What is Too High for Blood Sugar?

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Diabetes, a common (chronic) high blood sugar condition, can affect anyone — millions of people affected with this metabolic syndrome in the United States. So what is too high blood sugar, when the level is considered as diabetes? And what are safe blood sugar level ranges for non-diabetics (healthy individuals) and diabetics?

Normal blood sugar levels in healthy individuals

You’re considered as a diabetic, a term used to call an individual with diabetes, when the level of your blood sugar (also called glucose) is higher than normal. Unfortunately, some people are probably unaware when their level is high since they don’t know what diabetes symptoms look like.

According to NIDDK (the National Institute of Diabetes and Digestive and Kidney Diseases), a staggering 25 percent of individuals with diabetes don’t realize they live with the disease. Furthermore, 1 out of 3 people (adults) probably has a condition called pre-diabetes, one CDC report suggests. Pre-diabetes is borderline diabetes, a phase when your blood sugar is higher than normal but it’s not high enough to be classified as diabetes.

It’s usually hard to tell whether or not you’re diabetic if you only rely on the symptoms. The best way to accurately catch it is by measuring your blood sugar level! This can help figure out whether you’re in a healthy range.

Blood sugar levels are usually classified into two categories; when fasting and after eating (postprandial). In most healthy individuals, these are as follows (according to NICE guidelines):

  1. When fasting (usually taken in the morning before you eat anything): between 72 to 99 mg /dL (4.0 to 5.4 mmol/L).
  2. Two hours after eating: 140 mg /dl (7.8 mmol/L) or lower.

It seems the normal level may also vary from person to person. For some people, 60 mg /dL (fasting) is probably still OK – ask a doctor for more guidance!

Who should check the level?

Blood test to check blood sugar level is not always recommended for healthy individuals. But you may need to take the test if you experience signs and symptoms of diabetes.

The early warning signs could be vogue or so mild, making you unaware to the existence of the disease (particularly true for type-2 diabetes, the most common form of diabetes). Some people may not have any noticeable symptom until the disease causes long-term damage.

But in general, here are a few common signs and symptoms of diabetes [1]:

  1. Frequent urination, which may also be followed with being thirstier. It’s normal in 24 hours to pass urine 4-7 times. But with diabetes, you’re likely to go a lot more due to high amounts of glucose in the bloodstream.
  2. Fatigue and hunger! The disease pushes your blood sugar up, but this is not enough to be transferred into cells of the body for energy since there’s something wrong with insulin. As a result, you’re easier to feel more tired than usual and hungrier.
  3. Itchy skin and dry mouth. These symptoms could be a consequence when your body uses more fluids to make pee.
  4. Blurred, changes in vision. Fluid imbalance in the body may affect the lenses of your eyes, causing swelling and decreased vision.

Additionally, type 2 diabetes is likely to cause yeasts infections, slow healing wounds /sores /cuts, and pain (numbness) in the legs. Type 1 diabetes might also cause unintentional weight loss, nausea, and vomiting [2].


Checking blood sugar regularly is usually important for people with the following situations:

  1. Diabetics, especially those who’re taking insulin.
  2. Having a hard time in managing blood glucose levels.
  3. Pregnant women. Pregnancy may cause gestational diabetes, which could be dangerous if not regularly monitored.
  4. Low blood glucose level (hypoglycemia) without warning signs and symptoms.
  5. Or if you have ketones, blood acids that build up when your body is craving for energy by burning fat. 

Checking blood sugar probably is not as practical as checking blood pressure. But in general, most people can do it at home. Just poke your fingertip and then use a blood glucose meter unit to check the level!

Also, some people (depending on their situations) may need to have a continuous glucose monitor (CGM) to get a more complete picture of the levels. For more guidance about this CGM, talk to your healthcare team!

When abnormal high blood sugar is considered diabetes?

Your normal blood glucose level is an important variable to support your overall health, especially your cardiovascular system. If the level is too low, lower than normal (hypoglycemia), the natural mechanism of your body to function is affected.

The same goes when the level increases higher than normal. High blood sugar (hyperglycemia) can hurt blood vessels, nerves, and primary organs of the body. Over the long run, this will lead to a vast number of complications, which some could be dangerous and life-threatening if left untreated!

The common preferred methods to look for diabetes are plasma glucose test when fasting and 2 hours after meal.

Fasting plasma glucose test (FPG), taken at least 8 hours after meal, is considered as a signal of diabetes when the level is 126 ml/dl or higher. In such case, the test is usually followed with plasma glucose test 2 hours after eating (the result should be higher for diabetes diagnosis, that’s greater than 200 mg/dl) or repeated FPG on a subsequent day for more accurate diagnosis.

How about pre-diabetes? A FPG 100 mg/dl to 125 mg/dl – and 140 mg/dl to 199 mg/dl (2 hours after meal) are considered as pre-diabetes [3].

In addition, (if necessary) random glucose plasma test is also probably suggested. In this test, your healthcare team takes your blood sample for the test at any time (random).

For summary, check the following table!

Fasting 2 hours after eating Random
Normal 5.5 mmol/l (100 mg/dl) or lower 7.8 mmol/l (140 mg/dl) or lower 11.1 mmol/l (200 mg/dl) or lower
Pre-diabetes 5.5 to 6.9 mmol/l ( 100 to 125 mg/dl) 7.8 to 11.0 mmol/l (140 to 199 mg/dl) N/A
Diabetes 7.0 mmol/l (126 mg/dl ) or higher 11.1 mmol/l (200 mg/dl) or higher 11.1 mmol/l (200 mg/dl) or higher

*The metric system for ‘mmol/L’ is a scientific unit to measure chemicals. It stands for milimoles per liter.

(Extreme) too high blood sugar condition, diabetic hyperosmolar syndrome!

In diabetics, keeping blood sugar level as normal as possible will be a key part to control the disease and prevent its complications. So it’s very important to understand what the level means!

If you’re diabetic, ask your doctor about your blood sugar level targets. Because the level targets may have a degree of different interpretation for each case! But in general, blood sugar level targets for people with diabetes are as follows [4]:

  1. About 4 to 7 mmol/L (70 to 126 mg/ dl) – before meal; for both type 1 and type 2 diabetes.
  2. About 8.5 mmol/L (153 mg /dl) or lower in people with type 2 diabetes –or– about 9 mmol/L (162 mg/dl) or lower in people with type 1 diabetes – after meal (at least 90 minutes or 2 hours after eating)!

Actually, there should be nothing to worry when you have diabetes as long as it’s managed as well. It could be dangerous (fatal) when it has caused its complications.

Uncontrolled diabetes may cause a condition called diabetic hyperosmolar syndrome, when the body has an extreme spike in blood sugar level (too high, much higher than normal).

Diabetic hyperosmolar syndrome is serious condition. It is relatively more common in type 2 diabetes, intensive immediate treatment is necessary!

When you have too high blood sugar level, your body works harder to get rid of the excess glucose in the bloodstream! In such case, this will usually drive you to pass more urine to eliminate the excess through urine!

With diabetic hyperosmolar syndrome, the level could be 33.3 mmol /L (600 mg /dl), and this would lead to serious complications such as diabetic coma [5]. Diabetic coma can drive you to have unconsciousness, you’re alive but you lose control in purposefully responding stimulation (sounds or sights) and you can’t awaken!

Without immediate proper treatment, diabetic coma could be fatal! This is scary situation, but you can take preventive steps to reduce the risk of this complication — yes it’s preventable!

Controlling the blood sugar level is the key to keep diabetes complications (including diabetic coma) at bay. Here are a few easy things you can do to deal with high blood sugar: