Is My Blood Sugar Normal?
Is my blood sugar normal?” seems like a simple question – but it’s not! The answer can vary dramatically based on your situation. Let’s look at some of the factors to consider. Please remember: you should figure out your personal goals in consultation with your doctor.
Normal Blood Sugar in Diabetic vs. Non-Diabetic
First, a quick note on how we measure blood sugar. In the USA, blood sugars are measured by weight in milligrams per deciliter, abbreviated as mg/dL. Most everyone else uses millimole per liter, abbreviated mmol. If you are in the USA, look at the big numbers, most everyone else look at the small numbers.
In a person without diabetes, blood sugars tend to stay between 70 and 100 mg/dL (3.8 and 5.5 mmol). After a meal, blood sugars can rise up to 120 mg/dL or 6.7 mmol. It will typically fall back into the normal range within two hours.
In a person with diabetes, the story is much more complex:
|Below 70 mg/dL
Below 3.8 mmol
|Low Blood Sugars (Hypoglycemia). When blood sugars drop below this level, you may start feeling hunger, shakiness, or racing of the heart. Your body is starved for sugar (glucose). Read how to detect and treat low blood sugars.|
|70 mg/dL to 140 mg/dL
3.8 mmol to 7.7 mmol
|Normal Blood Sugar. In this range, the body is functioning normally. In someone without diabetes, the vast majority of the time is spent in the lower half of this range.|
|140 mg/dL to 180 mg/dL
7.7 mmol to 10 mmol
|Elevated Blood Sugars. In this range, the body can function relatively normally. However, extended periods of time in this zone put you at risk for long-term complications.|
|Above 180 mg/dL
Abovoe 10 mmol
|High Blood Sugars. At this range, the kidney is unable to reabsorb all of the glucose in your blood and you begin to spill glucose in your urine. Your body may begin to turn to fat for energy and release ketones in your urine. (You can purchase strips to test your urine for ketones. Contact your doctor immediately if you have ketones in your urine.)|
Normal Waking Blood Sugar (or Fasting Blood Sugar)
Ideally, everyone with diabetes will wake up with blood sugars in the normal range. However, many people experience what is called the “dawn phenomenon.” As the body prepares to wake and start moving, it releases stored sugar into the blood. This can cause a moderate spike in blood sugar. You can read How to Fix High Morning Blood Sugars for tips on how to improve these numbers.
To confirm if this is happening to you, you can wake up in the middle of the night and check your blood sugar. If it’s in the normal range then but high after waking, this is probably the cause. If the spike is small and goes away quickly, then it’s likely nothing to worry about (check with your doctor). The spike from dawn phenomenon is often less than the one you get from eating a typical meal.
Morning blood sugars can also be impacted by what happened the night before. The amount of carbohydrates you ate and how much medicine you took can have an impact. Even stressful night of tossing and turning can lead to high blood sugars. Learning what causes your blood sugars to rise and fall by checking your blood sugars strategically is the key to figuring out why your blood sugars are what they are in the morning.
Normal Blood Sugars After Meals (or Post-Prandial Blood Sugar)
The chart below compares post-meal blood sugars in a typical person with diabetes and someone without diabetes. Most diabetes organizations recommend keeping your post-meal rise below 180 mg/dL or 10 mmol.
So is 200 mg/dL or 11 mmol a surprisingly high blood sugar an hour after a meal? If you were at 150 mg/dL or 8.3 mmol before you began eating, then probably not. Your meal only caused a modest bump of 50 mg/dL or 2.8 mmol. That would be perfectly reasonable in someone with a perfectly functioning pancreas!
To know whether a blood sugar is what one would expect, it’s important to understand where you started. If you would like to reduce your blood sugars after meals, read How to Start a Low-Carb Diabetes Diet.
What Blood Sugar Levels Are Healthy?
This is an area of some debate. The long-term studies show that the risk of complications drop off dramatically when an HbA1c is lower than 7%, an estimated average blood glucose of 154 mg/dL or 8.6 mmol. It continues to drop until it’s below 6%, an average blood sugar of 126 mg/dL or 7 mmol. There are many people who strive for lower targets, but there is not a lot of research outlining the benefits of that approach yet.
(Read HbA1c: Everything You Need to Know)
One challenge is that studies of A1c are just looking at averages. In reality, there seems to be a huge difference in risk of complications based on genetics. There are many people who have lived thirty or forty years with type 1 diabetes running high blood sugars almost continuously and have no complications. There are others who have had nearly perfect blood sugars that still get complications. But for most people, it’s safe to say that striving for an HbA1c of below 7% and probably below 6.5% is a realistic goal for staying healthy.
There are exceptions, of course. Doctors might often recommend higher targets for those that can’t sense low blood sugars, are elderly or have some other health conditions. The reasoning is that the health risks of striving for lower targets may be outweighed by the risks of doing so. For example, most complications take decades to appear. If someone is diagnosed with type 2 diabetes at 90, there’s almost no chance of living to see those complications. So a doctor might prescribe less intensive therapies.
There is also a lot of research suggesting that the total time you spend in a health range is more important than your A1c. For example, if your low A1c comes from a lot of severe lows balancing out highs, this is less good than just having more steady blood sugars near the normal range.
A Note About Meter Accuracy
In the USA, a meter can be approved for sale so long as the results are consistently within 20% of the right number. That means that if your blood sugar was 180 mg/dL or 10 mmol, than a result of 216 mg/dL (12 mmol) or 144 mg/dL (8 mmol) would still be considered accurate. In practice, most meters are more accurate than that, but even an expensive hospital blood test using calibrated equipment has a 10% margin of error.
So don’t automatically panic if you check your blood sugar and it’s 140 mg/dL (7.7 mmol) and a few minutes later it’s 150 mg/dL (8.3 mmol), a change of under 10 mg/dL or 1 mmol. This may just be the meter. Look for trends over time to truly understand what’s happening.
You can check out this chart comparing blood glucose meter accuracy. Keep in mind that this study is not current and, unfortunately, that no one has published more current data. (There should be some independent group testing meter accuracy in the real world, but it just isn’t happening… yet.)
Is My Blood Sugar Normal?
So there you have it: a long and winding answer to what seems like a simple question! And remember: please consult your doctor to understand what healthy blood sugars are for you.
- Read Everything You Need to Know About Your A1c.
- Need to know what causes highs and lows? Check out 22 Factors That Affect Your Blood Sugars.