What is HbA1c?
HbA1c (sometimes written as A1c) measures the percentage of your red blood cells that have sugar stuck to them. Because red blood cells live for about 2–3 months, this test gives you an average picture of your blood sugar over that period — not just a snapshot of one morning.
Think of it like this: if fasting glucose is a single photo, HbA1c is a time-lapse. It shows the bigger pattern.
Why it matters for longevity
Blood sugar control is one of the strongest predictors of how well you age. Chronically elevated blood sugar damages blood vessels, nerves, and organs over time — even at levels that aren't high enough to be diagnosed as diabetes.
Research consistently shows that people with lower HbA1c levels (within a healthy range) have lower rates of heart disease, cognitive decline, kidney disease, and all-cause mortality. For longevity-focused doctors, HbA1c is one of the first things they check.
What the numbers mean
The conventional medical ranges for HbA1c are:
- Normal: below 5.7%
- Prediabetes: 5.7–6.4%
- Diabetes: 6.5% or higher
However, many longevity-focused physicians aim for an optimal range of below 5.0%. Being "normal" at 5.6% still means your blood sugar is spending a lot of time elevated. The tighter your control, the less damage accumulates over decades.
What affects your HbA1c
- Diet: Processed carbohydrates, added sugars, and large meals cause bigger blood sugar spikes. Meals with protein, fat, and fiber produce slower, gentler rises.
- Exercise: Physical activity helps your muscles absorb glucose without needing as much insulin. Even walking after meals makes a measurable difference.
- Sleep: Poor sleep increases insulin resistance — meaning your body needs more insulin to handle the same amount of sugar.
- Stress: raises blood sugar directly. Chronic stress keeps it elevated.
- Genetics: Some people have naturally tighter or looser blood sugar control. But lifestyle still makes the biggest difference.
How to get tested
HbA1c is a simple blood test that does not require fasting. You can get it through your regular doctor, or order it online through services like Quest or Ulta Lab Tests. Most insurance covers it, especially if you have risk factors for diabetes. Testing once or twice a year is usually enough.
How to improve it
- Walk after meals. Even a 10–15 minute walk after eating significantly reduces blood sugar spikes. This is one of the simplest and most effective habits you can build.
- Eat protein and fiber first. Starting a meal with vegetables, protein, or healthy fats — and saving carbs for last — slows digestion and flattens the glucose curve.
- Strength train regularly. Muscle is the largest glucose sink in your body. The more muscle you have, the more efficiently you process sugar.
- Prioritize sleep. Even one night of poor sleep can raise insulin resistance the next day. Consistent, quality sleep is one of the most underrated tools for blood sugar control. Use our Sleep Calculator to find your ideal bedtime.
- Reduce processed carbs and sugar. You don't need to go low-carb, but cutting back on sugary drinks, white bread, and packaged snacks makes a big difference. Our Macro Calculator can help you find a balanced approach.