Questions about blood glucose levels are common these days. Asking about the average range for blood glucose may seem like a simple question, but it isn’t. The answer may vary based on each individual’s situation. Let’s review some of the blood glucose levels factors to consider. Remember to discuss your concerns about blood glucose with an endocrinologist or internal medicine provider.
Normal Blood Sugar in Non-Diabetic vs. Diabetic People
In the United States, blood glucose levels are measured as milligrams per deciliter (mg/dL):
- For a non-diabetic person, blood glucose levels tend to remain in the 70 – 100 mg/dL range.
- After consuming a meal, blood glucose levels tend to rise to 120 mg/dL.
- In a person without diabetes, blood glucose levels usually return to the normal range in two hours.
As shown in the glucose levels chart below, blood sugar control is more complicated for people with diabetes:
|Below 70 mg/dL||Low Blood Glucose Levels/Hypoglycemia||When blood glucose levels drop below this important level, the diabetic person feels hungry, shaky, or feels the heart race. The body has used its stores of glucose. It needs glucose fuel to function.|
|Between 70 mg/dL – 140 mg/dL||Normal Blood Glucose Levels||The body functions normally in the average range. Non-diabetics’ blood glucose levels are typically in the lower 50 percent of the blood glucose average range.|
|Between 140 mg/dL – 180 mg/dL||Elevated Blood Glucose Levels||When elevated blood glucose levels are present, the diabetic’s function remains relatively normal. Unfortunately, if he or she spends extended time in the elevated blood glucose range, the potential for long-term complications from diabetes increases.|
|Above 180 mg/dL||High Blood Glucose Levels||When high blood glucose levels are present, the diabetic person’s kidneys can’t reabsorb glucose in the bloodstream. The glucose begins to spill into the urinary tract. The diabetic’s body may turn to fat stores for energy, releasing ketones into the urine. Diabetics often use test strips to check for ketones. It’s important to contact the doctor when ketones are present in urine.|
Normal Fasting Blood Glucose Levels (Waking Blood Glucose Levels)
If the diabetic person’s blood glucose levels are well-controlled, he or she wakes up with blood glucose levels within the average range.
Some people have what’s known as the <i>dawn phenomenon.</i> When the diabetic begins to move in the morning, released stored glucose pours into the bloodstream. This may create a blood glucose level spike. The dawn phenomenon spike is usually less than the rise of blood glucose levels after eating a meal.
To check if this is happening, the diabetic can check his or her blood glucose levels in the middle of the night. If the blood glucose levels are in the average range at that time but higher upon waking, this may be the cause. When the blood glucose spike is small and normalizes quickly, it may not be a concern. Check with the internist or endocrinologist.
Blood glucose levels may be affected by what the diabetic ate the night before. Factors like 1) the amount of carbohydrates eaten before bed, 2) the medicines are taken, 3) poor sleep, or 4) tossing and turning during the night can result in increased blood glucose levels. It’s important to learn the cause of increased blood sugars.
Average Range Blood Glucose after Meals (Postprandial Blood Glucose Levels)
The blood glucose levels chart compares blood glucose levels after a meal in a typical diabetic vs. a non-diabetic person. The ADA recommends keeping postprandial blood glucose levels below 180 mg/dL:
|Before a meal||The typical non-diabetic’s blood glucose levels are about 80 mg/dL.|
|The typical diabetic’s blood glucose levels are about 120 mg/dL.|
|One hour after consuming a meal||The typical non-diabetic’s blood glucose levels rise to 140 mg/dL or less.|
|The typical diabetic’s blood glucose levels rise to about 210 mg/dL or less.|
|Two hours after consuming a meal||The typical non-diabetic’s blood glucose levels decline to about 95 mg/dL or less.|
|The typical diabetic’s blood glucose levels decline to about 180-190 mg/dL or less.|
|Three hours after consuming a meal||The typical non-diabetic’s blood glucose levels normalize to the average range of 90 mg/dL or less.|
|In comparison, the typical diabetic’s blood glucose levels remain elevated at about 160-179 mg/dL.|
|Four hours after consuming a meal||The typical non-diabetic’s blood glucose levels remain at 90 mg/dL or less.|
|The typical diabetic’s blood glucose levels decline to about 150 mg/dL or less.|
|Five hours after consuming a meal||The typical non-diabetic’s blood glucose levels steadily remain in the average range.|
|The typical diabetic’s blood glucose levels slowly decline to about 140 mg/dL or less.|
|Six hours after consuming a meal||The typical non-diabetic’s blood glucose levels are in the average range.|
|The typical diabetic’s blood glucose levels remain at about 140 mg/dL or less.|
Clearly, the diabetic individual should avoid eating refined carbohydrates between meals. Exercise before or after a meal can help the diabetic to normalize elevated blood glucose levels.
High Blood Sugar After Meals
A blood glucose reading or 210 mg/dL seems surprisingly high, but it may be a matter of what’s relative for the diabetic:
- If his or her blood glucose levels were at 150 mg/dL before eating a meal, a rise to 210 mg/dL might not be too high for him or her.
- If consuming a meal caused a modest bump of about 50 mg/dL, that may be reasonable.
It’s very important for the diabetic to know where he or she started.
Healthy Blood Sugar Levels
The research shows this is a heavily debated topic:
- NIH studies show that complications risks decline when the diabetic’s A1C level is less than 7.0 percent (an average blood glucose level of 154 mg/dL).
- Complications of diabetes continue to decline when the diabetic’s A1C levels drop below 6.0 percent (average blood glucose level of 126 mg/dL).
Some people work for lower targets but it’s important to keep realistic expectations. In addition, there isn’t a great deal of research that outlines the benefits of maintaining A1C levels below 6.0 percent for the diabetic. For example:
- A1C studies consider the averages of many diabetics.
- A difference in individuals’ risk of complications from diabetes is based on individual genetics. For instance, an individual can live with diabetes for 30-40 years and run higher blood glucose levels without complications. Others with almost “perfect” blood glucose levels get complications.
- The research shows that, for most people, an A1C level of 6.0 – 7.0 percent is a realistic health maintenance goal.
Exceptions to this rule-of-thumb exist:
- Higher A1C targets may be sensible for elderly or individuals with multiple chronic conditions.
- Doctors theorize that achieving lower blood glucose targets for some people may be risky. For instance, if an elderly person receives a Type 2 diabetes diagnoses at age 90, the doctor is likely to prescribe moderate therapies.
Much of the research suggests that the diabetic’s total time in the average range is more critical than his or her A1C number:
- If the diabetic’s low A1C result derives from many low blood glucose levels balancing out many highs, this result is less beneficial than maintaining steady blood glucose levels near the average range.