can test your blood sugar at home to determine if you're having blood sugar fluctuations.

These will only reflect that particular moment in time, so unless you do it often it won't show any trends towards higher or lower blood sugars, but these tests are super helpful in determining if certain meals or foods are affecting your blood sugars negatively. It also can really help you to determine if you get low blood sugars.

Glucose Meter (glucometer)

glucose meter
The first method is via a glucose meter, also known as a glucometer. These are inexpensive devices that you can usually find at any drug store, grocery store, etc.

You do need to prick your finger and draw a small amount of blood, so that might be a problem for some, but it shouldn't hurt very much and you do get used to doing it.

To use a glucose meter, you use a lancing device (a retractable needle) to prick your finger and get a small drop of blood. You then place that blood on a test strip in the glucose meter. After a few seconds, the meter will give you a number – that's your current blood sugar number.

These are nice because you can test now and then again in 30 minutes (or any interval of time) to see if it’s changed – all at home, within seconds, and without having to wait for a lab to give you results, etc. You can also use it frequently to start to identify trends. 

I recommend you do a few tests before and after all of your meals initially just to get an idea of what your blood sugar does, but after that I think it's only necessary if you experience symptoms or if you're really trying to determine if a particular meal or food affects you. If doing the latter, I recommend testing before you eat, and then again at 1, 2, and maybe even 3 hours after.

Frequent testing like this will help give you a picture of what happens after you eat and whether you get a spike (either high or low), gradual rise, or not much of an effect at all. It also may help you to understand if you stay at a high range for a long time afterward vs. spiking just for a few minutes and then returning to normal (or going low).

Test strips can be expensive, but we have found that the Contour Next and Dario brands are not too bad and are compact enough to take with you in your purse or pocket (good to see how a restaurant meal affects you).

Continuous Glucose Monitor (CGM)

continuous glucose montioring cgm
The other at-home test is a Continuous Glucose Monitor, or CGM. This is a small device that you wear for 10-14 days, typically on either your arm or abdomen, that measures glucose every 5 minutes.

Specifically, it measures the interstitial fluid between your cells and not your blood directly, but it's been found to be accurate in determining blood sugar levels.

It helps fill in all those gaps that you get when only testing occasionally with a glucose monitor to get a complete picture of what your blood sugar is doing, all day and all night.

However, it is quite expensive and also could be a bit of overkill for many people. It's definitely NOT a requirement to figure out if your blood sugars are fluctuating.

But for those of you who really want to dig deeper, find out what else might affect your blood sugar (stress, heat, and exercise just to name a few), and really get your blood sugars into range, it can be a really insightful and helpful tool.

I personally have been wearing a CGM for several months and have really found it helpful for correlating those symptoms I mentioned at the beginning of this post with whether I have a higher or lower blood sugar, as well as finding out how things like exercise, stress, lack of sleep, etc affect my blood sugar, and for dialing in my diet so my blood sugars don't fluctuate nearly as much.  (This is the program I use to get my CGM – Levels Health)


You now have several methods of finding out whether your blood sugars are higher or lower than the normal range and perhaps affecting your autoimmune disease in a negative way.

The technology changes constantly as well, so there could be new methods soon that will be even more accurate, less invasive, less expensive, etc. So if this is something you need to dig deeper on, pay attention to those as well!

But the bottom line is that using at least one of the above tools – and maybe a few together – can help you to know if blood sugar is something you need to worry about.

SEE PART 3 –> Part 3 of this series is my own personal experience using a Continuous Glucose Monitor for several months. See what I've learned, what spikes my blood sugar, and how it's helped me adjust my diet to balance my blood sugars. What I've Learned From Wearing A Continuous Glucose Monitor

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