Prediabetes, Insulin Resistance and Hyperglycemia: What’s the Difference?

Understanding how your body responds to sugar and knowing the difference between these blood sugar disorders can help you better prevent or control diabetes.

sugar written in sugar Hyperglycemia, prediabetes, and insulin resistance: Understanding how the body processes sugar can help you prevent or manage diabetes. (Photo:123rf)

Three different blood sugar disorders that can affect anyone—high blood sugar (also known as hyperglycemia), insulin resistance, and prediabetes—have one thing in common: They are all associated with diabetes.

To understand the nature of these conditions, and how to control or even reverse them, it helps to first understand what happens to dietary sugar when it enters your body and ultimately becomes blood sugar.

How Food Becomes Fuel 

The process of digestion begins in your mouth, as you chew and swallow, and enzymes are released to begin the process of breaking food down and releasing carbohydrates and other nutrients. Carbohydrates are further broken down in your gastrointestinal tract into simple sugars like glucose, which are then easily absorbed through your intestinal wall into your bloodstream. As you absorb carbohydrates, your blood sugar level rises.

Normally, your pancreas simultaneously releases enough of the hormone insulin into your bloodstream to help move glucose from your blood into muscle, fat, and liver cells, where it is metabolized into energy or stored for later use. As cells take in glucose, your blood sugar levels return to normal. When something interferes with this process, however, insulin production and blood sugar levels may become abnormal and a number of conditions can develop.

High Blood Sugar

When you don’t produce or supply enough insulin to move glucose into cells, sugar from your food remains in your blood. This condition is known as hyperglycemia or high blood sugar. It is also possible to have enough insulin but still have high blood sugar/hyperglycemia because your insulin supply is simply ineffective.

If you have diabetes, your blood sugar can also rise if you become ill, are overly stressed, experience a hormonal surge, eat too much or get too little exercise. Over time, high blood sugar will damage body cells and cause other health problems.

Normal blood sugar for people who do not have diabetes ranges from 70 to 100 mg/dl. Blood sugar will rise after eating but will fall back to normal within a couple of hours. Normal blood sugar for people with diabetes ranges up to 140 mg/dl. People who don’t have diabetes but have high blood sugar are at higher risk of developing diabetes than people with normal blood sugar levels.

For many people with type 1 or type 2 diabetes, maintaining normal blood sugar levels is a complicated balancing act that requires constant glucose monitoring. Blood sugar in the range of 140 to 180 mg/dl is considered elevated; anything above 180 mg/dl is considered high. Very high blood sugar levels in people with diabetes must be treated immediately in order to prevent the life-threatening condition ketoacidosis or diabetic coma.

Insulin Resistance

The job of insulin is to “unlock” body cells to allow glucose in. Insulin resistance occurs when your pancreas produces enough insulin as you eat, but your muscle, fat and liver cells still “resist” taking in glucose from your blood. As a result, your pancreas must go into overtime, producing additional insulin to try to “unlock” resistant cells and allow the process to move along as it should. Just as excess sugar circulating in your bloodstream can ultimately damage your health, so can excess insulin. It is estimated that more than 3 million Americans are insulin-resistant.

If you have insulin resistance, you may have normal blood sugar levels and no other symptoms, as long as your pancreas keeps producing insulin. Ultimately, however, as sugar builds up to higher-than-normal levels, you may develop a condition now recognized as prediabetes (described below). Insulin resistance is generally considered a precursor to both prediabetes and type 2 diabetes.

You may be genetically inclined to develop insulin resistance, and you may be overweight or at a healthy weight. If you are overweight, losing excess weight by changing your diet and getting more exercise can lower resistance before the condition becomes serious.

Routine physical activity is key to increasing insulin sensitivity and reversing insulin resistance in anyone with this condition because exercise helps facilitate glucose uptake into cells and stops the body from releasing stored glucose or unnecessarily producing more of glucose on its own.


More than 84 million Americans, or one out of every three adults, have prediabetes, a condition that can lead to type 2 diabetes. Marked by blood sugar levels that are higher than normal but not yet in the diabetes range, prediabetes is usually a result of either insulin resistance or insufficient production of insulin.

Like insulin resistance, prediabetes may have a genetic basis. Genetic factors that increase your risk include being of African American, Native American, Asian American, Hispanic/Latino or Pacific Islander ethnicity, or being any ethnicity and having a parent or sibling with diabetes.

Although being overweight or obese are risk factors, people at a healthy weight can also become prediabetic. Lack of physical activity, older age, a history of gestational diabetes (diabetes of pregnancy), and conditions such as polycystic ovary syndrome, heart disease, and stroke can all put you at higher risk of developing prediabetes.

Updated on: April 18, 2019
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