Insulin is a hormone made by your pancreas. It allows your cells to use glucose (sugar) for energy.
People with insulin resistance have cells that don’t use insulin effectively. This means the cells have trouble absorbing glucose, which causes a buildup of sugar in the blood. If your blood glucose levels are higher than normal, but not high enough to be considered type 2 diabetes, you have a condition called prediabetes.
It’s not entirely clear why some people develop insulin resistance and others don’t. Being overweight or obese are the leading risk factors. A sedentary lifestyle can also cause prediabetes or type 2 diabetes, especially if you’re also overweight.
Insulin resistance often doesn’t trigger any noticeable symptoms, especially in the early phases. You could be insulin resistant for years without knowing, especially if your blood glucose levels aren’t checked.
Some people with insulin resistance may develop a condition known as acanthosis nigricans. This condition creates dark patches on the back of the neck, groin, and armpits. It also puts you at higher risk for type 2 diabetes. There’s no cure for acanthosis nigricans, but if you treat the causes, some of your natural skin color may return.
If you have insulin resistance, you’re at significant risk for progressing to diabetes. The symptoms of type 2 diabetes can be mild, so you may not know you have the condition until a doctor runs diagnostic tests on you.
Classic diabetes symptoms include:
- extreme thirst or hunger
- feeling hungry even after a meal
- frequent or increased urination
- tingling sensations in your hands or feet
- feeling more tired than usual
If you don’t have obvious symptoms, your insulin resistance, prediabetes, and diabetes are usually detected with a blood draw.
One way to diagnose prediabetes or diabetes is with an A1C test. This test measures your average blood sugar over the past two to three months.
- An A1C under 5.7 percent is considered normal.
- An A1C between 5.7 and 6.4 percent is diagnostic for prediabetes.
- An A1C equal to or above 6.5 percent is diagnostic for diabetes.
Your doctor may want to reconfirm this test on another day. However, depending on the lab where you have your blood drawn, these numbers could vary anywhere from 0.1 to 0.2 percent.
Fasting Blood Glucose Test
A fasting blood glucose test is taken after not eating or drinking for at least eight hours. It provides your fasting blood sugar level.
A high level may require a second test a few days later to confirm the reading. If both tests show elevated levels of blood glucose, you may be diagnosed with prediabetes or diabetes.
- Fasting blood sugar levels under 100 mg/dL are considered normal.
- Levels between 100 and 125 mg/dL are diagnostic for prediabetes.
- Levels equal to or greater than 126 mg/dL are diagnostic for diabetes.
Again, depending on the lab, these numbers could vary up to 3 mg/dL points in the cutoff numbers.
Random Blood Draws
You can also have your blood glucose levels checked at any time of day. For these “random” blood draws:
- blood sugar levels under 140 mg/dL are considered normal
- levels between 140 and 199 mg/dL are considered prediabetes
- levels equal to or over 200 mg/dL are diagnostic for Type 2 diabetes
When You Should Get Tested
Testing for diabetes should begin at about age 40, along with the usual tests for cholesterol and other markers of health. Ideally, you can get tested at your annual physical exam or preventive screening with your primary doctor.
Earlier testing may be recommended if you are overweight and you:
- live a sedentary lifestyle
- have low good (HDL) levels or high triglyceride levels
- have a parent or sibling with diabetes
- are American-Indian, African-American, Latino, Asian-American, or Pacific Islander
- have high blood pressure (140/90 mm Hg or above)
- have symptoms of insulin resistance
- were diagnosed with gestational diabetes (a temporary condition that develops while pregnant)
- had a baby who weighed more than 9 pounds
Even if your test comes back in the normal range, you should have your blood glucose levels checked at least every two to three years.
You may be able to prevent diabetes by exercising daily and eating a balanced diet. Losing weight and keeping it at a healthy level is the best way to get your blood glucose levels in the desired range.
It’s important to remember that a diagnosis of insulin resistance or prediabetes is only a warning. You can often reverse these early conditions with healthy lifestyle choices.