What Is A1C and Why Does it Matter?

What do A1C Numbers Mean?

The result is a percentage. The higher your A1C levels, the higher your average blood sugar has been over the past few months. Here is how the ranges break down according to American Diabetes Association guidelines:

Source: American Diabetes Association, 2024 Standards of Care in Diabetes.

The number on its own only tells part of the story. A result of 6.2% looks very different in a 45-year-old who just had their first elevated reading than in a 78-year-old with multiple health conditions. Your physician will look at your A1C along with your age, health history, medications and other test results.

Why does an A1C Number Matter Beyond the Diagnosis?

If you do not have diabetes, a high A1C can be a warning sign. It may mean you have prediabetes, which raises your risk for type 2 diabetes. The good news is that research from the National Institutes of Health Diabetes Prevention Program found that lifestyle changes, such as losing 5 to 7% of your body weight and getting 150 minutes of moderate exercise each week, can reduce the risk of progression from prediabetes to type 2 diabetes by 58%.

 If you already have diabetes, A1C helps show whether your treatment is working. When A1C stays too high over time, the risk for nerve damage, kidney disease, vision loss and other diabetes-related problems rises. “When a patient’s A1C comes back elevated, my first question is always what has changed?” said Dr. Musso. “Sometimes it is stress, sometimes a medication is not working as well as it used to, sometimes life got busy and habits slipped. The A1C gives us something concrete to work from.”

How Often Should You Get Tested?

For most healthy adults over 45, A1C testing should be part of routine care every few years at a minimum. The U.S. Centers for Disease Control and Prevention recommends screening earlier for adults under 35 who are overweight and have at least one additional risk factor for diabetes, including a family history of the disease, a history of gestational diabetes or cardiovascular disease.

For people with prediabetes, testing every 12 months is typical. For people managing diabetes, most physicians order the test two to four times per year, depending on how stable blood sugar control has been and whether they have made any treatment changes.

What Can Affect A1C Accuracy?

The A1C test is reliable for most people, but certain conditions can affect how accurately it reflects average blood sugar. Conditions like hemolytic anemia, iron deficiency anemia, sickle cell disease, kidney disease and some blood disorders can make test results appear higher or lower than they actually are.

 Pregnancy also affects A1C, as red blood cell turnover increases during gestation. If any of these factors apply to you, your physician may recommend alternative monitoring approaches, including fructosamine testing or continuous glucose monitoring, to get a more accurate picture of your blood sugar control.

How to Lower Your A1C

You can reduce an elevated A1C, but it takes time. One healthy meal or one week of exercise will not change the number right away. But with consistent healthy changes, you can see a difference. Many people start to see improvement within three to six months. Try these tips to help lower your numbers:

1. Eat to Manage Blood Sugar, Not Just Calories

Carbohydrates have the most effect on blood sugar. Choose whole food sources such as vegetables, legumes, whole grains and fruit, over processed foods and added sugars. Mediterranean-style eating has consistent research support for lowering A1C in people with and without diabetes. Working with a registered dietitian who specializes in diabetes management is one of the best ways to improve your A1C.

2. Get Consistent Exercise

Physical activity makes the body more sensitive to insulin, which means blood sugar clears from the bloodstream more efficiently. The ADA recommends at least 150 minutes of moderate activity per week, spread across most days. Walking after meals is a great habit to start. Studies show that a 10 to 15-minute walk after eating can reduce post-meal blood sugar spikes.

3. Take Medications as Prescribed

For people with diabetes, medication adherence is one of the most important ways to control A1C. Oral medications can reduce A1C by 0.5 to 2%, and insulin therapy can bring A1C to target within three months. If cost, side effects or a complicated regimen make it hard to stay consistent, talk to your physician.

4. Manage Stress

Chronic stress raises cortisol, and elevated cortisol raises blood sugar. This is a relationship most people do not think about when reviewing an A1C result. People managing a lot of life stress, those who get poor sleep or have untreated anxiety often see A1C results that do not respond to diet and exercise changes. Addressing stress through counseling, sleep hygiene, physical activity or other approaches is part of comprehensive blood sugar management.

Find Care at Catholic Health

If your A1C is high or you have questions about your diabetes risk, a Catholic Health physician can help. We can review your results, talk through your risk factors and help you build a plan to manage your blood sugar.

 Call 866-MY-LI-DOC (866-695-4362) to find a Catholic Health doctor near you.