Understanding HbA1c: Your Most Important Diabetes Number

Key Takeaway: HbA1c measures your average blood sugar over the past 2-3 months. A level below 6.5% is the goal for most people with diabetes, though your target may vary based on your individual circumstances.

If you have diabetes or prediabetes, you’ve likely heard your doctor mention HbA1c. This simple blood test provides crucial information about how well you’re managing your blood sugar over time. Understanding what HbA1c means and how to improve it can significantly impact your long-term health outcomes.

What Is HbA1c?

HbA1c stands for glycated hemoglobin. Hemoglobin is a protein in your red blood cells that carries oxygen throughout your body. When glucose (sugar) circulates in your bloodstream, some of it naturally attaches to hemoglobin molecules. The more glucose in your blood, the more hemoglobin becomes glycated.

Because red blood cells live for approximately three months, measuring glycated hemoglobin gives us a picture of your average blood sugar levels over that time period. This makes HbA1c more useful than a single blood sugar reading, which only tells you what your glucose level is at that specific moment.

Understanding Your HbA1c Numbers

HbA1c is reported as a percentage. The higher the percentage, the higher your average blood sugar has been. Different ranges indicate different levels of blood sugar control and diabetes risk.

For most people with diabetes, the goal is to keep HbA1c below 7%. However, your individual target may be different. Some people, particularly those who are younger, recently diagnosed, or without other health conditions, may aim for a target below 6.5%. Others, especially older adults or those with other serious health conditions, may have a higher target of 7.5% or 8% to reduce the risk of dangerously low blood sugar.

Why HbA1c Matters

Maintaining good HbA1c levels significantly reduces your risk of diabetes complications. Research has consistently shown that lower HbA1c correlates with better long-term outcomes.

The landmark Diabetes Control and Complications Trial (DCCT) demonstrated that every percentage point decrease in HbA1c reduces the risk of microvascular complications by approximately 40%. These complications include diabetic retinopathy (eye damage), nephropathy (kidney damage), and neuropathy (nerve damage).

For cardiovascular health, the benefits are also substantial. The UK Prospective Diabetes Study (UKPDS) found that each 1% reduction in HbA1c was associated with a 21% reduction in deaths related to diabetes and a 14% reduction in heart attacks.

How to Improve Your HbA1c

Lowering your HbA1c requires consistent attention to the factors that affect blood sugar. The good news is that even modest improvements can have meaningful health benefits.

1. Focus on Your Diet

What you eat has the most immediate impact on blood sugar. Reducing refined carbohydrates and added sugars while increasing fiber, protein, and healthy fats can lead to significant HbA1c improvements. Many people see a drop of 0.5-1% simply by making consistent dietary changes.

Emphasize non-starchy vegetables, lean proteins, whole grains in controlled portions, and healthy fats from sources like olive oil, nuts, and avocados. Limit sugary beverages, white bread, white rice, and processed snacks. The Mediterranean diet and low-carbohydrate diets have both shown strong evidence for improving HbA1c.

2. Increase Physical Activity

Exercise improves insulin sensitivity, meaning your cells become better at using available insulin to absorb glucose from the bloodstream. Both aerobic exercise (walking, cycling, swimming) and resistance training (weights, resistance bands) are beneficial.

Aim for at least 150 minutes of moderate-intensity activity per week, spread across most days. Even short 10-15 minute walks after meals can significantly reduce post-meal blood sugar spikes. Studies show that regular exercise can lower HbA1c by 0.5-0.7% on average.

3. Lose Weight If Needed

For people with type 2 diabetes who are overweight, weight loss is one of the most powerful interventions. Losing just 5-10% of your body weight can lead to substantial improvements in blood sugar control. Some studies show HbA1c reductions of 1-2% with significant weight loss.

Weight loss improves insulin sensitivity and reduces the burden on your pancreas. For some people, substantial weight loss can even lead to diabetes remission, meaning normal blood sugar levels without medication.

4. Take Medications as Prescribed

If lifestyle changes alone aren’t enough to reach your target, diabetes medications play an important role. Metformin, the most commonly prescribed first-line medication, typically lowers HbA1c by 1-2%. Newer medications like GLP-1 receptor agonists and SGLT2 inhibitors can provide even greater reductions while offering additional benefits like weight loss and cardiovascular protection.

Never stop or adjust your medications without consulting your doctor. If you’re experiencing side effects or your current regimen isn’t working well, discuss alternatives with your healthcare team.

5. Manage Stress and Sleep

Chronic stress and poor sleep both raise cortisol and other hormones that increase blood sugar. Prioritizing 7-9 hours of quality sleep and finding effective stress management techniques (meditation, yoga, deep breathing, regular exercise) can support better blood sugar control.

Studies have shown that improving sleep quality and duration can lead to modest but meaningful HbA1c improvements of 0.2-0.4%.

How Often Should You Test HbA1c?

The frequency of HbA1c testing depends on your diabetes control and treatment plan. General guidelines include:

• Every 3 months: If your diabetes is not well controlled or if your treatment plan has recently changed.
• Every 6 months: If you’re meeting your treatment goals and your blood sugar is stable.
• More frequently: If you’re pregnant or trying to conceive, as tighter control is needed.

Your doctor will recommend the appropriate testing schedule based on your individual situation.

Limitations of HbA1c

While HbA1c is an excellent tool, it has some limitations. Certain conditions that affect red blood cell turnover can make HbA1c less accurate. These include anemia, recent blood loss, kidney disease, and certain genetic conditions affecting hemoglobin.

Additionally, HbA1c doesn’t show blood sugar variability. Two people with the same HbA1c might have very different daily patterns. One might have stable, consistent readings, while the other experiences frequent highs and lows. This is why combining HbA1c testing with regular home blood sugar monitoring provides the most complete picture.

Frequently Asked Questions