What is HbA1c?

HbA1c measures the percentage of hemoglobin in your blood that has glucose attached to it. Higher blood sugar over time means more glucose sticks to hemoglobin. The test reflects your average blood sugar over the past 2–3 months.

What the numbers mean

Each 1% increase in HbA1c corresponds to about a 30 mg/dL increase in average blood sugar.

Why HbA1c alone can miss insulin resistance

Insulin resistance is a precursor to prediabetes and diabetes. But it can be hard to catch because your pancreas compensates by producing extra insulin, keeping blood sugar and HbA1c normal.

Meanwhile, insulin resistance is already reshaping your metabolism in ways that damage arteries: higher triglycerides, lower HDL, smaller denser LDL particles, stiffer blood vessels, higher blood pressure, and a body tilted toward clotting.

People with insulin resistance patterns have meaningfully higher heart disease risk even at normal glucose. Risk multiplies further once diabetes develops.

Signs of insulin resistance to watch for

• High triglycerides with low HDL.
• Waist above half your height.
• Fasting insulin above 10 µIU/mL (ask your doctor to test this).
• Acanthosis nigricans (dark patches on neck, armpits, or groin).

If you see these patterns, the biology driving plaque may be active even if HbA1c looks normal.

How to improve insulin sensitivity

• Reduce refined carbs and added sugars.
• Exercise regularly (both cardio and resistance training).
• Lose visceral fat (it drives insulin resistance directly).
• Sleep 7–8 hours (poor sleep worsens insulin sensitivity).
• Manage stress (cortisol raises blood sugar and promotes fat storage).

The bottom line

HbA1c tells you if diabetes is present. It doesn't tell you if insulin resistance is already damaging your arteries. Look at the full picture: triglycerides, HDL, waist size. If those are off, act now rather than waiting for HbA1c to rise.